fix(simulation): tune physical UGV braking

apps/control-station/src/components/simulation/SimulationUgvController.ts

@@ -24,7 +24,9 @@ const PHYSICS_PROXY_ERROR = 0.0003;
 const PHYSICS_PROXY_MAX_TRIANGLES = 240_000;
 const SERVICE_BRAKE_DECELERATION_MPS2 = 1.8;
 const COAST_DECELERATION_MPS2 = 0.18;
-const BRAKE_ATTITUDE_DAMPING = 6;
+const PARKING_BRAKE_HOLD_DECELERATION_MPS2 = 6;
+const PARKING_BRAKE_ENGAGE_SPEED_MPS = 0.08;
+const TYRE_FRICTION_SLIP = 8.5;
 const DEFAULT_ORBIT_PITCH = 0.48;
 const CAMERA_RETURN_DELAY_SECONDS = 1.2;
 const CAMERA_RETURN_DURATION_SECONDS = 2;
@@ -311,6 +313,7 @@ export class SimulationUgvController {
     const maxSpeed = this.settings.maxSpeedMetersPerSecond;
     const maxTurnRate = this.settings.maxTurnRateDegrees * Math.PI / 180;
     const pureTurn = !braking && forwardInput === 0 && turnInput !== 0;
+    const holding = !braking && forwardInput === 0 && turnInput === 0;
     const desiredSpeed = forwardInput * maxSpeed;
     const speedError = desiredSpeed - speedMetersPerSecond;
     const speedResponseRange = Math.max(0.35, maxSpeed * 0.2);
@@ -325,13 +328,22 @@ export class SimulationUgvController {
     const leftCommand = clamp(forwardCommand - turnCommand, -1, 1);
     const rightCommand = clamp(forwardCommand + turnCommand, -1, 1);
     const engineForce = pureTurn ? pivotForcePerWheel : driveForcePerWheel;
+    const brakeDeceleration = braking
+      ? SERVICE_BRAKE_DECELERATION_MPS2
+      : holding
+        ? Math.abs(speedMetersPerSecond) <= PARKING_BRAKE_ENGAGE_SPEED_MPS
+          ? PARKING_BRAKE_HOLD_DECELERATION_MPS2
+          : COAST_DECELERATION_MPS2
+        : 0;
+    const wheelBrakeForce = this.settings.massKg * brakeDeceleration
+      / Math.max(1, this.wheelDefinitions.length);
 
     for (let index = 0; index < this.wheelDefinitions.length; index += 1) {
       const definition = this.wheelDefinitions[index];
       const command = definition.left ? leftCommand : rightCommand;
       this.vehicle.setSteeringValue(0, index);
       this.vehicle.applyEngineForce(command * engineForce, index);
-      this.vehicle.setBrake(0, index);
+      this.vehicle.setBrake(wheelBrakeForce, index);
       this.vehicle.updateWheelTransform(index, true);
       const transform = this.vehicle.getWheelTransformWS(index);
       const position = transform.getOrigin();
@@ -345,17 +357,6 @@ export class SimulationUgvController {
       let nextLinearX = linearVelocity.x;
       let nextLinearZ = linearVelocity.z;
       let horizontalSpeed = Math.hypot(nextLinearX, nextLinearZ);
-      const coasting = !braking && forwardInput === 0 && turnInput === 0;
-      if ((braking || coasting) && horizontalSpeed > 0.001) {
-        const deceleration = braking
-          ? SERVICE_BRAKE_DECELERATION_MPS2
-          : COAST_DECELERATION_MPS2;
-        const nextSpeed = Math.max(0, horizontalSpeed - deceleration * Math.max(0, deltaSeconds));
-        const scale = nextSpeed / horizontalSpeed;
-        nextLinearX *= scale;
-        nextLinearZ *= scale;
-        horizontalSpeed = nextSpeed;
-      }
       if (pureTurn && horizontalSpeed > 0.001) {
         const pivotDamping = Math.exp(-Math.max(0, deltaSeconds) * 8);
         nextLinearX *= pivotDamping;
@@ -372,9 +373,6 @@ export class SimulationUgvController {
         rigidbody.linearVelocity = this.limitedLinearVelocity;
       }
       const angularVelocity = rigidbody.angularVelocity;
-      const attitudeDamping = braking
-        ? Math.exp(-Math.max(0, deltaSeconds) * BRAKE_ATTITUDE_DAMPING)
-        : 1;
       let nextAngularY = angularVelocity.y;
       if (pureTurn) {
         const desiredYawRate = -turnInput * maxTurnRate;
@@ -387,11 +385,11 @@ export class SimulationUgvController {
       } else if (Math.abs(angularVelocity.y) > maxTurnRate) {
         nextAngularY = Math.sign(angularVelocity.y) * maxTurnRate;
       }
-      if (attitudeDamping !== 1 || nextAngularY !== angularVelocity.y) {
+      if (nextAngularY !== angularVelocity.y) {
         this.limitedAngularVelocity.set(
-          angularVelocity.x * attitudeDamping,
+          angularVelocity.x,
           nextAngularY,
-          angularVelocity.z * attitudeDamping,
+          angularVelocity.z,
         );
         rigidbody.angularVelocity = this.limitedAngularVelocity;
       }
@@ -464,8 +462,9 @@ export class SimulationUgvController {
       type: "dynamic",
       mass: this.settings.massKg,
       friction: 0.85,
-      linearDamping: 0.08,
+      rollingFriction: 0.12,
-      angularDamping: 0.45,
+      linearDamping: 0.12,
+      angularDamping: 0.6,
     });
 
