Polynomial stiffness and damping https://youtu.be/aKa3ZlEF9_Y
PiperOrigin-RevId: 884607673 Change-Id: If8088dbf37fed1055304778a7eb84dec52cba920
This commit is contained in:
Yuval Tassa
committed by
Copybara-Service
Copybara-Service
parent
aec1b45dce
commit
efae9157a7
@@ -1168,6 +1168,73 @@ TEST_F(DerivativeTest, ForcerangeClampedDerivative) {
|
||||
mj_deleteModel(m);
|
||||
}
|
||||
|
||||
TEST_F(DerivativeTest, NonlinearDampingDerivative) {
|
||||
static constexpr char xml[] = R"(
|
||||
<mujoco>
|
||||
<worldbody>
|
||||
<body>
|
||||
<joint type="slide" damping="2 3 4"/>
|
||||
<geom size="1" mass="1"/>
|
||||
</body>
|
||||
</worldbody>
|
||||
|
||||
<keyframe>
|
||||
<key qvel="3"/>
|
||||
</keyframe>
|
||||
</mujoco>
|
||||
)";
|
||||
|
||||
char error[1024];
|
||||
mjModel* m = LoadModelFromString(xml, error, sizeof(error));
|
||||
ASSERT_THAT(m, NotNull()) << error;
|
||||
|
||||
mjtNum dt_small = 1e-4;
|
||||
mjtNum dt_large = 1e-2;
|
||||
mjtNum duration = 1.0;
|
||||
|
||||
mjData* d_gt = mj_makeData(m);
|
||||
mjData* d_enabled = mj_makeData(m);
|
||||
mjData* d_disabled = mj_makeData(m);
|
||||
|
||||
mj_resetDataKeyframe(m, d_gt, 0);
|
||||
mj_resetDataKeyframe(m, d_enabled, 0);
|
||||
mj_resetDataKeyframe(m, d_disabled, 0);
|
||||
|
||||
m->opt.integrator = mjINT_EULER;
|
||||
mjtNum error_enabled = 0;
|
||||
mjtNum error_disabled = 0;
|
||||
int nsteps_large = static_cast<int>(duration / dt_large);
|
||||
int substeps = static_cast<int>(dt_large / dt_small);
|
||||
|
||||
for (int i = 0; i < nsteps_large; i++) {
|
||||
m->opt.timestep = dt_small;
|
||||
m->opt.disableflags |= mjDSBL_EULERDAMP; // disable implicit damping
|
||||
for (int j = 0; j < substeps; j++) {
|
||||
mj_step(m, d_gt);
|
||||
}
|
||||
|
||||
m->opt.timestep = dt_large;
|
||||
mj_step(m, d_disabled);
|
||||
|
||||
m->opt.disableflags &= ~mjDSBL_EULERDAMP; // enable implicit damping
|
||||
mj_step(m, d_enabled);
|
||||
|
||||
mjtNum diff_enabled = d_gt->qvel[0] - d_enabled->qvel[0];
|
||||
mjtNum diff_disabled = d_gt->qvel[0] - d_disabled->qvel[0];
|
||||
error_enabled += diff_enabled * diff_enabled;
|
||||
error_disabled += diff_disabled * diff_disabled;
|
||||
}
|
||||
|
||||
EXPECT_LT(error_enabled, error_disabled)
|
||||
<< "Euler with implicit damping should be more accurate than without "
|
||||
<< "when nonlinear damping derivatives are correctly handled";
|
||||
|
||||
mj_deleteData(d_disabled);
|
||||
mj_deleteData(d_enabled);
|
||||
mj_deleteData(d_gt);
|
||||
mj_deleteModel(m);
|
||||
}
|
||||
|
||||
// implicit derivatives should use next activation when actearly is set
|
||||
TEST_F(DerivativeTest, ActearlyDerivative) {
|
||||
static constexpr char xml[] = R"(
|
||||
|
||||
@@ -1665,6 +1665,7 @@ TEST_F(ForwardTest, FlexTrilinearInstability) {
|
||||
mj_deleteData(data);
|
||||
mj_deleteModel(model);
|
||||
}
|
||||
