Drake

Defines an interface for a path in a Segment object surface. More...

#include <drake/automotive/maliput/multilane/road_curve.h>

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## Public Member Functions

const CubicPolynomialelevation () const

const CubicPolynomialsuperelevation () const

double trajectory_length () const
Computes the composed curve path integral in the interval of p = [0; 1]. More...

virtual Vector2< doublexy_of_p (double p) const =0
Computes the reference curve. More...

virtual Vector2< doublexy_dot_of_p (double p) const =0
Computes the first derivative of the reference curve. More...

virtual double heading_of_p (double p) const =0
Computes the heading of the reference curve. More...

virtual double heading_dot_of_p (double p) const =0
Computes the first derivative heading of the reference curve. More...

virtual double p_scale () const =0
Computes the path length integral of the reference curve for the interval [0;1] of p. More...

virtual Vector3< doubleToCurveFrame (const Vector3< double > &geo_coordinate, const api::RBounds &lateral_bounds, const api::HBounds &height_bounds) const =0
Converts a geo_coordinate in the world frame to the composed curve frame, i.e., the superposition of the reference curve, elevation and superelevation polynomials. More...

virtual bool IsValid (const api::RBounds &lateral_bounds, const api::HBounds &height_bounds) const =0
Checks that there are no self-intersections (singularities) in the volume created by applying the constant lateral_bounds and height_bounds to the RoadCurve. More...

Does not allow copy, move, or assignment

## Protected Member Functions

RoadCurve (const CubicPolynomial &elevation, const CubicPolynomial &superelevation)
Constructs a road curve given elevation and superelevation curves. More...

## Detailed Description

Defines an interface for a path in a Segment object surface.

The path is defined by an elevation and superelevation CubicPolynomial objects and a reference curve. This reference curve is a C1 function over the z=0 plane. Its domain is constrained in [0;1] interval and it should map a ℝ² curve. As per notation, p is the parameter of the reference curve, and function interpolations and function derivatives as well as headings and heading derivatives are expressed in world coordinates, which is the same frame as api::GeoPosition. By implementing this interface the road curve is defined and a complete.

## Constructor & Destructor Documentation

delete
delete
virtualdefault
 RoadCurve ( const CubicPolynomial & elevation, const CubicPolynomial & superelevation )
inlineprotected

Constructs a road curve given elevation and superelevation curves.

Parameters
 elevation CubicPolynomial object that represents the elevation function (see below for more details). superelevation CubicPolynomial object that represents the superelevation function (see below for more details).

elevation and superelevation are cubic-polynomial functions which define the elevation and superelevation as a function of position along the planar reference curve. elevation specifies the z-component of the surface at (r,h) = (0,0). superelevation specifies the angle of the r-axis with respect to the horizon, i.e., how the road twists. Thus, non-zero superelevation contributes to the z-component at r != 0.

These two functions (elevation and superelevation) must be isotropically scaled to operate over the domain p in [0, 1], where p is linear in the path-length of the planar reference curve, p = 0 corresponds to the start and p = 1 to the end. p_scale() is the scale factor. In other words...

Given:

• a reference curve R(p) parameterized by p in domain [0, 1], which has a path-length q(p) in range [0, q_max], linearly related to p, where q_max is the total path-length of R (in real-world units);
• the true elevation function E_true(q), parameterized by the path-length q of R;
• the true superelevation function S_true(q), parameterized by the path-length q of R;

then:

• p_scale is q_max (and p = q / p_scale);
• elevation is E_scaled = (1 / p_scale) * E_true(p_scale * p);
• superelevation is S_scaled = (1 / p_scale) * S_true(p_scale * p).

## Member Function Documentation

 const CubicPolynomial& elevation ( ) const
inline

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 virtual double heading_dot_of_p ( double p ) const
pure virtual

Computes the first derivative heading of the reference curve.

Parameters
 p The reference curve parameter.
Returns
The derivative of the heading with respect to p, i.e., d_heading/dp evaluated at p.

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 virtual double heading_of_p ( double p ) const
pure virtual

Computes the heading of the reference curve.

Parameters
 p The reference curve parameter.
Returns
The heading of the curve at p, i.e., the angle of the tangent vector (with respect to x-axis) in the increasing-p direction.

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 virtual bool IsValid ( const api::RBounds & lateral_bounds, const api::HBounds & height_bounds ) const
pure virtual

Checks that there are no self-intersections (singularities) in the volume created by applying the constant lateral_bounds and height_bounds to the RoadCurve.

Parameters
 lateral_bounds An api::RBounds object that represents the lateral bounds of the surface mapping. height_bounds An api::HBounds object that represents the elevation bounds of the surface mapping.
Returns
True when there are no self-intersections.

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delete
delete
 virtual double p_scale ( ) const
pure virtual

Computes the path length integral of the reference curve for the interval [0;1] of p.

Returns
The path length integral of the reference curve.

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 const CubicPolynomial& superelevation ( ) const
inline

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 virtual Vector3 ToCurveFrame ( const Vector3< double > & geo_coordinate, const api::RBounds & lateral_bounds, const api::HBounds & height_bounds ) const
pure virtual

Converts a geo_coordinate in the world frame to the composed curve frame, i.e., the superposition of the reference curve, elevation and superelevation polynomials.

The resulting coordinates are saturated to lateral_bounds and height_bounds in the lateral and vertical directions over the composed curve trajectory. The path length coordinate is saturated in the interval [0; trajectory_length()].

Parameters
 geo_coordinate A 3D vector in the world frame to be converted to the composed curve frame. lateral_bounds An api::RBounds object that represents the lateral bounds of the surface mapping. height_bounds An api::HBounds object that represents the elevation bounds of the surface mapping.
Returns
A 3D vector that represents the coordinates with respect to the composed curve. The first dimension represents the path length coordinate, the second dimension is the lateral deviation from the composed curve and the third one is the vertical deviation from the composed curve too. The frame where this vector is defined is the same as api::LanePosition.

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 double trajectory_length ( ) const
inline

Computes the composed curve path integral in the interval of p = [0; 1].

Returns
The path length integral of the curve composed with the elevation polynomial.

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 virtual Vector2 xy_dot_of_p ( double p ) const
pure virtual

Computes the first derivative of the reference curve.

Parameters
 p The reference curve parameter.
Returns
The derivative of the curve with respect to p, at p, i.e., F'(p0) = (dx/dp, dy/dp) at p0.

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 virtual Vector2 xy_of_p ( double p ) const
pure virtual

Computes the reference curve.

Parameters
 p The reference curve parameter.
Returns
The reference curve itself, F(p).

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