     this.chassisMaterial = createMaterial(readThemeAccent(), new Color(0.03, 0.04, 0.05));
@@ -559,7 +558,7 @@ export class SimulationUgvController {
       wheel.set_m_suspensionStiffness(24);
       wheel.set_m_wheelsDampingRelaxation(3.2);
       wheel.set_m_wheelsDampingCompression(4.8);
-      wheel.set_m_frictionSlip(5.5);
+      wheel.set_m_frictionSlip(TYRE_FRICTION_SLIP);
       wheel.set_m_rollInfluence(0.08);
     }
     this.ammo.destroy(axle);

apps/control-station/test/simulationWorkspace.test.mjs

@@ -179,8 +179,16 @@ test("PlayCanvas owns the realtime scene graph without an iframe or React entity
   assert.match(ugv, /desiredSpeed = forwardInput \* maxSpeed/);
   assert.match(ugv, /maximumAcceleration = clamp\(1\.4 \+ maxSpeed \* 0\.35, 1\.8, 4\.2\)/);
   assert.match(ugv, /SERVICE_BRAKE_DECELERATION_MPS2 = 1\.8/);
-  assert.match(ugv, /horizontalSpeed - deceleration \* Math\.max\(0, deltaSeconds\)/);
+  assert.match(ugv, /PARKING_BRAKE_HOLD_DECELERATION_MPS2 = 6/);
-  assert.match(ugv, /this\.vehicle\.setBrake\(0, index\)/);
+  assert.match(ugv, /PARKING_BRAKE_ENGAGE_SPEED_MPS = 0\.08/);
+  assert.match(ugv, /TYRE_FRICTION_SLIP = 8\.5/);
+  assert.match(ugv, /holding = !braking && forwardInput === 0 && turnInput === 0/);
+  assert.match(ugv, /this\.settings\.massKg \* brakeDeceleration/);
+  assert.match(ugv, /this\.vehicle\.setBrake\(wheelBrakeForce, index\)/);
+  assert.doesNotMatch(ugv, /horizontalSpeed - deceleration \* Math\.max\(0, deltaSeconds\)/);
+  assert.match(ugv, /rollingFriction: 0\.12/);
+  assert.match(ugv, /angularDamping: 0\.6/);
+  assert.match(ugv, /wheel\.set_m_frictionSlip\(TYRE_FRICTION_SLIP\)/);
   assert.doesNotMatch(ugv, /massKg \* 3/);
   assert.match(ugv, /pureTurn = !braking && forwardInput === 0 && turnInput !== 0/);
   assert.match(ugv, /desiredYawRate = -turnInput \* maxTurnRate/);