|
||||
// Verify that flex damping does not affect rigid body motion
|
||||
TEST_F(ForwardTest, FlexDampingRigidMotion) {
|
||||
constexpr char xml[] = R"(
|
||||
|
||||
@@ -102,6 +102,142 @@ TEST_F(PassiveTest, GravcompNestedBody) {
|
||||
mj_deleteModel(m);
|
||||
}
|
||||
|
||||
TEST_F(PassiveTest, PolyStiffnessSlide) {
|
||||
static constexpr char xml[] = R"(
|
||||
<mujoco>
|
||||
<worldbody>
|
||||
<body>
|
||||
<joint type="slide" stiffness="10 5 1"/>
|
||||
<geom size="1" mass="1"/>
|
||||
</body>
|
||||
</worldbody>
|
||||
|
||||
<keyframe>
|
||||
<key qpos="2"/>
|
||||
</keyframe>
|
||||
</mujoco>
|
||||
)";
|
||||
|
||||
char error[1024];
|
||||
mjModel* m = LoadModelFromString(xml, error, sizeof(error));
|
||||
ASSERT_THAT(m, NotNull()) << error;
|
||||
mjData* d = mj_makeData(m);
|
||||
mj_resetDataKeyframe(m, d, 0);
|
||||
|
||||
mj_forward(m, d);
|
||||
EXPECT_FLOAT_EQ(d->qfrc_spring[0], -48);
|
||||
|
||||
mj_deleteData(d);
|
||||
mj_deleteModel(m);
|
||||
}
|
||||
|
||||
TEST_F(PassiveTest, PolyStiffnessAntiSymmetric) {
|
||||
static constexpr char xml[] = R"(
|
||||
<mujoco>
|
||||
<worldbody>
|
||||
<body>
|
||||
<joint type="slide" stiffness="10 5 1"/>
|
||||
<geom size="1" mass="1"/>
|
||||
</body>
|
||||
</worldbody>
|
||||
|
||||
<keyframe>
|
||||
<key qpos="-2"/>
|
||||
</keyframe>
|
||||
</mujoco>
|
||||
)";
|
||||
|
||||
char error[1024];
|
||||
mjModel* m = LoadModelFromString(xml, error, sizeof(error));
|
||||
ASSERT_THAT(m, NotNull()) << error;
|
||||
mjData* d = mj_makeData(m);
|
||||
mj_resetDataKeyframe(m, d, 0);
|
||||
|
||||
mj_forward(m, d);
|
||||
EXPECT_FLOAT_EQ(d->qfrc_spring[0], 8);
|
||||
|
||||
mj_deleteData(d);
|
||||
mj_deleteModel(m);
|
||||
}
|
||||
|
||||
TEST_F(PassiveTest, PolyStiffnessTendon) {
|
||||
static constexpr char xml[] = R"(
|
||||
<mujoco>
|
||||
<worldbody>
|
||||
<body>
|
||||
<joint type="slide" name="j"/>
|
||||
<geom size="1" mass="1"/>
|
||||
</body>
|
||||
</worldbody>
|
||||
|
||||
<tendon>
|
||||
<fixed>
|
||||
<joint joint="j" coef="1"/>
|
||||
</fixed>
|
||||
</tendon>
|
||||
|
||||
<keyframe>
|
||||
<key qpos="2"/>
|
||||
</keyframe>
|
||||
</mujoco>
|
||||
)";
|
||||
|
||||
char error[1024];
|
||||
mjModel* m = LoadModelFromString(xml, error, sizeof(error));
|
||||
ASSERT_THAT(m, NotNull()) << error;
|
||||
|
||||
m->tendon_stiffness[0] = 10;
|
||||
m->tendon_stiffnesspoly[0] = 5;
|
||||
m->tendon_stiffnesspoly[1] = 1;
|
||||
|
||||
mjData* d = mj_makeData(m);
|
||||
mj_resetDataKeyframe(m, d, 0);
|
||||
|
||||
mj_forward(m, d);
|
||||
EXPECT_FLOAT_EQ(d->qfrc_spring[0], -48);
|
||||
|
||||
mj_deleteData(d);
|
||||
mj_deleteModel(m);
|
||||
}
|
||||
|
||||
TEST_F(PassiveTest, PolyStiffnessEnergy) {
|
||||
static constexpr char xml[] = R"(
|
||||
<mujoco>
|
||||
<option timestep="0.0001">
|
||||
<flag energy="enable"/>
|
||||
</option>
|
