StaticEquilibriumProblem Class Reference

Detailed Description

Finds the static equilibrium pose of a multibody system through optimization.

The constraints are

1. 0 = g(q) + Bu + ∑ᵢ JᵢᵀFᵢ_AB_W(λᵢ) (generalized force equals to 0).
2. Fᵢ_AB_W(λᵢ) is within the admissible contact wrench (for example, contact force is in the friction cone).
3. sdf(q) >= 0 (signed distance function is no smaller than 0, hence no penetration).
4. complementarity condition between the contact force and the signed distance.
5. q within the joint limit.

#include <drake/multibody/optimization/static_equilibrium_problem.h>

Public Member Functions
	StaticEquilibriumProblem (const MultibodyPlant< AutoDiffXd > *plant, systems::Context< AutoDiffXd > *context, const std::set< std::pair< geometry::GeometryId, geometry::GeometryId >> &ignored_collision_pairs)
	~StaticEquilibriumProblem ()
solvers::MathematicalProgram *	get_mutable_prog () const
const solvers::MathematicalProgram &	prog () const
	Getter for the immutable optimization program. More...
const VectorX< symbolic::Variable > &	q_vars () const
	Getter for q, the decision variable for the generalized position. More...
const VectorX< symbolic::Variable > &	u_vars () const
	Getter for u, the decision variable for the input. More...
std::vector< ContactWrench >	GetContactWrenchSolution (const solvers::MathematicalProgramResult &result)
	Retrieve the solution to all contact wrenches. More...
void	UpdateComplementarityTolerance (double tol)
	Updates the tolerance on all the complementarity constraints α * β = 0. More...
Does not allow copy, move, or assignment
	StaticEquilibriumProblem (const StaticEquilibriumProblem &)=delete
StaticEquilibriumProblem &	operator= (const StaticEquilibriumProblem &)=delete
	StaticEquilibriumProblem (StaticEquilibriumProblem &&)=delete
StaticEquilibriumProblem &	operator= (StaticEquilibriumProblem &&)=delete

Constructor & Destructor Documentation

StaticEquilibriumProblem() [1/3]

StaticEquilibriumProblem ( const StaticEquilibriumProblem &  )

delete

StaticEquilibriumProblem() [2/3]

StaticEquilibriumProblem ( StaticEquilibriumProblem &&  )

delete

StaticEquilibriumProblem() [3/3]

StaticEquilibriumProblem	(	const MultibodyPlant< AutoDiffXd > *	plant,
		systems::Context< AutoDiffXd > *	context,
		const std::set< std::pair< geometry::GeometryId, geometry::GeometryId >> &	ignored_collision_pairs
	)

Parameters

plant	The plant for which the static equilibrium posture is computed. plant should remain alive as long as this StaticEquilibriumProblem exists.
context	The context for plant. context should remain alive as long as this StaticEquilibriumProblem exists.
ignored_collision_pairs	The contact between the pair of geometry in ignored_collision_pairs will be ignored. We will not impose non-penetration constraint between these pairs, and no contact wrench will be applied between these pairs.

~StaticEquilibriumProblem()

~StaticEquilibriumProblem

(

)

Member Function Documentation

get_mutable_prog()

solvers::MathematicalProgram* get_mutable_prog

(

)

const

GetContactWrenchSolution()

std::vector<ContactWrench> GetContactWrenchSolution

(

const solvers::MathematicalProgramResult &

result

)

Retrieve the solution to all contact wrenches.

Parameters

result

The result of solving prog().

operator=() [1/2]

StaticEquilibriumProblem& operator= ( StaticEquilibriumProblem &&  )

delete

operator=() [2/2]

StaticEquilibriumProblem& operator= ( const StaticEquilibriumProblem &  )

delete

prog()

const solvers::MathematicalProgram& prog

(

)

const

Getter for the immutable optimization program.

q_vars()

const VectorX<symbolic::Variable>& q_vars

(

)

const

Getter for q, the decision variable for the generalized position.

u_vars()

const VectorX<symbolic::Variable>& u_vars

(

)

const

Getter for u, the decision variable for the input.

UpdateComplementarityTolerance()

void UpdateComplementarityTolerance

(

double

tol

)

Updates the tolerance on all the complementarity constraints α * β = 0.

The complementarity constraint is relaxed as 0 ≤ α * β ≤ tol. See AddStaticFrictionConeComplementarityConstraint() for more details.

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

• drake/multibody/optimization/static_equilibrium_problem.h