Add <dcmotor> actuator and related docs and tests.
PiperOrigin-RevId: 892927987 Change-Id: I38ed6412801341ba03ddf5fe7b93a6081df24d37
This commit is contained in:
Yuval Tassa
committed by
Copybara-Service
Copybara-Service
parent
6da210c794
commit
70a7647ad9
@@ -1148,6 +1148,949 @@ TEST_F(ActuatorTest, DampRatioTendon) {
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mj_deleteModel(model);
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}
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// ----------------------- DC motor actuators ----------------------------------
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using DCMotorTest = MujocoTest;
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TEST_F(DCMotorTest, IntVelocityEquivalence) {
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static constexpr char xml[] = R"(
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<mujoco>
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<option integrator="implicit"/>
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<worldbody>
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<body pos="0 0 0">
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<joint name="slide1" type="slide" axis="1 0 0"/>
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<geom size=".1"/>
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</body>
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<body pos="0 1 0">
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<joint name="slide2" type="slide" axis="1 0 0"/>
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<geom size=".1"/>
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</body>
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</worldbody>
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<actuator>
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<!--
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Equivalence mapping:
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intvelocity force: F = kp * \int(ctrl - v) - kv * v
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dcmotor force: F = (V*K - K^2*v) / R
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where V = ki * \int(ctrl - v) (since kp=0, kd=0)
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Setting K=1, R=0.2, ki=2 yields:
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F = (2 * \int(ctrl - v) - v) / 0.2
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= 10 * \int(ctrl - v) - 5 * v
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This perfectly matches intvelocity with kp=10, kv=5.
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-->
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<intvelocity name="intvel" joint="slide1" kp="10" kv="5" actrange="-0.01 0.01"/>
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<dcmotor name="dcmotor" joint="slide2" motorconst="1" resistance="0.2" input="velocity" controller="0 2 0 0 0.01"/>
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</actuator>
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</mujoco>
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)";
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char error[1024];
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mjModel* model = LoadModelFromString(xml, error, sizeof(error));
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ASSERT_THAT(model, NotNull()) << error;
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mjData* data = mj_makeData(model);
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// Apply a time-varying velocity command
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while (data->time < 1.0) {
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data->ctrl[0] = mju_sin(20 * data->time);
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data->ctrl[1] = mju_sin(20 * data->time);
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mj_step(model, data);
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// Both actuators should integrate identical states
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EXPECT_MJTNUM_EQ(data->act[0], data->act[1]);
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// Both bodies should move identically
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EXPECT_NEAR(data->qpos[0], data->qpos[1], MjTol(1e-14, 1e-7));
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EXPECT_NEAR(data->qvel[0], data->qvel[1], MjTol(1e-14, 1e-7));
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EXPECT_NEAR(data->qacc[0], data->qacc[1], MjTol(1e-14, 1e-6));
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// Both actuators should produce identical force
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EXPECT_NEAR(data->actuator_force[0], data->actuator_force[1],
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MjTol(1e-14, 1e-6));
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}
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mj_deleteData(data);
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mj_deleteModel(model);
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}
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TEST_F(DCMotorTest, StatelessSteadyState) {
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static constexpr char xml[] = R"(
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<mujoco>
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<worldbody>
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<body>
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<joint name="joint"/>
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<geom size="1"/>
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</body>
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</worldbody>
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<actuator>
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<dcmotor joint="joint" motorconst="0.05" resistance="2.0"/>
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</actuator>
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</mujoco>
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)";
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char error[1024];
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mjModel* model = LoadModelFromString(xml, error, sizeof(error));
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ASSERT_THAT(model, NotNull()) << error;
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mjData* data = mj_makeData(model);
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double K = 0.05;
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double R = 2.0;
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double V = 12.0;
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double omega = 3.0;
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data->ctrl[0] = V;
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data->qvel[0] = omega;
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mj_forward(model, data);
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double expected_force = K / R * (V - K * omega);
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EXPECT_NEAR(data->actuator_force[0], expected_force, MjTol(1e-12, 1e-5));
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EXPECT_EQ(model->actuator_actnum[0], 0);
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mj_deleteData(data);
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mj_deleteModel(model);
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}
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TEST_F(DCMotorTest, CurrentFilterConverges) {
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static constexpr char xml[] = R"(
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<mujoco>
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<option timestep="0.0001"/>
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<worldbody>
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<body>
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<joint name="joint" damping="1000"/>
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<geom size="1" mass="100"/>
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</body>
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</worldbody>
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<actuator>
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<dcmotor joint="joint" motorconst="0.05" resistance="2.0"
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inductance="0.01 0"/>
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</actuator>
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</mujoco>
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)";
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char error[1024];
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mjModel* model = LoadModelFromString(xml, error, sizeof(error));
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ASSERT_THAT(model, NotNull()) << error;
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mjData* data = mj_makeData(model);
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ASSERT_EQ(model->actuator_actnum[0], 1);
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double K = 0.05;
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double R = 2.0;
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double V = 12.0;
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data->ctrl[0] = V;
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for (int i = 0; i < 10000; i++) {
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mj_step(model, data);
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}
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double omega = data->qvel[0];
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double i_ss = V / R - K / R * omega;
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double expected_force = K * i_ss;
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EXPECT_NEAR(data->act[0], i_ss, MjTol(1e-6, 1e-4));