||||
|
||||
<worldbody>
|
||||
<body>
|
||||
<joint type="slide" stiffness="10 5 1"/>
|
||||
<geom size="1" mass="1"/>
|
||||
</body>
|
||||
</worldbody>
|
||||
|
||||
<keyframe>
|
||||
<key qpos="2"/>
|
||||
</keyframe>
|
||||
</mujoco>
|
||||
)";
|
||||
|
||||
char error[1024];
|
||||
mjModel* m = LoadModelFromString(xml, error, sizeof(error));
|
||||
ASSERT_THAT(m, NotNull()) << error;
|
||||
mjData* d = mj_makeData(m);
|
||||
mj_resetDataKeyframe(m, d, 0);
|
||||
|
||||
mj_forward(m, d);
|
||||
mjtNum total_energy = d->energy[0] + d->energy[1];
|
||||
|
||||
for (int i = 0; i < 100; i++) {
|
||||
mj_step(m, d);
|
||||
EXPECT_NEAR(d->energy[0] + d->energy[1], total_energy, 0.002);
|
||||
}
|
||||
|
||||
mj_deleteData(d);
|
||||
mj_deleteModel(m);
|
||||
}
|
||||
|
||||
// ------------------------ ellipsoid fluid model ------------------------------
|
||||
|
||||
using EllipsoidFluidTest = MujocoTest;
|
||||
@@ -475,5 +611,240 @@ TEST_F(ElasticityTest, ElasticEnergySolid) {
|
||||
mj_deleteModel(m);
|
||||
}
|
||||
|
||||
TEST_F(PassiveTest, PolynomialStiffnessJoint) {
|
||||
static constexpr char xml[] = R"(
|
||||
<mujoco>
|
||||
<worldbody>
|
||||
<body>
|
||||
<joint type="slide" stiffness="2 3 4"/>
|
||||
<geom size="1" mass="1"/>
|
||||
</body>
|
||||
</worldbody>
|
||||
<keyframe>
|
||||
<key qpos="0.5"/>
|
||||
</keyframe>
|
||||
</mujoco>
|
||||
)";
|
||||
mjModel* m = LoadModelFromString(xml);
|
||||
ASSERT_THAT(m, NotNull());
|
||||
mjData* d = mj_makeData(m);
|
||||
mj_resetDataKeyframe(m, d, 0);
|
||||
mj_forward(m, d);
|
||||
|
||||
mjtNum x = 0.5;
|
||||
mjtNum a = 2, b = 3, c = 4;
|
||||
mjtNum expected = -(a + b * x + c * x * x) * x;
|
||||
EXPECT_NEAR(d->qfrc_spring[0], expected, 1e-12);
|
||||
|
||||
mj_deleteData(d);
|
||||
mj_deleteModel(m);
|
||||
}
|
||||
|
||||
TEST_F(PassiveTest, PolynomialStiffnessNegativeDisplacement) {
|
||||
static constexpr char xml[] = R"(
|
||||
<mujoco>
|
||||
<worldbody>
|
||||
<body>
|
||||
<joint type="slide" stiffness="2 3 4"/>
|
||||
<geom size="1" mass="1"/>
|
||||
</body>
|
||||
</worldbody>
|
||||
<keyframe>
|
||||
<key qpos="-0.5"/>
|
||||
</keyframe>
|
||||
</mujoco>
|
||||
)";
|
||||
mjModel* m = LoadModelFromString(xml);
|
||||
ASSERT_THAT(m, NotNull());
|
||||
mjData* d = mj_makeData(m);
|
||||
mj_resetDataKeyframe(m, d, 0);
|
||||
mj_forward(m, d);
|
||||
|
||||
mjtNum x = -0.5;
|
||||
mjtNum a = 2, b = 3, c = 4;
|
||||
mjtNum expected = -(a + b * x + c * x * x) * x;
|
||||
EXPECT_NEAR(d->qfrc_spring[0], expected, 1e-12);
|
||||
|
||||
mj_deleteData(d);
|
||||
mj_deleteModel(m);
|
||||
}
|
||||
|
||||
TEST_F(PassiveTest, PolyStiffnessFixedTendon) {
|
||||
static constexpr char xml[] = R"(
|
||||
<mujoco>
|
||||
<worldbody>
|
||||
<body>
|
||||
<joint type="slide" name="j"/>
|
||||
<geom size="1" mass="1"/>
|
||||
</body>
|
||||
</worldbody>
|
||||
