fix: mirror rack input across hardpoint corners

.github/workflows/build.yml

@@ -147,8 +147,10 @@ jobs:
       - name: Configure (validation preset)
         run: cmake --preset validation -Dpybind11_DIR="$(python3 -m pybind11 --cmakedir)"
 
+      # Bound validation compilation memory so hosted runners do not terminate
+      # concurrent compiler processes before the authoritative test run.
       - name: Build (validation preset)
-        run: cmake --build --preset validation
+        run: cmake --build --preset validation --parallel 2
 
       - name: List registered tests
         run: ctest --preset validation -N | tee ctest-list.txt

core/src/fourteen_dof_dynamics.cpp

@@ -377,15 +377,22 @@ class FourteenDOFDynamics : public IVehicleDynamics {
         mb::WheelLoad wl {};
         const auto F = inner_->tire_forces_body();
         wl.force_world = 0.5 * (F[wheel_base] + F[wheel_base + 1]);
-        const auto mot = axle_prescribed_motion(wheel_base, steer_rad);
-        const auto wp = dae->step(*st, mot, wl, 0.0);
+        const auto mot_left = axle_prescribed_motion(wheel_base, steer_rad);
+        auto mot_right = mot_left;
+        mot_right.steer_rack_dy = -mot_left.steer_rack_dy;
+        auto st_left = *st;
+        auto st_right = *st;
+        const auto wp_left = dae->step(st_left, mot_left, wl, 0.0);
+        const auto wp_right = dae->step(st_right, mot_right, wl, 0.0);
+        *st = std::move(st_left);
         double toe_comp = 0.0, camber_comp = 0.0;
         mb::compliance_targets_rad(*topo, wl, toe_comp, camber_comp);
         mb_compliance_toe_rad_[wheel_base == 0 ? 0 : 1] = toe_comp;
         for (int j = 0; j < 2; ++j) {
             const int i = wheel_base + j;
             const bool right = (i == WHEEL_FR || i == WHEEL_RR);
             const double s = right ? -1.0 : 1.0;
+            const auto& wp = right ? wp_right : wp_left;
             gamma[i] = s * (wp.camber_rad + camber_comp);
             toe[i]   = s * (wp.toe_rad + toe_comp);
         }

core/src/free_3d_dynamics.cpp

@@ -1001,16 +1001,18 @@ class Free3DDynamics final : public IVehicleDynamics {
         const Mat3 R = state_.orientation.toRotationMatrix();
         for (int i = 0; i < NUM_WHEELS; ++i) {
             const bool front = (i == WHEEL_FL || i == WHEEL_FR);
+            const bool right = (i == WHEEL_FR || i == WHEEL_RR);
             mb::IHardJointDaeModel* dae = front ? mb_dae_front_.get() : mb_dae_rear_.get();
             if (!dae) continue;
             mb::PrescribedCornerMotion mot;
             mot.travel_z      = state_.susp_compression[i];
             mot.travel_z_dot  = state_.susp_velocity[i];
             mot.steer_rack_dy = front ? steer_rad * kRackPerRad : 0.0;
+            if (right) mot.steer_rack_dy = -mot.steer_rack_dy;
             mb::WheelLoad wl;
             wl.force_world = R * tire_F_[i];
             const mb::WheelPose wp = dae->step(mb_state_[i], mot, wl, dt);
-            const double s = (i == WHEEL_FR || i == WHEEL_RR) ? -1.0 : 1.0;
+            const double s = right ? -1.0 : 1.0;
             gamma_dae_[i] = s * wp.camber_rad;
             toe_dae_[i]   = s * wp.toe_rad;
             // Real linkage travel geometry at the current vertical travel: the wheel-centre

docs/VALIDATION.md

@@ -83,12 +83,12 @@ version and the new numbers have to land in the same commit.
 
