[sysid] Fix wrong position Kd with unnormalized time (#6433)

Fix typo.

.github/workflows/cmake.yml

@@ -88,28 +88,13 @@ jobs:
         uses: lukka/run-vcpkg@v11.1
         with:
           vcpkgDirectory: ${{ runner.workspace }}/vcpkg
-          vcpkgGitCommitId: 78b61582c9e093fda56a01ebb654be15a0033897 # HEAD on 2023-08-6
+          vcpkgGitCommitId: 37c3e63a1306562f7f59c4c3c8892ddd50fdf992 # HEAD on 2024-02-24
 
       - name: configure
         run: cmake -S . -B build -G "Ninja" -DCMAKE_C_COMPILER_LAUNCHER=sccache -DCMAKE_CXX_COMPILER_LAUNCHER=sccache -DCMAKE_BUILD_TYPE=Release -DWITH_JAVA=OFF -DWITH_EXAMPLES=ON -DUSE_SYSTEM_FMTLIB=ON -DUSE_SYSTEM_LIBUV=ON -DUSE_SYSTEM_EIGEN=OFF -DCMAKE_TOOLCHAIN_FILE=${{ runner.workspace }}/vcpkg/scripts/buildsystems/vcpkg.cmake -DVCPKG_INSTALL_OPTIONS=--clean-after-build -DVCPKG_TARGET_TRIPLET=x64-windows-release -DVCPKG_HOST_TRIPLET=x64-windows-release
         env:
           SCCACHE_GHA_ENABLED: "true"
 
-      # Build wpiutil at full speed, wpimath depends on wpiutil
-      - name: build wpiutil
-        working-directory: build
-        run: cmake --build . --parallel $(nproc) --target wpiutil/all
-        env:
-          SCCACHE_GHA_ENABLED: "true"
-
-      # Build wpimath slow to prevent OOM
-      - name: build wpimath
-        working-directory: build
-        run: cmake --build . --parallel 1 --target wpimath/all
-        env:
-          SCCACHE_GHA_ENABLED: "true"
-
-      # Build everything else fast
       - name: build
         working-directory: build
         run: cmake --build . --parallel $(nproc)

.github/workflows/lint-format.yml

@@ -27,7 +27,7 @@ jobs:
         with:
           python-version: 3.8
       - name: Install wpiformat
-        run: pip3 install wpiformat==2023.36
+        run: pip3 install wpiformat==2024.32
       - name: Run
         run: wpiformat
       - name: Check output

hal/src/main/java/edu/wpi/first/hal/HAL.java

@@ -75,6 +75,9 @@ public final class HAL extends JNIWrapper {
    */
   public static native void exitMain();
 
+  /** Terminates the executable (at the native level). Does nothing in simulation. */
+  public static native void terminate();
+
   private static native void simPeriodicBeforeNative();
 
   private static final List<Runnable> s_simPeriodicBefore = new ArrayList<>();

hal/src/main/java/edu/wpi/first/hal/PowerDistributionJNI.java

@@ -83,6 +83,8 @@ public class PowerDistributionJNI extends JNIWrapper {
   /**
    * Gets the temperature of the PowerDistribution.
    *
+   * <p>Not supported on the Rev PDH and returns 0.
+   *
    * @param handle the module handle
    * @return the module temperature (celsius)
    * @see "HAL_GetPowerDistributionTemperature"
@@ -129,7 +131,9 @@ public class PowerDistributionJNI extends JNIWrapper {
   public static native double getTotalCurrent(int handle);
 
   /**
-   * Gets the total power of the PowerDistribution.
+   * Gets the total power of the Power Distribution Panel.
+   *
+   * <p>Not supported on the Rev PDH and returns 0.
    *
    * @param handle the module handle
    * @return the total power (watts)
@@ -138,7 +142,9 @@ public class PowerDistributionJNI extends JNIWrapper {
   public static native double getTotalPower(int handle);
 
   /**
-   * Gets the total energy of the PowerDistribution.
+   * Gets the total energy of the Power Distribution Panel.
+   *
+   * <p>Not supported on the Rev PDH and does nothing.
    *
    * @param handle the module handle
    * @return the total energy (joules)
@@ -147,7 +153,9 @@ public class PowerDistributionJNI extends JNIWrapper {
   public static native double getTotalEnergy(int handle);
 
   /**
-   * Resets the PowerDistribution accumulated energy.
+   * Resets the Power Distribution Panel accumulated energy.
+   *
+   * <p>Not supported on the Rev PDH and returns 0.
    *
    * @param handle the module handle
    * @see "HAL_ClearPowerDistributionStickyFaults"

hal/src/main/native/athena/HAL.cpp

@@ -594,6 +594,14 @@ HAL_Bool HAL_Initialize(int32_t timeout, int32_t mode) {
   });
 
   if (!SetupNowRio()) {
+    fmt::print(stderr,
+               "Failed to run SetupNowRio(). This is a fatal error. The "
+               "process is being terminated.\n");
+    std::fflush(stderr);
+    // Attempt to force a segfault to get a better java log
+    *reinterpret_cast<int*>(0) = 0;
+    // If that fails, terminate
+    std::terminate();
     return false;
   }
 

hal/src/main/native/cpp/jni/HAL.cpp

@@ -6,6 +6,10 @@
 
 #include <jni.h>
 
+#ifdef __FRC_ROBORIO__
+#include <signal.h>
+#endif
+
 #include <cassert>
 #include <cstring>
 
@@ -82,6 +86,20 @@ Java_edu_wpi_first_hal_HAL_exitMain
   HAL_ExitMain();
 }
 
+/*
+ * Class:     edu_wpi_first_hal_HAL
+ * Method:    terminate
+ * Signature: ()V
+ */
+JNIEXPORT void JNICALL
+Java_edu_wpi_first_hal_HAL_terminate
+  (JNIEnv*, jclass)
+{
+#ifdef __FRC_ROBORIO__
+  ::raise(SIGKILL);
+#endif
+}
+
 /*
  * Class:     edu_wpi_first_hal_HAL
  * Method:    simPeriodicBeforeNative

hal/src/main/native/include/hal/PowerDistribution.h

@@ -101,7 +101,9 @@ int32_t HAL_GetPowerDistributionNumChannels(HAL_PowerDistributionHandle handle,
                                             int32_t* status);
 
 /**
- * Gets the temperature of the PowerDistribution.
+ * Gets the temperature of the Power Distribution Panel.
+ *
+ * Not supported on the Rev PDH and returns 0.
  *
  * @param[in] handle the module handle
  * @param[out] status Error status variable. 0 on success.
@@ -156,7 +158,9 @@ double HAL_GetPowerDistributionTotalCurrent(HAL_PowerDistributionHandle handle,
                                             int32_t* status);
 
 /**
- * Gets the total power of the PowerDistribution.
+ * Gets the total power of the Power Distribution Panel.
+ *
+ * Not supported on the Rev PDH and returns 0.
  *
  * @param[in] handle the module handle
  * @param[out] status Error status variable. 0 on success.
@@ -166,7 +170,9 @@ double HAL_GetPowerDistributionTotalPower(HAL_PowerDistributionHandle handle,
                                           int32_t* status);
 
 /**
- * Gets the total energy of the PowerDistribution.
+ * Gets the total energy of the Power Distribution Panel.
+ *
+ * Not supported on the Rev PDH and returns 0.
  *
  * @param[in] handle the module handle
  * @param[out] status Error status variable. 0 on success.
@@ -178,6 +184,8 @@ double HAL_GetPowerDistributionTotalEnergy(HAL_PowerDistributionHandle handle,
 /**
  * Resets the PowerDistribution accumulated energy.
  *
+ * Not supported on the Rev PDH and does nothing.
+ *
  * @param[in] handle the module handle
  * @param[out] status Error status variable. 0 on success.
  */

simulation/halsim_gui/src/main/native/cpp/main.cpp

@@ -51,6 +51,8 @@ __declspec(dllexport)
 
   glass::SetStorageName("simgui");
 
+  gui::AddInit([] { ImGui::GetIO().ConfigDockingWithShift = true; });
+
   HAL_RegisterExtension(HALSIMGUI_EXT_ADDGUIINIT,
                         reinterpret_cast<void*>((AddGuiInitFn)&AddGuiInit));
   HAL_RegisterExtension(

sysid/src/main/native/cpp/analysis/FeedbackAnalysis.cpp

@@ -4,9 +4,10 @@
 
 #include "sysid/analysis/FeedbackAnalysis.h"
 
+#include <cmath>
+
 #include <frc/controller/LinearQuadraticRegulator.h>
 #include <frc/system/LinearSystem.h>
-#include <frc/system/plant/LinearSystemId.h>
 #include <units/acceleration.h>
 #include <units/velocity.h>
 #include <units/voltage.h>
@@ -21,22 +22,30 @@ using Ka_t = decltype(1_V / 1_mps_sq);
 FeedbackGains sysid::CalculatePositionFeedbackGains(
     const FeedbackControllerPreset& preset, const LQRParameters& params,
     double Kv, double Ka) {
+  if (!std::isfinite(Kv) || !std::isfinite(Ka)) {
+    return {0.0, 0.0};
+  }
+
   // If acceleration requires no effort, velocity becomes an input for position
   // control. We choose an appropriate model in this case to avoid numerical
   // instabilities in the LQR.
   if (Ka > 1E-7) {
     // Create a position system from our feedforward gains.
-    auto system = frc::LinearSystemId::IdentifyPositionSystem<units::meter>(
-        Kv_t(Kv), Ka_t(Ka));
+    frc::LinearSystem<2, 1, 1> system{
+        frc::Matrixd<2, 2>{{0.0, 1.0}, {0.0, -Kv / Ka}},
+        frc::Matrixd<2, 1>{0.0, 1.0 / Ka}, frc::Matrixd<1, 2>{1.0, 0.0},
+        frc::Matrixd<1, 1>{0.0}};
     // Create an LQR with 2 states to control -- position and velocity.
     frc::LinearQuadraticRegulator<2, 1> controller{
         system, {params.qp, params.qv}, {params.r}, preset.period};
     // Compensate for any latency from sensor measurements, filtering, etc.
-    controller.LatencyCompensate(system, preset.period, 0.0_s);
+    controller.LatencyCompensate(system, preset.period,
+                                 preset.measurementDelay);
 
