Rod2D< T > Class Template Reference

Detailed Description

template<typename T>
class drake::examples::rod2d::Rod2D< T >

Dynamical system representation of a rod contacting a half-space in two dimensions.

Notation

In the discussion below and in code comments, we will use the 2D analog of our standard multibody notation as described in detail here: Multibody Terminology and Notation.

For a quick summary and translation to 2D:

• When we combine rotational and translational quantities into a single quantity in 3D, we call those "spatial" quantities. In 2D those combined quantities are actually planar, but we will continue to refer to them as "spatial" to keep the notation analogous and promote easy extension of 2D pedagogical examples to 3D.
• We use capital letters to represent bodies and coordinate frames. Frame F has an origin point Fo, and a basis formed by orthogonal unit vector axes Fx and Fy, with an implicit Fz=Fx × Fy always pointing out of the screen for a 2D system. The inertial frame World is W, and the rod frame is R.
• We also use capitals to represent points, and we allow a frame name F to be used where a point is expected to represent its origin Fo.
• We use p_CD to represent the position vector from point C to point D. Note that if A and B are frames, p_AB means p_AoBo.
• If we need to be explicit about the expressed-in frame F for any quantity, we add the suffix _F to its symbol. So the position vector from C to D, expressed in W, is p_CD_W.
• R_AB is the rotation matrix giving frame B's orientation in frame A.
• X_AB is the transformation matrix giving frame B's pose in frame A, combining both a rotation and a translation; this is conventionally called a "transform". A transform is a spatial quantity.

In 2D, with frames A and B the above quantities are (conceptually) matrices with the indicated dimensions:

    p_AB = Bo-Ao = |x|      R_AB=| cθ -sθ |       X_AB=| R_AB p_AB |
                   |y|₂ₓ₁        | sθ  cθ |₂ₓ₂         | 0  0   1  |₃ₓ₃

where x,y are B's Cartesian coordinates in the A frame, and θ is the counterclockwise angle from Ax to Bx, measured about Az (and Bz). In practice, 2D rotations are represented just by the scalar angle θ, and 2D transforms are represented by (x,y,θ).

We use v for translational velocity of a point and w (ω) for rotational velocity of a frame. The symbols are:

• v_AP is point P's velocity in frame A, expressed in frame A if no other frame is given as a suffix.
• w_AB is frame B's angular velocity in frame A, expressed in frame A if no other frame is given as a suffix.
• V_AB is frame B's spatial velocity in A, meaning v_ABo and w_AB.

These quantities are conceptually:

    v_AB = |vx|      w_AB=|0|       V_AB=| w_AB |
           |vy|           |0|            | v_AB |₆ₓ₁
           | 0|₃ₓ₁        |ω|₃ₓ₁

but in 2D we represent translational velocity with just (vx,vy), angular velocity with just the scalar w=ω= \(\dot{\theta}\) (that is, d/dt θ), and spatial velocity as (vx,vy,ω).

Forces f and torques τ are represented similarly:

• f_P is an in-plane force applied to a point P fixed to some rigid body.
• t_A is an in-plane torque applied to frame A (meaning it is about Az).
• F_A is a spatial force including both f_Ao and t_A.

The above symbols can be suffixed with an expressed-in frame if the frame is not already obvious, so F_A_W is a spatial force applied to frame A (at Ao) but expressed in W. These quantities are conceptually:

    f_A = |fx|      t_A=|0|       F_A=| t_A |
          |fy|          |0|           | f_A |₆ₓ₁
          | 0|₃ₓ₁       |τ|₃ₓ₁

but in 2D we represent translational force with just (fx,fy), torque with just the scalar t=τ, and spatial force as (fx,fy,τ).

The 2D rod model

The rod's coordinate frame R is placed at the rod's center point Ro, which is also its center of mass Rcm. R's planar pose is given by a planar transform X_WR=(x,y,θ). When X_WR=0 (identity transform), R is coincident with the World frame W, and aligned horizontally as shown:

       +Wy                                  +Ry
        |                                    |
        |                                    |<---- h ----->
        |                      ==============|==============
      Wo*-----> +Wx         Rl*            Ro*-----> +Rx    *Rr
                               =============================
       World frame                      Rod R, θ=0

θ is the angle between Rx and Wx, measured using the right hand rule about Wz (out of the screen), that is, counterclockwise. The rod has half-length h, and "left" and "right" endpoints Rl=Ro-h*Rx and Rr=Ro+h*Rx at which it can contact the halfspace whose surface is at Wy=0.

This system can be simulated using one of three models:

• continuously, using a compliant contact model (the rod is rigid, but contact between the rod and the half-space is modeled as compliant) simulated using ordinary differential equations (ODEs),
• a fully rigid model simulated with piecewise differential algebraic equations (DAEs), and
• a fully rigid model simulated as a discrete system using a first-order discretization approach.

The rod state is initialized to the configuration that corresponds to the Painlevé Paradox problem, described in [Stewart 2000]. The paradox consists of a rod contacting a planar surface without impact and subject to sliding Coulomb friction. The problem is well known to correspond to an inconsistent rigid contact configuration*, where impulsive forces are necessary to resolve the problem.

Inputs: planar force (two-dimensional) and torque (scalar), which are arbitrary "external" forces (expressed in the world frame) applied at the center-of-mass of the rod.

States: planar position (state indices 0 and 1) and orientation (state index 2), and planar linear velocity (state indices 3 and 4) and scalar angular velocity (state index 5) in units of m, radians, m/s, and rad/s, respectively. Orientation is measured counter- clockwise with respect to the x-axis.

Outputs: Output Port 0 corresponds to the state vector.

• [Stewart, 2000] D. Stewart, "Rigid-Body Dynamics with Friction and Impact". SIAM Rev., 42(1), 3-39, 2000.

u0→

Rod2D

→ state_output

Template Parameters

T	The scalar type, which must be double.

#include <drake/examples/rod2d/rod2d.h>

Public Types
enum	SystemType { kPiecewiseDAE, kDiscretized, kContinuous }
	System model and approach for simulating the system. More...
Public Types inherited from System< T >
using	Scalar = T
	The scalar type with which this System was instantiated. More...