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EXPECT_NEAR(data->actuator_force[0], expected_force, MjTol(1e-6, 1e-4));
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mj_deleteData(data);
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mj_deleteModel(model);
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}
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TEST_F(DCMotorTest, CurrentFilterExactIntegration) {
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static constexpr char xml[] = R"(
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<mujoco>
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<option timestep="0.001"/>
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<worldbody>
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<body>
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<joint name="joint" damping="10000"/>
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<geom size="1" mass="10000"/>
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</body>
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</worldbody>
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<actuator>
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<dcmotor joint="joint" motorconst="0.05" resistance="2.0"
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inductance="0.01 0"/>
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</actuator>
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</mujoco>
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)";
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char error[1024];
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mjModel* model = LoadModelFromString(xml, error, sizeof(error));
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ASSERT_THAT(model, NotNull()) << error;
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mjData* data = mj_makeData(model);
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double R = 2.0;
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double te = 0.01 / R;
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double V = 12.0;
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data->ctrl[0] = V;
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mj_step(model, data);
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double h = model->opt.timestep;
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double exact_current = V / R * (1 - mju_exp(-h / te));
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EXPECT_NEAR(data->act[0], exact_current, MjTol(1e-10, 1e-4));
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double euler_current = V / R * h / te;
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EXPECT_GT(std::abs(data->act[0] - euler_current),
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std::abs(data->act[0] - exact_current));
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mj_deleteData(data);
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mj_deleteModel(model);
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}
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TEST_F(DCMotorTest, CoggingTorque) {
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static constexpr char xml[] = R"(
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<mujoco>
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<worldbody>
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<body>
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<joint name="joint"/>
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<geom size="1"/>
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</body>
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</worldbody>
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<actuator>
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<dcmotor joint="joint" motorconst="0.05" resistance="2.0"
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cogging="0.1 6 0"/>
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</actuator>
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</mujoco>
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)";
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char error[1024];
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mjModel* model = LoadModelFromString(xml, error, sizeof(error));
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ASSERT_THAT(model, NotNull()) << error;
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mjData* data = mj_makeData(model);
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double A = 0.1, Np = 6, phi = 0;
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double K = 0.05, R = 2.0;
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double V = 5.0;
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double pos = 1.0;
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data->ctrl[0] = V;
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data->qpos[0] = pos;
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mj_forward(model, data);
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double electrical_force = K / R * V;
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double cogging = A * mju_sin(Np * pos + phi);
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EXPECT_NEAR(data->actuator_force[0], electrical_force + cogging,
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MjTol(1e-12, 1e-5));
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mj_deleteData(data);
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mj_deleteModel(model);
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}
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TEST_F(DCMotorTest, CoggingBypassesSaturation) {
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static constexpr char xml[] = R"(
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<mujoco>
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<worldbody>
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<body>
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<joint name="joint"/>
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<geom size="1"/>
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</body>
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</worldbody>
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<actuator>
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<dcmotor joint="joint" motorconst="0.05" resistance="2.0"
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saturation="0.001 0" cogging="0.1 6 0"/>
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</actuator>
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</mujoco>
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)";
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char error[1024];
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mjModel* model = LoadModelFromString(xml, error, sizeof(error));
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ASSERT_THAT(model, NotNull()) << error;
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mjData* data = mj_makeData(model);
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double A = 0.1, Np = 6, phi = 0;
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double pos = 1.0;
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data->ctrl[0] = 100.0;
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data->qpos[0] = pos;
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mj_forward(model, data);
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double cogging = A * mju_sin(Np * pos + phi);
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EXPECT_NEAR(model->actuator_forcerange[1], 0.001, MjTol(1e-12, 1e-5));
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EXPECT_GT(mju_abs(data->actuator_force[0]), 0.001);
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EXPECT_NEAR(data->actuator_force[0], 0.001 + cogging, MjTol(1e-12, 1e-5));
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mj_deleteData(data);
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mj_deleteModel(model);
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}
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TEST_F(DCMotorTest, LuGreViscousFriction) {
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static constexpr char xml[] = R"(
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<mujoco>
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<worldbody>
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<body>
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<joint name="joint"/>
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<geom size="1"/>
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</body>
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</worldbody>
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<actuator>
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<dcmotor joint="joint" motorconst="0.05" resistance="2.0"
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lugre="100 1 0.01 0.5 0.7 10"/>
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</actuator>
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</mujoco>
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)";
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char error[1024];
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mjModel* model = LoadModelFromString(xml, error, sizeof(error));
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ASSERT_THAT(model, NotNull()) << error;
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mjData* data = mj_makeData(model);
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ASSERT_EQ(model->actuator_actnum[0], 1);
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double sigma1 = 1, sigma2 = 0.01;
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double K = 0.05, R = 2.0;
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double omega = 2.0;
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data->ctrl[0] = 0;
