[wpimath] Make LTV controller constructors use faster DARE solver (#5543)

Made JNI modifications to expose the faster function, made the API use
the typesafe Matrix API, and synchronized the documentation with C++.

Sped up C++ LTV diff drive test from 20 ms to 15 ms.
Sped up C++ LTV unicycle test from 15 ms to 10 ms.
This commit is contained in:
Tyler Veness
2023-08-17 13:56:15 -07:00
committed by GitHub
parent 6953a303b3
commit 0cf6e37dc1
9 changed files with 596 additions and 220 deletions

View File

@@ -12,33 +12,122 @@ public final class DARE {
}
/**
* Solves the discrete algebraic Riccati equation.
* Computes the unique stabilizing solution X to the discrete-time algebraic Riccati equation.
*
* <p>AᵀXA X AᵀXB(BᵀXB + R)⁻¹BᵀXA + Q = 0
*
* <p>This internal function skips expensive precondition checks for increased performance. The
* solver may hang if any of the following occur:
*
* <ul>
* <li>Q isn't symmetric positive semidefinite
* <li>R isn't symmetric positive definite
* <li>The (A, B) pair isn't stabilizable
* <li>The (A, C) pair where Q = CᵀC isn't detectable
* </ul>
*
* <p>Only use this function if you're sure the preconditions are met.
*
* @param <States> Number of states.
* @param <Inputs> Number of inputs.
* @param A System matrix.
* @param B Input matrix.
* @param Q State cost matrix.
* @param R Input cost matrix.
* @return Solution of DARE.
* @throws IllegalArgumentException if Q isn't symmetric positive semidefinite.
* @throws IllegalArgumentException if R isn't symmetric positive definite.
* @throws IllegalArgumentException if the (A, B) pair isn't stabilizable.
* @throws IllegalArgumentException if the (A, C) pair where Q = CᵀC isn't detectable.
*/
public static SimpleMatrix dare(SimpleMatrix A, SimpleMatrix B, SimpleMatrix Q, SimpleMatrix R) {
var S = new SimpleMatrix(A.getNumRows(), A.getNumCols());
WPIMathJNI.dareABQR(
A.getDDRM().getData(),
B.getDDRM().getData(),
Q.getDDRM().getData(),
R.getDDRM().getData(),
public static <States extends Num, Inputs extends Num> Matrix<States, States> dareDetail(
Matrix<States, States> A,
Matrix<States, Inputs> B,
Matrix<States, States> Q,
Matrix<Inputs, Inputs> R) {
var S = new Matrix<States, States>(new SimpleMatrix(A.getNumRows(), A.getNumCols()));
WPIMathJNI.dareDetailABQR(
A.getStorage().getDDRM().getData(),
B.getStorage().getDDRM().getData(),
Q.getStorage().getDDRM().getData(),
R.getStorage().getDDRM().getData(),
A.getNumCols(),
B.getNumCols(),
S.getDDRM().getData());
S.getStorage().getDDRM().getData());
return S;
}
/**
* Solves the discrete algebraic Riccati equation.
* Computes the unique stabilizing solution X to the discrete-time algebraic Riccati equation.
*
* <p>AᵀXA X (AᵀXB + N)(BᵀXB + R)⁻¹(BᵀXA + Nᵀ) + Q = 0
*
* <p>This overload of the DARE is useful for finding the control law uₖ that minimizes the
* following cost function subject to xₖ₊₁ = Axₖ + Buₖ.
*
* <pre>
* ∞ [xₖ]ᵀ[Q N][xₖ]
* J = Σ [uₖ] [Nᵀ R][uₖ] ΔT
* k=0
* </pre>
*
* <p>This is a more general form of the following. The linear-quadratic regulator is the feedback
* control law uₖ that minimizes the following cost function subject to xₖ₊₁ = Axₖ + Buₖ:
*
* <pre>
* ∞
* J = Σ (xₖᵀQxₖ + uₖᵀRuₖ) ΔT
* k=0
* </pre>
*
* <p>This can be refactored as:
*
* <pre>
* ∞ [xₖ]ᵀ[Q 0][xₖ]
* J = Σ [uₖ] [0 R][uₖ] ΔT
* k=0
* </pre>
*
* <p>This internal function skips expensive precondition checks for increased performance. The
* solver may hang if any of the following occur:
*
* <ul>
* <li>Q NR⁻¹Nᵀ isn't symmetric positive semidefinite
* <li>R isn't symmetric positive definite
* <li>The (A, B) pair isn't stabilizable
* <li>The (A, C) pair where Q = CᵀC isn't detectable
* </ul>
*
* <p>Only use this function if you're sure the preconditions are met.
*
* @param <States> Number of states.
* @param <Inputs> Number of inputs.
* @param A System matrix.
* @param B Input matrix.