Public Member Functions
	~Rod2D () override
	Rod2D (SystemType system_type, double dt)
	Constructor for the 2D rod system using the piecewise DAE (differential algebraic equation) based approach, the discretization approach, or the continuous ordinary differential equation based approach. More...
double	TransformDissipationToDampingAboutDeformation (double characteristic_deformation) const
	Transforms dissipation (α) to damping, given a characteristic. More...
double	TransformDampingToDissipationAboutDeformation (double characteristic_deformation, double b) const
	Transforms damping (b) to dissipation (α) , given a characteristic deformation. More...
double	get_cfm () const
	Gets the constraint force mixing parameter (CFM, used for discretized systems only), which should lie in the interval [0, infinity]. More...
double	get_erp () const
	Gets the error reduction parameter (ERP, used for discretized systems only), which should lie in the interval [0, 1]. More...
Vector3< T >	GetRodConfig (const systems::Context< T > &context) const
	Gets the generalized position of the rod, given a Context. More...
Vector3< T >	GetRodVelocity (const systems::Context< T > &context) const
	Gets the generalized velocity of the rod, given a Context. More...
double	get_gravitational_acceleration () const
	Gets the acceleration (with respect to the positive y-axis) due to gravity (i.e., this number should generally be negative). More...
void	set_gravitational_acceleration (double g)
	Sets the acceleration (with respect to the positive y-axis) due to gravity (i.e., this number should generally be negative). More...
double	get_mu_coulomb () const
	Gets the coefficient of dynamic (sliding) Coulomb friction. More...
void	set_mu_coulomb (double mu)
	Sets the coefficient of dynamic (sliding) Coulomb friction. More...
double	get_rod_mass () const
	Gets the mass of the rod. More...
void	set_rod_mass (double mass)
	Sets the mass of the rod. More...
double	get_rod_half_length () const
	Gets the half-length h of the rod. More...
void	set_rod_half_length (double half_length)
	Sets the half-length h of the rod. More...
double	get_rod_moment_of_inertia () const
	Gets the rod moment of inertia. More...
void	set_rod_moment_of_inertia (double J)
	Sets the rod moment of inertia. More...
double	get_stiffness () const
	Get compliant contact normal stiffness in N/m. More...
void	set_stiffness (double stiffness)
	Set compliant contact normal stiffness in N/m (>= 0). More...
double	get_dissipation () const
	Get compliant contact normal dissipation in 1/velocity (s/m). More...
void	set_dissipation (double dissipation)
	Set compliant contact normal dissipation in 1/velocity (s/m, >= 0). More...
void	SetStiffnessAndDissipation (double cfm, double erp)
	Sets stiffness and dissipation for the rod from cfm and erp values (used for discretized system implementations). More...
double	get_mu_static () const
	Get compliant contact static friction (stiction) coefficient μ_s. More...
void	set_mu_static (double mu_static)
	Set contact stiction coefficient (>= mu_coulomb). More...
double	get_stiction_speed_tolerance () const
	Get the stiction speed tolerance (m/s). More...
void	set_stiction_speed_tolerance (double v_stick_tol)
	Set the stiction speed tolerance (m/s). More...
Matrix2< T >	GetSlidingContactFrameToWorldTransform (const T &xaxis_velocity) const
	Gets the rotation matrix that transforms velocities from a sliding contact frame to the global frame. More...
Matrix2< T >	GetNonSlidingContactFrameToWorldTransform () const
	Gets the rotation matrix that transforms velocities from a non-sliding contact frame to the global frame. More...
bool	IsImpacting (const systems::Context< T > &context) const
	Checks whether the system is in an impacting state, meaning that the relative velocity along the contact normal between the rod and the halfspace is such that the rod will begin interpenetrating the halfspace at any time Δt in the future (i.e., Δt > 0). More...
double	get_integration_step_size () const
	Gets the integration step size for the discretized system. More...
SystemType	get_system_type () const
	Gets the model and simulation type for this system. More...
Vector3< T >	CalcCompliantContactForces (const systems::Context< T > &context) const
	Return net contact forces as a spatial force F_Ro_W=(fx,fy,τ) where translational force f_Ro_W=(fx,fy) is applied at the rod origin Ro, and torque t_R=τ is the moment due to the contact forces actually being applied elsewhere. More...
int	DetermineNumWitnessFunctions (const systems::Context< T > &context) const
	Gets the number of witness functions for the system active in the system for a given state (using context). More...
const systems::OutputPort< T > &	state_output () const
	Returns the state of this rod. More...
void	GetContactPoints (const systems::Context< T > &context, std::vector< Vector2< T >> *points) const
	Gets the point(s) of contact for the 2D rod. More...
void	GetContactPointsTangentVelocities (const systems::Context< T > &context, const std::vector< Vector2< T >> &points, std::vector< T > *vels) const
	Gets the tangent velocities for all contact points. More...
void	CalcConstraintProblemData (const systems::Context< T > &context, const std::vector< Vector2< T >> &points, const std::vector< T > &tangent_vels, ConstraintAccelProblemData< T > *data) const
	Initializes the contact data for the rod, given a set of contact points. More...
void	CalcImpactProblemData (const systems::Context< T > &context, const std::vector< Vector2< T >> &points, ConstraintVelProblemData< T > *data) const
	Initializes the impacting contact data for the rod, given a set of contact points. More...
Public Member Functions inherited from LeafSystem< T >
	~LeafSystem () override
std::unique_ptr< LeafContext< T > >	AllocateContext () const
	Shadows System<T>::AllocateContext to provide a more concrete return type LeafContext<T>. More...
std::unique_ptr< ContextBase >	DoAllocateContext () const final
	Derived class implementations should allocate a suitable concrete Context type, then invoke the above InitializeContextBase() method. More...
void	SetDefaultParameters (const Context< T > &context, Parameters< T > *parameters) const override
	Default implementation: sets all numeric parameters to the model vector given to DeclareNumericParameter, or else if no model was provided sets the numeric parameter to one. More...
void	SetDefaultState (const Context< T > &context, State< T > *state) const override
	Default implementation: sets all continuous state to the model vector given in DeclareContinuousState (or zero if no model vector was given) and discrete states to zero. More...
std::unique_ptr< ContinuousState< T > >	AllocateTimeDerivatives () const final
	Returns a ContinuousState of the same size as the continuous_state allocated in CreateDefaultContext. More...
std::unique_ptr< DiscreteValues< T > >	AllocateDiscreteVariables () const final
	Returns a DiscreteValues of the same dimensions as the discrete_state allocated in CreateDefaultContext. More...
std::multimap< int, int >	GetDirectFeedthroughs () const final
	Reports all direct feedthroughs from input ports to output ports. More...
	LeafSystem (const LeafSystem &)=delete
LeafSystem &	operator= (const LeafSystem &)=delete
	LeafSystem (LeafSystem &&)=delete
LeafSystem &	operator= (LeafSystem &&)=delete
Public Member Functions inherited from System< T >
	~System () override
virtual void	Accept (SystemVisitor< T > *v) const
	Implements a visitor pattern. More...
void	GetWitnessFunctions (const Context< T > &context, std::vector< const WitnessFunction< T > * > *w) const
	Gets the witness functions active for the given state. More...
T	CalcWitnessValue (const Context< T > &context, const WitnessFunction< T > &witness_func) const
	Evaluates a witness function at the given context. More...
DependencyTicket	discrete_state_ticket (DiscreteStateIndex index) const
	Returns a ticket indicating dependence on a particular discrete state variable xdᵢ (may be a vector). More...
DependencyTicket	abstract_state_ticket (AbstractStateIndex index) const
	Returns a ticket indicating dependence on a particular abstract state variable xaᵢ. More...
DependencyTicket	numeric_parameter_ticket (NumericParameterIndex index) const
	Returns a ticket indicating dependence on a particular numeric parameter pnᵢ (may be a vector). More...
DependencyTicket	abstract_parameter_ticket (AbstractParameterIndex index) const
	Returns a ticket indicating dependence on a particular abstract parameter paᵢ. More...
DependencyTicket	input_port_ticket (InputPortIndex index) const
	Returns a ticket indicating dependence on input port uᵢ indicated by index. More...
DependencyTicket	cache_entry_ticket (CacheIndex index) const
	Returns a ticket indicating dependence on the cache entry indicated by index. More...
	System (const System &)=delete
System &	operator= (const System &)=delete
	System (System &&)=delete
System &	operator= (System &&)=delete
std::unique_ptr< Context< T > >	AllocateContext () const
	(Advanced) Returns an uninitialized Context<T> suitable for use with this System<T>. More...
std::unique_ptr< CompositeEventCollection< T > >	AllocateCompositeEventCollection () const
	Allocates a CompositeEventCollection for this system. More...
std::unique_ptr< BasicVector< T > >	AllocateInputVector (const InputPort< T > &input_port) const
	Given an input port, allocates the vector storage. More...
std::unique_ptr< AbstractValue >	AllocateInputAbstract (const InputPort< T > &input_port) const
	Given an input port, allocates the abstract storage. More...
std::unique_ptr< SystemOutput< T > >	AllocateOutput () const
	Returns a container that can hold the values of all of this System's output ports. More...
VectorX< T >	AllocateImplicitTimeDerivativesResidual () const
	Returns an Eigen VectorX suitable for use as the output argument to the CalcImplicitTimeDerivativesResidual() method. More...
std::unique_ptr< Context< T > >	CreateDefaultContext () const
	This convenience method allocates a context using AllocateContext() and sets its default values using SetDefaultContext(). More...
void	SetDefaultContext (Context< T > *context) const
	Sets Context fields to their default values. More...
virtual void	SetRandomState (const Context< T > &context, State< T > *state, RandomGenerator *generator) const
	Assigns random values to all elements of the state. More...
virtual void	SetRandomParameters (const Context< T > &context, Parameters< T > *parameters, RandomGenerator *generator) const
	Assigns random values to all parameters. More...
void	SetRandomContext (Context< T > *context, RandomGenerator *generator) const
	Sets Context fields to random values. More...
void	AllocateFixedInputs (Context< T > *context) const
	For each input port, allocates a fixed input of the concrete type that this System requires, and binds it to the port, disconnecting any prior input. More...
bool	HasAnyDirectFeedthrough () const
	Returns true if any of the inputs to the system might be directly fed through to any of its outputs and false otherwise. More...
bool	HasDirectFeedthrough (int output_port) const
	Returns true if there might be direct-feedthrough from any input port to the given output_port, and false otherwise. More...
bool	HasDirectFeedthrough (int input_port, int output_port) const
	Returns true if there might be direct-feedthrough from the given input_port to the given output_port, and false otherwise. More...
virtual std::multimap< int, int >	GetDirectFeedthroughs () const=0
	Reports all direct feedthroughs from input ports to output ports. More...
EventStatus	Publish (const Context< T > &context, const EventCollection< PublishEvent< T >> &events) const
	This method is the public entry point for dispatching all publish event handlers. More...
void	ForcedPublish (const Context< T > &context) const
	(Advanced) Manually triggers any PublishEvent that has trigger type kForced. More...
const ContinuousState< T > &	EvalTimeDerivatives (const Context< T > &context) const
	Returns a reference to the cached value of the continuous state variable time derivatives, evaluating first if necessary using CalcTimeDerivatives(). More...
const CacheEntry &	get_time_derivatives_cache_entry () const
	(Advanced) Returns the CacheEntry used to cache time derivatives for EvalTimeDerivatives(). More...
const T &	EvalPotentialEnergy (const Context< T > &context) const
	Returns a reference to the cached value of the potential energy (PE), evaluating first if necessary using CalcPotentialEnergy(). More...
const T &	EvalKineticEnergy (const Context< T > &context) const
	Returns a reference to the cached value of the kinetic energy (KE), evaluating first if necessary using CalcKineticEnergy(). More...
const T &	EvalConservativePower (const Context< T > &context) const
	Returns a reference to the cached value of the conservative power (Pc), evaluating first if necessary using CalcConservativePower(). More...
const T &	EvalNonConservativePower (const Context< T > &context) const
	Returns a reference to the cached value of the non-conservative power (Pnc), evaluating first if necessary using CalcNonConservativePower(). More...
template<template< typename > class Vec = BasicVector>
const Vec< T > *	EvalVectorInput (const Context< T > &context, int port_index) const
	Returns the value of the vector-valued input port with the given port_index as a BasicVector or a specific subclass Vec derived from BasicVector. More...
SystemConstraintIndex	AddExternalConstraint (ExternalSystemConstraint constraint)
	Adds an "external" constraint to this System. More...
void	CalcTimeDerivatives (const Context< T > &context, ContinuousState< T > *derivatives) const
	Calculates the time derivatives ẋ꜀ of the continuous state x꜀ into a given output argument. More...
void	CalcImplicitTimeDerivativesResidual (const Context< T > &context, const ContinuousState< T > &proposed_derivatives, EigenPtr< VectorX< T >> residual) const
	Evaluates the implicit form of the System equations and returns the residual. More...
EventStatus	CalcDiscreteVariableUpdate (const Context< T > &context, const EventCollection< DiscreteUpdateEvent< T >> &events, DiscreteValues< T > *discrete_state) const
	This method is the public entry point for dispatching all discrete variable update event handlers. More...
void	ApplyDiscreteVariableUpdate (const EventCollection< DiscreteUpdateEvent< T >> &events, DiscreteValues< T > *discrete_state, Context< T > *context) const
	Given the discrete_state results of a previous call to CalcDiscreteVariableUpdate() that dispatched the given collection of events, modifies the context to reflect the updated discrete_state. More...
void	CalcForcedDiscreteVariableUpdate (const Context< T > &context, DiscreteValues< T > *discrete_state) const
	(Advanced) Manually triggers any DiscreteUpdateEvent that has trigger type kForced. More...
EventStatus	CalcUnrestrictedUpdate (const Context< T > &context, const EventCollection< UnrestrictedUpdateEvent< T >> &events, State< T > *state) const
	This method is the public entry point for dispatching all unrestricted update event handlers. More...
void	ApplyUnrestrictedUpdate (const EventCollection< UnrestrictedUpdateEvent< T >> &events, State< T > *state, Context< T > *context) const
	Given the state results of a previous call to CalcUnrestrictedUpdate() that dispatched the given collection of events, modifies the context to reflect the updated state. More...