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data->qvel[0] = omega;
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mj_forward(model, data);
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EXPECT_MJTNUM_EQ(model->actuator_damping[0], sigma2);
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double electrical_force = K / R * (0 - K * omega);
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double z = data->act[model->actuator_actadr[0]];
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double z_dot = data->act_dot[model->actuator_actadr[0]];
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double lugre_force = 100 * z + sigma1 * z_dot;
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EXPECT_NEAR(data->actuator_force[0], electrical_force - lugre_force,
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MjTol(1e-12, 1e-5));
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mj_deleteData(data);
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mj_deleteModel(model);
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}
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TEST_F(DCMotorTest, ThermalRiseAndFall) {
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static constexpr char xml[] = R"(
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<mujoco>
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<option timestep="0.001"/>
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<worldbody>
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<body>
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<joint name="joint" damping="10000"/>
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<geom size="1" mass="10000"/>
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</body>
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</worldbody>
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<actuator>
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<dcmotor joint="joint" motorconst="0.05" resistance="2.0"
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thermal="10 5 0 0 25 25"/>
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</actuator>
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</mujoco>
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)";
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char error[1024];
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mjModel* model = LoadModelFromString(xml, error, sizeof(error));
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ASSERT_THAT(model, NotNull()) << error;
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mjData* data = mj_makeData(model);
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int adr = model->actuator_actadr[0];
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ASSERT_EQ(model->actuator_actnum[0], 1);
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EXPECT_EQ(data->act[adr], 0);
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double R = 2.0, V = 10.0;
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double RT = 10.0, C = 5.0;
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double h = model->opt.timestep;
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double P = V * V / R;
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data->ctrl[0] = V;
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mj_step(model, data);
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double dT1 = h * P / C;
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EXPECT_NEAR(data->act[adr], dT1, MjTol(1e-11, 1e-4));
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mj_step(model, data);
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double dT2 = dT1 + h * (P - dT1 / RT) / C;
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EXPECT_NEAR(data->act[adr], dT2, MjTol(1e-11, 1e-4));
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data->ctrl[0] = 0;
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mj_step(model, data);
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double dT3 = dT2 + h * (0 - dT2 / RT) / C;
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EXPECT_NEAR(data->act[adr], dT3, MjTol(1e-11, 1e-4));
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EXPECT_LT(data->act[adr], dT2);
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mj_deleteData(data);
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mj_deleteModel(model);
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}
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TEST_F(DCMotorTest, ThermalSteadyState) {
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static constexpr char xml[] = R"(
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<mujoco>
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<option timestep="0.001"/>
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<worldbody>
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<body>
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<joint name="joint" damping="10000"/>
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<geom size="1" mass="10000"/>
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</body>
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</worldbody>
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<actuator>
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<dcmotor joint="joint" motorconst="0.05" resistance="2.0"
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thermal="0.1 0.1 0 0 25 25"/>
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</actuator>
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</mujoco>
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)";
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char error[1024];
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mjModel* model = LoadModelFromString(xml, error, sizeof(error));
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ASSERT_THAT(model, NotNull()) << error;
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mjData* data = mj_makeData(model);
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double R = 2.0, V = 10.0;
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double RT = 0.1;
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double dT_ss = RT * V * V / R;
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data->ctrl[0] = V;
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for (int i = 0; i < 10000; i++) {
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mj_step(model, data);
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}
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int adr = model->actuator_actadr[0];
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EXPECT_NEAR(data->act[adr], dT_ss, 1e-4);
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mj_deleteData(data);
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mj_deleteModel(model);
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}
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TEST_F(DCMotorTest, ThermalAffectsForce) {
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static constexpr char xml[] = R"(
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<mujoco>
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<worldbody>
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<body>
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<joint name="joint"/>
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<geom size="1"/>
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</body>
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</worldbody>
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<actuator>
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<dcmotor joint="joint" motorconst="0.05" resistance="2.0"
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thermal="0.1 0.1 0 0.004 25 25"/>
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</actuator>
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</mujoco>
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)";
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char error[1024];
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mjModel* model = LoadModelFromString(xml, error, sizeof(error));
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ASSERT_THAT(model, NotNull()) << error;
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mjData* data = mj_makeData(model);
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double K = 0.05, R = 2.0, V = 10.0;
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double alpha = 0.004;
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int adr = model->actuator_actadr[0];
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data->ctrl[0] = V;
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data->act[adr] = 0;
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mj_forward(model, data);
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double force_cold = data->actuator_force[0];
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EXPECT_NEAR(force_cold, K / R * V, MjTol(1e-12, 1e-5));
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double dT = 50;
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data->act[adr] = dT;
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mj_forward(model, data);
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double R_hot = R * (1 + alpha * dT);
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double force_hot = data->actuator_force[0];
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EXPECT_NEAR(force_hot, K / R_hot * V, MjTol(1e-12, 1e-5));
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EXPECT_LT(force_hot, force_cold);
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mj_deleteData(data);
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mj_deleteModel(model);
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}
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// Temperature slot must be correctly offset past slew and integral states.