* @param Q State cost matrix.
* @param R Input cost matrix.
* @param N State-input cross-term cost matrix.
* @return Solution of DARE.
*/
public static <States extends Num, Inputs extends Num> Matrix<States, States> dareDetail(
Matrix<States, States> A,
Matrix<States, Inputs> B,
Matrix<States, States> Q,
Matrix<Inputs, Inputs> R,
Matrix<States, Inputs> N) {
var S = new Matrix<States, States>(new SimpleMatrix(A.getNumRows(), A.getNumCols()));
WPIMathJNI.dareDetailABQRN(
A.getStorage().getDDRM().getData(),
B.getStorage().getDDRM().getData(),
Q.getStorage().getDDRM().getData(),
R.getStorage().getDDRM().getData(),
N.getStorage().getDDRM().getData(),
A.getNumCols(),
B.getNumCols(),
S.getStorage().getDDRM().getData());
return S;
}
/**
* Computes the unique stabilizing solution X to the discrete-time algebraic Riccati equation.
*
* <p>AᵀXA X AᵀXB(BᵀXB + R)⁻¹BᵀXA + Q = 0
*
* @param <States> Number of states.
* @param <Inputs> Number of inputs.
@@ -57,40 +146,48 @@ public final class DARE {
Matrix<States, Inputs> B,
Matrix<States, States> Q,
Matrix<Inputs, Inputs> R) {
return new Matrix<>(dare(A.getStorage(), B.getStorage(), Q.getStorage(), R.getStorage()));
}
/**
* Solves the discrete algebraic Riccati equation.
*
* @param A System matrix.
* @param B Input matrix.
* @param Q State cost matrix.
* @param R Input cost matrix.
* @param N State-input cross-term cost matrix.
* @return Solution of DARE.
* @throws IllegalArgumentException if Q NR⁻¹Nᵀ isn't symmetric positive semidefinite.
* @throws IllegalArgumentException if R isn't symmetric positive definite.
* @throws IllegalArgumentException if the (A, B) pair isn't stabilizable.
* @throws IllegalArgumentException if the (A, C) pair where Q = CᵀC isn't detectable.
*/
public static SimpleMatrix dare(
SimpleMatrix A, SimpleMatrix B, SimpleMatrix Q, SimpleMatrix R, SimpleMatrix N) {
var S = new SimpleMatrix(A.getNumRows(), A.getNumCols());
WPIMathJNI.dareABQRN(
A.getDDRM().getData(),
B.getDDRM().getData(),
Q.getDDRM().getData(),
R.getDDRM().getData(),
N.getDDRM().getData(),
var S = new Matrix<States, States>(new SimpleMatrix(A.getNumRows(), A.getNumCols()));
WPIMathJNI.dareABQR(
A.getStorage().getDDRM().getData(),
B.getStorage().getDDRM().getData(),
Q.getStorage().getDDRM().getData(),
R.getStorage().getDDRM().getData(),
A.getNumCols(),
B.getNumCols(),
S.getDDRM().getData());
S.getStorage().getDDRM().getData());
return S;
}
/**
* Solves the discrete algebraic Riccati equation.
* Computes the unique stabilizing solution X to the discrete-time algebraic Riccati equation.
*
* <p>AᵀXA X (AᵀXB + N)(BᵀXB + R)⁻¹(BᵀXA + Nᵀ) + Q = 0
*
* <p>This overload of the DARE is useful for finding the control law uₖ that minimizes the
* following cost function subject to xₖ₊₁ = Axₖ + Buₖ.
*
* <pre>
* ∞ [xₖ]ᵀ[Q N][xₖ]
* J = Σ [uₖ] [Nᵀ R][uₖ] ΔT
* k=0
* </pre>
*
* <p>This is a more general form of the following. The linear-quadratic regulator is the feedback
* control law uₖ that minimizes the following cost function subject to xₖ₊₁ = Axₖ + Buₖ:
*
* <pre>
* ∞
* J = Σ (xₖᵀQxₖ + uₖᵀRuₖ) ΔT
* k=0
* </pre>
*
* <p>This can be refactored as:
*
* <pre>
* ∞ [xₖ]ᵀ[Q 0][xₖ]
* J = Σ [uₖ] [0 R][uₖ] ΔT
* k=0
* </pre>
*
* @param <States> Number of states.
* @param <Inputs> Number of inputs.
@@ -111,7 +208,16 @@ public final class DARE {
Matrix<States, States> Q,
Matrix<Inputs, Inputs> R,
Matrix<States, Inputs> N) {
return new Matrix<>(
dare(A.getStorage(), B.getStorage(), Q.getStorage(), R.getStorage(), N.getStorage()));
var S = new Matrix<States, States>(new SimpleMatrix(A.getNumRows(), A.getNumCols()));
WPIMathJNI.dareABQRN(
A.getStorage().getDDRM().getData(),
B.getStorage().getDDRM().getData(),
Q.getStorage().getDDRM().getData(),
R.getStorage().getDDRM().getData(),
N.getStorage().getDDRM().getData(),
A.getNumCols(),
B.getNumCols(),
S.getStorage().getDDRM().getData());
return S;
}
}