-    return {controller.K(0, 0) * preset.outputConversionFactor,
-            controller.K(0, 1) * preset.outputConversionFactor /
-                (preset.normalized ? 1 : preset.period.value())};
+    return {
+        controller.K(0, 0) * preset.outputConversionFactor,
+        controller.K(0, 1) * preset.outputConversionFactor /
+            (preset.normalized ? 1 : units::second_t{preset.period}.value())};
   }
 
   // This is our special model to avoid instabilities in the LQR.
@@ -47,7 +56,7 @@ FeedbackGains sysid::CalculatePositionFeedbackGains(
   frc::LinearQuadraticRegulator<1, 1> controller{
       system, {params.qp}, {params.r}, preset.period};
   // Compensate for any latency from sensor measurements, filtering, etc.
-  controller.LatencyCompensate(system, preset.period, 0.0_s);
+  controller.LatencyCompensate(system, preset.period, preset.measurementDelay);
 
   return {Kv * controller.K(0, 0) * preset.outputConversionFactor, 0.0};
 }
@@ -55,6 +64,10 @@ FeedbackGains sysid::CalculatePositionFeedbackGains(
 FeedbackGains sysid::CalculateVelocityFeedbackGains(
     const FeedbackControllerPreset& preset, const LQRParameters& params,
     double Kv, double Ka, double encFactor) {
+  if (!std::isfinite(Kv) || !std::isfinite(Ka)) {
+    return {0.0, 0.0};
+  }
+
   // If acceleration for velocity control requires no effort, the feedback
   // control gains approach zero. We special-case it here because numerical
   // instabilities arise in LQR otherwise.
@@ -63,8 +76,9 @@ FeedbackGains sysid::CalculateVelocityFeedbackGains(
   }
 
   // Create a velocity system from our feedforward gains.
-  auto system = frc::LinearSystemId::IdentifyVelocitySystem<units::meter>(
-      Kv_t(Kv), Ka_t(Ka));
+  frc::LinearSystem<1, 1, 1> system{
+      frc::Matrixd<1, 1>{-Kv / Ka}, frc::Matrixd<1, 1>{1.0 / Ka},
+      frc::Matrixd<1, 1>{1.0}, frc::Matrixd<1, 1>{0.0}};
   // Create an LQR controller with 1 state -- velocity.
   frc::LinearQuadraticRegulator<1, 1> controller{
       system, {params.qv}, {params.r}, preset.period};

sysid/src/main/native/include/sysid/analysis/ArmSim.h

@@ -33,7 +33,7 @@ class ArmSim {
    * forward dt seconds.
    *
    * @param voltage Voltage to apply over the timestep.
-   * @param dt      Sammple period.
+   * @param dt      Sample period.
    */
   void Update(units::volt_t voltage, units::second_t dt);
 

sysid/src/main/native/include/sysid/analysis/ElevatorSim.h

@@ -31,7 +31,7 @@ class ElevatorSim {
    * dt seconds.
    *
    * @param voltage Voltage to apply over the timestep.
-   * @param dt      Sammple period.
+   * @param dt      Sample period.
    */
   void Update(units::volt_t voltage, units::second_t dt);
 

sysid/src/main/native/include/sysid/analysis/SimpleMotorSim.h

@@ -30,7 +30,7 @@ class SimpleMotorSim {
    * seconds.
    *
    * @param voltage Voltage to apply over the timestep.
-   * @param dt      Sammple period.
+   * @param dt      Sample period.
    */
   void Update(units::volt_t voltage, units::second_t dt);
 

sysid/src/test/native/cpp/analysis/FeedbackAnalysisTest.cpp

@@ -103,3 +103,43 @@ TEST(FeedbackAnalysisTest, VelocityREVConversion) {
   EXPECT_NEAR(Kp, 0.00241 / 3, 0.005);
   EXPECT_NEAR(Kd, 0.00, 0.05);
 }
+
+TEST(FeedbackAnalysisTest, Position) {
+  auto Kv = 3.060;
+  auto Ka = 0.327;
+
+  sysid::LQRParameters params{1, 1.5, 7};
+
+  auto [Kp, Kd] = sysid::CalculatePositionFeedbackGains(
+      sysid::presets::kDefault, params, Kv, Ka);
+
+  EXPECT_NEAR(Kp, 6.41, 0.05);
+  EXPECT_NEAR(Kd, 2.48, 0.05);
+}
+
+TEST(FeedbackAnalysisTest, PositionWithLatencyCompensation) {
+  auto Kv = 3.060;
+  auto Ka = 0.327;
+
+  sysid::LQRParameters params{1, 1.5, 7};
+  sysid::FeedbackControllerPreset preset{sysid::presets::kDefault};
+
+  preset.measurementDelay = 10_ms;
+  auto [Kp, Kd] = sysid::CalculatePositionFeedbackGains(preset, params, Kv, Ka);
+
+  EXPECT_NEAR(Kp, 5.92, 0.05);
+  EXPECT_NEAR(Kd, 2.12, 0.05);
+}
+
+TEST(FeedbackAnalysisTest, PositionREV) {
+  auto Kv = 3.060;
+  auto Ka = 0.327;
+
+  sysid::LQRParameters params{1, 1.5, 7};
+
+  auto [Kp, Kd] = sysid::CalculatePositionFeedbackGains(
+      sysid::presets::kREVNEOBuiltIn, params, Kv, Ka);
+
+  EXPECT_NEAR(Kp, 0.30202, 0.05);
+  EXPECT_NEAR(Kd, 48.518, 0.05);
+}

vcpkg.json

@@ -7,5 +7,5 @@
     "libuv",
     "protobuf"
   ],
-  "builtin-baseline": "78b61582c9e093fda56a01ebb654be15a0033897"
+  "builtin-baseline": "37c3e63a1306562f7f59c4c3c8892ddd50fdf992"
 }

wpilibc/src/main/native/include/frc/PowerDistribution.h

@@ -58,7 +58,10 @@ class PowerDistribution : public wpi::Sendable,
   double GetVoltage() const;
 
   /**
-   * Query the temperature of the PDP/PDH.
+   * Query the temperature of the PDP.
+   *
+   * Not supported on the Rev PDH and returns 0.
+   *
    *
    * @return The temperature in degrees Celsius
    */
@@ -80,21 +83,27 @@ class PowerDistribution : public wpi::Sendable,
   double GetTotalCurrent() const;
 
   /**
-   * Query the total power drawn from all monitored PDP/PDH channels.
+   * Query the total power drawn from all monitored PDP channels.
+   *
+   * Not supported on the Rev PDH and returns 0.
    *
    * @return The total power drawn in Watts
    */
   double GetTotalPower() const;
 
   /**
-   * Query the total energy drawn from the monitored PDP/PDH channels.
+   * Query the total energy drawn from the monitored PDP channels.
+   *
+   * Not supported on the Rev PDH and returns 0.
    *
    * @return The total energy drawn in Joules
    */
   double GetTotalEnergy() const;
 
   /**
-   * Reset the total energy drawn from the PDP/PDH.
+   * Reset the total energy drawn from the PDP.
+   *
+   * Not supported on the Rev PDH and does nothing.
    *
    * @see PowerDistribution#GetTotalEnergy
    */

wpilibcExamples/src/main/cpp/examples/GearsBot/include/subsystems/Elevator.h

@@ -44,7 +44,6 @@ class Elevator : public frc2::PIDSubsystem {
 
  private:
   frc::PWMSparkMax m_motor{5};
-  double m_setpoint = 0;
 
 // Conversion value of potentiometer varies between the real world and
 // simulation

wpilibcExamples/src/main/cpp/examples/GearsBot/include/subsystems/Wrist.h

@@ -41,7 +41,6 @@ class Wrist : public frc2::PIDSubsystem {
 
  private:
   frc::PWMSparkMax m_motor{6};
-  double m_setpoint = 0;
 
 // Conversion value of potentiometer varies between the real world and
 // simulation

wpilibj/src/main/java/edu/wpi/first/wpilibj/PowerDistribution.java

@@ -93,7 +93,9 @@ public class PowerDistribution implements Sendable, AutoCloseable {
   }
 
   /**
-   * Query the temperature of the PDP/PDH.
+   * Query the temperature of the PDP.
+   *
+   * <p>Not supported on the Rev PDH and returns 0.
    *
    * @return The temperature in degrees Celsius
    */
@@ -121,7 +123,9 @@ public class PowerDistribution implements Sendable, AutoCloseable {
   }
 
   /**
-   * Query the total power drawn from the monitored channels.
+   * Query the total power drawn from the monitored channels of the PDP.
+   *
+   * <p>Not supported on the Rev PDH and returns 0.
    *
    * @return the total power in Watts
    */
@@ -130,7 +134,9 @@ public class PowerDistribution implements Sendable, AutoCloseable {
   }
 