void	CalcForcedUnrestrictedUpdate (const Context< T > &context, State< T > *state) const
	(Advanced) Manually triggers any UnrestrictedUpdateEvent that has trigger type kForced. More...
T	CalcNextUpdateTime (const Context< T > &context, CompositeEventCollection< T > *events) const
	This method is called by a Simulator during its calculation of the size of the next continuous step to attempt. More...
void	GetPeriodicEvents (const Context< T > &context, CompositeEventCollection< T > *events) const
	Returns all periodic events in this System. More...
void	GetPerStepEvents (const Context< T > &context, CompositeEventCollection< T > *events) const
	This method is called by Simulator::Initialize() to gather all update and publish events that are to be handled in AdvanceTo() at the point before Simulator integrates continuous state. More...
void	GetInitializationEvents (const Context< T > &context, CompositeEventCollection< T > *events) const
	This method is called by Simulator::Initialize() to gather all update and publish events that need to be handled at initialization before the simulator starts integration. More...
void	ExecuteInitializationEvents (Context< T > *context) const
	This method triggers all of the initialization events returned by GetInitializationEvents(). More...
void	ExecuteForcedEvents (Context< T > *context, bool publish=true) const
	This method triggers all of the forced events registered with this System (which might be a Diagram). More...
std::optional< PeriodicEventData >	GetUniquePeriodicDiscreteUpdateAttribute () const
	Determines whether there exists a unique periodic timing (offset and period) that triggers one or more discrete update events (and, if so, returns that unique periodic timing). More...
const DiscreteValues< T > &	EvalUniquePeriodicDiscreteUpdate (const Context< T > &context) const
	If this System contains a unique periodic timing for discrete update events, this function executes the handlers for those periodic events to determine what their effect would be. More...
bool	IsDifferenceEquationSystem (double *time_period=nullptr) const
	Returns true iff the state dynamics of this system are governed exclusively by a difference equation on a single discrete state group and with a unique periodic update (having zero offset). More...
bool	IsDifferentialEquationSystem () const
	Returns true iff the state dynamics of this system are governed exclusively by a differential equation. More...
std::map< PeriodicEventData, std::vector< const Event< T > * >, PeriodicEventDataComparator >	MapPeriodicEventsByTiming (const Context< T > *context=nullptr) const
	Maps all periodic triggered events for a System, organized by timing. More...
void	CalcOutput (const Context< T > &context, SystemOutput< T > *outputs) const
	Utility method that computes for every output port i the value y(i) that should result from the current contents of the given Context. More...
T	CalcPotentialEnergy (const Context< T > &context) const
	Calculates and returns the potential energy represented by the current configuration provided in context. More...
T	CalcKineticEnergy (const Context< T > &context) const
	Calculates and returns the kinetic energy represented by the current configuration and velocity provided in context. More...
T	CalcConservativePower (const Context< T > &context) const
	Calculates and returns the conservative power represented by the current contents of the given context. More...
T	CalcNonConservativePower (const Context< T > &context) const
	Calculates and returns the non-conservative power represented by the current contents of the given context. More...
void	MapVelocityToQDot (const Context< T > &context, const VectorBase< T > &generalized_velocity, VectorBase< T > *qdot) const
	Transforms a given generalized velocity v to the time derivative qdot of the generalized configuration q taken from the supplied Context. More...
void	MapVelocityToQDot (const Context< T > &context, const Eigen::Ref< const VectorX< T >> &generalized_velocity, VectorBase< T > *qdot) const
	Transforms the given generalized velocity to the time derivative of generalized configuration. More...
void	MapQDotToVelocity (const Context< T > &context, const VectorBase< T > &qdot, VectorBase< T > *generalized_velocity) const
	Transforms the time derivative qdot of the generalized configuration q to generalized velocities v. More...
void	MapQDotToVelocity (const Context< T > &context, const Eigen::Ref< const VectorX< T >> &qdot, VectorBase< T > *generalized_velocity) const
	Transforms the given time derivative qdot of generalized configuration q to generalized velocity v. More...
const Context< T > &	GetSubsystemContext (const System< T > &subsystem, const Context< T > &context) const
	Returns a const reference to the subcontext that corresponds to the contained System subsystem. More...
Context< T > &	GetMutableSubsystemContext (const System< T > &subsystem, Context< T > *context) const
	Returns a mutable reference to the subcontext that corresponds to the contained System subsystem. More...
const Context< T > &	GetMyContextFromRoot (const Context< T > &root_context) const
	Returns the const Context for this subsystem, given a root context. More...
Context< T > &	GetMyMutableContextFromRoot (Context< T > *root_context) const
	Returns the mutable subsystem context for this system, given a root context. More...
const InputPort< T > &	get_input_port (int port_index, bool warn_deprecated=true) const
	Returns the typed input port at index port_index. More...
const InputPort< T > &	get_input_port () const
	Convenience method for the case of exactly one input port. More...
const InputPort< T > *	get_input_port_selection (std::variant< InputPortSelection, InputPortIndex > port_index) const
	Returns the typed input port specified by the InputPortSelection or by the InputPortIndex. More...
const InputPort< T > &	GetInputPort (const std::string &port_name) const
	Returns the typed input port with the unique name port_name. More...
bool	HasInputPort (const std::string &port_name) const
	Returns true iff the system has an InputPort of the given port_name. More...
const OutputPort< T > &	get_output_port (int port_index, bool warn_deprecated=true) const
	Returns the typed output port at index port_index. More...
const OutputPort< T > &	get_output_port () const
	Convenience method for the case of exactly one output port. More...
const OutputPort< T > *	get_output_port_selection (std::variant< OutputPortSelection, OutputPortIndex > port_index) const
	Returns the typed output port specified by the OutputPortSelection or by the OutputPortIndex. More...
const OutputPort< T > &	GetOutputPort (const std::string &port_name) const
	Returns the typed output port with the unique name port_name. More...
bool	HasOutputPort (const std::string &port_name) const
	Returns true iff the system has an OutputPort of the given port_name. More...
int	num_constraints () const
	Returns the number of constraints specified for the system. More...
const SystemConstraint< T > &	get_constraint (SystemConstraintIndex constraint_index) const
	Returns the constraint at index constraint_index. More...
boolean< T >	CheckSystemConstraintsSatisfied (const Context< T > &context, double tol) const
	Returns true if context satisfies all of the registered SystemConstraints with tolerance tol. More...
VectorX< T >	CopyContinuousStateVector (const Context< T > &context) const
	Returns a copy of the continuous state vector x꜀ into an Eigen vector. More...
std::string	GetMemoryObjectName () const
	Returns a name for this System based on a stringification of its type name and memory address. More...
int	num_input_ports () const
	Returns the number of input ports currently allocated in this System. More...
int	num_output_ports () const
	Returns the number of output ports currently allocated in this System. More...
void	FixInputPortsFrom (const System< double > &other_system, const Context< double > &other_context, Context< T > *target_context) const
	Fixes all of the input ports in target_context to their current values in other_context, as evaluated by other_system. More...
const SystemScalarConverter &	get_system_scalar_converter () const
	(Advanced) Returns the SystemScalarConverter for this object. More...
std::string	GetGraphvizString (std::optional< int > max_depth={}, const std::map< std::string, std::string > &options={}) const
	Returns a Graphviz string describing this System. More...
std::unique_ptr< System< T > >	Clone () const
	Creates a deep copy of this system. More...
std::unique_ptr< System< AutoDiffXd > >	ToAutoDiffXd () const
	Creates a deep copy of this System, transmogrified to use the autodiff scalar type, with a dynamic-sized vector of partial derivatives. More...
std::unique_ptr< System< AutoDiffXd > >	ToAutoDiffXdMaybe () const
	Creates a deep copy of this system exactly like ToAutoDiffXd(), but returns nullptr if this System does not support autodiff, instead of throwing an exception. More...
std::unique_ptr< System< symbolic::Expression > >	ToSymbolic () const
	Creates a deep copy of this System, transmogrified to use the symbolic scalar type. More...
std::unique_ptr< System< symbolic::Expression > >	ToSymbolicMaybe () const
	Creates a deep copy of this system exactly like ToSymbolic(), but returns nullptr if this System does not support symbolic, instead of throwing an exception. More...
template<typename U >
std::unique_ptr< System< U > >	ToScalarType () const
	Creates a deep copy of this System, transmogrified to use the scalar type selected by a template parameter. More...
template<typename U >
std::unique_ptr< System< U > >	ToScalarTypeMaybe () const
	Creates a deep copy of this system exactly like ToScalarType(), but returns nullptr if this System does not support the destination type, instead of throwing an exception. More...
Public Member Functions inherited from SystemBase
	~SystemBase () override
void	set_name (const std::string &name)
	Sets the name of the system. More...
const std::string &	get_name () const
	Returns the name last supplied to set_name(), if any. More...
std::string	GetMemoryObjectName () const
	Returns a name for this System based on a stringification of its type name and memory address. More...
const std::string &	GetSystemName () const final
	Returns a human-readable name for this system, for use in messages and logging. More...
std::string	GetSystemPathname () const final
	Generates and returns a human-readable full path name of this subsystem, for use in messages and logging. More...
std::string	GetSystemType () const final
	Returns the most-derived type of this concrete System object as a human-readable string suitable for use in error messages. More...
std::unique_ptr< ContextBase >	AllocateContext () const
	Returns a Context suitable for use with this System. More...
int	num_input_ports () const
	Returns the number of input ports currently allocated in this System. More...
int	num_output_ports () const
	Returns the number of output ports currently allocated in this System. More...
const InputPortBase &	get_input_port_base (InputPortIndex port_index) const
	Returns a reference to an InputPort given its port_index. More...
const OutputPortBase &	get_output_port_base (OutputPortIndex port_index) const
	Returns a reference to an OutputPort given its port_index. More...
int	num_total_inputs () const
	Returns the total dimension of all of the vector-valued input ports (as if they were muxed). More...
int	num_total_outputs () const
	Returns the total dimension of all of the vector-valued output ports (as if they were muxed). More...
int	num_cache_entries () const
	Returns the number nc of cache entries currently allocated in this System. More...
const CacheEntry &	get_cache_entry (CacheIndex index) const
	Returns a reference to a CacheEntry given its index. More...
CacheEntry &	get_mutable_cache_entry (CacheIndex index)
	(Advanced) Returns a mutable reference to a CacheEntry given its index. More...
int	num_continuous_states () const
	Returns the number of declared continuous state variables. More...
int	num_discrete_state_groups () const
	Returns the number of declared discrete state groups (each group is a vector-valued discrete state variable). More...
int	num_abstract_states () const
	Returns the number of declared abstract state variables. More...
int	num_numeric_parameter_groups () const
	Returns the number of declared numeric parameters (each of these is a vector-valued parameter). More...
int	num_abstract_parameters () const
	Returns the number of declared abstract parameters. More...
int	implicit_time_derivatives_residual_size () const
	Returns the size of the implicit time derivatives residual vector. More...
void	ValidateContext (const ContextBase &context) const final
	Checks whether the given context was created for this system. More...
void	ValidateContext (const ContextBase *context) const
	Checks whether the given context was created for this system. More...
template<class Clazz >
void	ValidateCreatedForThisSystem (const Clazz &object) const
	Checks whether the given object was created for this system. More...
	SystemBase (const SystemBase &)=delete
SystemBase &	operator= (const SystemBase &)=delete
	SystemBase (SystemBase &&)=delete
SystemBase &	operator= (SystemBase &&)=delete
std::string	GetGraphvizString (std::optional< int > max_depth={}, const std::map< std::string, std::string > &options={}) const
	Returns a Graphviz string describing this System. More...
GraphvizFragment	GetGraphvizFragment (std::optional< int > max_depth={}, const std::map< std::string, std::string > &options={}) const
	(Advanced) Like GetGraphvizString() but does not wrap the string in a digraph { … }. More...
const AbstractValue *	EvalAbstractInput (const ContextBase &context, int port_index) const
	Returns the value of the input port with the given port_index as an AbstractValue, which is permitted for ports of any type. More...
template<typename V >
const V *	EvalInputValue (const ContextBase &context, int port_index) const
	Returns the value of an abstract-valued input port with the given port_index as a value of known type V. More...
DependencyTicket	discrete_state_ticket (DiscreteStateIndex index) const
	Returns a ticket indicating dependence on a particular discrete state variable xdᵢ (may be a vector). More...
DependencyTicket	abstract_state_ticket (AbstractStateIndex index) const
	Returns a ticket indicating dependence on a particular abstract state variable xaᵢ. More...
DependencyTicket	numeric_parameter_ticket (NumericParameterIndex index) const
	Returns a ticket indicating dependence on a particular numeric parameter pnᵢ (may be a vector). More...
DependencyTicket	abstract_parameter_ticket (AbstractParameterIndex index) const
	Returns a ticket indicating dependence on a particular abstract parameter paᵢ. More...
DependencyTicket	input_port_ticket (InputPortIndex index) const
	Returns a ticket indicating dependence on input port uᵢ indicated by index. More...
DependencyTicket	cache_entry_ticket (CacheIndex index) const
	Returns a ticket indicating dependence on the cache entry indicated by index. More...
DependencyTicket	output_port_ticket (OutputPortIndex index) const
	(Internal use only) Returns a ticket indicating dependence on the output port indicated by index. More...