View File

@@ -38,6 +38,18 @@ public class Matrix<R extends Num, C extends Num> {
Objects.requireNonNull(rows).getNum(), Objects.requireNonNull(columns).getNum());
}
/**
* Constructs a new {@link Matrix} with the given storage. Caller should make sure that the
* provided generic bounds match the shape of the provided {@link Matrix}.
*
* @param rows The number of rows of the matrix.
* @param columns The number of columns of the matrix.
* @param storage The double array to back this value.
*/
public Matrix(Nat<R> rows, Nat<C> columns, double[] storage) {
this.m_storage = new SimpleMatrix(rows.getNum(), columns.getNum(), true, storage);
}
/**
* Constructs a new {@link Matrix} with the given storage. Caller should make sure that the
* provided generic bounds match the shape of the provided {@link Matrix}.

View File

@@ -44,7 +44,100 @@ public final class WPIMathJNI {
}
/**
* Solves the discrete alegebraic Riccati equation.
* Computes the unique stabilizing solution X to the discrete-time algebraic Riccati equation.
*
* <p>AᵀXA X AᵀXB(BᵀXB + R)⁻¹BᵀXA + Q = 0
*
* <p>This internal function skips expensive precondition checks for increased performance. The
* solver may hang if any of the following occur:
*
* <ul>
* <li>Q isn't symmetric positive semidefinite
* <li>R isn't symmetric positive definite
* <li>The (A, B) pair isn't stabilizable
* <li>The (A, C) pair where Q = CᵀC isn't detectable
* </ul>
*
* <p>Only use this function if you're sure the preconditions are met. Solves the discrete
* alegebraic Riccati equation.
*
* @param A Array containing elements of A in row-major order.
* @param B Array containing elements of B in row-major order.
* @param Q Array containing elements of Q in row-major order.
* @param R Array containing elements of R in row-major order.
* @param states Number of states in A matrix.
* @param inputs Number of inputs in B matrix.
* @param S Array storage for DARE solution.
*/
public static native void dareDetailABQR(
double[] A, double[] B, double[] Q, double[] R, int states, int inputs, double[] S);
/**
* Computes the unique stabilizing solution X to the discrete-time algebraic Riccati equation.
*
* <p>AᵀXA X (AᵀXB + N)(BᵀXB + R)⁻¹(BᵀXA + Nᵀ) + Q = 0
*
* <p>This overload of the DARE is useful for finding the control law uₖ that minimizes the
* following cost function subject to xₖ₊₁ = Axₖ + Buₖ.
*
* <pre>
* ∞ [xₖ]ᵀ[Q N][xₖ]
* J = Σ [uₖ] [Nᵀ R][uₖ] ΔT
* k=0
* </pre>
*
* <p>This is a more general form of the following. The linear-quadratic regulator is the feedback