   /**
-   * Query the total energy drawn from the monitored channels.
+   * Query the total energy drawn from the monitored channels of the PDP.
+   *
+   * <p>Not supported on the Rev PDH and returns 0.
    *
    * @return the total energy in Joules
    */
@@ -138,7 +144,11 @@ public class PowerDistribution implements Sendable, AutoCloseable {
     return PowerDistributionJNI.getTotalEnergy(m_handle);
   }
 
-  /** Reset the total energy to 0. */
+  /**
+   * Reset the total energy to 0 of the PDP.
+   *
+   * <p>Not supported on the Rev PDH and does nothing.
+   */
   public void resetTotalEnergy() {
     PowerDistributionJNI.resetTotalEnergy(m_handle);
   }

wpilibj/src/main/java/edu/wpi/first/wpilibj/RobotBase.java

@@ -453,6 +453,11 @@ public abstract class RobotBase implements AutoCloseable {
       runRobot(robotSupplier);
     }
 
+    // On RIO, this will just terminate rather than shutting down cleanly (it's a no-op in sim).
+    // It's not worth the risk of hanging on shutdown when we want the code to restart as quickly
+    // as possible.
+    HAL.terminate();
+
     HAL.shutdown();
 
     System.exit(0);

wpimath/src/generated/main/java/edu/wpi/first/math/proto/Kinematics.java

@@ -19,61 +19,65 @@ import us.hebi.quickbuf.RepeatedByte;
 import us.hebi.quickbuf.RepeatedMessage;
 
