Class PathParameterizerTOPPRA

Class Documentation

class PathParameterizerTOPPRA

Trajectory time parameterizer using the TOPP-RA algorithm.

This directly uses https://github.com/hungpham2511/toppra.

Public Functions

PathParameterizerTOPPRA(const std::shared_ptr<Scene> scene, const std::string &group_name = "")

Constructor.

Parameters:

  • scene – A pointer to the scene to use for path parameterization.

  • group_name – The name of the joint group to use.

tl::expected<JointTrajectory, std::string> generate(const JointPath &path, const double dt, const SplineFittingMode mode = SplineFittingMode::Hermite, const double velocity_scale = 1.0, const double acceleration_scale = 1.0, const int max_adaptive_iterations = 10, const double max_adaptive_step_size = 0.05)

Time-parameterizes a joint-space path using TOPP-RA.

  • SplineFittingMode::Hermite: Fits a cubic Hermite spline with zero velocity at all waypoints. This can cause slow execution, but guarantees perfect adherence to the path.

  • SplineFittingMode::Cubic: Fits a cubic spline with zero velocity only at the endpoints. This is smoother, but can cause deviations from the desired path that could lead to collision.

  • SplineFittingMode::Adaptive: Uses the cubic mode but iteratively collision checks and adds intermediate points if it finds collisions, up to a maximum number of iterations. If the path is not collision-free after the maximum iterations, falls back to Hermite mode. Refer to Section 3.5 of https://groups.csail.mit.edu/rrg/papers/Richter_ISRR13.pdf for more details on this approach.

Parameters:

  • velocity_scale – A scaling factor (between 0 and 1) for velocity limits.

  • acceleration_scale – A scaling factor (between 0 and 1) for acceleration limits.

  • max_adaptive_iterations – Maximum number of adaptive iterations, if adaptive mode is enabled.

  • max_adaptive_step_size – If adaptive mode is enabled, this is the maximum joint configuration step size to sample generated splines for collision checking.

  • path – The path to time parameterize.

  • dt – The sample time of the output trajectory, in seconds.

  • mode – The mode to use for spline fitting the path. Options include:

Returns:

A time-parameterized joint trajectory.