chompCollisionOptions

Collision options for CHOMP trajectories

Since R2023a

Description

The chompCollisionOptions object stores collision options for Covariant Hamiltonian Optimization for Motion Planning (CHOMP) trajectories. Use this object to optimize a CHOMP trajectory to avoid collisions.

Creation

Syntax

OPTS = chompCollisionOptions

OPTS = chompCollisionOptions(Name=Value)

Description

OPTS = chompCollisionOptions creates a collision options object OPTS that you can use to optimize a CHOMP trajectory to avoid collisions.

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

Properties

CollisionClearance — Minimum distance to maintain from obstacles

1e-3 (default) | positive numeric scalar

Minimum distance to maintain from obstacles, specified as a positive numeric scalar.

SkippedSelfCollisions — Body pairs to omit from self-collision costs

"parent" (default) | "adjacent"

Body pairs to omit from self-collision costs, specified as either "parent" or "adjacent".

• "parent" — Skip collision checking between child and parent bodies.

• "adjacent" — Skip collision checking between bodies on adjacent indices.

Data Types: char | string

IgnoreSelfCollision — Weight on cost of ignoring self-collision avoidance

1 (default) | positive numeric scalar

Weight on cost of ignoring self-collision avoidance, specified as a numeric scalar.

CollisionCostWeight — Weight on cost of collision

10 (default) | positive numeric scalar

Weight on the cost of collision, specified as a positive numeric scalar.

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