core/com.acmerobotics.roadrunner.control/LQRController

LQRController

class LQRController : RobotPosVelController

A Linear Quadratic Regulator (LQR) for controlling a system modeled by state-space equations.

LQR is a form of optimal control that finds the best control input to apply to a system by minimizing a quadratic cost function. The cost function balances two competing goals:

  1. State Error: How far the system is from its desired target state (penalized by the Q matrix).

  2. Control Effort: How much energy or effort is used to control the system (penalized by the R matrix).

The controller computes the optimal control input u using a simple state-feedback law: u = -Kx, where x is the system's state error and K is the optimal gain matrix.

This should be used by holonomic robots only.

Thank you to Tyler Veness and WPILib!

See also

Constructors

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constructor(qX: Double, qY: Double, qHeading: Double, qVx: Double, qVy: Double, qOmega: Double, rAx: Double, rAy: Double, rAlpha: Double, dt: Double = 0.0303)

Constructor for the common holonomic robot control use case.

@JvmOverloads
constructor(A: Matrix, B: Matrix, Q: Matrix, R: Matrix, dt: Double = 0.0303)

General-purpose constructor for any linear time-invariant (LTI) system.

Functions

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open override fun compute(targetPose: Pose2dDual<Time>, actualPose: Pose2d, actualVelActual: PoseVelocity2d): PoseVelocity2dDual<Time>

Computes the velocity and acceleration command. The frame Target is the reference robot, and the frame Actual is the measured, physical robot.

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fun update(error: Matrix): Matrix

Calculates the optimal control input (accelerations) to correct for the given state error.

fun <Param : DualParameter> update(error: Twist2dDual<Param>): Acceleration2d

Calculates the optimal control input to correct for the given state error.