* control law uₖ that minimizes the following cost function subject to xₖ₊₁ = Axₖ + Buₖ:
*
* <pre>
* ∞
* J = Σ (xₖᵀQxₖ + uₖᵀRuₖ) ΔT
* k=0
* </pre>
*
* <p>This can be refactored as:
*
* <pre>
* ∞ [xₖ]ᵀ[Q 0][xₖ]
* J = Σ [uₖ] [0 R][uₖ] ΔT
* k=0
* </pre>
*
* <p>This internal function skips expensive precondition checks for increased performance. The
* solver may hang if any of the following occur:
*
* <ul>
* <li>Q NR⁻¹Nᵀ isn't symmetric positive semidefinite
* <li>R isn't symmetric positive definite
* <li>The (A, B) pair isn't stabilizable
* <li>The (A, C) pair where Q = CᵀC isn't detectable
* </ul>
*
* <p>Only use this function if you're sure the preconditions are met.
*
* @param A Array containing elements of A in row-major order.
* @param B Array containing elements of B in row-major order.
* @param Q Array containing elements of Q in row-major order.
* @param R Array containing elements of R in row-major order.
* @param N Array containing elements of N in row-major order.
* @param states Number of states in A matrix.
* @param inputs Number of inputs in B matrix.
* @param S Array storage for DARE solution.
*/
public static native void dareDetailABQRN(
double[] A,
double[] B,
double[] Q,
double[] R,
double[] N,
int states,
int inputs,
double[] S);
/**
* Computes the unique stabilizing solution X to the discrete-time algebraic Riccati equation.
*
* <p>AᵀXA X AᵀXB(BᵀXB + R)⁻¹BᵀXA + Q = 0
*
* @param A Array containing elements of A in row-major order.
* @param B Array containing elements of B in row-major order.
@@ -62,7 +155,35 @@ public final class WPIMathJNI {
double[] A, double[] B, double[] Q, double[] R, int states, int inputs, double[] S);
/**
* Solves the discrete alegebraic Riccati equation.
* Computes the unique stabilizing solution X to the discrete-time algebraic Riccati equation.
*
* <p>AᵀXA X (AᵀXB + N)(BᵀXB + R)⁻¹(BᵀXA + Nᵀ) + Q = 0
*
* <p>This overload of the DARE is useful for finding the control law uₖ that minimizes the
* following cost function subject to xₖ₊₁ = Axₖ + Buₖ.
*
* <pre>
* ∞ [xₖ]ᵀ[Q N][xₖ]
* J = Σ [uₖ] [Nᵀ R][uₖ] ΔT
* k=0
* </pre>
*
* <p>This is a more general form of the following. The linear-quadratic regulator is the feedback
* control law uₖ that minimizes the following cost function subject to xₖ₊₁ = Axₖ + Buₖ:
*
* <pre>
* ∞
* J = Σ (xₖᵀQxₖ + uₖᵀRuₖ) ΔT
* k=0
* </pre>
*
* <p>This can be refactored as:
*
* <pre>
* ∞ [xₖ]ᵀ[Q 0][xₖ]
* J = Σ [uₖ] [0 R][uₖ] ΔT
* k=0
* </pre>
*
* @param A Array containing elements of A in row-major order.
* @param B Array containing elements of B in row-major order.

