Rotation Overrides¶

Temporarily replace BLine's rotational output while keeping its translation path following. Common uses include vision aiming, pointing an intake, or handing heading control to another controller during part of a path.

Start an override¶

The supplier returns angular velocity in radians per second and is sampled every follower cycle:

FollowPath.overrideRotation(
    shooterAimController::getOmegaRadiansPerSecond
);

The one-argument overload uses BYPASS_CONSTRAINTS: the supplied omega replaces the final follower omega after BLine's normal rotational limiting.

To retain BLine's rotation velocity/acceleration limits:

FollowPath.overrideRotation(
    shooterAimController::getOmegaRadiansPerSecond,
    FollowPath.RotationOverrideBehavior.RESPECT_CONSTRAINTS
);

Clear it reliably¶

The override is static and affects every FollowPath command until cleared.

Command aimedPath = Commands.sequence(
    Commands.runOnce(() -> FollowPath.overrideRotation(
        shooterAimController::getOmegaRadiansPerSecond,
        FollowPath.RotationOverrideBehavior.RESPECT_CONSTRAINTS
    )),
    pathBuilder.build(path)
).finallyDo(interrupted -> FollowPath.clearRotationOverride());

Attach cleanup to the whole wrapper, not only the path child: the routine could be canceled after setting the static override but before the path starts. Also clear it when leaving the robot mode if another owner can cancel or replace the wrapper.

Choose the behavior¶

Mode	Use when	Responsibility
`RESPECT_CONSTRAINTS`	The external controller provides the target omega, but project/path limits should still apply	BLine limits rotational velocity/acceleration
`BYPASS_CONSTRAINTS`	Another subsystem fully owns the final rotational command	Your code must enforce safe rate/acceleration limits

Translation remains rate-limited by BLine in both modes.

Completion still uses the authored path rotation¶

An override changes output, not the path's finish test. FollowPath still checks the active authored rotation target and end rotation tolerance.

An incompatible override can prevent completion

If vision aiming holds a heading different from the final waypoint, the path may reach its final position but never finish rotation. Add an event that clears the override before the endpoint, author a compatible final heading, or compose an intentional timeout/fallback. Interruption cleanup alone cannot solve a finish predicate that is waiting on the override.

Diagnose an override¶

Plot:

FollowPath/rotationOverrideActive
FollowPath/rotationOverrideBypassesConstraints
FollowPath/rotationOverrideOmegaRadPerSec
FollowPath/outputOmegaRadPerSec
FollowPath/targetRotationDeg
FollowPath/rotationErrorDeg
FollowPath/finishedRotationAtSetpoint

If outputOmegaRadPerSec differs from the supplier in RESPECT_CONSTRAINTS, inspect the active rotation max and acceleration. In bypass mode, they should match except for your own upstream logic.

Avoid global-state surprises¶

Set one override owner at a time.
Clear it in interruption cleanup.
Do not let two subsystems repeatedly overwrite the static supplier.
Test transition back to profiled path rotation.
Verify the final heading and finish behavior at full path speed.

See Logging & AdvantageScope and Handoffs, t-ratio & Completion.