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TEST_F(DCMotorTest, ThermalAffectsForceWithController) {
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static constexpr char xml[] = R"(
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<mujoco>
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<worldbody>
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<body>
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<joint name="joint"/>
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<geom size="1"/>
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</body>
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</worldbody>
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<actuator>
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<dcmotor joint="joint" motorconst="0.05" resistance="2.0"
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input="position" controller="1.0 1.0 0 5.0 0"
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thermal="0.1 0.1 0 0.004 25 25"/>
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</actuator>
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</mujoco>
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)";
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char error[1024];
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mjModel* model = LoadModelFromString(xml, error, sizeof(error));
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ASSERT_THAT(model, NotNull()) << error;
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mjData* data = mj_makeData(model);
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// slot order: slew(0), integral(1), temperature(2)
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ASSERT_EQ(model->actuator_actnum[0], 3);
|
||||
int adr = model->actuator_actadr[0];
|
||||
int temp_adr = adr + 2; // temperature is slot 2
|
||||
|
||||
double K = 0.05, R = 2.0, alpha = 0.004;
|
||||
double dT = 50;
|
||||
data->act[adr] = 1.0; // slew state = ctrl: no rate-limiting applied
|
||||
data->act[adr + 1] = 0.0; // integral state x_I = 0
|
||||
data->act[temp_adr] = dT; // temperature rise above ambient
|
||||
data->ctrl[0] = 1.0; // position setpoint = 1.0, qpos = 0, error = 1.0
|
||||
mj_forward(model, data);
|
||||
|
||||
// u_eff = ctrl = 1.0 (no slew applied since act[slew] == ctrl)
|
||||
// V = kp*(u_eff - length) + ki*x_I - kd*omega = 1.0*1.0 + 1.0*0.0 - 0*0 = 1.0
|
||||
// R(T) = 2.0 * (1 + 0.004 * 50) = 2.4
|
||||
// stateless (no te): force = K/R(T) * V = 0.05/2.4 * 1.0
|
||||
double R_hot = R * (1 + alpha * dT);
|
||||
EXPECT_NEAR(data->actuator_force[0], K / R_hot * 1.0, MjTol(1e-12, 1e-5));
|
||||
|
||||
mj_deleteData(data);
|
||||
mj_deleteModel(model);
|
||||
}
|
||||
|
||||
TEST_F(DCMotorTest, StatelessPositionMode) {
|
||||
static constexpr char xml[] = R"(
|
||||
<mujoco>
|
||||
<option timestep="0.001"/>
|
||||
<worldbody>
|
||||
<body>
|
||||
<joint name="joint"/>
|
||||
<geom size="1"/>
|
||||
</body>
|
||||
</worldbody>
|
||||
<actuator>
|
||||
<dcmotor joint="joint" input="position" controller="2.0 0 0.5 0 0"
|
||||
motorconst="0.05" resistance="2.0"/>
|
||||
</actuator>
|
||||
</mujoco>
|
||||
)";
|
||||
char error[1024];
|
||||
mjModel* model = LoadModelFromString(xml, error, sizeof(error));
|
||||
ASSERT_THAT(model, NotNull()) << error;
|
||||
mjData* data = mj_makeData(model);
|
||||
|
||||
// Position target 5.0, current pos 0.0, current vel 0.0
|
||||
data->ctrl[0] = 5.0;
|
||||
mj_forward(model, data);
|
||||
|
||||
// V = Kp * (u - theta) = 2.0 * 5.0 = 10.0
|
||||
// force = K / R * V + bias = (0.05 / 2.0) * 10.0 + 0 = 0.25
|
||||
