Configure Motion Constraints

You can constrain the motion of your robot using the Motion Service’s built-in constraint options. Constraints are passed as arguments to the Move method.

The following constraints are available:

Linear Constraint

The linear constraint ({"motion_profile": "linear"}) forces the path taken by component_name to follow an exact linear path from the start to the goal. If the start and goal orientations are different, the orientation along the path will follow the quaternion Slerp (Spherical Linear Interpolation) of the orientation from start to goal. This has the following sub-options:

Parameter NameTypeDefaultDescription
line_tolerancefloat0.1Max linear deviation from straight-line between start and goal, in mm.
orient_tolerancefloat0.05Allowable deviation from Slerp between start/goal orientations, unit is the norm of the R3AA between start and goal.

Example usage:

# Move a gripper with a linear constraint
moved = await motion.move(
    component_name=my_gripper,
    destination=PoseInFrame(
        reference_frame="myFrame",
        pose=goal_pose), 
    world_state=worldState, 
    constraints={
        "motion_profile": "linear", 
        "line_tolerance": 0.2
     },
     extra={})

Orientation Constraint

The orientation constraint ({"motion_profile": "orientation"}) places a restriction on the orientation change during a motion, such that the orientation during the motion does not deviate from the Slerp between start and goal by more than a set amount. This is similar to the “orient_tolerance” option in the linear profile, but without any path restrictions. If set to zero, a movement with identical starting and ending orientations will hold that orientation throughout the movement.

Parameter NameTypeDefaultDescription
tolerancefloat0.05Allowable deviation from Slerp between start/goal orientations, unit is the norm of the R3AA between start and goal.

Example usage:

## Move a gripper with an orientation constraint
moved = await motion.move(
    component_name=my_gripper, 
    destination=PoseInFrame(
        reference_frame="myFrame",
        pose=goal_pose),
    world_state=worldState,
    constraints={"motion_profile": "orientation"},
    extra={})


Have questions, or want to meet other people working on robots? Join our Community Discord.