|
||||
<tendon>
|
||||
<fixed stiffness="10 5 1">
|
||||
<joint joint="j" coef="1"/>
|
||||
</fixed>
|
||||
</tendon>
|
||||
|
||||
<keyframe>
|
||||
<key qpos="2"/>
|
||||
</keyframe>
|
||||
</mujoco>
|
||||
)";
|
||||
|
||||
char error[1024];
|
||||
mjModel* m = LoadModelFromString(xml, error, sizeof(error));
|
||||
ASSERT_THAT(m, NotNull()) << error;
|
||||
mjData* d = mj_makeData(m);
|
||||
mj_resetDataKeyframe(m, d, 0);
|
||||
|
||||
mj_forward(m, d);
|
||||
|
||||
mjtNum x = d->ten_length[0] - m->tendon_lengthspring[1];
|
||||
mjtNum expected = -(10 + 5*x + 1*x*x) * x;
|
||||
EXPECT_NEAR(d->qfrc_spring[0], expected, 1e-12);
|
||||
|
||||
mj_deleteData(d);
|
||||
mj_deleteModel(m);
|
||||
}
|
||||
|
||||
TEST_F(PassiveTest, PolyStiffnessSpatialTendon) {
|
||||
static constexpr char xml[] = R"(
|
||||
<mujoco>
|
||||
<worldbody>
|
||||
<site name="s0"/>
|
||||
<body>
|
||||
<joint type="slide" name="j"/>
|
||||
<geom size="1" mass="1"/>
|
||||
<site name="s1"/>
|
||||
</body>
|
||||
</worldbody>
|
||||
|
||||
<tendon>
|
||||
<spatial stiffness="10 5 1">
|
||||
<site site="s0"/>
|
||||
<site site="s1"/>
|
||||
</spatial>
|
||||
</tendon>
|
||||
|
||||
<keyframe>
|
||||
<key qpos="2"/>
|
||||
</keyframe>
|
||||
</mujoco>
|
||||
)";
|
||||
|
||||
char error[1024];
|
||||
mjModel* m = LoadModelFromString(xml, error, sizeof(error));
|
||||
ASSERT_THAT(m, NotNull()) << error;
|
||||
mjData* d = mj_makeData(m);
|
||||
mj_resetDataKeyframe(m, d, 0);
|
||||
|
||||
mj_forward(m, d);
|
||||
|
||||
mjtNum x = d->ten_length[0] - m->tendon_lengthspring[1];
|
||||
mjtNum expected = -x * (10 + 5*x + 1*x*x);
|
||||
EXPECT_NEAR(d->qfrc_spring[0], expected, 1e-12);
|
||||
|
||||
mj_deleteData(d);
|
||||
mj_deleteModel(m);
|
||||
}
|
||||
|
||||
|
||||
|
||||
TEST_F(PassiveTest, PolynomialDampingJoint) {
|
||||
static constexpr char xml[] = R"(
|
||||
<mujoco>
|
||||
<worldbody>
|
||||
<body>
|
||||
<joint type="slide" damping="2 3 4"/>
|
||||
<geom size="1" mass="1"/>
|
||||
</body>
|
||||
</worldbody>
|
||||
<keyframe>
|
||||
<key qvel="0.5"/>
|
||||
</keyframe>
|
||||
</mujoco>
|
||||
)";
|
||||
mjModel* m = LoadModelFromString(xml);
|
||||
ASSERT_THAT(m, NotNull());
|
||||
mjData* d = mj_makeData(m);
|
||||
mj_resetDataKeyframe(m, d, 0);
|
||||
mj_forward(m, d);
|
||||
|
||||
mjtNum v = 0.5;
|
||||
mjtNum a = 2, b = 3, c = 4;
|
||||
mjtNum expected = -(a * v + b * v * mju_abs(v) + c * v * v * v);
|
||||
EXPECT_NEAR(d->qfrc_damper[0], expected, 1e-12);
|
||||
|
||||
mj_deleteData(d);
|
||||
mj_deleteModel(m);
|
||||
}
|
||||
|
||||
TEST_F(PassiveTest, PolynomialDampingNegativeVelocity) {
|
||||
static constexpr char xml[] = R"(
|
||||
<mujoco>
|
||||
<worldbody>
|
||||
<body>
|
||||
<joint type="slide" damping="2 3 4"/>
|
||||
<geom size="1" mass="1"/>
|
||||
</body>
|
||||
</worldbody>
|
||||
<keyframe>
|
||||