 public final class Kinematics {
-  private static final RepeatedByte descriptorData = ProtoUtil.decodeBase64(3208,
+  private static final RepeatedByte descriptorData = ProtoUtil.decodeBase64(3427,
     "ChBraW5lbWF0aWNzLnByb3RvEgl3cGkucHJvdG8aEGdlb21ldHJ5MmQucHJvdG8iTQoVUHJvdG9idWZD" + 
     "aGFzc2lzU3BlZWRzEg4KAnZ4GAEgASgBUgJ2eBIOCgJ2eRgCIAEoAVICdnkSFAoFb21lZ2EYAyABKAFS" + 
     "BW9tZWdhIkYKI1Byb3RvYnVmRGlmZmVyZW50aWFsRHJpdmVLaW5lbWF0aWNzEh8KC3RyYWNrX3dpZHRo" + 
     "GAEgASgBUgp0cmFja1dpZHRoIlAKJFByb3RvYnVmRGlmZmVyZW50aWFsRHJpdmVXaGVlbFNwZWVkcxIS" + 
-    "CgRsZWZ0GAEgASgBUgRsZWZ0EhQKBXJpZ2h0GAIgASgBUgVyaWdodCKkAgoeUHJvdG9idWZNZWNhbnVt" + 
-    "RHJpdmVLaW5lbWF0aWNzEj8KCmZyb250X2xlZnQYASABKAsyIC53cGkucHJvdG8uUHJvdG9idWZUcmFu" + 
-    "c2xhdGlvbjJkUglmcm9udExlZnQSQQoLZnJvbnRfcmlnaHQYAiABKAsyIC53cGkucHJvdG8uUHJvdG9i" + 
-    "dWZUcmFuc2xhdGlvbjJkUgpmcm9udFJpZ2h0Ej0KCXJlYXJfbGVmdBgDIAEoCzIgLndwaS5wcm90by5Q" + 
-    "cm90b2J1ZlRyYW5zbGF0aW9uMmRSCHJlYXJMZWZ0Ej8KCnJlYXJfcmlnaHQYBCABKAsyIC53cGkucHJv" + 
-    "dG8uUHJvdG9idWZUcmFuc2xhdGlvbjJkUglyZWFyUmlnaHQinwEKIVByb3RvYnVmTWVjYW51bURyaXZl" + 
-    "TW90b3JWb2x0YWdlcxIdCgpmcm9udF9sZWZ0GAEgASgBUglmcm9udExlZnQSHwoLZnJvbnRfcmlnaHQY" + 
-    "AiABKAFSCmZyb250UmlnaHQSGwoJcmVhcl9sZWZ0GAMgASgBUghyZWFyTGVmdBIdCgpyZWFyX3JpZ2h0" + 
-    "GAQgASgBUglyZWFyUmlnaHQioAEKIlByb3RvYnVmTWVjYW51bURyaXZlV2hlZWxQb3NpdGlvbnMSHQoK" + 
-    "ZnJvbnRfbGVmdBgBIAEoAVIJZnJvbnRMZWZ0Eh8KC2Zyb250X3JpZ2h0GAIgASgBUgpmcm9udFJpZ2h0" + 
-    "EhsKCXJlYXJfbGVmdBgDIAEoAVIIcmVhckxlZnQSHQoKcmVhcl9yaWdodBgEIAEoAVIJcmVhclJpZ2h0" + 
-    "Ip0BCh9Qcm90b2J1Zk1lY2FudW1Ecml2ZVdoZWVsU3BlZWRzEh0KCmZyb250X2xlZnQYASABKAFSCWZy" + 
-    "b250TGVmdBIfCgtmcm9udF9yaWdodBgCIAEoAVIKZnJvbnRSaWdodBIbCglyZWFyX2xlZnQYAyABKAFS" + 
-    "CHJlYXJMZWZ0Eh0KCnJlYXJfcmlnaHQYBCABKAFSCXJlYXJSaWdodCJbCh1Qcm90b2J1ZlN3ZXJ2ZURy" + 
-    "aXZlS2luZW1hdGljcxI6Cgdtb2R1bGVzGAEgAygLMiAud3BpLnByb3RvLlByb3RvYnVmVHJhbnNsYXRp" + 
-    "b24yZFIHbW9kdWxlcyJvChxQcm90b2J1ZlN3ZXJ2ZU1vZHVsZVBvc2l0aW9uEhoKCGRpc3RhbmNlGAEg",
-    "ASgBUghkaXN0YW5jZRIzCgVhbmdsZRgCIAEoCzIdLndwaS5wcm90by5Qcm90b2J1ZlJvdGF0aW9uMmRS" + 
-    "BWFuZ2xlImYKGVByb3RvYnVmU3dlcnZlTW9kdWxlU3RhdGUSFAoFc3BlZWQYASABKAFSBXNwZWVkEjMK" + 
-    "BWFuZ2xlGAIgASgLMh0ud3BpLnByb3RvLlByb3RvYnVmUm90YXRpb24yZFIFYW5nbGVCGgoYZWR1Lndw" + 
-    "aS5maXJzdC5tYXRoLnByb3RvSocOCgYSBAAAPwEKCAoBDBIDAAASCggKAQISAwIAEgoJCgIDABIDBAAa" + 
-    "CggKAQgSAwYAMQoJCgIIARIDBgAxCgoKAgQAEgQIAAwBCgoKAwQAARIDCAgdCgsKBAQAAgASAwkCEAoM" + 
-    "CgUEAAIABRIDCQIICgwKBQQAAgABEgMJCQsKDAoFBAACAAMSAwkODwoLCgQEAAIBEgMKAhAKDAoFBAAC" + 
-    "AQUSAwoCCAoMCgUEAAIBARIDCgkLCgwKBQQAAgEDEgMKDg8KCwoEBAACAhIDCwITCgwKBQQAAgIFEgML" + 
-    "AggKDAoFBAACAgESAwsJDgoMCgUEAAICAxIDCxESCgoKAgQBEgQOABABCgoKAwQBARIDDggrCgsKBAQB" + 
-    "AgASAw8CGQoMCgUEAQIABRIDDwIICgwKBQQBAgABEgMPCRQKDAoFBAECAAMSAw8XGAoKCgIEAhIEEgAV" + 
-    "AQoKCgMEAgESAxIILAoLCgQEAgIAEgMTAhIKDAoFBAICAAUSAxMCCAoMCgUEAgIAARIDEwkNCgwKBQQC" + 
-    "AgADEgMTEBEKCwoEBAICARIDFAITCgwKBQQCAgEFEgMUAggKDAoFBAICAQESAxQJDgoMCgUEAgIBAxID" + 
-    "FBESCgoKAgQDEgQXABwBCgoKAwQDARIDFwgmCgsKBAQDAgASAxgCJwoMCgUEAwIABhIDGAIXCgwKBQQD" + 
-    "AgABEgMYGCIKDAoFBAMCAAMSAxglJgoLCgQEAwIBEgMZAigKDAoFBAMCAQYSAxkCFwoMCgUEAwIBARID" + 
-    "GRgjCgwKBQQDAgEDEgMZJicKCwoEBAMCAhIDGgImCgwKBQQDAgIGEgMaAhcKDAoFBAMCAgESAxoYIQoM" + 
-    "CgUEAwICAxIDGiQlCgsKBAQDAgMSAxsCJwoMCgUEAwIDBhIDGwIXCgwKBQQDAgMBEgMbGCIKDAoFBAMC" + 
-    "AwMSAxslJgoKCgIEBBIEHgAjAQoKCgMEBAESAx4IKQoLCgQEBAIAEgMfAhgKDAoFBAQCAAUSAx8CCAoM" + 
-    "CgUEBAIAARIDHwkTCgwKBQQEAgADEgMfFhcKCwoEBAQCARIDIAIZCgwKBQQEAgEFEgMgAggKDAoFBAQC" + 
-    "AQESAyAJFAoMCgUEBAIBAxIDIBcYCgsKBAQEAgISAyECFwoMCgUEBAICBRIDIQIICgwKBQQEAgIBEgMh" + 
-    "CRIKDAoFBAQCAgMSAyEVFgoLCgQEBAIDEgMiAhgKDAoFBAQCAwUSAyICCAoMCgUEBAIDARIDIgkTCgwK" + 
-    "BQQEAgMDEgMiFhcKCgoCBAUSBCUAKgEKCgoDBAUBEgMlCCoKCwoEBAUCABIDJgIYCgwKBQQFAgAFEgMm",
-    "AggKDAoFBAUCAAESAyYJEwoMCgUEBQIAAxIDJhYXCgsKBAQFAgESAycCGQoMCgUEBQIBBRIDJwIICgwK" + 
-    "BQQFAgEBEgMnCRQKDAoFBAUCAQMSAycXGAoLCgQEBQICEgMoAhcKDAoFBAUCAgUSAygCCAoMCgUEBQIC" + 
-    "ARIDKAkSCgwKBQQFAgIDEgMoFRYKCwoEBAUCAxIDKQIYCgwKBQQFAgMFEgMpAggKDAoFBAUCAwESAykJ" + 
-    "EwoMCgUEBQIDAxIDKRYXCgoKAgQGEgQsADEBCgoKAwQGARIDLAgnCgsKBAQGAgASAy0CGAoMCgUEBgIA" + 
-    "BRIDLQIICgwKBQQGAgABEgMtCRMKDAoFBAYCAAMSAy0WFwoLCgQEBgIBEgMuAhkKDAoFBAYCAQUSAy4C" + 
-    "CAoMCgUEBgIBARIDLgkUCgwKBQQGAgEDEgMuFxgKCwoEBAYCAhIDLwIXCgwKBQQGAgIFEgMvAggKDAoF" + 
-    "BAYCAgESAy8JEgoMCgUEBgICAxIDLxUWCgsKBAQGAgMSAzACGAoMCgUEBgIDBRIDMAIICgwKBQQGAgMB" + 
-    "EgMwCRMKDAoFBAYCAwMSAzAWFwoKCgIEBxIEMwA1AQoKCgMEBwESAzMIJQoLCgQEBwIAEgM0Ai0KDAoF" + 
-    "BAcCAAQSAzQCCgoMCgUEBwIABhIDNAsgCgwKBQQHAgABEgM0ISgKDAoFBAcCAAMSAzQrLAoKCgIECBIE" + 
-    "NwA6AQoKCgMECAESAzcIJAoLCgQECAIAEgM4AhYKDAoFBAgCAAUSAzgCCAoMCgUECAIAARIDOAkRCgwK" + 
-    "BQQIAgADEgM4FBUKCwoEBAgCARIDOQIfCgwKBQQIAgEGEgM5AhQKDAoFBAgCAQESAzkVGgoMCgUECAIB" + 
-    "AxIDOR0eCgoKAgQJEgQ8AD8BCgoKAwQJARIDPAghCgsKBAQJAgASAz0CEwoMCgUECQIABRIDPQIICgwK" + 
-    "BQQJAgABEgM9CQ4KDAoFBAkCAAMSAz0REgoLCgQECQIBEgM+Ah8KDAoFBAkCAQYSAz4CFAoMCgUECQIB" + 
-    "ARIDPhUaCgwKBQQJAgEDEgM+HR5iBnByb3RvMw==");
+    "CgRsZWZ0GAEgASgBUgRsZWZ0EhQKBXJpZ2h0GAIgASgBUgVyaWdodCJTCidQcm90b2J1ZkRpZmZlcmVu" + 
+    "dGlhbERyaXZlV2hlZWxQb3NpdGlvbnMSEgoEbGVmdBgBIAEoAVIEbGVmdBIUCgVyaWdodBgCIAEoAVIF" + 
+    "cmlnaHQipAIKHlByb3RvYnVmTWVjYW51bURyaXZlS2luZW1hdGljcxI/Cgpmcm9udF9sZWZ0GAEgASgL" + 
+    "MiAud3BpLnByb3RvLlByb3RvYnVmVHJhbnNsYXRpb24yZFIJZnJvbnRMZWZ0EkEKC2Zyb250X3JpZ2h0" + 
+    "GAIgASgLMiAud3BpLnByb3RvLlByb3RvYnVmVHJhbnNsYXRpb24yZFIKZnJvbnRSaWdodBI9CglyZWFy" + 
+    "X2xlZnQYAyABKAsyIC53cGkucHJvdG8uUHJvdG9idWZUcmFuc2xhdGlvbjJkUghyZWFyTGVmdBI/Cgpy" + 
+    "ZWFyX3JpZ2h0GAQgASgLMiAud3BpLnByb3RvLlByb3RvYnVmVHJhbnNsYXRpb24yZFIJcmVhclJpZ2h0" + 
+    "Ip8BCiFQcm90b2J1Zk1lY2FudW1Ecml2ZU1vdG9yVm9sdGFnZXMSHQoKZnJvbnRfbGVmdBgBIAEoAVIJ" + 
+    "ZnJvbnRMZWZ0Eh8KC2Zyb250X3JpZ2h0GAIgASgBUgpmcm9udFJpZ2h0EhsKCXJlYXJfbGVmdBgDIAEo" + 
+    "AVIIcmVhckxlZnQSHQoKcmVhcl9yaWdodBgEIAEoAVIJcmVhclJpZ2h0IqABCiJQcm90b2J1Zk1lY2Fu" + 
+    "dW1Ecml2ZVdoZWVsUG9zaXRpb25zEh0KCmZyb250X2xlZnQYASABKAFSCWZyb250TGVmdBIfCgtmcm9u" + 
+    "dF9yaWdodBgCIAEoAVIKZnJvbnRSaWdodBIbCglyZWFyX2xlZnQYAyABKAFSCHJlYXJMZWZ0Eh0KCnJl" + 
+    "YXJfcmlnaHQYBCABKAFSCXJlYXJSaWdodCKdAQofUHJvdG9idWZNZWNhbnVtRHJpdmVXaGVlbFNwZWVk" + 
+    "cxIdCgpmcm9udF9sZWZ0GAEgASgBUglmcm9udExlZnQSHwoLZnJvbnRfcmlnaHQYAiABKAFSCmZyb250" + 
+    "UmlnaHQSGwoJcmVhcl9sZWZ0GAMgASgBUghyZWFyTGVmdBIdCgpyZWFyX3JpZ2h0GAQgASgBUglyZWFy" + 
+    "UmlnaHQiWwodUHJvdG9idWZTd2VydmVEcml2ZUtpbmVtYXRpY3MSOgoHbW9kdWxlcxgBIAMoCzIgLndw",
+    "aS5wcm90by5Qcm90b2J1ZlRyYW5zbGF0aW9uMmRSB21vZHVsZXMibwocUHJvdG9idWZTd2VydmVNb2R1" + 
+    "bGVQb3NpdGlvbhIaCghkaXN0YW5jZRgBIAEoAVIIZGlzdGFuY2USMwoFYW5nbGUYAiABKAsyHS53cGku" + 
+    "cHJvdG8uUHJvdG9idWZSb3RhdGlvbjJkUgVhbmdsZSJmChlQcm90b2J1ZlN3ZXJ2ZU1vZHVsZVN0YXRl" + 
+    "EhQKBXNwZWVkGAEgASgBUgVzcGVlZBIzCgVhbmdsZRgCIAEoCzIdLndwaS5wcm90by5Qcm90b2J1ZlJv" + 
+    "dGF0aW9uMmRSBWFuZ2xlQhoKGGVkdS53cGkuZmlyc3QubWF0aC5wcm90b0qNDwoGEgQAAEQBCggKAQwS" + 
+    "AwAAEgoICgECEgMCABIKCQoCAwASAwQAGgoICgEIEgMGADEKCQoCCAESAwYAMQoKCgIEABIECAAMAQoK" + 
+    "CgMEAAESAwgIHQoLCgQEAAIAEgMJAhAKDAoFBAACAAUSAwkCCAoMCgUEAAIAARIDCQkLCgwKBQQAAgAD" + 
+    "EgMJDg8KCwoEBAACARIDCgIQCgwKBQQAAgEFEgMKAggKDAoFBAACAQESAwoJCwoMCgUEAAIBAxIDCg4P" + 
+    "CgsKBAQAAgISAwsCEwoMCgUEAAICBRIDCwIICgwKBQQAAgIBEgMLCQ4KDAoFBAACAgMSAwsREgoKCgIE" + 
+    "ARIEDgAQAQoKCgMEAQESAw4IKwoLCgQEAQIAEgMPAhkKDAoFBAECAAUSAw8CCAoMCgUEAQIAARIDDwkU" + 
+    "CgwKBQQBAgADEgMPFxgKCgoCBAISBBIAFQEKCgoDBAIBEgMSCCwKCwoEBAICABIDEwISCgwKBQQCAgAF" + 
+    "EgMTAggKDAoFBAICAAESAxMJDQoMCgUEAgIAAxIDExARCgsKBAQCAgESAxQCEwoMCgUEAgIBBRIDFAII" + 
+    "CgwKBQQCAgEBEgMUCQ4KDAoFBAICAQMSAxQREgoKCgIEAxIEFwAaAQoKCgMEAwESAxcILwoLCgQEAwIA" + 
+    "EgMYAhIKDAoFBAMCAAUSAxgCCAoMCgUEAwIAARIDGAkNCgwKBQQDAgADEgMYEBEKCwoEBAMCARIDGQIT" + 
+    "CgwKBQQDAgEFEgMZAggKDAoFBAMCAQESAxkJDgoMCgUEAwIBAxIDGRESCgoKAgQEEgQcACEBCgoKAwQE" + 
+    "ARIDHAgmCgsKBAQEAgASAx0CJwoMCgUEBAIABhIDHQIXCgwKBQQEAgABEgMdGCIKDAoFBAQCAAMSAx0l" + 
+    "JgoLCgQEBAIBEgMeAigKDAoFBAQCAQYSAx4CFwoMCgUEBAIBARIDHhgjCgwKBQQEAgEDEgMeJicKCwoE" + 
+    "BAQCAhIDHwImCgwKBQQEAgIGEgMfAhcKDAoFBAQCAgESAx8YIQoMCgUEBAICAxIDHyQlCgsKBAQEAgMS" + 
+    "AyACJwoMCgUEBAIDBhIDIAIXCgwKBQQEAgMBEgMgGCIKDAoFBAQCAwMSAyAlJgoKCgIEBRIEIwAoAQoK" + 
+    "CgMEBQESAyMIKQoLCgQEBQIAEgMkAhgKDAoFBAUCAAUSAyQCCAoMCgUEBQIAARIDJAkTCgwKBQQFAgAD",
+    "EgMkFhcKCwoEBAUCARIDJQIZCgwKBQQFAgEFEgMlAggKDAoFBAUCAQESAyUJFAoMCgUEBQIBAxIDJRcY" + 
+    "CgsKBAQFAgISAyYCFwoMCgUEBQICBRIDJgIICgwKBQQFAgIBEgMmCRIKDAoFBAUCAgMSAyYVFgoLCgQE" + 
+    "BQIDEgMnAhgKDAoFBAUCAwUSAycCCAoMCgUEBQIDARIDJwkTCgwKBQQFAgMDEgMnFhcKCgoCBAYSBCoA" + 
+    "LwEKCgoDBAYBEgMqCCoKCwoEBAYCABIDKwIYCgwKBQQGAgAFEgMrAggKDAoFBAYCAAESAysJEwoMCgUE" + 
+    "BgIAAxIDKxYXCgsKBAQGAgESAywCGQoMCgUEBgIBBRIDLAIICgwKBQQGAgEBEgMsCRQKDAoFBAYCAQMS" + 
+    "AywXGAoLCgQEBgICEgMtAhcKDAoFBAYCAgUSAy0CCAoMCgUEBgICARIDLQkSCgwKBQQGAgIDEgMtFRYK" + 
+    "CwoEBAYCAxIDLgIYCgwKBQQGAgMFEgMuAggKDAoFBAYCAwESAy4JEwoMCgUEBgIDAxIDLhYXCgoKAgQH" + 
+    "EgQxADYBCgoKAwQHARIDMQgnCgsKBAQHAgASAzICGAoMCgUEBwIABRIDMgIICgwKBQQHAgABEgMyCRMK" + 
+    "DAoFBAcCAAMSAzIWFwoLCgQEBwIBEgMzAhkKDAoFBAcCAQUSAzMCCAoMCgUEBwIBARIDMwkUCgwKBQQH" + 
+    "AgEDEgMzFxgKCwoEBAcCAhIDNAIXCgwKBQQHAgIFEgM0AggKDAoFBAcCAgESAzQJEgoMCgUEBwICAxID" + 
+    "NBUWCgsKBAQHAgMSAzUCGAoMCgUEBwIDBRIDNQIICgwKBQQHAgMBEgM1CRMKDAoFBAcCAwMSAzUWFwoK" + 
+    "CgIECBIEOAA6AQoKCgMECAESAzgIJQoLCgQECAIAEgM5Ai0KDAoFBAgCAAQSAzkCCgoMCgUECAIABhID" + 
+    "OQsgCgwKBQQIAgABEgM5ISgKDAoFBAgCAAMSAzkrLAoKCgIECRIEPAA/AQoKCgMECQESAzwIJAoLCgQE" + 
+    "CQIAEgM9AhYKDAoFBAkCAAUSAz0CCAoMCgUECQIAARIDPQkRCgwKBQQJAgADEgM9FBUKCwoEBAkCARID" + 
+    "PgIfCgwKBQQJAgEGEgM+AhQKDAoFBAkCAQESAz4VGgoMCgUECQIBAxIDPh0eCgoKAgQKEgRBAEQBCgoK" + 
+    "AwQKARIDQQghCgsKBAQKAgASA0ICEwoMCgUECgIABRIDQgIICgwKBQQKAgABEgNCCQ4KDAoFBAoCAAMS" + 
+    "A0IREgoLCgQECgIBEgNDAh8KDAoFBAoCAQYSA0MCFAoMCgUECgIBARIDQxUaCgwKBQQKAgEDEgNDHR5i" + 
+    "BnByb3RvMw==");
 