EXPECT_NEAR(data->actuator_force[0], 0.25, MjTol(1e-12, 1e-5));
|
||||
|
||||
// Velocity penalty
|
||||
data->qvel[0] = 2.0;
|
||||
mj_forward(model, data);
|
||||
// V = 10.0 - Kd * omega = 10.0 - (0.5 * 2.0) = 9.0
|
||||
// bias = - K^2 / R * omega = -0.0025 / 2.0 * 2.0 = -0.0025
|
||||
// force = K / R * V + bias = 0.225 - 0.0025 = 0.2225
|
||||
EXPECT_NEAR(data->actuator_force[0], 0.2225, MjTol(1e-12, 1e-5));
|
||||
|
||||
mj_deleteData(data);
|
||||
mj_deleteModel(model);
|
||||
}
|
||||
|
||||
TEST_F(DCMotorTest, StatelessVelocityMode) {
|
||||
static constexpr char xml[] = R"(
|
||||
<mujoco>
|
||||
<option timestep="0.001"/>
|
||||
<worldbody>
|
||||
<body>
|
||||
<joint name="joint"/>
|
||||
<geom size="1"/>
|
||||
</body>
|
||||
</worldbody>
|
||||
<actuator>
|
||||
<dcmotor joint="joint" input="velocity" controller="3.0 0 0 0 0"
|
||||
motorconst="0.05" resistance="2.0"/>
|
||||
</actuator>
|
||||
</mujoco>
|
||||
)";
|
||||
char error[1024];
|
||||
mjModel* model = LoadModelFromString(xml, error, sizeof(error));
|
||||
ASSERT_THAT(model, NotNull()) << error;
|
||||
mjData* data = mj_makeData(model);
|
||||
|
||||
// Velocity target 4.0, current vel 1.0
|
||||
data->ctrl[0] = 4.0;
|
||||
data->qvel[0] = 1.0;
|
||||
mj_forward(model, data);
|
||||
|
||||
// V = Kp * (u - omega) = 3.0 * (4.0 - 1.0) = 9.0
|
||||
// bias = - K^2 / R * omega = -0.0025 / 2.0 * 1.0 = -0.00125
|
||||
// force = K / R * V + bias = (0.05 / 2.0) * 9.0 - 0.00125 = 0.22375
|
||||
EXPECT_NEAR(data->actuator_force[0], 0.22375, MjTol(1e-12, 1e-5));
|
||||
|
||||
mj_deleteData(data);
|
||||
mj_deleteModel(model);
|
||||
}
|
||||
|
||||
TEST_F(DCMotorTest, StatefulPositionMode) {
|
||||
static constexpr char xml[] = R"(
|
||||
<mujoco>
|
||||
<option timestep="0.001"/>
|
||||
<worldbody>
|
||||
<body>
|
||||
<joint name="joint"/>
|
||||
<geom size="1"/>
|
||||
</body>
|
||||
</worldbody>
|
||||
<actuator>
|
||||
<dcmotor joint="joint" input="position" controller="2.0 0.5 0.1 10.0 5.0"
|
||||
motorconst="0.05" resistance="2.0"/>
|
||||
</actuator>
|
||||
</mujoco>
|
||||
)";
|
||||
char error[1024];
|
||||
mjModel* model = LoadModelFromString(xml, error, sizeof(error));
|
||||
ASSERT_THAT(model, NotNull()) << error;
|
||||
mjData* data = mj_makeData(model);
|
||||
|
||||
// Controller states: 1 for slew, 1 for ki -> actnum = 2
|
||||
ASSERT_EQ(model->actuator_actnum[0], 2);
|
||||
int adr = model->actuator_actadr[0];
|
||||
|
||||
// Current states
|
||||
double u_prev = 1.0;
|
||||
double x_I = 2.0;
|
||||
data->act[adr] = u_prev;
|
||||
data->act[adr+1] = x_I;
|
||||
|
||||
// target 5.0 position, current 0.0
|
||||
data->ctrl[0] = 5.0;
|
||||
data->qvel[0] = 0.5;
|
||||
mj_forward(model, data);
|
||||
|
||||
// slew bounding: s = 10.0, dt = 0.001. max_change = 0.01
|
||||
// Target = 5.0. It is upper bounded by u_prev + 0.01 = 1.01
|
||||
EXPECT_NEAR(data->act_dot[adr], 10.0, MjTol(1e-12, 1e-5));
|
||||
|
||||
// PI error: error = u_eff - length = 1.01 - 0.0 = 1.01
|
||||
EXPECT_NEAR(data->act_dot[adr+1], 1.01, MjTol(1e-12, 1e-5));
|
||||
|
||||
// V = Kp(u_eff - length) + Ki * x_I - Kd * omega
|
||||
// V = 2.0 * 1.01 + 0.5 * 2.0 - 0.1 * 0.5 = 2.97
|
||||
// bias = - K^2/R * omega = -(0.05)^2 / 2.0 * 0.5 = -0.000625
|
||||
// force = K/R * V + bias = 0.025 * 2.97 - 0.000625 = 0.073625
|
||||
EXPECT_NEAR(data->actuator_force[0], 0.073625, MjTol(1e-12, 1e-5));
|
||||
|
||||
mj_deleteData(data);
|
||||
mj_deleteModel(model);
|
||||
}
|
||||
|
||||
TEST_F(DCMotorTest, StatefulPositionWithCurrentMode) {
|
||||
static constexpr char xml[] = R"(
|
||||
<mujoco>
|
||||
<option timestep="0.001"/>
|
||||
<worldbody>
|
||||
<body>
|
||||
<joint name="joint"/>