<key qvel="-0.5"/>
|
||||
</keyframe>
|
||||
</mujoco>
|
||||
)";
|
||||
mjModel* m = LoadModelFromString(xml);
|
||||
ASSERT_THAT(m, NotNull());
|
||||
mjData* d = mj_makeData(m);
|
||||
mj_resetDataKeyframe(m, d, 0);
|
||||
mj_forward(m, d);
|
||||
|
||||
mjtNum v = -0.5;
|
||||
mjtNum a = 2, b = 3, c = 4;
|
||||
mjtNum expected = -(a * v + b * v * mju_abs(v) + c * v * v * v);
|
||||
EXPECT_NEAR(d->qfrc_damper[0], expected, 1e-12);
|
||||
|
||||
mj_deleteData(d);
|
||||
mj_deleteModel(m);
|
||||
}
|
||||
|
||||
TEST_F(PassiveTest, PolynomialDampingTendon) {
|
||||
static constexpr char xml[] = R"(
|
||||
<mujoco>
|
||||
<worldbody>
|
||||
<body>
|
||||
<joint type="slide" name="j"/>
|
||||
<geom size="1" mass="1"/>
|
||||
</body>
|
||||
</worldbody>
|
||||
|
||||
<tendon>
|
||||
<fixed damping="10 5 1">
|
||||
<joint joint="j" coef="1"/>
|
||||
</fixed>
|
||||
</tendon>
|
||||
|
||||
<keyframe>
|
||||
<key qvel="2"/>
|
||||
</keyframe>
|
||||
</mujoco>
|
||||
)";
|
||||
|
||||
char error[1024];
|
||||
mjModel* m = LoadModelFromString(xml, error, sizeof(error));
|
||||
ASSERT_THAT(m, NotNull()) << error;
|
||||
mjData* d = mj_makeData(m);
|
||||
mj_resetDataKeyframe(m, d, 0);
|
||||
|
||||
mj_forward(m, d);
|
||||
|
||||
mjtNum v = d->ten_velocity[0];
|
||||
mjtNum expected = -(10*v + 5*v*mju_abs(v) + 1*v*v*v);
|
||||
EXPECT_NEAR(d->qfrc_damper[0], expected, 1e-12);
|
||||
|
||||
mj_deleteData(d);
|
||||
mj_deleteModel(m);
|
||||
}
|
||||
|
||||
} // namespace
|
||||
} // namespace mujoco
|
||||
|
||||
@@ -538,6 +538,44 @@ TEST_F(SensorTest, KineticEnergy) {
|
||||
mj_deleteModel(model);
|
||||
}
|
||||
|
||||
TEST_F(SensorTest, PolyStiffnessEnergy) {
|
||||
static constexpr char xml[] = R"(
|
||||
<mujoco>
|
||||
<option timestep="0.0001">
|
||||
<flag energy="enable"/>
|
||||
</option>
|
||||
|
||||
<worldbody>
|
||||
<body>
|
||||
<joint type="slide" stiffness="10 5 1"/>
|
||||
<geom size="1" mass="1"/>
|
||||
</body>
|
||||
</worldbody>
|
||||
|
||||
<keyframe>
|
||||
<key qpos="2"/>
|
||||
</keyframe>
|
||||
</mujoco>
|
||||
)";
|
||||
|
||||
char error[1024];
|
||||
mjModel* m = LoadModelFromString(xml, error, sizeof(error));
|
||||
ASSERT_THAT(m, NotNull()) << error;
|
||||
mjData* d = mj_makeData(m);
|
||||
mj_resetDataKeyframe(m, d, 0);
|
||||
|
||||
mj_forward(m, d);
|
||||
mjtNum total_energy = d->energy[0] + d->energy[1];
|
||||
|
||||
for (int i = 0; i < 100; i++) {
|
||||
mj_step(m, d);
|
||||
EXPECT_NEAR(d->energy[0] + d->energy[1], total_energy, 0.002);
|
||||
}
|
||||
|
||||
mj_deleteData(d);
|
||||
mj_deleteModel(m);
|
||||
}
|
||||
|
||||
// test clock sensor
|
||||
TEST_F(SensorTest, Clock) {
|
||||
constexpr char xml[] = R"(
|
||||
|
||||
+89
@@ -0,0 +1,89 @@
|
||||
<mujoco model="Polynomial Stiffness">
|
||||
<!--
|
||||
Four boxes hanging from spatial tendons, demonstrating polynomial stiffness.