 <!-- VALIDATION-CURRENCY BEGIN -->
 ```text
-tests:    585/585
+tests:    587/587
 config:   cmake --preset validation && cmake --build --preset validation && ctest --preset validation
 presets:  CMakePresets.json@c98fe5e64c842faaeb06598af46476f3507c18a6
 toolchain: cmake 3.31.10
-commit:   fc897a014b54a541520be5be2c4082c8c509746d
-date:     2026-10-30
+commit:   69d5da46f6aac8e4a937747c91d42e9caf145833
+date:     2026-11-02
 excluded: gui_v3_e2e (GUI v3 test group formally deferred -- VDSIM_BUILD_GUI_V3_TESTS=OFF)
 excluded: gui_v3_api_smoke (GUI v3 test group formally deferred -- VDSIM_BUILD_GUI_V3_TESTS=OFF)
 excluded: closedloop_wallclock_timing (label timing, excluded by the validation test preset: wall-clock S6/S7 verdicts depend on host load -- local low-load evidence in the work order 31 PR description)

tests/fixtures/d0_flat_contact_l4_baseline.csv

@@ -3,6 +3,6 @@ step,t_s,state_pos_x_m,state_pos_y_m,state_pos_z_m,state_q_w,state_q_x,state_q_y
 1,0.0050000000000000001,0.075000842055719205,0,0,0.99999999999992606,0,-3.8469516600097953e-07,0,15.000489835976351,0,0,0,-0.00030535708261022289,0,46.875452868993435,46.875452868993435,46.997078463169778,46.997078463169778,0.12258230659828048,0.12258230659828048,0.098067519786607327,0.098067519786607327,-0.00030564731232229827,-0.00030564731232229827,0.00038025295321797691,0.00038025295321797691,0,0,-1.5400227480573836,0,0,-1.5400227480573836,-0,-0,139.52854928508373,0,0,139.52854928508373,0,0,4064.5345604728045,4064.5345604728045,3290.4529395271943,3290.4529395271943,-2.296319937249304e-05,-2.296319937249304e-05,0.0025718297971890382,0.0025718297971890382,0,0,0,0,0,0,0,0,0,-7.69390332001978e-07,0.16863157719149249,0,0
 20,0.10000000000000001,1.5022170147817413,0,0,0.99999994458621799,0,-0.00033290773639700058,0,15.049791163504317,0,0,0,-0.012212710858036506,0,47.022456772614568,47.022456772614568,47.406244784091506,47.406244784091506,0.12201397600590154,0.12201397600590154,0.09874876387528729,0.09874876387528729,-0.012395339232331271,-0.012395339232331271,0.014479770152611439,0.014479770152611439,0,0,-11.411368349790227,0.40931735055312296,0,-11.411368349790227,-0.40931735055312296,-0,439.63300236674439,0,0,439.63300236674439,0,0,3995.5658852032761,3995.5658852032761,3359.4216147967227,3359.4216147967227,-0.00017309191190712653,-0.00017309191190712653,0.0079872980629114108,0.0079872980629114108,-9.8529845104622846e-06,9.8529845104622846e-06,0,0,0,0,0,0,0,-0.00066581548509245258,0.57096101560810031,0,0
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-200,1,15.235744012369338,0.32504193164313022,0,0.99844009671353695,0.020551245310336818,0.00050946083423899493,0.051911078206058642,15.426441614431715,-0.15681686481537321,0,0.03419453967165912,-0.0011298234413202803,0.26999012395235572,47.407940753988477,48.85140499505836,47.987193150050636,49.091262219198882,0.093597775872696062,0.14909221340663417,0.071698289439124735,0.12719272697306283,-0.02551155315505451,0.021679905042366408,-0.022631653574999019,0.024559804622422052,0,0,-191.63562806687256,2100.420790275276,0,-37.960031370697536,1067.4333787015578,0,336.7667166197113,844.31154036015619,0,338.38117476245009,1592.2695665244128,0,2982.8015717899639,5095.1852934245671,2259.8022065754321,4372.1859282100349,-8.5191744723423857e-05,-5.7730205581704137e-05,0.0091148595465764693,0.004702053945345344,-0.078011719601018922,-0.020311797920368507,-0.036902126734384352,-0.035915312447611758,0,0,0,0,0.041102866169148253,-0.0011163425877231045,0.2970504098996537,3.7350615738686321,0
-300,1.5,22.878848395693332,1.5378920219833456,0,0.99272128667030057,0.023651104844006354,0.0022515169050280927,0.11806778943872558,15.545574488839133,-0.22557939030474722,0,0.00027365873951771895,3.074700310741997e-05,0.26224469553479518,47.770780697549775,49.198741990545528,48.403959577635682,49.442783159806481,0.088862078298180186,0.15365706478971594,0.066995113702774986,0.13179010019431076,-1.0992165787572111e-05,0.0004411110313866229,-0.00012153090935185865,0.00033057228782232484,0,0,-198.49763992253122,2145.7097096153375,0,-43.261319387505388,1293.8762513463619,0,338.96325133413421,879.60291269602385,0,339.98106917498654,1768.2738250619045,0,2891.6246644592816,5188.1425708841398,2166.8449291158586,4463.3628355407172,-9.7793681557438556e-05,-5.2994676012562844e-05,0.0095769167883368693,0.0046274223399719143,-0.084272926612623963,-0.024260336997927883,-0.040320524098892106,-0.039280929590051437,0,0,0,0,0.047507471603900897,-0.0011146100463822024,0.29146280500573257,4.0582686705757203,0