   static final Descriptors.FileDescriptor descriptor = Descriptors.FileDescriptor.internalBuildGeneratedFileFrom("kinematics.proto", "wpi.proto", descriptorData, Geometry2D.getDescriptor());
 
@@ -83,19 +87,21 @@ public final class Kinematics {
 
   static final Descriptors.Descriptor wpi_proto_ProtobufDifferentialDriveWheelSpeeds_descriptor = descriptor.internalContainedType(200, 80, "ProtobufDifferentialDriveWheelSpeeds", "wpi.proto.ProtobufDifferentialDriveWheelSpeeds");
 
-  static final Descriptors.Descriptor wpi_proto_ProtobufMecanumDriveKinematics_descriptor = descriptor.internalContainedType(283, 292, "ProtobufMecanumDriveKinematics", "wpi.proto.ProtobufMecanumDriveKinematics");
+  static final Descriptors.Descriptor wpi_proto_ProtobufDifferentialDriveWheelPositions_descriptor = descriptor.internalContainedType(282, 83, "ProtobufDifferentialDriveWheelPositions", "wpi.proto.ProtobufDifferentialDriveWheelPositions");
 
-  static final Descriptors.Descriptor wpi_proto_ProtobufMecanumDriveMotorVoltages_descriptor = descriptor.internalContainedType(578, 159, "ProtobufMecanumDriveMotorVoltages", "wpi.proto.ProtobufMecanumDriveMotorVoltages");
+  static final Descriptors.Descriptor wpi_proto_ProtobufMecanumDriveKinematics_descriptor = descriptor.internalContainedType(368, 292, "ProtobufMecanumDriveKinematics", "wpi.proto.ProtobufMecanumDriveKinematics");
 
-  static final Descriptors.Descriptor wpi_proto_ProtobufMecanumDriveWheelPositions_descriptor = descriptor.internalContainedType(740, 160, "ProtobufMecanumDriveWheelPositions", "wpi.proto.ProtobufMecanumDriveWheelPositions");
+  static final Descriptors.Descriptor wpi_proto_ProtobufMecanumDriveMotorVoltages_descriptor = descriptor.internalContainedType(663, 159, "ProtobufMecanumDriveMotorVoltages", "wpi.proto.ProtobufMecanumDriveMotorVoltages");
 
-  static final Descriptors.Descriptor wpi_proto_ProtobufMecanumDriveWheelSpeeds_descriptor = descriptor.internalContainedType(903, 157, "ProtobufMecanumDriveWheelSpeeds", "wpi.proto.ProtobufMecanumDriveWheelSpeeds");
+  static final Descriptors.Descriptor wpi_proto_ProtobufMecanumDriveWheelPositions_descriptor = descriptor.internalContainedType(825, 160, "ProtobufMecanumDriveWheelPositions", "wpi.proto.ProtobufMecanumDriveWheelPositions");
 
-  static final Descriptors.Descriptor wpi_proto_ProtobufSwerveDriveKinematics_descriptor = descriptor.internalContainedType(1062, 91, "ProtobufSwerveDriveKinematics", "wpi.proto.ProtobufSwerveDriveKinematics");
+  static final Descriptors.Descriptor wpi_proto_ProtobufMecanumDriveWheelSpeeds_descriptor = descriptor.internalContainedType(988, 157, "ProtobufMecanumDriveWheelSpeeds", "wpi.proto.ProtobufMecanumDriveWheelSpeeds");
 
-  static final Descriptors.Descriptor wpi_proto_ProtobufSwerveModulePosition_descriptor = descriptor.internalContainedType(1155, 111, "ProtobufSwerveModulePosition", "wpi.proto.ProtobufSwerveModulePosition");
+  static final Descriptors.Descriptor wpi_proto_ProtobufSwerveDriveKinematics_descriptor = descriptor.internalContainedType(1147, 91, "ProtobufSwerveDriveKinematics", "wpi.proto.ProtobufSwerveDriveKinematics");
 
-  static final Descriptors.Descriptor wpi_proto_ProtobufSwerveModuleState_descriptor = descriptor.internalContainedType(1268, 102, "ProtobufSwerveModuleState", "wpi.proto.ProtobufSwerveModuleState");
+  static final Descriptors.Descriptor wpi_proto_ProtobufSwerveModulePosition_descriptor = descriptor.internalContainedType(1240, 111, "ProtobufSwerveModulePosition", "wpi.proto.ProtobufSwerveModulePosition");
+
+  static final Descriptors.Descriptor wpi_proto_ProtobufSwerveModuleState_descriptor = descriptor.internalContainedType(1353, 102, "ProtobufSwerveModuleState", "wpi.proto.ProtobufSwerveModuleState");
 
   /**
    * @return this proto file's descriptor.
@@ -1113,6 +1119,344 @@ public final class Kinematics {
     }
   }
 