Static Public Member Functions
static const Rod2dStateVector< T > &	get_state (const systems::ContinuousState< T > &cstate)
static Rod2dStateVector< T > &	get_mutable_state (systems::ContinuousState< T > *cstate)
static const Rod2dStateVector< T > &	get_state (const systems::Context< T > &context)
static Rod2dStateVector< T > &	get_mutable_state (systems::Context< T > *context)
static Vector2< T >	CalcRodEndpoint (const T &x, const T &y, int k, const T &ctheta, const T &stheta, double half_rod_len)
	Utility method for determining the World frame location of one of three points on the rod whose origin is Ro. More...
static Vector2< T >	CalcCoincidentRodPointVelocity (const Vector2< T > &p_WRo, const Vector2< T > &v_WRo, const T &w_WR, const Vector2< T > &p_WC)
	Given a location p_WC of a point C in the World frame, define the point Rc on the rod that is coincident with C, and report Rc's World frame velocity v_WRc. More...
Static Public Member Functions inherited from System< T >
static DependencyTicket	nothing_ticket ()
	Returns a ticket indicating that a computation does not depend on any source value; that is, it is a constant. More...
static DependencyTicket	time_ticket ()
	Returns a ticket indicating dependence on time. More...
static DependencyTicket	accuracy_ticket ()
	Returns a ticket indicating dependence on the accuracy setting in the Context. More...
static DependencyTicket	q_ticket ()
	Returns a ticket indicating that a computation depends on configuration state variables q. More...
static DependencyTicket	v_ticket ()
	Returns a ticket indicating dependence on velocity state variables v. More...
static DependencyTicket	z_ticket ()
	Returns a ticket indicating dependence on any or all of the miscellaneous continuous state variables z. More...
static DependencyTicket	xc_ticket ()
	Returns a ticket indicating dependence on all of the continuous state variables q, v, or z. More...
static DependencyTicket	xd_ticket ()
	Returns a ticket indicating dependence on all of the numerical discrete state variables, in any discrete variable group. More...
static DependencyTicket	xa_ticket ()
	Returns a ticket indicating dependence on all of the abstract state variables in the current Context. More...
static DependencyTicket	all_state_ticket ()
	Returns a ticket indicating dependence on all state variables x in this system, including continuous variables xc, discrete (numeric) variables xd, and abstract state variables xa. More...
static DependencyTicket	pn_ticket ()
	Returns a ticket indicating dependence on all of the numerical parameters in the current Context. More...
static DependencyTicket	pa_ticket ()
	Returns a ticket indicating dependence on all of the abstract parameters pa in the current Context. More...
static DependencyTicket	all_parameters_ticket ()
	Returns a ticket indicating dependence on all parameters p in this system, including numeric parameters pn, and abstract parameters pa. More...
static DependencyTicket	all_input_ports_ticket ()
	Returns a ticket indicating dependence on all input ports u of this system. More...
static DependencyTicket	all_sources_ticket ()
	Returns a ticket indicating dependence on every possible independent source value, including time, accuracy, state, input ports, and parameters (but not cache entries). More...
static DependencyTicket	configuration_ticket ()
	Returns a ticket indicating dependence on all source values that may affect configuration-dependent computations. More...
static DependencyTicket	kinematics_ticket ()
	Returns a ticket indicating dependence on all source values that may affect configuration- or velocity-dependent computations. More...
static DependencyTicket	xcdot_ticket ()
	Returns a ticket for the cache entry that holds time derivatives of the continuous variables. More...
static DependencyTicket	pe_ticket ()
	Returns a ticket for the cache entry that holds the potential energy calculation. More...
static DependencyTicket	ke_ticket ()
	Returns a ticket for the cache entry that holds the kinetic energy calculation. More...
static DependencyTicket	pc_ticket ()
	Returns a ticket for the cache entry that holds the conservative power calculation. More...
static DependencyTicket	pnc_ticket ()
	Returns a ticket for the cache entry that holds the non-conservative power calculation. More...
template<template< typename > class S = ::drake::systems::System>
static std::unique_ptr< S< T > >	Clone (const S< T > &from)
	Creates a deep copy of this system. More...
template<template< typename > class S = ::drake::systems::System>
static std::unique_ptr< S< AutoDiffXd > >	ToAutoDiffXd (const S< T > &from)
	Creates a deep copy of from, transmogrified to use the autodiff scalar type, with a dynamic-sized vector of partial derivatives. More...
template<template< typename > class S = ::drake::systems::System>
static std::unique_ptr< S< symbolic::Expression > >	ToSymbolic (const S< T > &from)
	Creates a deep copy of from, transmogrified to use the symbolic scalar type. More...
template<typename U , template< typename > class S = ::drake::systems::System>
static std::unique_ptr< S< U > >	ToScalarType (const S< T > &from)
	Creates a deep copy of from, transmogrified to use the scalar type selected by a template parameter. More...
Static Public Member Functions inherited from SystemBase
static DependencyTicket	nothing_ticket ()
	Returns a ticket indicating that a computation does not depend on any source value; that is, it is a constant. More...
static DependencyTicket	time_ticket ()
	Returns a ticket indicating dependence on time. More...
static DependencyTicket	accuracy_ticket ()
	Returns a ticket indicating dependence on the accuracy setting in the Context. More...
static DependencyTicket	q_ticket ()
	Returns a ticket indicating that a computation depends on configuration state variables q. More...
static DependencyTicket	v_ticket ()
	Returns a ticket indicating dependence on velocity state variables v. More...
static DependencyTicket	z_ticket ()
	Returns a ticket indicating dependence on any or all of the miscellaneous continuous state variables z. More...
static DependencyTicket	xc_ticket ()
	Returns a ticket indicating dependence on all of the continuous state variables q, v, or z. More...
static DependencyTicket	xd_ticket ()
	Returns a ticket indicating dependence on all of the numerical discrete state variables, in any discrete variable group. More...
static DependencyTicket	xa_ticket ()
	Returns a ticket indicating dependence on all of the abstract state variables in the current Context. More...
static DependencyTicket	all_state_ticket ()
	Returns a ticket indicating dependence on all state variables x in this system, including continuous variables xc, discrete (numeric) variables xd, and abstract state variables xa. More...
static DependencyTicket	pn_ticket ()
	Returns a ticket indicating dependence on all of the numerical parameters in the current Context. More...
static DependencyTicket	pa_ticket ()
	Returns a ticket indicating dependence on all of the abstract parameters pa in the current Context. More...
static DependencyTicket	all_parameters_ticket ()
	Returns a ticket indicating dependence on all parameters p in this system, including numeric parameters pn, and abstract parameters pa. More...
static DependencyTicket	all_input_ports_ticket ()
	Returns a ticket indicating dependence on all input ports u of this system. More...
static DependencyTicket	all_sources_except_input_ports_ticket ()
	Returns a ticket indicating dependence on every possible independent source value except input ports. More...
static DependencyTicket	all_sources_ticket ()
	Returns a ticket indicating dependence on every possible independent source value, including time, accuracy, state, input ports, and parameters (but not cache entries). More...
static DependencyTicket	configuration_ticket ()
	Returns a ticket indicating dependence on all source values that may affect configuration-dependent computations. More...
static DependencyTicket	kinematics_ticket ()
	Returns a ticket indicating dependence on all source values that may affect configuration- or velocity-dependent computations. More...
static DependencyTicket	xcdot_ticket ()
	Returns a ticket for the cache entry that holds time derivatives of the continuous variables. More...
static DependencyTicket	pe_ticket ()
	Returns a ticket for the cache entry that holds the potential energy calculation. More...
static DependencyTicket	ke_ticket ()
	Returns a ticket for the cache entry that holds the kinetic energy calculation. More...
static DependencyTicket	pc_ticket ()
	Returns a ticket for the cache entry that holds the conservative power calculation. More...
static DependencyTicket	pnc_ticket ()
	Returns a ticket for the cache entry that holds the non-conservative power calculation. More...
static DependencyTicket	xd_unique_periodic_update_ticket ()
	(Internal use only) Returns a ticket for the cache entry that holds the unique periodic discrete update computation. More...