|
||||
<geom size="1"/>
|
||||
</body>
|
||||
</worldbody>
|
||||
<actuator>
|
||||
<dcmotor joint="joint" input="position" controller="2.0 0.5 0.1 10.0 5.0"
|
||||
motorconst="0.05" resistance="2.0" inductance="1.0"/>
|
||||
</actuator>
|
||||
</mujoco>
|
||||
)";
|
||||
char error[1024];
|
||||
mjModel* model = LoadModelFromString(xml, error, sizeof(error));
|
||||
ASSERT_THAT(model, NotNull()) << error;
|
||||
mjData* data = mj_makeData(model);
|
||||
|
||||
// Controller states: slew (0), ki (1), current (2). actnum = 3
|
||||
ASSERT_EQ(model->actuator_actnum[0], 3);
|
||||
int adr = model->actuator_actadr[0];
|
||||
|
||||
double u_prev = 1.0;
|
||||
double x_I = 2.0;
|
||||
double current = 0.5;
|
||||
data->act[adr] = u_prev;
|
||||
data->act[adr+1] = x_I;
|
||||
data->act[adr+2] = current;
|
||||
|
||||
// Target 5.0 position, velocity 0.5
|
||||
data->ctrl[0] = 5.0;
|
||||
data->qvel[0] = 0.5;
|
||||
mj_forward(model, data);
|
||||
|
||||
// Slew bounding: max_change = 0.01, u_eff = 1.01
|
||||
EXPECT_NEAR(data->act_dot[adr], 10.0, MjTol(1e-12, 1e-5));
|
||||
|
||||
// PI error: error = u_eff - length = 1.01
|
||||
EXPECT_NEAR(data->act_dot[adr+1], 1.01, MjTol(1e-12, 1e-5));
|
||||
|
||||
// Voltage computation:
|
||||
// V = Kp(u_eff - length) + Ki * x_I - Kd * omega
|
||||
// V = 2.0 * 1.01 + 0.5 * 2.0 - 0.1 * 0.5 = 2.97
|
||||
|
||||
// Current filter:
|
||||
// t_e = L / R = 1.0 / 2.0 = 0.5
|
||||
// di/dt = (V/R - K/R * omega - i) / t_e
|
||||
// di/dt = (2.97/2.0 - 0.05/2.0 * 0.5 - 0.5) / 0.5
|
||||
// di/dt = (1.485 - 0.0125 - 0.5) / 0.5 = 0.9725 / 0.5 = 1.945
|
||||
EXPECT_NEAR(data->act_dot[adr+2], 1.945, MjTol(1e-12, 1e-5));
|
||||
|
||||
// Force is just K * current since current is stateful
|
||||
EXPECT_NEAR(data->actuator_force[0], 0.05 * 0.5, MjTol(1e-12, 1e-5));
|
||||
|
||||
mj_deleteData(data);
|
||||
mj_deleteModel(model);
|
||||
}
|
||||
|
||||
TEST_F(DCMotorTest, StatefulVelocityMode) {
|
||||
static constexpr char xml[] = R"(
|
||||
<mujoco>
|
||||
<option timestep="0.001"/>
|
||||
<worldbody>
|
||||
<body>
|
||||
<joint name="joint"/>
|
||||
<geom size="1"/>
|
||||
</body>
|
||||
</worldbody>
|
||||
<actuator>
|
||||
<dcmotor joint="joint" input="velocity" controller="3.0 1.0 0 0 2.0"
|
||||
motorconst="0.05" resistance="2.0"/>
|
||||
</actuator>
|
||||
</mujoco>
|
||||
)";
|
||||
char error[1024];
|
||||
mjModel* model = LoadModelFromString(xml, error, sizeof(error));
|
||||
ASSERT_THAT(model, NotNull()) << error;
|
||||
mjData* data = mj_makeData(model);
|
||||
|
||||
// Controller states: 1 for ki (no slew)
|
||||
ASSERT_EQ(model->actuator_actnum[0], 1);
|
||||
int adr = model->actuator_actadr[0];
|
||||
|
||||
double x_I = 2.0; // Exactly at Imax limit (Imax = 2.0)
|
||||
data->act[adr] = x_I;
|
||||
|
||||
// target vel 4.0, current vel 1.0
|
||||
data->ctrl[0] = 4.0;
|
||||
data->qvel[0] = 1.0;
|
||||
mj_forward(model, data);
|
||||
|
||||
// integrate command directly: error = target = 4.0
|
||||
// since x_I == Imax (2.0) and error (4.0) > 0, act_dot should be clamped to 0
|
||||
EXPECT_NEAR(data->act_dot[adr], 0.0, MjTol(1e-12, 1e-5));
|
||||
|
||||
// V = Kp * (u_eff - omega) + Ki * (x_I - length)
|
||||
// V = 3.0 * (4.0 - 1.0) + 1.0 * (2.0 - 0.0) = 9.0 + 2.0 = 11.0
|
||||
// bias = - K^2/R * omega = -(0.05)^2 / 2.0 * 1.0 = -0.00125
|
||||
// force = K/R * V + bias = 0.025 * 11.0 - 0.00125 = 0.275 - 0.00125 = 0.27375
|
||||
EXPECT_NEAR(data->actuator_force[0], 0.27375, MjTol(1e-12, 1e-5));
|
||||
|
||||
// repeat with non-zero joint position
|
||||
data->qpos[0] = 1.5;
|
||||
mj_forward(model, data);
|
||||
|
||||
// V = 3.0 * (4.0 - 1.0) + 1.0 * (2.0 - 1.5) = 9.0 + 0.5 = 9.5