+  /**
+   * Protobuf type {@code ProtobufDifferentialDriveWheelPositions}
+   */
+  public static final class ProtobufDifferentialDriveWheelPositions extends ProtoMessage<ProtobufDifferentialDriveWheelPositions> implements Cloneable {
+    private static final long serialVersionUID = 0L;
+
+    /**
+     * <code>optional double left = 1;</code>
+     */
+    private double left;
+
+    /**
+     * <code>optional double right = 2;</code>
+     */
+    private double right;
+
+    private ProtobufDifferentialDriveWheelPositions() {
+    }
+
+    /**
+     * @return a new empty instance of {@code ProtobufDifferentialDriveWheelPositions}
+     */
+    public static ProtobufDifferentialDriveWheelPositions newInstance() {
+      return new ProtobufDifferentialDriveWheelPositions();
+    }
+
+    /**
+     * <code>optional double left = 1;</code>
+     * @return whether the left field is set
+     */
+    public boolean hasLeft() {
+      return (bitField0_ & 0x00000001) != 0;
+    }
+
+    /**
+     * <code>optional double left = 1;</code>
+     * @return this
+     */
+    public ProtobufDifferentialDriveWheelPositions clearLeft() {
+      bitField0_ &= ~0x00000001;
+      left = 0D;
+      return this;
+    }
+
+    /**
+     * <code>optional double left = 1;</code>
+     * @return the left
+     */
+    public double getLeft() {
+      return left;
+    }
+
+    /**
+     * <code>optional double left = 1;</code>
+     * @param value the left to set
+     * @return this
+     */
+    public ProtobufDifferentialDriveWheelPositions setLeft(final double value) {
+      bitField0_ |= 0x00000001;
+      left = value;
+      return this;
+    }
+
+    /**
+     * <code>optional double right = 2;</code>
+     * @return whether the right field is set
+     */
+    public boolean hasRight() {
+      return (bitField0_ & 0x00000002) != 0;
+    }
+
+    /**
+     * <code>optional double right = 2;</code>
+     * @return this
+     */
+    public ProtobufDifferentialDriveWheelPositions clearRight() {
+      bitField0_ &= ~0x00000002;
+      right = 0D;
+      return this;
+    }
+
+    /**
+     * <code>optional double right = 2;</code>
+     * @return the right
+     */
+    public double getRight() {
+      return right;
+    }
+
+    /**
+     * <code>optional double right = 2;</code>
+     * @param value the right to set
+     * @return this
+     */
+    public ProtobufDifferentialDriveWheelPositions setRight(final double value) {
+      bitField0_ |= 0x00000002;
+      right = value;
+      return this;
+    }
+
+    @Override
+    public ProtobufDifferentialDriveWheelPositions copyFrom(
+        final ProtobufDifferentialDriveWheelPositions other) {
+      cachedSize = other.cachedSize;
+      if ((bitField0_ | other.bitField0_) != 0) {
+        bitField0_ = other.bitField0_;
+        left = other.left;
+        right = other.right;
+      }
+      return this;
+    }
+
+    @Override
+    public ProtobufDifferentialDriveWheelPositions mergeFrom(
+        final ProtobufDifferentialDriveWheelPositions other) {
+      if (other.isEmpty()) {
+        return this;
+      }
+      cachedSize = -1;
+      if (other.hasLeft()) {
+        setLeft(other.left);
+      }
+      if (other.hasRight()) {
+        setRight(other.right);
+      }
+      return this;
+    }
+
+    @Override
+    public ProtobufDifferentialDriveWheelPositions clear() {
+      if (isEmpty()) {
+        return this;
+      }
+      cachedSize = -1;
+      bitField0_ = 0;
+      left = 0D;
+      right = 0D;
+      return this;
+    }
+
+    @Override
+    public ProtobufDifferentialDriveWheelPositions clearQuick() {
+      if (isEmpty()) {
+        return this;
+      }
+      cachedSize = -1;
+      bitField0_ = 0;
+      return this;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+      if (o == this) {
+        return true;
+      }
+      if (!(o instanceof ProtobufDifferentialDriveWheelPositions)) {
+        return false;
+      }
+      ProtobufDifferentialDriveWheelPositions other = (ProtobufDifferentialDriveWheelPositions) o;
+      return bitField0_ == other.bitField0_
+        && (!hasLeft() || ProtoUtil.isEqual(left, other.left))
+        && (!hasRight() || ProtoUtil.isEqual(right, other.right));
+    }
+
+    @Override
+    public void writeTo(final ProtoSink output) throws IOException {
+      if ((bitField0_ & 0x00000001) != 0) {
+        output.writeRawByte((byte) 9);
+        output.writeDoubleNoTag(left);
+      }
+      if ((bitField0_ & 0x00000002) != 0) {
+        output.writeRawByte((byte) 17);
+        output.writeDoubleNoTag(right);
+      }
+    }
+
+    @Override
+    protected int computeSerializedSize() {
+      int size = 0;
+      if ((bitField0_ & 0x00000001) != 0) {
+        size += 9;
+      }
+      if ((bitField0_ & 0x00000002) != 0) {
+        size += 9;
+      }
+      return size;
+    }
+
+    @Override
+    @SuppressWarnings("fallthrough")
+    public ProtobufDifferentialDriveWheelPositions mergeFrom(final ProtoSource input) throws
+        IOException {
+      // Enabled Fall-Through Optimization (QuickBuffers)
+      int tag = input.readTag();
+      while (true) {
+        switch (tag) {
+          case 9: {
+            // left
+            left = input.readDouble();
+            bitField0_ |= 0x00000001;
+            tag = input.readTag();
+            if (tag != 17) {
+              break;
+            }
+          }
+          case 17: {
+            // right
+            right = input.readDouble();
+            bitField0_ |= 0x00000002;
+            tag = input.readTag();
+            if (tag != 0) {
+              break;
+            }
+          }
+          case 0: {
+            return this;
+          }
+          default: {
+            if (!input.skipField(tag)) {
+              return this;
+            }
+            tag = input.readTag();
+            break;
+          }
+        }
+      }
+    }
+
+    @Override
+    public void writeTo(final JsonSink output) throws IOException {
+      output.beginObject();
+      if ((bitField0_ & 0x00000001) != 0) {
+        output.writeDouble(FieldNames.left, left);
+      }
+      if ((bitField0_ & 0x00000002) != 0) {
+        output.writeDouble(FieldNames.right, right);
+      }
+      output.endObject();
+    }
+
+    @Override
+    public ProtobufDifferentialDriveWheelPositions mergeFrom(final JsonSource input) throws
+        IOException {
+      if (!input.beginObject()) {
+        return this;
+      }
+      while (!input.isAtEnd()) {
+        switch (input.readFieldHash()) {
+          case 3317767: {
+            if (input.isAtField(FieldNames.left)) {
+              if (!input.trySkipNullValue()) {
+                left = input.readDouble();
+                bitField0_ |= 0x00000001;
+              }
+            } else {
+              input.skipUnknownField();
+            }
+            break;
+          }
+          case 108511772: {
+            if (input.isAtField(FieldNames.right)) {
+              if (!input.trySkipNullValue()) {
+                right = input.readDouble();
+                bitField0_ |= 0x00000002;
+              }
+            } else {
+              input.skipUnknownField();
+            }
+            break;
+          }
+          default: {
+            input.skipUnknownField();
+            break;
+          }
+        }
+      }
+      input.endObject();
+      return this;
+    }
+
+    @Override
+    public ProtobufDifferentialDriveWheelPositions clone() {
+      return new ProtobufDifferentialDriveWheelPositions().copyFrom(this);
+    }
+
+    @Override
+    public boolean isEmpty() {
+      return ((bitField0_) == 0);
+    }
+
+    public static ProtobufDifferentialDriveWheelPositions parseFrom(final byte[] data) throws
+        InvalidProtocolBufferException {
+      return ProtoMessage.mergeFrom(new ProtobufDifferentialDriveWheelPositions(), data).checkInitialized();
+    }
+
+    public static ProtobufDifferentialDriveWheelPositions parseFrom(final ProtoSource input) throws
+        IOException {
+      return ProtoMessage.mergeFrom(new ProtobufDifferentialDriveWheelPositions(), input).checkInitialized();
+    }
+
+    public static ProtobufDifferentialDriveWheelPositions parseFrom(final JsonSource input) throws
+        IOException {
+      return ProtoMessage.mergeFrom(new ProtobufDifferentialDriveWheelPositions(), input).checkInitialized();
+    }
+
+    /**
+     * @return factory for creating ProtobufDifferentialDriveWheelPositions messages
+     */
+    public static MessageFactory<ProtobufDifferentialDriveWheelPositions> getFactory() {
+      return ProtobufDifferentialDriveWheelPositionsFactory.INSTANCE;
+    }
+
+    /**
+     * @return this type's descriptor.
+     */
+    public static Descriptors.Descriptor getDescriptor() {
+      return Kinematics.wpi_proto_ProtobufDifferentialDriveWheelPositions_descriptor;
+    }
+
+    private enum ProtobufDifferentialDriveWheelPositionsFactory implements MessageFactory<ProtobufDifferentialDriveWheelPositions> {
+      INSTANCE;
+
+      @Override
+      public ProtobufDifferentialDriveWheelPositions create() {
+        return ProtobufDifferentialDriveWheelPositions.newInstance();
+      }
+    }
+
+    /**
+     * Contains name constants used for serializing JSON
+     */
+    static class FieldNames {
+      static final FieldName left = FieldName.forField("left");
+
+      static final FieldName right = FieldName.forField("right");
+    }
+  }
+
   /**
    * Protobuf type {@code ProtobufMecanumDriveKinematics}
    */

wpimath/src/main/java/edu/wpi/first/math/kinematics/DifferentialDriveWheelPositions.java

@@ -7,6 +7,8 @@ package edu.wpi.first.math.kinematics;
 import static edu.wpi.first.units.Units.Meters;
 
 import edu.wpi.first.math.MathUtil;
+import edu.wpi.first.math.kinematics.proto.DifferentialDriveWheelPositionsProto;
+import edu.wpi.first.math.kinematics.struct.DifferentialDriveWheelPositionsStruct;
 import edu.wpi.first.units.Distance;
 import edu.wpi.first.units.Measure;
 import java.util.Objects;
@@ -20,6 +22,14 @@ public class DifferentialDriveWheelPositions
   /** Distance measured by the right side. */
   public double rightMeters;
 