Friends
class	Rod2DDAETest
class	Rod2DDAETest_RigidContactProblemDataBallistic_Test

Additional Inherited Members
Protected Member Functions inherited from LeafSystem< T >
	LeafSystem ()
	Default constructor that declares no inputs, outputs, state, parameters, events, nor scalar-type conversion support (AutoDiff, etc.). More...
	LeafSystem (SystemScalarConverter converter)
	Constructor that declares no inputs, outputs, state, parameters, or events, but allows subclasses to declare scalar-type conversion support (AutoDiff, etc.). More...
virtual std::unique_ptr< LeafContext< T > >	DoMakeLeafContext () const
	Provides a new instance of the leaf context for this system. More...
virtual void	DoValidateAllocatedLeafContext (const LeafContext< T > &context) const
	Derived classes that impose restrictions on what resources are permitted should check those restrictions by implementing this. More...
T	DoCalcWitnessValue (const Context< T > &context, const WitnessFunction< T > &witness_func) const final
	Derived classes will implement this method to evaluate a witness function at the given context. More...
void	AddTriggeredWitnessFunctionToCompositeEventCollection (Event< T > *event, CompositeEventCollection< T > *events) const final
	Add event to events due to a witness function triggering. More...
void	DoCalcNextUpdateTime (const Context< T > &context, CompositeEventCollection< T > *events, T *time) const override
	Computes the next update time based on the configured periodic events, for scalar types that are arithmetic, or aborts for scalar types that are not arithmetic. More...
std::unique_ptr< ContinuousState< T > >	AllocateContinuousState () const
	Returns a copy of the state declared in the most recent DeclareContinuousState() call, or else a zero-sized state if that method has never been called. More...
std::unique_ptr< DiscreteValues< T > >	AllocateDiscreteState () const
	Returns a copy of the states declared in DeclareDiscreteState() calls. More...
std::unique_ptr< AbstractValues >	AllocateAbstractState () const
	Returns a copy of the states declared in DeclareAbstractState() calls. More...
std::unique_ptr< Parameters< T > >	AllocateParameters () const
	Returns a copy of the parameters declared in DeclareNumericParameter() and DeclareAbstractParameter() calls. More...
int	DeclareNumericParameter (const BasicVector< T > &model_vector)
	Declares a numeric parameter using the given model_vector. More...
template<template< typename > class U = BasicVector>
const U< T > &	GetNumericParameter (const Context< T > &context, int index) const
	Extracts the numeric parameters of type U from the context at index. More...
template<template< typename > class U = BasicVector>
U< T > &	GetMutableNumericParameter (Context< T > *context, int index) const
	Extracts the numeric parameters of type U from the context at index. More...
int	DeclareAbstractParameter (const AbstractValue &model_value)
	Declares an abstract parameter using the given model_value. More...
template<class MySystem >
SystemConstraintIndex	DeclareEqualityConstraint (void(MySystem::*calc)(const Context< T > &, VectorX< T > *) const, int count, std::string description)
	Declares a system constraint of the form f(context) = 0 by specifying a member function to use to calculate the (VectorX) constraint value with a signature: More...
SystemConstraintIndex	DeclareEqualityConstraint (ContextConstraintCalc< T > calc, int count, std::string description)
	Declares a system constraint of the form f(context) = 0 by specifying a std::function to use to calculate the (Vector) constraint value with a signature: More...
template<class MySystem >
SystemConstraintIndex	DeclareInequalityConstraint (void(MySystem::*calc)(const Context< T > &, VectorX< T > *) const, SystemConstraintBounds bounds, std::string description)
	Declares a system constraint of the form bounds.lower() <= calc(context) <= bounds.upper() by specifying a member function to use to calculate the (VectorX) constraint value with a signature: More...
SystemConstraintIndex	DeclareInequalityConstraint (ContextConstraintCalc< T > calc, SystemConstraintBounds bounds, std::string description)
	Declares a system constraint of the form bounds.lower() <= calc(context) <= bounds.upper() by specifying a std::function to use to calculate the (Vector) constraint value with a signature: More...
template<class MySystem >
void	DeclarePeriodicPublishEvent (double period_sec, double offset_sec, EventStatus(MySystem::*publish)(const Context< T > &) const)
	Declares that a Publish event should occur periodically and that it should invoke the given event handler method. More...
template<class MySystem >
void	DeclarePeriodicPublishEvent (double period_sec, double offset_sec, void(MySystem::*publish)(const Context< T > &) const)
	This variant accepts a handler that is assumed to succeed rather than one that returns an EventStatus result. More...
template<class MySystem >
void	DeclarePeriodicDiscreteUpdateEvent (double period_sec, double offset_sec, EventStatus(MySystem::*update)(const Context< T > &, DiscreteValues< T > *) const)
	Declares that a DiscreteUpdate event should occur periodically and that it should invoke the given event handler method. More...
template<class MySystem >
void	DeclarePeriodicDiscreteUpdateEvent (double period_sec, double offset_sec, void(MySystem::*update)(const Context< T > &, DiscreteValues< T > *) const)
	This variant accepts a handler that is assumed to succeed rather than one that returns an EventStatus result. More...
template<class MySystem >
void	DeclarePeriodicUnrestrictedUpdateEvent (double period_sec, double offset_sec, EventStatus(MySystem::*update)(const Context< T > &, State< T > *) const)
	Declares that an UnrestrictedUpdate event should occur periodically and that it should invoke the given event handler method. More...
template<class MySystem >
void	DeclarePeriodicUnrestrictedUpdateEvent (double period_sec, double offset_sec, void(MySystem::*update)(const Context< T > &, State< T > *) const)
	This variant accepts a handler that is assumed to succeed rather than one that returns an EventStatus result. More...
template<typename EventType >
void	DeclarePeriodicEvent (double period_sec, double offset_sec, const EventType &event)
	(Advanced) Declares that a particular Event object should be dispatched periodically. More...
template<class MySystem >
void	DeclarePerStepPublishEvent (EventStatus(MySystem::*publish)(const Context< T > &) const)
	Declares that a Publish event should occur at initialization and at the end of every trajectory-advancing step and that it should invoke the given event handler method. More...
template<class MySystem >
void	DeclarePerStepDiscreteUpdateEvent (EventStatus(MySystem::*update)(const Context< T > &, DiscreteValues< T > *) const)
	Declares that a DiscreteUpdate event should occur at the start of every trajectory-advancing step and that it should invoke the given event handler method. More...
template<class MySystem >
void	DeclarePerStepUnrestrictedUpdateEvent (EventStatus(MySystem::*update)(const Context< T > &, State< T > *) const)
	Declares that an UnrestrictedUpdate event should occur at the start of every trajectory-advancing step and that it should invoke the given event handler method. More...
template<typename EventType >
void	DeclarePerStepEvent (const EventType &event)
	(Advanced) Declares that a particular Event object should be dispatched at every trajectory-advancing step. More...
template<class MySystem >
void	DeclareInitializationPublishEvent (EventStatus(MySystem::*publish)(const Context< T > &) const)
	Declares that a Publish event should occur at initialization and that it should invoke the given event handler method. More...
template<class MySystem >
void	DeclareInitializationDiscreteUpdateEvent (EventStatus(MySystem::*update)(const Context< T > &, DiscreteValues< T > *) const)
	Declares that a DiscreteUpdate event should occur at initialization and that it should invoke the given event handler method. More...
template<class MySystem >
void	DeclareInitializationUnrestrictedUpdateEvent (EventStatus(MySystem::*update)(const Context< T > &, State< T > *) const)
	Declares that an UnrestrictedUpdate event should occur at initialization and that it should invoke the given event handler method. More...
template<typename EventType >
void	DeclareInitializationEvent (const EventType &event)
	(Advanced) Declares that a particular Event object should be dispatched at initialization. More...
template<class MySystem >
void	DeclareForcedPublishEvent (EventStatus(MySystem::*publish)(const Context< T > &) const)
	Declares a function that is called whenever a user directly calls ForcedPublish(const Context&). More...
template<class MySystem >
void	DeclareForcedDiscreteUpdateEvent (EventStatus(MySystem::*update)(const Context< T > &, DiscreteValues< T > *) const)
	Declares a function that is called whenever a user directly calls CalcForcedDiscreteVariableUpdate(const Context&, DiscreteValues<T>*). More...
template<class MySystem >
void	DeclareForcedUnrestrictedUpdateEvent (EventStatus(MySystem::*update)(const Context< T > &, State< T > *) const)
	Declares a function that is called whenever a user directly calls CalcForcedUnrestrictedUpdate(const Context&, State<T>*). More...
ContinuousStateIndex	DeclareContinuousState (int num_state_variables)
	Declares that this System should reserve continuous state with num_state_variables state variables, which have no second-order structure. More...
ContinuousStateIndex	DeclareContinuousState (int num_q, int num_v, int num_z)
	Declares that this System should reserve continuous state with num_q generalized positions, num_v generalized velocities, and num_z miscellaneous state variables. More...
ContinuousStateIndex	DeclareContinuousState (const BasicVector< T > &model_vector)
	Declares that this System should reserve continuous state with model_vector.size() miscellaneous state variables, stored in a vector cloned from model_vector. More...
ContinuousStateIndex	DeclareContinuousState (const BasicVector< T > &model_vector, int num_q, int num_v, int num_z)
	Declares that this System should reserve continuous state with num_q generalized positions, num_v generalized velocities, and num_z miscellaneous state variables, stored in a vector cloned from model_vector. More...
DiscreteStateIndex	DeclareDiscreteState (const BasicVector< T > &model_vector)
	Declares a discrete state group with model_vector.size() state variables, stored in a vector cloned from model_vector (preserving the concrete type and value). More...
DiscreteStateIndex	DeclareDiscreteState (const Eigen::Ref< const VectorX< T >> &vector)
	Declares a discrete state group with vector.size() state variables, stored in a BasicVector initialized with the contents of vector. More...
DiscreteStateIndex	DeclareDiscreteState (int num_state_variables)
	Declares a discrete state group with num_state_variables state variables, stored in a BasicVector initialized to be all-zero. More...
AbstractStateIndex	DeclareAbstractState (const AbstractValue &model_value)
	Declares an abstract state variable and provides a model value for it. More...
void	DeclareImplicitTimeDerivativesResidualSize (int n)
	(Advanced) Overrides the default size for the implicit time derivatives residual. More...
InputPort< T > &	DeclareVectorInputPort (std::variant< std::string, UseDefaultName > name, const BasicVector< T > &model_vector, std::optional< RandomDistribution > random_type=std::nullopt)
	Declares a vector-valued input port using the given model_vector. More...
InputPort< T > &	DeclareVectorInputPort (std::variant< std::string, UseDefaultName > name, int size, std::optional< RandomDistribution > random_type=std::nullopt)
	Declares a vector-valued input port with type BasicVector and size size. More...
InputPort< T > &	DeclareAbstractInputPort (std::variant< std::string, UseDefaultName > name, const AbstractValue &model_value)
	Declares an abstract-valued input port using the given model_value. More...
void	DeprecateInputPort (const InputPort< T > &port, std::string message)
	Flags an already-declared input port as deprecated. More...
template<class MySystem , typename BasicVectorSubtype >
LeafOutputPort< T > &	DeclareVectorOutputPort (std::variant< std::string, UseDefaultName > name, const BasicVectorSubtype &model_vector, void(MySystem::*calc)(const Context< T > &, BasicVectorSubtype *) const, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
	Declares a vector-valued output port by specifying (1) a model vector of type BasicVectorSubtype derived from BasicVector and initialized to the correct size and desired initial value, and (2) a calculator function that is a class member function (method) with signature: More...
template<class MySystem >
LeafOutputPort< T > &	DeclareVectorOutputPort (std::variant< std::string, UseDefaultName > name, int size, void(MySystem::*calc)(const Context< T > &, BasicVector< T > *) const, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
	Declares a vector-valued output port with type BasicVector and size size, using the drake::dummy_value<T>, which is NaN when T = double. More...
template<class MySystem , typename BasicVectorSubtype >
LeafOutputPort< T > &	DeclareVectorOutputPort (std::variant< std::string, UseDefaultName > name, void(MySystem::*calc)(const Context< T > &, BasicVectorSubtype *) const, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
	Declares a vector-valued output port by specifying only a calculator function that is a class member function (method) with signature: More...
LeafOutputPort< T > &	DeclareVectorOutputPort (std::variant< std::string, UseDefaultName > name, const BasicVector< T > &model_vector, typename LeafOutputPort< T >::CalcVectorCallback vector_calc_function, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
	(Advanced) Declares a vector-valued output port using the given model_vector and a function for calculating the port's value at runtime. More...
LeafOutputPort< T > &	DeclareVectorOutputPort (std::variant< std::string, UseDefaultName > name, int size, typename LeafOutputPort< T >::CalcVectorCallback vector_calc_function, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
	(Advanced) Declares a vector-valued output port with type BasicVector<T> and size size, using the drake::dummy_value<T>, which is NaN when T = double. More...
template<class MySystem , typename OutputType >
LeafOutputPort< T > &	DeclareAbstractOutputPort (std::variant< std::string, UseDefaultName > name, const OutputType &model_value, void(MySystem::*calc)(const Context< T > &, OutputType *) const, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
	Declares an abstract-valued output port by specifying a model value of concrete type OutputType and a calculator function that is a class member function (method) with signature: More...
template<class MySystem , typename OutputType >
LeafOutputPort< T > &	DeclareAbstractOutputPort (std::variant< std::string, UseDefaultName > name, void(MySystem::*calc)(const Context< T > &, OutputType *) const, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
	Declares an abstract-valued output port by specifying only a calculator function that is a class member function (method) with signature: More...
LeafOutputPort< T > &	DeclareAbstractOutputPort (std::variant< std::string, UseDefaultName > name, typename LeafOutputPort< T >::AllocCallback alloc, typename LeafOutputPort< T >::CalcCallback calc, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
	(Advanced) Declares an abstract-valued output port using the given allocator and calculator functions provided in their most generic forms. More...
LeafOutputPort< T > &	DeclareStateOutputPort (std::variant< std::string, UseDefaultName > name, ContinuousStateIndex state_index)
	Declares a vector-valued output port whose value is the continuous state of this system. More...
LeafOutputPort< T > &	DeclareStateOutputPort (std::variant< std::string, UseDefaultName > name, DiscreteStateIndex state_index)
	Declares a vector-valued output port whose value is the given discrete state group of this system. More...
LeafOutputPort< T > &	DeclareStateOutputPort (std::variant< std::string, UseDefaultName > name, AbstractStateIndex state_index)
	Declares an abstract-valued output port whose value is the given abstract state of this system. More...
void	DeprecateOutputPort (const OutputPort< T > &port, std::string message)
	Flags an already-declared output port as deprecated. More...
template<class MySystem >
std::unique_ptr< WitnessFunction< T > >	MakeWitnessFunction (const std::string &description, const WitnessFunctionDirection &direction_type, T(MySystem::*calc)(const Context< T > &) const) const
	Constructs the witness function with the given description (used primarily for debugging and logging), direction type, and calculator function; and with no event object. More...