|
||||
Each tendon has a different stiffness profile:
|
||||
1. Linear: k(q) = a*q (stiffness="100 0 0")
|
||||
2. Quadratic: k(q) = b*q^2 (stiffness="0 200 0")
|
||||
3. Cubic: k(q) = c*q^3 (stiffness="0 0 300")
|
||||
4. Combination: k(q) = a*q + b*q^2 + c*q^3 (stiffness="100 -400 400")
|
||||
-->
|
||||
|
||||
<visual>
|
||||
<map force="0.1" zfar="30"/>
|
||||
<rgba haze="0.15 0.25 0.35 1"/>
|
||||
<global offwidth="1280" offheight="720" elevation="-10"/>
|
||||
</visual>
|
||||
|
||||
<asset>
|
||||
<texture type="skybox" builtin="gradient" rgb1="0.3 0.5 0.7" rgb2="0 0 0" width="32" height="32"/>
|
||||
<texture name="grid" type="2d" builtin="checker" rgb1=".2 .3 .4" rgb2=".1 .15 .2" width="512" height="512"/>
|
||||
<material name="grid" reflectance="0.3" texture="grid" texrepeat="5 5" texuniform="true"/>
|
||||
</asset>
|
||||
|
||||
<default>
|
||||
<geom condim="3"/>
|
||||
<site rgba="0 .8 0 .5" size=".03"/>
|
||||
<tendon width=".01" rgba=".9 .9 .9 1" springlength="0 .3"/>
|
||||
<default class="box">
|
||||
<geom type="box" size=".2 .2 .2" mass="5"/>
|
||||
</default>
|
||||
</default>
|
||||
|
||||
<worldbody>
|
||||
<geom type="plane" size="3 3 .01" material="grid"/>
|
||||
<light directional="true" diffuse=".4 .4 .4" specular="0 0 0" pos="0 0 5" dir="0 0 -1" castshadow="false"/>
|
||||
<light directional="false" diffuse=".8 .8 .8" specular=".3 .3 .3" pos="0 -2 4" dir="0 .5 -1"/>
|
||||
|
||||
<!-- anchor sites -->
|
||||
<site name="anchor_linear" pos="-1.5 0 2"/>
|
||||
<site name="anchor_quadratic" pos="-.5 0 2"/>
|
||||
<site name="anchor_cubic" pos=".5 0 2"/>
|
||||
<site name="anchor_combi" pos="1.5 0 2"/>
|
||||
|
||||
<body name="linear" pos="-1.5 0 1.5">
|
||||
<freejoint/>
|
||||
<geom class="box" rgba=".2 .6 1 1"/>
|
||||
<site name="hook_linear" pos="0 0 .2"/>
|
||||
</body>
|
||||
|
||||
<body name="quadratic" pos="-.5 0 1.5">
|
||||
<freejoint/>
|
||||
<geom class="box" rgba="1 .4 .1 1"/>
|
||||
<site name="hook_quadratic" pos="0 0 .2"/>
|
||||
</body>
|
||||
|
||||
<body name="cubic" pos=".5 0 1.5">
|
||||
<freejoint/>
|
||||
<geom class="box" rgba=".2 .8 .2 1"/>
|
||||
<site name="hook_cubic" pos="0 0 .2"/>
|
||||
</body>
|
||||
|
||||
<body name="combi" pos="1.5 0 1.5">
|
||||
<freejoint/>
|
||||
<geom class="box" rgba=".8 .2 .8 1"/>
|
||||
<site name="hook_combi" pos="0 0 .2"/>
|
||||
</body>
|
||||
</worldbody>
|
||||
|
||||
<tendon>
|
||||
<spatial name="linear" stiffness="100">
|
||||
<site site="anchor_linear"/>
|
||||
<site site="hook_linear"/>
|
||||
</spatial>
|
||||
|
||||
<spatial name="quadratic" stiffness="0 200">
|
||||
<site site="anchor_quadratic"/>
|
||||
<site site="hook_quadratic"/>
|
||||
</spatial>
|
||||
|
||||
<spatial name="cubic" stiffness="0 0 300">
|
||||
<site site="anchor_cubic"/>
|
||||
<site site="hook_cubic"/>
|
||||
</spatial>
|
||||
|
||||
<spatial name="combination" stiffness="100 -400 400">
|
||||
<site site="anchor_combi"/>
|
||||
<site site="hook_combi"/>
|
||||
</spatial>
|
||||
</tendon>
|
||||
</mujoco>
|
||||
Reference in New Issue
Block a user