chompSmoothnessOptions

Smoothness options for CHOMP trajectories

Since R2023a

Description

The chompSmoothnessOptions object stores smoothness options that determine how to weight smoothness costs for trajectories generated using Covariant Hamiltonian Optimization for Motion Planning (CHOMP). Use this object to optimize the smoothness of a trajectory generated using CHOMP.

Creation

Syntax

OPTS = chompSmoothnessOptions

OPTS = chompSmoothnessOptions(Name=Value)

Description

OPTS = chompSmoothnessOptions creates a smoothness options object OPTS that you can use to optimize the smoothness of a trajectory using CHOMP.

OPTS = chompSmoothnessOptions(Name=Value) specifies properties using one or more name-value arguments.

Properties

VelocitySmoothnessWeight — Weight on velocity smoothness of trajectory

1 (default) | nonnegative numeric scalar

Weight on the velocity smoothness cost of the trajectory, specified as a nonnegative numeric scalar. This is a weight on the cost obtained by the summation of squared velocity along the trajectory.

AccelerationSmoothnessWeight — Weight on acceleration smoothness of trajectory

1 (default) | nonnegative numeric scalar

Weight on the acceleration smoothness cost of the trajectory, specified as a nonnegative numeric scalar. This is a weight on the cost obtained by the summation of squared acceleration along the trajectory.

JerkSmoothnessWeight — Weight on jerk smoothness of trajectory

1 (default) | nonnegative numeric scalar

Weight on the jerk smoothness cost of the trajectory, specified as a nonnegative numeric scalar. This is a weight on the cost obtained by the summation of squared jerk along the trajectory.

SmoothnessCostWeight — Weight on overall smoothness of trajectory

1e-3 (default) | nonnegative numeric scalar

Weight on the overall smoothness of the trajectory, specified as a nonnegative numeric scalar. This is a weight on the cost obtained by the summation of the velocity, jerk, and acceleration smoothness costs.

Examples

Optimize Collision-Free Trajectory with CHOMP

Load a robot model into the workspace, and create a CHOMP solver.

robot = loadrobot("kinovaGen3",DataFormat="row");
chomp = manipulatorCHOMP(robot);

Create spheres to represent obstacles, and add them to the CHOMP solver.

env = [0.20 0.2 -0.1 -0.1;   % sphere, radius 0.20 at (0.2,-0.1,-0.1)
       0.15 0.2  0.0  0.5]'; % sphere, radius 0.15 at (0.2,0.0,0.5)
chomp.SphericalObstacles = env;

To prioritize a collision-free trajectory, set the smoothness cost weight to a lower value than the collision cost weight. Then add the options to the CHOMP solver.

chomp.SmoothnessOptions = chompSmoothnessOptions(SmoothnessCostWeight=1e-3);
chomp.CollisionOptions = chompCollisionOptions(CollisionCostWeight=10);
chomp.SolverOptions = chompSolverOptions(Verbosity="none",LearningRate=7.0);

Initialize a trajectory, optimize it using the CHOMP solver, and show the waypoints in a figure.

startconfig = homeConfiguration(robot);
goalconfig = [0.5 1.75 -2.25 2.0 0.3 -1.65 -0.4];
timepoints = [0 5];
timestep = 0.1;
trajtype = "minjerkpolytraj";
[wptsamples,tsamples] = optimize(chomp, ...
    [startconfig; goalconfig], ...
    timepoints, ...
    timestep, ...
    InitialTrajectoryFitType=trajtype);
show(chomp,wptsamples,NumSamples=10);
zlim([-0.5 1.3])

References

[1] Ratliff, Nathan, Siddhartha Srinivasa, Matt Zucker, and Andrew Bagnell. “CHOMP: Gradient Optimization Techniques for Efficient Motion Planning.” In 2009 IEEE International Conference on Robotics and Automation, 489–94. Kobe, Japan: IEEE, 2009. https://doi.org/10.1109/ROBOT.2009.5152817.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

Version History

Introduced in R2023a