std::unique_ptr< WitnessFunction< T > >	MakeWitnessFunction (const std::string &description, const WitnessFunctionDirection &direction_type, std::function< T(const Context< T > &)> calc) const
	Constructs the witness function with the given description (used primarily for debugging and logging), direction type, and calculator function; and with no event object. More...
template<class MySystem >
std::unique_ptr< WitnessFunction< T > >	MakeWitnessFunction (const std::string &description, const WitnessFunctionDirection &direction_type, T(MySystem::*calc)(const Context< T > &) const, void(MySystem::*publish_callback)(const Context< T > &, const PublishEvent< T > &) const) const
	Constructs the witness function with the given description (used primarily for debugging and logging), direction type, calculator function, and publish event callback function for when this triggers. More...
template<class MySystem >
std::unique_ptr< WitnessFunction< T > >	MakeWitnessFunction (const std::string &description, const WitnessFunctionDirection &direction_type, T(MySystem::*calc)(const Context< T > &) const, void(MySystem::*du_callback)(const Context< T > &, const DiscreteUpdateEvent< T > &, DiscreteValues< T > *) const) const
	Constructs the witness function with the given description (used primarily for debugging and logging), direction type, calculator function, and discrete update event callback function for when this triggers. More...
template<class MySystem >
std::unique_ptr< WitnessFunction< T > >	MakeWitnessFunction (const std::string &description, const WitnessFunctionDirection &direction_type, T(MySystem::*calc)(const Context< T > &) const, void(MySystem::*uu_callback)(const Context< T > &, const UnrestrictedUpdateEvent< T > &, State< T > *) const) const
	Constructs the witness function with the given description (used primarily for debugging and logging), direction type, calculator function, and unrestricted update event callback function for when this triggers. More...
template<class MySystem >
std::unique_ptr< WitnessFunction< T > >	MakeWitnessFunction (const std::string &description, const WitnessFunctionDirection &direction_type, T(MySystem::*calc)(const Context< T > &) const, const Event< T > &e) const
	Constructs the witness function with the given description (used primarily for debugging and logging), direction type, and calculator function, and with an object corresponding to the event that is to be dispatched when this witness function triggers. More...
std::unique_ptr< WitnessFunction< T > >	MakeWitnessFunction (const std::string &description, const WitnessFunctionDirection &direction_type, std::function< T(const Context< T > &)> calc, const Event< T > &e) const
	Constructs the witness function with the given description (used primarily for debugging and logging), direction type, and calculator function, and with an object corresponding to the event that is to be dispatched when this witness function triggers. More...
Protected Member Functions inherited from System< T >
virtual void	DoGetWitnessFunctions (const Context< T > &, std::vector< const WitnessFunction< T > * > *) const
	Derived classes can override this method to provide witness functions active for the given state. More...
SystemConstraintIndex	AddConstraint (std::unique_ptr< SystemConstraint< T >> constraint)
	Adds an already-created constraint to the list of constraints for this System. More...
bool	forced_publish_events_exist () const
bool	forced_discrete_update_events_exist () const
bool	forced_unrestricted_update_events_exist () const
EventCollection< PublishEvent< T > > &	get_mutable_forced_publish_events ()
EventCollection< DiscreteUpdateEvent< T > > &	get_mutable_forced_discrete_update_events ()
EventCollection< UnrestrictedUpdateEvent< T > > &	get_mutable_forced_unrestricted_update_events ()
const EventCollection< DiscreteUpdateEvent< T > > &	get_forced_discrete_update_events () const
const EventCollection< UnrestrictedUpdateEvent< T > > &	get_forced_unrestricted_update_events () const
void	set_forced_publish_events (std::unique_ptr< EventCollection< PublishEvent< T >>> forced)
void	set_forced_discrete_update_events (std::unique_ptr< EventCollection< DiscreteUpdateEvent< T >>> forced)
void	set_forced_unrestricted_update_events (std::unique_ptr< EventCollection< UnrestrictedUpdateEvent< T >>> forced)
SystemScalarConverter &	get_mutable_system_scalar_converter ()
	Returns the SystemScalarConverter for this system. More...
CacheEntry &	DeclareCacheEntry (std::string description, ValueProducer value_producer, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
	Declares a new CacheEntry in this System using the most generic form of the calculation function. More...
template<class MySystem , class MyContext , typename ValueType >
CacheEntry &	DeclareCacheEntry (std::string description, const ValueType &model_value, void(MySystem::*calc)(const MyContext &, ValueType *) const, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
	Declares a cache entry by specifying a model value of concrete type ValueType and a calculator function that is a class member function (method) with signature: More...
template<class MySystem , class MyContext , typename ValueType >
CacheEntry &	DeclareCacheEntry (std::string description, void(MySystem::*calc)(const MyContext &, ValueType *) const, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
	Declares a cache entry by specifying only a calculator function that is a class member function (method) with signature: More...
	System (SystemScalarConverter converter)
	Constructs an empty System base class object and allocates base class resources, possibly supporting scalar-type conversion support (AutoDiff, etc.) using converter. More...
InputPort< T > &	DeclareInputPort (std::variant< std::string, UseDefaultName > name, PortDataType type, int size, std::optional< RandomDistribution > random_type=std::nullopt)
	Adds a port with the specified type and size to the input topology. More...
virtual void	DoCalcTimeDerivatives (const Context< T > &context, ContinuousState< T > *derivatives) const
	Override this if you have any continuous state variables x꜀ in your concrete System to calculate their time derivatives. More...
virtual void	DoCalcImplicitTimeDerivativesResidual (const Context< T > &context, const ContinuousState< T > &proposed_derivatives, EigenPtr< VectorX< T >> residual) const
	Override this if you have an efficient way to evaluate the implicit time derivatives residual for this System. More...
virtual T	DoCalcPotentialEnergy (const Context< T > &context) const
	Override this method for physical systems to calculate the potential energy PE currently stored in the configuration provided in the given Context. More...
virtual T	DoCalcKineticEnergy (const Context< T > &context) const
	Override this method for physical systems to calculate the kinetic energy KE currently present in the motion provided in the given Context. More...
virtual T	DoCalcConservativePower (const Context< T > &context) const
	Override this method to return the rate Pc at which mechanical energy is being converted from potential energy to kinetic energy by this system in the given Context. More...
virtual T	DoCalcNonConservativePower (const Context< T > &context) const
	Override this method to return the rate Pnc at which work W is done on the system by non-conservative forces. More...
virtual void	DoMapQDotToVelocity (const Context< T > &context, const Eigen::Ref< const VectorX< T >> &qdot, VectorBase< T > *generalized_velocity) const
	Provides the substantive implementation of MapQDotToVelocity(). More...
virtual void	DoMapVelocityToQDot (const Context< T > &context, const Eigen::Ref< const VectorX< T >> &generalized_velocity, VectorBase< T > *qdot) const
	Provides the substantive implementation of MapVelocityToQDot(). More...
Eigen::VectorBlock< VectorX< T > >	GetMutableOutputVector (SystemOutput< T > *output, int port_index) const
	Returns a mutable Eigen expression for a vector valued output port with index port_index in this system. More...
Protected Member Functions inherited from SystemBase
	SystemBase ()=default
	(Internal use only). More...
void	AddInputPort (std::unique_ptr< InputPortBase > port)
	(Internal use only) Adds an already-constructed input port to this System. More...
void	AddOutputPort (std::unique_ptr< OutputPortBase > port)
	(Internal use only) Adds an already-constructed output port to this System. More...
std::string	NextInputPortName (std::variant< std::string, UseDefaultName > given_name) const
	(Internal use only) Returns a name for the next input port, using the given name if it isn't kUseDefaultName, otherwise making up a name like "u3" from the next available input port index. More...
std::string	NextOutputPortName (std::variant< std::string, UseDefaultName > given_name) const
	(Internal use only) Returns a name for the next output port, using the given name if it isn't kUseDefaultName, otherwise making up a name like "y3" from the next available output port index. More...
void	AddDiscreteStateGroup (DiscreteStateIndex index)
	(Internal use only) Assigns a ticket to a new discrete variable group with the given index. More...
void	AddAbstractState (AbstractStateIndex index)
	(Internal use only) Assigns a ticket to a new abstract state variable with the given index. More...
void	AddNumericParameter (NumericParameterIndex index)
	(Internal use only) Assigns a ticket to a new numeric parameter with the given index. More...
void	AddAbstractParameter (AbstractParameterIndex index)
	(Internal use only) Assigns a ticket to a new abstract parameter with the given index. More...
CacheEntry &	DeclareCacheEntryWithKnownTicket (DependencyTicket known_ticket, std::string description, ValueProducer value_producer, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
	(Internal use only) This is for cache entries associated with pre-defined tickets, for example the cache entry for time derivatives. More...
const internal::SystemParentServiceInterface *	get_parent_service () const
	Returns a pointer to the service interface of the immediately enclosing Diagram if one has been set, otherwise nullptr. More...
DependencyTicket	assign_next_dependency_ticket ()
	(Internal use only) Assigns the next unused dependency ticket number, unique only within a particular system. More...
bool	IsObviouslyNotInputDependent (DependencyTicket dependency_ticket) const
	(Internal use only) Checks if a ticket depends on (any) input port. More...
const AbstractValue *	EvalAbstractInputImpl (const char *func, const ContextBase &context, InputPortIndex port_index) const
	(Internal use only) Shared code for updating an input port and returning a pointer to its abstract value, or nullptr if the port is not connected. More...
void	ThrowNegativePortIndex (const char *func, int port_index) const
	Throws std::exception to report a negative port_index that was passed to API method func. More...
void	ThrowInputPortIndexOutOfRange (const char *func, InputPortIndex port_index) const
	Throws std::exception to report bad input port_index that was passed to API method func. More...
void	ThrowOutputPortIndexOutOfRange (const char *func, OutputPortIndex port_index) const
	Throws std::exception to report bad output port_index that was passed to API method func. More...
void	ThrowNotAVectorInputPort (const char *func, InputPortIndex port_index) const
	Throws std::exception because someone misused API method func, that is only allowed for declared-vector input ports, on an abstract port whose index is given here. More...
void	ThrowInputPortHasWrongType (const char *func, InputPortIndex port_index, const std::string &expected_type, const std::string &actual_type) const
	Throws std::exception because someone called API method func claiming the input port had some value type that was wrong. More...
void	ThrowCantEvaluateInputPort (const char *func, InputPortIndex port_index) const
	Throws std::exception because someone called API method func, that requires this input port to be evaluatable, but the port was neither fixed nor connected. More...
const InputPortBase &	GetInputPortBaseOrThrow (const char *func, int port_index, bool warn_deprecated) const
	(Internal use only) Returns the InputPortBase at index port_index, throwing std::exception we don't like the port index. More...
const OutputPortBase &	GetOutputPortBaseOrThrow (const char *func, int port_index, bool warn_deprecated) const
	(Internal use only) Returns the OutputPortBase at index port_index, throwing std::exception if we don't like the port index. More...
void	ThrowValidateContextMismatch (const ContextBase &) const
	(Internal use only) Throws std::exception with a message that the sanity check(s) given by ValidateContext have failed. More...
virtual std::string	GetUnsupportedScalarConversionMessage (const std::type_info &source_type, const std::type_info &destination_type) const
	(Internal use only) Returns the message to use for a std::exception in the case of unsupported scalar type conversions. More...
void	InitializeContextBase (ContextBase *context) const
	This method must be invoked from within derived class DoAllocateContext() implementations right after the concrete Context object has been allocated. More...
const ContextSizes &	get_context_sizes () const
	Obtains access to the declared Context partition sizes as accumulated during LeafSystem or Diagram construction . More...
ContextSizes &	get_mutable_context_sizes ()
	Obtains mutable access to the Context sizes struct. More...
void	set_implicit_time_derivatives_residual_size (int n)
	Allows a LeafSystem to override the default size for the implicit time derivatives residual and a Diagram to sum up the total size. More...
internal::SystemId	get_system_id () const
	(Internal) Gets the id used to tag context data as being created by this system. More...
virtual GraphvizFragment	DoGetGraphvizFragment (const GraphvizFragmentParams &params) const
	The NVI implementation of GetGraphvizFragment() for subclasses to override if desired. More...
CacheEntry &	DeclareCacheEntry (std::string description, ValueProducer value_producer, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
	Declares a new CacheEntry in this System using the most generic form of the calculation function. More...
template<class MySystem , class MyContext , typename ValueType >
CacheEntry &	DeclareCacheEntry (std::string description, const ValueType &model_value, void(MySystem::*calc)(const MyContext &, ValueType *) const, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
	Declares a cache entry by specifying a model value of concrete type ValueType and a calculator function that is a class member function (method) with signature: More...
template<class MySystem , class MyContext , typename ValueType >
CacheEntry &	DeclareCacheEntry (std::string description, void(MySystem::*calc)(const MyContext &, ValueType *) const, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
	Declares a cache entry by specifying only a calculator function that is a class member function (method) with signature: More...
Static Protected Member Functions inherited from LeafSystem< T >
static DependencyTicket	all_sources_ticket ()
	Returns a ticket indicating dependence on every possible independent source value, including time, accuracy, state, input ports, and parameters (but not cache entries). More...
Static Protected Member Functions inherited from System< T >
static void	FindUniquePeriodicDiscreteUpdatesOrThrow (const char *api_name, const System< T > &system, const Context< T > &context, std::optional< PeriodicEventData > *timing, EventCollection< DiscreteUpdateEvent< T >> *events)
	(Internal use only) Static interface to DoFindUniquePeriodicDiscreteUpdatesOrThrow() to allow a Diagram to invoke that private method on its subsystems. More...
template<typename U >
static void	HandlePostConstructionScalarConversion (const System< U > &from, System< T > *to)
	(Internal use only) Scalar conversion (e.g., ToAutoDiffXd) will first call the SystemScalarConverter to construct the converted system, and then call this function for any post-construction cleanup. More...
Static Protected Member Functions inherited from SystemBase
static void	set_parent_service (SystemBase *child, const internal::SystemParentServiceInterface *parent_service)
	(Internal use only) Declares that parent_service is the service interface of the Diagram that owns this subsystem. More...
static void	ThrowInputPortHasWrongType (const char *func, const std::string &system_pathname, InputPortIndex, const std::string &port_name, const std::string &expected_type, const std::string &actual_type)
	Throws std::exception because someone called API method func claiming the input port had some value type that was wrong. More...
static const ContextSizes &	get_context_sizes (const SystemBase &system)
	Allows Diagram to access protected get_context_sizes() recursively on its subsystems. More...