|
||||
// force = K/R * V + bias = 0.025 * 9.5 - 0.00125 = 0.2375 - 0.00125 = 0.23625
|
||||
EXPECT_NEAR(data->actuator_force[0], 0.23625, MjTol(1e-12, 1e-5));
|
||||
|
||||
mj_deleteData(data);
|
||||
mj_deleteModel(model);
|
||||
}
|
||||
|
||||
TEST_F(DCMotorTest, CurrentPlusThermal) {
|
||||
static constexpr char xml[] = R"(
|
||||
<mujoco>
|
||||
<option timestep="0.001"/>
|
||||
<worldbody>
|
||||
<body>
|
||||
<joint name="joint" damping="10000"/>
|
||||
<geom size="1" mass="10000"/>
|
||||
</body>
|
||||
</worldbody>
|
||||
<actuator>
|
||||
<dcmotor joint="joint" motorconst="0.05" resistance="2.0"
|
||||
inductance="0.01 0" thermal="10 5 0 0.004 25 25"/>
|
||||
</actuator>
|
||||
</mujoco>
|
||||
)";
|
||||
char error[1024];
|
||||
mjModel* model = LoadModelFromString(xml, error, sizeof(error));
|
||||
ASSERT_THAT(model, NotNull()) << error;
|
||||
mjData* data = mj_makeData(model);
|
||||
|
||||
ASSERT_EQ(model->actuator_actnum[0], 2);
|
||||
int adr = model->actuator_actadr[0];
|
||||
|
||||
double K = 0.05, R = 2.0, V = 12.0;
|
||||
double te = 0.01 / R;
|
||||
double RT = 10.0, C = 5.0;
|
||||
|
||||
double current = 3.0;
|
||||
double dT = 10.0;
|
||||
data->act[adr] = dT;
|
||||
data->act[adr+1] = current;
|
||||
data->ctrl[0] = V;
|
||||
mj_forward(model, data);
|
||||
|
||||
EXPECT_NEAR(data->actuator_force[0], K * current, MjTol(1e-12, 1e-5));
|
||||
|
||||
double R_hot = R * (1 + 0.004 * dT);
|
||||
double T_dot = (R_hot * current * current - dT / RT) / C;
|
||||
EXPECT_NEAR(data->act_dot[adr], T_dot, MjTol(1e-10, 1e-4));
|
||||
|
||||
double omega = data->qvel[0];
|
||||
double i_dot = (V/R_hot - K/R_hot*omega - current) / te;
|
||||
EXPECT_NEAR(data->act_dot[adr+1], i_dot, MjTol(1e-10, 1e-3));
|
||||
|
||||
mj_deleteData(data);
|
||||
mj_deleteModel(model);
|
||||
}
|
||||
|
||||
TEST_F(DCMotorTest, CurrentRateLimit) {
|
||||
// Verifies that saturation:current_rate clamps di/dt.
|
||||
static constexpr char xml[] = R"(
|
||||
<mujoco>
|
||||
<option timestep="0.001"/>
|
||||
<worldbody>
|
||||
<body>
|
||||
<joint name="joint" damping="10000"/>
|
||||
<geom size="1" mass="10000"/>
|
||||
</body>
|
||||
</worldbody>
|
||||
<actuator>
|
||||
<dcmotor joint="joint" motorconst="0.05" resistance="2.0"
|
||||
inductance="0.01 0" saturation="0 0 100 0"/>
|
||||
</actuator>
|
||||
</mujoco>
|
||||
)";
|
||||
char error[1024];
|
||||
mjModel* model = LoadModelFromString(xml, error, sizeof(error));
|
||||
ASSERT_THAT(model, NotNull()) << error;
|
||||
mjData* data = mj_makeData(model);
|
||||
|
||||
ASSERT_EQ(model->actuator_actnum[0], 1);
|
||||
int adr = model->actuator_actadr[0];
|
||||
|
||||
double V = 12.0;
|
||||
double dimax = 100.0; // A/s rate limit
|
||||
|
||||
// unclamped: i_dot = (V/R - 0 - 0) / te = 6 / 0.005 = 1200 A/s >> dimax
|
||||
data->act[adr] = 0; // current = 0
|
||||
data->ctrl[0] = V;
|
||||
mj_forward(model, data);
|
||||
|
||||
// i_dot should be clipped to +dimax
|
||||
EXPECT_NEAR(data->act_dot[adr], dimax, MjTol(1e-12, 1e-5));
|
||||
|
||||
// reverse: large negative drive
|
||||
data->ctrl[0] = -V;
|
||||
mj_forward(model, data);
|
||||
|
||||
// i_dot should be clipped to -dimax
|
||||
EXPECT_NEAR(data->act_dot[adr], -dimax, MjTol(1e-12, 1e-5));
|
||||
|
||||
mj_deleteData(data);
|
||||
mj_deleteModel(model);
|
||||
}
|
||||
|
||||
TEST_F(DCMotorTest, LuGreExactIntegration) {
|
||||
static constexpr char xml[] = R"(
|
||||
<mujoco>
|
||||
<option timestep="0.001"/>
|
||||
<worldbody>
|
||||
<body>
|
||||
<joint name="joint"/>
|
||||
<geom size="1" mass="1e6"/>
|
||||
</body>
|
||||
</worldbody>
|
||||
<actuator>
|
||||
