End Constraints

End Constraints control when a path segment (and the overall path) is considered finished. All of the End Constraints are configured in ForesightConfig.

How Path Completion Works:
A path segment completes once the robot reaches the Parametric T threshold AND either:

The Translational, Heading, and Velocity conditions are all satisfied simultaneously, OR
The Timeout duration expires after parametric completion.

Parametric T

parametricTConstraint defines how close the robot's progress along the Bézier curve ( $t \in [0, 1]$ ) must be to 1 before the path segment is considered parametrically complete.

The default value is 0.025, meaning the closest t-value must reach at least 0.975.

c.parametricTConstraint.set(0.025);

Increasing this value allows the path to reach its parametric end earlier, while decreasing it requires the robot to get closer to t = 1.

Velocity

velocityConstraint sets the velocity threshold used while correcting at the final Pose. This prevents the path from completing when the robot is still moving fast.

The default value is 0.1 inches/second.

The robot's velocity must be lower than the threshold for the velocityConstraint to be met.

c.velocityConstraint.set(0.1);

Translational

translationalConstraint sets the maximum allowed distance between the robot's position and the final target position.

The default value is 0.1 inches.

c.translationalConstraint.set(0.1);

The translational error must be below this value for the translational constraint to be met.

Heading

headingConstraint sets the maximum allowed heading error between the robot's heading and the final target heading.

The value is in radians, and the default is 0.007 radians (~0.4 degrees).

c.headingConstraint.set(0.007);

Math.toRadians() can also be used when setting the value:

c.headingConstraint.set(Math.toRadians(0.4));

The heading error must be below this value for the heading constraint to be met.

Timeout

timeoutConstraint sets how long, in milliseconds, the follower is allowed to correct at the final Pose before the timeout constraint is met.

The default value is 100 milliseconds.

c.timeoutConstraint.set(100.0);

Increasing the timeout gives the robot more time to correct at the endpoint. Decreasing it allows the follower to finish sooner if the other endpoint constraints cannot be met.

Setting End Constraints

End Constraints can be changed in ForesightConfig alongside the other follower constants:

public static ForesightConfig foresightConfig = new ForesightConfig(
    c -> {
        c.parametricTConstraint.set(0.025);
        c.velocityConstraint.set(0.1);
        c.translationalConstraint.set(0.1);
        c.headingConstraint.set(0.007);
        c.timeoutConstraint.set(100.0);

        // Other Foresight constants...
    }
);

Path Completion

During path following, the current path reaches its parametric end when parametricTConstraint is met.

At the final endpoint, when endpoint holding is enabled, the follower corrects toward the final Pose. follower.isBusy() becomes false when the velocity, translational, and heading constraints are all met, or when the timeout is reached.

Tip

If the follower takes too long to finish at the endpoint, check the final position, heading, and velocity errors before changing the constraints. Increasing parametricTConstraint reaches the parametric end earlier, while decreasing timeoutConstraint reduces how long the follower continues correcting at the end.