Member Enumeration Documentation

SystemType

enum SystemType

strong

System model and approach for simulating the system.

Enumerator
kPiecewiseDAE	For modeling the system using rigid contact, Coulomb friction, and hybrid mode variables and simulating the system through piecewise solutions of differential algebraic equations.
kDiscretized	For modeling the system using either rigid or compliant contact, Coulomb friction, and a first-order time discretization (which can be applied to simulating the system without an integrator).
kContinuous	For modeling the system using compliant contact, Coulomb friction, and ordinary differential equations and simulating the system through standard algorithms for solving initial value problems.

Constructor & Destructor Documentation

~Rod2D()

~Rod2D ( )

override

Rod2D()

Rod2D ( SystemType  system_type, double  dt  )

explicit

Constructor for the 2D rod system using the piecewise DAE (differential algebraic equation) based approach, the discretization approach, or the continuous ordinary differential equation based approach.

Parameters

dt	The integration step size. This step size cannot be reset after construction.

Exceptions

std::exception

if dt is not positive and system_type is kDiscretized or dt is not zero and system_type is kPiecewiseDAE or kContinuous.

Member Function Documentation

CalcCoincidentRodPointVelocity()

static Vector2<T> CalcCoincidentRodPointVelocity ( const Vector2< T > &  p_WRo, const Vector2< T > &  v_WRo, const T &  w_WR, const Vector2< T > &  p_WC  )

static

Given a location p_WC of a point C in the World frame, define the point Rc on the rod that is coincident with C, and report Rc's World frame velocity v_WRc.

We're given p_WRo=(x,y) and V_WRo = (v_WRo,w_WR) = (xdot,ydot,thetadot).