+  /** DifferentialDriveWheelPostions struct for serialization. */
+  public static final DifferentialDriveWheelPositionsStruct struct =
+      new DifferentialDriveWheelPositionsStruct();
+
+  /** DifferentialDriveWheelPostions struct for serialization. */
+  public static final DifferentialDriveWheelPositionsProto proto =
+      new DifferentialDriveWheelPositionsProto();
+
   /**
    * Constructs a DifferentialDriveWheelPositions.
    *

wpimath/src/main/java/edu/wpi/first/math/kinematics/proto/DifferentialDriveWheelPositionsProto.java

@@ -0,0 +1,40 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+package edu.wpi.first.math.kinematics.proto;
+
+import edu.wpi.first.math.kinematics.DifferentialDriveWheelPositions;
+import edu.wpi.first.math.proto.Kinematics.ProtobufDifferentialDriveWheelPositions;
+import edu.wpi.first.util.protobuf.Protobuf;
+import us.hebi.quickbuf.Descriptors.Descriptor;
+
+public class DifferentialDriveWheelPositionsProto
+    implements Protobuf<DifferentialDriveWheelPositions, ProtobufDifferentialDriveWheelPositions> {
+  @Override
+  public Class<DifferentialDriveWheelPositions> getTypeClass() {
+    return DifferentialDriveWheelPositions.class;
+  }
+
+  @Override
+  public Descriptor getDescriptor() {
+    return ProtobufDifferentialDriveWheelPositions.getDescriptor();
+  }
+
+  @Override
+  public ProtobufDifferentialDriveWheelPositions createMessage() {
+    return ProtobufDifferentialDriveWheelPositions.newInstance();
+  }
+
+  @Override
+  public DifferentialDriveWheelPositions unpack(ProtobufDifferentialDriveWheelPositions msg) {
+    return new DifferentialDriveWheelPositions(msg.getLeft(), msg.getRight());
+  }
+
+  @Override
+  public void pack(
+      ProtobufDifferentialDriveWheelPositions msg, DifferentialDriveWheelPositions value) {
+    msg.setLeft(value.leftMeters);
+    msg.setRight(value.rightMeters);
+  }
+}

wpimath/src/main/java/edu/wpi/first/math/kinematics/struct/DifferentialDriveWheelPositionsStruct.java

@@ -0,0 +1,45 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+package edu.wpi.first.math.kinematics.struct;
+
+import edu.wpi.first.math.kinematics.DifferentialDriveWheelPositions;
+import edu.wpi.first.util.struct.Struct;
+import java.nio.ByteBuffer;
+
+public class DifferentialDriveWheelPositionsStruct
+    implements Struct<DifferentialDriveWheelPositions> {
+  @Override
+  public Class<DifferentialDriveWheelPositions> getTypeClass() {
+    return DifferentialDriveWheelPositions.class;
+  }
+
+  @Override
+  public String getTypeString() {
+    return "struct:DifferentialDriveWheelPositions";
+  }
+
+  @Override
+  public int getSize() {
+    return kSizeDouble * 2;
+  }
+
+  @Override
+  public String getSchema() {
+    return "double left;double right";
+  }
+
+  @Override
+  public DifferentialDriveWheelPositions unpack(ByteBuffer bb) {
+    double left = bb.getDouble();
+    double right = bb.getDouble();
+    return new DifferentialDriveWheelPositions(left, right);
+  }
+
+  @Override
+  public void pack(ByteBuffer bb, DifferentialDriveWheelPositions value) {
+    bb.putDouble(value.leftMeters);
+    bb.putDouble(value.rightMeters);
+  }
+}

wpimath/src/main/java/edu/wpi/first/math/system/plant/LinearSystemId.java

@@ -135,14 +135,14 @@ public final class LinearSystemId {
    * <p>u = K_v v + K_a a
    *
    * @param kV The velocity gain, in volts/(unit/sec)
-   * @param kA The acceleration gain, in volts/(unit/sec^2)
+   * @param kA The acceleration gain, in volts/(unit/sec²)
    * @return A LinearSystem representing the given characterized constants.
-   * @throws IllegalArgumentException if kV &lt;= 0 or kA &lt;= 0.
+   * @throws IllegalArgumentException if kV &lt; 0 or kA &lt;= 0.
    * @see <a href="https://github.com/wpilibsuite/sysid">https://github.com/wpilibsuite/sysid</a>
    */
   public static LinearSystem<N2, N1, N2> createDCMotorSystem(double kV, double kA) {
-    if (kV <= 0.0) {
-      throw new IllegalArgumentException("Kv must be greater than zero.");
+    if (kV < 0.0) {
+      throw new IllegalArgumentException("Kv must be greater than or equal to zero.");
     }
     if (kA <= 0.0) {
       throw new IllegalArgumentException("Ka must be greater than zero.");
@@ -256,14 +256,14 @@ public final class LinearSystemId {
    * <p>u = K_v v + K_a a
    *
    * @param kV The velocity gain, in volts/(unit/sec)
-   * @param kA The acceleration gain, in volts/(unit/sec^2)
+   * @param kA The acceleration gain, in volts/(unit/sec²)
    * @return A LinearSystem representing the given characterized constants.
-   * @throws IllegalArgumentException if kV &lt;= 0 or kA &lt;= 0.
+   * @throws IllegalArgumentException if kV &lt; 0 or kA &lt;= 0.
    * @see <a href="https://github.com/wpilibsuite/sysid">https://github.com/wpilibsuite/sysid</a>
    */
   public static LinearSystem<N1, N1, N1> identifyVelocitySystem(double kV, double kA) {
     if (kV <= 0.0) {
-      throw new IllegalArgumentException("Kv must be greater than zero.");
+      throw new IllegalArgumentException("Kv must be greater than or equal to zero.");
     }
     if (kA <= 0.0) {
       throw new IllegalArgumentException("Ka must be greater than zero.");
@@ -291,12 +291,12 @@ public final class LinearSystemId {
    * @param kV The velocity gain, in volts/(unit/sec)
    * @param kA The acceleration gain, in volts/(unit/sec²)
    * @return A LinearSystem representing the given characterized constants.
-   * @throws IllegalArgumentException if kV &lt;= 0 or kA &lt;= 0.
+   * @throws IllegalArgumentException if kV &lt; 0 or kA &lt;= 0.
    * @see <a href="https://github.com/wpilibsuite/sysid">https://github.com/wpilibsuite/sysid</a>
    */
   public static LinearSystem<N2, N1, N1> identifyPositionSystem(double kV, double kA) {
     if (kV <= 0.0) {
-      throw new IllegalArgumentException("Kv must be greater than zero.");
+      throw new IllegalArgumentException("Kv must be greater than or equal to zero.");
     }
     if (kA <= 0.0) {
       throw new IllegalArgumentException("Ka must be greater than zero.");

wpimath/src/main/native/cpp/kinematics/proto/DifferentialDriveWheelPositionsProto.cpp

@@ -0,0 +1,34 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+#include "frc/kinematics/proto/DifferentialDriveWheelPositionsProto.h"
+
+#include "kinematics.pb.h"
+
+google::protobuf::Message* wpi::Protobuf<
+    frc::DifferentialDriveWheelPositions>::New(google::protobuf::Arena* arena) {
+  return google::protobuf::Arena::CreateMessage<
+      wpi::proto::ProtobufDifferentialDriveWheelPositions>(arena);
+}
+
+frc::DifferentialDriveWheelPositions
+wpi::Protobuf<frc::DifferentialDriveWheelPositions>::Unpack(
+    const google::protobuf::Message& msg) {
+  auto m =
+      static_cast<const wpi::proto::ProtobufDifferentialDriveWheelPositions*>(
+          &msg);
+  return frc::DifferentialDriveWheelPositions{
+      units::meter_t{m->left()},
+      units::meter_t{m->right()},
+  };
+}
+
+void wpi::Protobuf<frc::DifferentialDriveWheelPositions>::Pack(
+    google::protobuf::Message* msg,
+    const frc::DifferentialDriveWheelPositions& value) {
+  auto m =
+      static_cast<wpi::proto::ProtobufDifferentialDriveWheelPositions*>(msg);
+  m->set_left(value.left.value());
+  m->set_right(value.right.value());
+}

wpimath/src/main/native/cpp/kinematics/struct/DifferentialDriveWheelPositionsStruct.cpp

@@ -0,0 +1,26 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+#include "frc/kinematics/struct/DifferentialDriveWheelPositionsStruct.h"
+
+namespace {
+constexpr size_t kLeftOff = 0;
+constexpr size_t kRightOff = kLeftOff + 8;
+}  // namespace
+
+using StructType = wpi::Struct<frc::DifferentialDriveWheelPositions>;
+
+frc::DifferentialDriveWheelPositions StructType::Unpack(
+    std::span<const uint8_t> data) {
+  return frc::DifferentialDriveWheelPositions{
+      units::meter_t{wpi::UnpackStruct<double, kLeftOff>(data)},
+      units::meter_t{wpi::UnpackStruct<double, kRightOff>(data)},
+  };
+}
+
+void StructType::Pack(std::span<uint8_t> data,
+                      const frc::DifferentialDriveWheelPositions& value) {
+  wpi::PackStruct<kLeftOff>(data, value.left.value());
+  wpi::PackStruct<kRightOff>(data, value.right.value());
+}

wpimath/src/main/native/include/frc/kinematics/DifferentialDriveWheelPositions.h

@@ -49,3 +49,6 @@ struct WPILIB_DLLEXPORT DifferentialDriveWheelPositions {
   }
 };
 }  // namespace frc
+
+#include "frc/kinematics/proto/DifferentialDriveWheelPositionsProto.h"
+#include "frc/kinematics/struct/DifferentialDriveWheelPositionsStruct.h"

wpimath/src/main/native/include/frc/kinematics/proto/DifferentialDriveWheelPositionsProto.h