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tests/integration/test_fourteen_dof.cpp

@@ -88,6 +88,50 @@ TEST(FourteenDOF, L4KinematicLevelAndAttach) {
     EXPECT_GT(std::abs(dyn->state().velocity.x()), 5.0);
 }
 
+TEST(FourteenDOF, L4MirroredRackChangesFrontSlipInSameDirection) {
+    const std::string kin = std::string(VDSIM_SOURCE_DIR)
+        + "/configs/parts/susp_kinematics/kin/mp_front_sedan.yaml";
+    auto slip_for = [&](double steer, bool attach) {
+        auto dyn = vdsim::create_fourteen_dof_kinematic();
+        vdsim::VehicleParams vp;
+        vp.aero_drag_coeff = 0.0;
+        vp.camber_per_roll = 0.0;
+        vdsim::TireParams tp;
+        tp.lugre.enabled = false;
+        vdsim::SolverParams sp;
+        dyn->initialize(vp, tp, sp);
+        if (attach) {
+            auto topo = vdsim::mb::SuspensionTopology::from_yaml(kin);
+            EXPECT_TRUE(vdsim::mb::attach_topology_front(*dyn, topo));
+        }
+        dyn->reset(init_state(15.0, vp.wheel_radius_nominal));
+        vdsim::CmdL4 cmd;
+        cmd.steer_angle_wheel = steer;
+        dyn->step(cmd, flat_contacts(), 1e-6);
+        return dyn->wheel_slip_angle();
+    };
+
+    const auto attached_zero = slip_for(0.0, true);
+    const auto plain_zero = slip_for(0.0, false);
+    for (double steer : {0.06, -0.06}) {
+        const auto attached = slip_for(steer, true);
+        const auto plain = slip_for(steer, false);
+        const double kinematic_l =
+            (attached[vdsim::WHEEL_FL] - attached_zero[vdsim::WHEEL_FL])
+            - (plain[vdsim::WHEEL_FL] - plain_zero[vdsim::WHEEL_FL]);
+        const double kinematic_r =
+            (attached[vdsim::WHEEL_FR] - attached_zero[vdsim::WHEEL_FR])
+            - (plain[vdsim::WHEEL_FR] - plain_zero[vdsim::WHEEL_FR]);
+        EXPECT_GT(std::abs(kinematic_l), 1e-5);
+        EXPECT_GT(std::abs(kinematic_r), 1e-5);
+        EXPECT_GT(kinematic_l * kinematic_r, 0.0);
+    }
+
+    const auto attached_zero_again = slip_for(0.0, true);
+    EXPECT_EQ(attached_zero[vdsim::WHEEL_FL], attached_zero_again[vdsim::WHEEL_FL]);
+    EXPECT_EQ(attached_zero[vdsim::WHEEL_FR], attached_zero_again[vdsim::WHEEL_FR]);
+}
+
 TEST(FourteenDOF, StaticSuspensionPopulatedAtRest) {
     vdsim::VehicleParams vp; vp.aero_drag_coeff = 0.0;
     vdsim::TireParams tp;    vdsim::SolverParams sp;

tests/integration/test_l5_driving.cpp

@@ -290,6 +290,41 @@ TEST(L5StrutDae, AttachReportsEnabled) {
     EXPECT_TRUE(vdsim::free_3d_mb_dynamics_enabled(*h.dyn, 1));
 }
 
+TEST(L5StrutDae, MirroredRackSteersFrontWheelsInSameDirection) {
+    auto toe_for = [](double steer) {
+        L5StrutSetup h;
+        attach_corner_dae(*h.dyn);
+        h.reset_level(0.0);
+        vdsim::CmdL4 cmd;
+        cmd.steer_angle_wheel = steer;
+        h.run(cmd, 1, 0.001);
+        return vdsim::free_3d_wheel_toe(*h.dyn);
+    };
+
+    const auto zero = toe_for(0.0);
+    const auto pos = toe_for(0.06);
+    const auto neg = toe_for(-0.06);
+    const double pos_l = pos[vdsim::WHEEL_FL] - zero[vdsim::WHEEL_FL];
+    const double pos_r = pos[vdsim::WHEEL_FR] - zero[vdsim::WHEEL_FR];
+    const double neg_l = neg[vdsim::WHEEL_FL] - zero[vdsim::WHEEL_FL];
+    const double neg_r = neg[vdsim::WHEEL_FR] - zero[vdsim::WHEEL_FR];
+
+    EXPECT_GT(pos_l, 1e-5);
+    EXPECT_GT(pos_r, 1e-5);
+    EXPECT_LT(neg_l, -1e-5);
+    EXPECT_LT(neg_r, -1e-5);
+    EXPECT_EQ(zero[vdsim::WHEEL_FL], zero[vdsim::WHEEL_FR]);
+    const auto camber = [&] {
+        L5StrutSetup h;
+        attach_corner_dae(*h.dyn);
+        h.reset_level(0.0);
+        vdsim::CmdL4 cmd;
+        h.run(cmd, 1, 0.001);
+        return vdsim::free_3d_wheel_camber(*h.dyn);
+    }();
+    EXPECT_EQ(camber[vdsim::WHEEL_FL], -camber[vdsim::WHEEL_FR]);
+}
+
 TEST(L5StrutDae, SettleStillHoldsWeight) {
     L5StrutSetup h;
     attach_corner_dae(*h.dyn);