Parameters

p_WRo	The center-of-mass of the rod, expressed in the world frame.
v_WRo	The translational velocity of the rod, expressed in the world frame.
w_WR	The angular velocity of the rod.
p_WC	The location of a point on the rod.

Returns

The translational velocity of p_WC, expressed in the world frame.

CalcCompliantContactForces()

Vector3<T> CalcCompliantContactForces

(

const systems::Context< T > &

context

)

const

Return net contact forces as a spatial force F_Ro_W=(fx,fy,τ) where translational force f_Ro_W=(fx,fy) is applied at the rod origin Ro, and torque t_R=τ is the moment due to the contact forces actually being applied elsewhere.

The returned spatial force may be the resultant of multiple active contact points. Only valid for simulation type kContinuous.

CalcConstraintProblemData()

void CalcConstraintProblemData	(	const systems::Context< T > &	context,
		const std::vector< Vector2< T >> &	points,
		const std::vector< T > &	tangent_vels,
		ConstraintAccelProblemData< T > *	data
	)		const

Initializes the contact data for the rod, given a set of contact points.

Aborts if data is null or if points.size() != tangent_vels.size().

Parameters

	points	a vector of contact points, expressed in the world frame.
	tangent_vels	a vector of tangent velocities at the contact points, measured along the positive x-axis.
[out]	data	the rigid contact problem data.

CalcImpactProblemData()

void CalcImpactProblemData	(	const systems::Context< T > &	context,
		const std::vector< Vector2< T >> &	points,
		ConstraintVelProblemData< T > *	data
	)		const

Initializes the impacting contact data for the rod, given a set of contact points.

Aborts if data is null.

Parameters

	points	a vector of contact points, expressed in the world frame.
[out]	data	the rigid impact problem data.

CalcRodEndpoint()

static Vector2<T> CalcRodEndpoint ( const T &  x, const T &  y, int  k, const T &  ctheta, const T &  stheta, double  half_rod_len  )

static

Utility method for determining the World frame location of one of three points on the rod whose origin is Ro.

Let r be the half-length of the rod. Define point P = Ro+k*r where k = { -1, 0, 1 }. This returns p_WP.

Parameters

x	The horizontal location of the rod center of mass (expressed in the world frame).
y	The vertical location of the rod center of mass (expressed in the world frame).
k	The rod endpoint (k=+1 indicates the rod "right" endpoint, k=-1 indicates the rod "left" endpoint, and k=0 indicates the rod origin; each of these are described in the primary class documentation.
ctheta	cos(theta), where θ is the orientation of the rod (as described in the primary class documentation).
stheta	sin(theta), where θ is the orientation of the rod (as described in the class documentation).
half_rod_len	Half the length of the rod.

Returns

p_WP, the designated point on the rod, expressed in the world frame.

DetermineNumWitnessFunctions()

int DetermineNumWitnessFunctions

(

const systems::Context< T > &

context

)

const

Gets the number of witness functions for the system active in the system for a given state (using context).

get_cfm()

double get_cfm

(

)

const

Gets the constraint force mixing parameter (CFM, used for discretized systems only), which should lie in the interval [0, infinity].

get_dissipation()

double get_dissipation

(

)

const

Get compliant contact normal dissipation in 1/velocity (s/m).

get_erp()

double get_erp

(

)

const

Gets the error reduction parameter (ERP, used for discretized systems only), which should lie in the interval [0, 1].

get_gravitational_acceleration()

double get_gravitational_acceleration

(

)

const

Gets the acceleration (with respect to the positive y-axis) due to gravity (i.e., this number should generally be negative).

get_integration_step_size()

double get_integration_step_size

(

)

const

Gets the integration step size for the discretized system.

Returns

0 if this is a DAE-based system.

get_mu_coulomb()

double get_mu_coulomb

(

)

const

Gets the coefficient of dynamic (sliding) Coulomb friction.

get_mu_static()

double get_mu_static

(

)

const

Get compliant contact static friction (stiction) coefficient μ_s.

get_mutable_state() [1/2]

static Rod2dStateVector<T>& get_mutable_state ( systems::ContinuousState< T > *  cstate )

static

get_mutable_state() [2/2]

static Rod2dStateVector<T>& get_mutable_state ( systems::Context< T > *  context )

static

get_rod_half_length()

double get_rod_half_length

(

)

const

Gets the half-length h of the rod.

get_rod_mass()

double get_rod_mass

(

)

const

Gets the mass of the rod.

get_rod_moment_of_inertia()

double get_rod_moment_of_inertia

(

)

const

Gets the rod moment of inertia.

get_state() [1/2]

static const Rod2dStateVector<T>& get_state ( const systems::ContinuousState< T > &  cstate )

static

get_state() [2/2]

static const Rod2dStateVector<T>& get_state ( const systems::Context< T > &  context )

static

get_stiction_speed_tolerance()

double get_stiction_speed_tolerance

(

)

const

Get the stiction speed tolerance (m/s).

get_stiffness()

double get_stiffness

(

)

const

Get compliant contact normal stiffness in N/m.

get_system_type()

SystemType get_system_type

(

)

const

Gets the model and simulation type for this system.

GetContactPoints()

void GetContactPoints	(	const systems::Context< T > &	context,
		std::vector< Vector2< T >> *	points
	)		const

Gets the point(s) of contact for the 2D rod.

context The context storing the current configuration and velocity of the rod. points Contains the contact points (those rod endpoints touching or lying within the ground halfspace) on return. This function aborts if points is null or points is non-empty.

GetContactPointsTangentVelocities()

void GetContactPointsTangentVelocities	(	const systems::Context< T > &	context,
		const std::vector< Vector2< T >> &	points,
		std::vector< T > *	vels
	)		const

Gets the tangent velocities for all contact points.

context The context storing the current configuration and velocity of the rod. points The set of context points. vels Contains the velocities (measured along the x-axis) on return. This function aborts if vels is null. vels will be resized appropriately (to the same number of elements as points) on return.

GetNonSlidingContactFrameToWorldTransform()

Matrix2<T> GetNonSlidingContactFrameToWorldTransform

(

)

const

Gets the rotation matrix that transforms velocities from a non-sliding contact frame to the global frame.

Note: all such non-sliding frames are identical for this example.

Returns

a 2x2 orthogonal matrix with first column set to the contact normal, which is +y ([0 1]) and second column set to the contact tangent +x ([1 0]). Both directions are expressed in the global frame.

GetRodConfig()

Vector3<T> GetRodConfig

(

const systems::Context< T > &

context

)

const

Gets the generalized position of the rod, given a Context.

The first two components represent the location of the rod's center-of-mass, expressed in the global frame. The third component represents the orientation of the rod, measured counter-clockwise with respect to the x-axis.

GetRodVelocity()

Vector3<T> GetRodVelocity

(

const systems::Context< T > &

context

)

const

Gets the generalized velocity of the rod, given a Context.

The first two components represent the translational velocities of the center-of-mass. The third component represents the angular velocity of the rod.

GetSlidingContactFrameToWorldTransform()

Matrix2<T> GetSlidingContactFrameToWorldTransform

(

const T &

xaxis_velocity

)

const

Gets the rotation matrix that transforms velocities from a sliding contact frame to the global frame.

Parameters

xaxis_velocity

The velocity of the rod at the point of contact, projected along the +x-axis.

Returns

a 2x2 orthogonal matrix with first column set to the contact normal, which is +y ([0 1]) and second column set to the direction of sliding motion, ±x (±[1 0]). Both directions are expressed in the global frame.

Note

Aborts if xaxis_velocity is zero.

IsImpacting()

bool IsImpacting

(

const systems::Context< T > &

context

)

const

Checks whether the system is in an impacting state, meaning that the relative velocity along the contact normal between the rod and the halfspace is such that the rod will begin interpenetrating the halfspace at any time Δt in the future (i.e., Δt > 0).

If the context does not correspond to a configuration where the rod and halfspace are contacting, this method returns false.

set_dissipation()

void set_dissipation

(

double

dissipation

)

Set compliant contact normal dissipation in 1/velocity (s/m, >= 0).

set_gravitational_acceleration()

void set_gravitational_acceleration

(

double

g

)

Sets the acceleration (with respect to the positive y-axis) due to gravity (i.e., this number should generally be negative).

set_mu_coulomb()

void set_mu_coulomb

(

double

mu

)

Sets the coefficient of dynamic (sliding) Coulomb friction.

set_mu_static()

void set_mu_static

(

double

mu_static

)

Set contact stiction coefficient (>= mu_coulomb).

This has no effect if the rod model is discretized.

set_rod_half_length()

void set_rod_half_length

(

double

half_length

)

Sets the half-length h of the rod.

set_rod_mass()

void set_rod_mass

(

double

mass

)

Sets the mass of the rod.

set_rod_moment_of_inertia()

void set_rod_moment_of_inertia

(

double

J

)

Sets the rod moment of inertia.

set_stiction_speed_tolerance()

void set_stiction_speed_tolerance

(

double

v_stick_tol

)

Set the stiction speed tolerance (m/s).

This is the maximum slip speed that we are willing to consider as sticking. For a given normal force N this is the speed at which the friction force will be largest, at μ_s*N where μ_s is the static coefficient of friction. This has no effect if the rod model is not compliant.

set_stiffness()

void set_stiffness

(

double

stiffness

)

Set compliant contact normal stiffness in N/m (>= 0).

SetStiffnessAndDissipation()

void SetStiffnessAndDissipation	(	double	cfm,
		double	erp
	)

Sets stiffness and dissipation for the rod from cfm and erp values (used for discretized system implementations).

state_output()

const systems::OutputPort<T>& state_output

(

)

const

Returns the state of this rod.

TransformDampingToDissipationAboutDeformation()

double TransformDampingToDissipationAboutDeformation	(	double	characteristic_deformation,
		double	b
	)		const

Transforms damping (b) to dissipation (α) , given a characteristic deformation.

TransformDissipationToDampingAboutDeformation()

double TransformDissipationToDampingAboutDeformation

(

double

characteristic_deformation

)

const

Transforms dissipation (α) to damping, given a characteristic.

Friends And Related Function Documentation

Rod2DDAETest

friend class Rod2DDAETest

friend

Rod2DDAETest_RigidContactProblemDataBallistic_Test

friend class Rod2DDAETest_RigidContactProblemDataBallistic_Test

friend

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The documentation for this class was generated from the following file:

• drake/examples/rod2d/rod2d.h