@@ -0,0 +1,19 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+#pragma once
+
+#include <wpi/SymbolExports.h>
+#include <wpi/protobuf/Protobuf.h>
+
+#include "frc/kinematics/DifferentialDriveWheelPositions.h"
+
+template <>
+struct WPILIB_DLLEXPORT wpi::Protobuf<frc::DifferentialDriveWheelPositions> {
+  static google::protobuf::Message* New(google::protobuf::Arena* arena);
+  static frc::DifferentialDriveWheelPositions Unpack(
+      const google::protobuf::Message& msg);
+  static void Pack(google::protobuf::Message* msg,
+                   const frc::DifferentialDriveWheelPositions& value);
+};

wpimath/src/main/native/include/frc/kinematics/struct/DifferentialDriveWheelPositionsStruct.h

@@ -0,0 +1,28 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+#pragma once
+
+#include <wpi/SymbolExports.h>
+#include <wpi/struct/Struct.h>
+
+#include "frc/kinematics/DifferentialDriveWheelPositions.h"
+
+template <>
+struct WPILIB_DLLEXPORT wpi::Struct<frc::DifferentialDriveWheelPositions> {
+  static constexpr std::string_view GetTypeString() {
+    return "struct:DifferentialDriveWheelPositions";
+  }
+  static constexpr size_t GetSize() { return 16; }
+  static constexpr std::string_view GetSchema() {
+    return "double left;double right";
+  }
+
+  static frc::DifferentialDriveWheelPositions Unpack(
+      std::span<const uint8_t> data);
+  static void Pack(std::span<uint8_t> data,
+                   const frc::DifferentialDriveWheelPositions& value);
+};
+
+static_assert(wpi::StructSerializable<frc::DifferentialDriveWheelPositions>);

wpimath/src/main/native/include/frc/system/plant/LinearSystemId.h

@@ -79,7 +79,7 @@ class WPILIB_DLLEXPORT LinearSystemId {
    *
    * @param kV The velocity gain, in volts/(unit/sec).
    * @param kA The acceleration gain, in volts/(unit/sec²).
-   * @throws std::domain_error if kV <= 0 or kA <= 0.
+   * @throws std::domain_error if kV < 0 or kA <= 0.
    * @see <a
    * href="https://github.com/wpilibsuite/sysid">https://github.com/wpilibsuite/sysid</a>
    */
@@ -89,8 +89,8 @@ class WPILIB_DLLEXPORT LinearSystemId {
   static LinearSystem<1, 1, 1> IdentifyVelocitySystem(
       decltype(1_V / Velocity_t<Distance>(1)) kV,
       decltype(1_V / Acceleration_t<Distance>(1)) kA) {
-    if (kV <= decltype(kV){0}) {
-      throw std::domain_error("Kv must be greater than zero.");
+    if (kV < decltype(kV){0}) {
+      throw std::domain_error("Kv must be greater than or equal to zero.");
     }
     if (kA <= decltype(kA){0}) {
       throw std::domain_error("Ka must be greater than zero.");
@@ -122,7 +122,7 @@ class WPILIB_DLLEXPORT LinearSystemId {
    * @param kV The velocity gain, in volts/(unit/sec).
    * @param kA The acceleration gain, in volts/(unit/sec²).
    *
-   * @throws std::domain_error if kV <= 0 or kA <= 0.
+   * @throws std::domain_error if kV < 0 or kA <= 0.
    * @see <a
    * href="https://github.com/wpilibsuite/sysid">https://github.com/wpilibsuite/sysid</a>
    */
@@ -132,8 +132,8 @@ class WPILIB_DLLEXPORT LinearSystemId {
   static LinearSystem<2, 1, 1> IdentifyPositionSystem(
       decltype(1_V / Velocity_t<Distance>(1)) kV,
       decltype(1_V / Acceleration_t<Distance>(1)) kA) {
-    if (kV <= decltype(kV){0}) {
-      throw std::domain_error("Kv must be greater than zero.");
+    if (kV < decltype(kV){0}) {
+      throw std::domain_error("Kv must be greater than or equal to zero.");
     }
     if (kA <= decltype(kA){0}) {
       throw std::domain_error("Ka must be greater than zero.");
@@ -251,7 +251,7 @@ class WPILIB_DLLEXPORT LinearSystemId {
    * @param kV The velocity gain, in volts/(unit/sec).
    * @param kA The acceleration gain, in volts/(unit/sec²).
    *
-   * @throws std::domain_error if kV <= 0 or kA <= 0.
+   * @throws std::domain_error if kV < 0 or kA <= 0.
    */
   template <typename Distance>
     requires std::same_as<units::meter, Distance> ||
@@ -259,8 +259,8 @@ class WPILIB_DLLEXPORT LinearSystemId {
   static LinearSystem<2, 1, 2> DCMotorSystem(
       decltype(1_V / Velocity_t<Distance>(1)) kV,
       decltype(1_V / Acceleration_t<Distance>(1)) kA) {
-    if (kV <= decltype(kV){0}) {
-      throw std::domain_error("Kv must be greater than zero.");
+    if (kV < decltype(kV){0}) {
+      throw std::domain_error("Kv must be greater than or equal to zero.");
     }
     if (kA <= decltype(kA){0}) {
       throw std::domain_error("Ka must be greater than zero.");

wpimath/src/main/proto/kinematics.proto

@@ -21,6 +21,11 @@ message ProtobufDifferentialDriveWheelSpeeds {
   double right = 2;
 }
 
+message ProtobufDifferentialDriveWheelPositions {
+  double left = 1;
+  double right = 2;
+}
+
 message ProtobufMecanumDriveKinematics {
   ProtobufTranslation2d front_left = 1;
   ProtobufTranslation2d front_right = 2;

wpimath/src/test/java/edu/wpi/first/math/kinematics/struct/DifferentialDriveWheelPositionsStructTest.java

@@ -0,0 +1,29 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+package edu.wpi.first.math.kinematics.struct;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import edu.wpi.first.math.kinematics.DifferentialDriveWheelPositions;
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+import org.junit.jupiter.api.Test;
+
+class DifferentialDriveWheelPositionsStructTest {
+  private static final DifferentialDriveWheelPositions DATA =
+      new DifferentialDriveWheelPositions(1.74, 35.04);
+
+  @Test
+  void testRoundtrip() {
+    ByteBuffer buffer = ByteBuffer.allocate(DifferentialDriveWheelPositions.struct.getSize());
+    buffer.order(ByteOrder.LITTLE_ENDIAN);
+    DifferentialDriveWheelPositions.struct.pack(buffer, DATA);
+    buffer.rewind();
+
+    DifferentialDriveWheelPositions data = DifferentialDriveWheelPositions.struct.unpack(buffer);
+    assertEquals(DATA.leftMeters, data.leftMeters);
+    assertEquals(DATA.rightMeters, data.rightMeters);
+  }
+}

wpimath/src/test/native/cpp/kinematics/struct/DifferentialDriveWheelPositionsStructTest.cpp

@@ -0,0 +1,27 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+#include <gtest/gtest.h>
+
+#include "frc/kinematics/DifferentialDriveWheelPositions.h"
+
+using namespace frc;
+
+namespace {
+
+using StructType = wpi::Struct<frc::DifferentialDriveWheelPositions>;
+const DifferentialDriveWheelPositions kExpectedData{
+    DifferentialDriveWheelPositions{1.74_m, 35.04_m}};
+}  // namespace
+
+TEST(DifferentialDriveWheelPositionsStructTest, Roundtrip) {
+  uint8_t buffer[StructType::GetSize()];
+  std::memset(buffer, 0, StructType::GetSize());
+  StructType::Pack(buffer, kExpectedData);
+
+  DifferentialDriveWheelPositions unpacked_data = StructType::Unpack(buffer);
+
+  EXPECT_EQ(kExpectedData.left.value(), unpacked_data.left.value());
+  EXPECT_EQ(kExpectedData.right.value(), unpacked_data.right.value());
+}

wpiunits/src/main/java/edu/wpi/first/units/Distance.java

@@ -5,10 +5,10 @@
 package edu.wpi.first.units;
 
 /**
- * Unit of angular dimension.
+ * Unit of linear dimension.
  *
- * <p>This is the base type for units of distance dimension. It is also used to specify the
- * dimension for {@link Measure}: <code>Measure&lt;Distance&gt;</code>.
+ * <p>This is the base type for units of linear dimension. It is also used to specify the dimension
+ * for {@link Measure}: <code>Measure&lt;Distance&gt;</code>.
  *
  * <p>Actual units (such as {@link Units#Meters} and {@link Units#Inches}) can be found in the
  * {@link Units} class.

wpiutil/src/main/native/cpp/timestamp.cpp

@@ -273,10 +273,14 @@ uint64_t wpi::Now() {
     if (nowUseDefaultOnFailure.test()) {
       return timestamp() - offset_val;
     } else {
-      fmt::print(
-          stderr,
-          "FPGA not yet configured in wpi::Now(). Time will not be correct.\n");
+      fmt::print(stderr,
+                 "FPGA not yet configured in wpi::Now(). This is a fatal "
+                 "error. The process is being terminated.\n");
       std::fflush(stderr);
+      // Attempt to force a segfault to get a better java log
+      *reinterpret_cast<int*>(0) = 0;
+      // If that fails, terminate
+      std::terminate();
       return 1;
     }
   }