<dcmotor joint="joint" motorconst="0.05" resistance="2.0"
|
||||
lugre="100 1 0.01 0.5 0.7 10"/>
|
||||
</actuator>
|
||||
</mujoco>
|
||||
)";
|
||||
char error[1024];
|
||||
mjModel* model = LoadModelFromString(xml, error, sizeof(error));
|
||||
ASSERT_THAT(model, NotNull()) << error;
|
||||
mjData* data = mj_makeData(model);
|
||||
|
||||
ASSERT_EQ(model->actuator_actnum[0], 1);
|
||||
int adr = model->actuator_actadr[0];
|
||||
|
||||
double sigma0 = 100, F_C = 0.5, F_S = 0.7, v_S = 10;
|
||||
double z0 = 0.002;
|
||||
double v = 0.5;
|
||||
double h = model->opt.timestep;
|
||||
|
||||
data->act[adr] = z0;
|
||||
data->qvel[0] = v;
|
||||
|
||||
double ratio = v / v_S;
|
||||
double g_v = F_C + (F_S - F_C) * mju_exp(-ratio*ratio);
|
||||
double a = -sigma0 * std::abs(v) / g_v;
|
||||
double exp_ah = mju_exp(a * h);
|
||||
double int_h = (exp_ah - 1) / a;
|
||||
double z_new = exp_ah * z0 + int_h * v;
|
||||
|
||||
mj_step(model, data);
|
||||
EXPECT_NEAR(data->act[adr], z_new, MjTol(1e-12, 1e-5));
|
||||
|
||||
mj_deleteData(data);
|
||||
mj_deleteModel(model);
|
||||
}
|
||||
|
||||
TEST_F(DCMotorTest, LuGreSteadyState) {
|
||||
static constexpr char xml[] = R"(
|
||||
<mujoco>
|
||||
<option timestep="0.001"/>
|
||||
<worldbody>
|
||||
<body>
|
||||
<joint name="joint"/>
|
||||
<geom size="1" mass="1e6"/>
|
||||
</body>
|
||||
</worldbody>
|
||||
<actuator>
|
||||
<dcmotor joint="joint" motorconst="0.05" resistance="2.0"
|
||||
lugre="100 1 0.01 0.5 0.7 10"/>
|
||||
</actuator>
|
||||
</mujoco>
|
||||
)";
|
||||
char error[1024];
|
||||
mjModel* model = LoadModelFromString(xml, error, sizeof(error));
|
||||
ASSERT_THAT(model, NotNull()) << error;
|
||||
mjData* data = mj_makeData(model);
|
||||
|
||||
int adr = model->actuator_actadr[0];
|
||||
|
||||
double sigma0 = 100, sigma2 = 0.01;
|
||||
double F_C = 0.5, F_S = 0.7, v_S = 10;
|
||||
double K = 0.05, R = 2.0;
|
||||
double v = 0.5;
|
||||
|
||||
data->qvel[0] = v;
|
||||
data->ctrl[0] = 0;
|
||||
for (int i = 0; i < 10000; i++) {
|
||||
mj_step(model, data);
|
||||
}
|
||||
|
||||
double ratio = v / v_S;
|
||||
double g_v = F_C + (F_S - F_C) * mju_exp(-ratio*ratio);
|
||||
double z_ss = g_v / sigma0;
|
||||
EXPECT_NEAR(data->act[adr], z_ss, 1e-4);
|
||||
|
||||
EXPECT_MJTNUM_EQ(model->actuator_damping[0], sigma2);
|
||||
double back_emf = K * K / R * data->qvel[0];
|
||||
double lugre_ss = g_v;
|
||||
EXPECT_NEAR(data->actuator_force[0], -back_emf - lugre_ss, 1e-3);
|
||||
|
||||
mj_deleteData(data);
|
||||
mj_deleteModel(model);
|
||||
}
|
||||
|
||||
TEST_F(DCMotorTest, LuGreBristleSpring) {
|
||||
static constexpr char xml[] = R"(
|
||||
<mujoco>
|
||||
<worldbody>
|
||||
<body>
|
||||
<joint name="joint"/>
|
||||
<geom size="1"/>
|
||||
</body>
|
||||
</worldbody>
|
||||
<actuator>
|
||||
<dcmotor joint="joint" motorconst="0.05" resistance="2.0"
|
||||
lugre="100 1 0.01 0.5 0.7 10"/>
|
||||
</actuator>
|
||||
</mujoco>
|
||||
)";
|
||||
char error[1024];
|
||||
mjModel* model = LoadModelFromString(xml, error, sizeof(error));
|
||||
ASSERT_THAT(model, NotNull()) << error;
|
||||
mjData* data = mj_makeData(model);
|
||||
|
||||
int adr = model->actuator_actadr[0];
|
||||
double sigma0 = 100;
|
||||
double X = 0.01;
|
||||
|
||||
data->act[adr] = X;
|
||||
data->ctrl[0] = 0;
|
||||
mj_forward(model, data);
|
||||
|
||||
EXPECT_NEAR(data->actuator_force[0], -sigma0 * X, MjTol(1e-12, 1e-5));
|
||||
|
||||
mj_deleteData(data);
|
||||
mj_deleteModel(model);
|
||||
}
|
||||
|
||||
// ----------------------- filterexact actuators -------------------------------
|
||||
|
||||
using FilterExactTest = MujocoTest;
|
||||
|
||||
Reference in New Issue
Block a user