View File

@@ -4,6 +4,7 @@
package edu.wpi.first.math.controller;
import edu.wpi.first.math.DARE;
import edu.wpi.first.math.InterpolatingMatrixTreeMap;
import edu.wpi.first.math.MatBuilder;
import edu.wpi.first.math.MathUtil;
@@ -15,6 +16,7 @@ import edu.wpi.first.math.geometry.Pose2d;
import edu.wpi.first.math.numbers.N1;
import edu.wpi.first.math.numbers.N2;
import edu.wpi.first.math.numbers.N5;
import edu.wpi.first.math.system.Discretization;
import edu.wpi.first.math.system.LinearSystem;
import edu.wpi.first.math.trajectory.Trajectory;
@@ -146,11 +148,26 @@ public class LTVDifferentialDriveController {
// The DARE is ill-conditioned if the velocity is close to zero, so don't
// let the system stop.
if (Math.abs(velocity) < 1e-4) {
m_table.put(velocity, new Matrix<>(Nat.N2(), Nat.N5()));
A.set(State.kY.value, State.kHeading.value, 1e-4);
} else {
A.set(State.kY.value, State.kHeading.value, velocity);
m_table.put(velocity, new LinearQuadraticRegulator<N5, N2, N5>(A, B, Q, R, dt).getK());
}
var discABPair = Discretization.discretizeAB(A, B, dt);
var discA = discABPair.getFirst();
var discB = discABPair.getSecond();
var S = DARE.dareDetail(discA, discB, Q, R);
// K = (BᵀSB + R)⁻¹BᵀSA
m_table.put(
velocity,
discB
.transpose()
.times(S)
.times(discB)
.plus(R)
.solve(discB.transpose().times(S).times(discA)));
}
}

View File

@@ -4,6 +4,7 @@
package edu.wpi.first.math.controller;
import edu.wpi.first.math.DARE;
import edu.wpi.first.math.InterpolatingMatrixTreeMap;
import edu.wpi.first.math.MatBuilder;
import edu.wpi.first.math.Matrix;
@@ -15,6 +16,7 @@ import edu.wpi.first.math.geometry.Pose2d;
import edu.wpi.first.math.kinematics.ChassisSpeeds;
import edu.wpi.first.math.numbers.N2;
import edu.wpi.first.math.numbers.N3;
import edu.wpi.first.math.system.Discretization;
import edu.wpi.first.math.trajectory.Trajectory;
/**
@@ -152,11 +154,26 @@ public class LTVUnicycleController {
// The DARE is ill-conditioned if the velocity is close to zero, so don't
// let the system stop.
if (Math.abs(velocity) < 1e-4) {
m_table.put(velocity, new Matrix<>(Nat.N2(), Nat.N3()));
A.set(State.kY.value, State.kHeading.value, 1e-4);
} else {
A.set(State.kY.value, State.kHeading.value, velocity);
m_table.put(velocity, new LinearQuadraticRegulator<N3, N2, N3>(A, B, Q, R, dt).getK());
}
var discABPair = Discretization.discretizeAB(A, B, dt);
var discA = discABPair.getFirst();
var discB = discABPair.getSecond();
var S = DARE.dareDetail(discA, discB, Q, R);
// K = (BᵀSB + R)⁻¹BᵀSA
m_table.put(
velocity,
discB
.transpose()
.times(S)
.times(discB)
.plus(R)
.solve(discB.transpose().times(S).times(discA)));
}
}