I'm trying to build a model that is driven by servos. The joints are supposed to have enough friction to hold the model's weight with no power and prevent servos from oscillating. When I run the simulation, either the servos give in to the model's weight or if I increase the force enough they oscillate violently. I figured this is because I need to properly tune friction and density. However, the changes I make to the values are not affecting the simulation at all even if I set ridiculously large or small values. I'm running the simulation using RoboschoolMujocoXmlEnv, could this be a problem in Roboschool or am I doing something wrong? Here's my model. Code: <mujoco model="miko"> <compiler angle="degree" coordinate="local" inertiafromgeom="true"/> <option integrator="RK4" timestep="0.01"/> <custom> <numeric data="0.0 0.0 0.55 1.0 0.0 0.0 0.0 0.0 1.0 0.0 -1.0 0.0 -1.0 0.0 1.0" name="init_qpos"/> </custom> <default> <joint armature="1" damping="0" condimi="6" density="0.1" limited="true" friction="10 10 10"/> <geom damping="0" conaffinity="0" condim="6" density="0.1" friction="10 10 10" margin="0.01" rgba="0.8 0.6 0.4 1"/> </default> <worldbody> <body name="torso" pos="0 0 1.2"> <geom name="torso_geom" pos="0 0 0" size="1 1 0.1" type="box" rgba="0.7 0.6 0.3 1"/> <!--joint armature="0" damping="0" limited="false" margin="0.01" name="root" pos="0 0 0" type="free"/--> <body name="front_right_leg" pos="0 0 0"> <geom fromto="0.0 0.0 0.0 0.4242 0.4242 0.0" name="aux_1_geom" size="0.08" type="capsule" rgba="1 0 0 1"/> <body name="aux_1" pos="0.4242 0.4242 0"> <joint axis="0 0 1" name="hip_1" pos="0.0 0.0 0.0" range="-90 90" type="hinge"/> <geom fromto="0.0 0.0 0.0 0.318 0.318 0.0" name="front_left_leg_geom" size="0.08" type="capsule" rgba="0 1 0 1"/> <body pos="0.318 0.318 0" name="front_left_foot"> <joint axis="0 0 1" name="ankle_1" pos="0.0 0.0 0.0" range="0 0.35" type="slide"/> <geom fromto="0.0 0.0 0.0 0.0 0.0 -1.0" name="front_left_ankle_geom" size="0.08" type="capsule" rgba="0 0 1 1"/> </body> </body> </body> <body name="back_right_leg" pos="0 0 0"> <geom fromto="0.0 0.0 0.0 -0.4242 0.4242 0.0" name="aux_2_geom" size="0.08" type="capsule" rgba="1 1 0 1"/> <body name="aux_2" pos="-0.4242 0.4242 0"> <joint axis="0 0 1" name="hip_2" pos="0.0 0.0 0.0" range="-90 90" type="hinge"/> <geom fromto="0.0 0.0 0.0 -0.318 0.318 0.0" name="right_leg_geom" size="0.08" type="capsule" rgba="0 1 0 1"/> <body pos="-0.318 0.318 0" name="front_right_foot"> <joint axis="0 0 1" name="ankle_2" pos="0.0 0.0 0.0" range="0 0.35" type="slide"/> <geom fromto="0.0 0.0 0.0 0.0 0.0 -1.0" name="right_ankle_geom" size="0.08" type="capsule" rgba="0 0 1 1"/> </body> </body> </body> <body name="back_left_leg" pos="0 0 0"> <geom fromto="0.0 0.0 0.0 -0.4242 -0.4242 0.0" name="aux_3_geom" size="0.08" type="capsule" rgba="0 1 1 1"/> <body name="aux_3" pos="-0.4242 -0.4242 0"> <joint axis="0 0 1" name="hip_3" pos="0.0 0.0 0.0" range="-90 90" type="hinge"/> <geom fromto="0.0 0.0 0.0 -0.318 -0.318 0.0" name="back_leg_geom" size="0.08" type="capsule" rgba="0 1 0 1"/> <body pos="-0.318 -0.318 0" name="left_back_foot"> <joint axis="0 0 1" name="ankle_3" pos="0.0 0.0 0.0" range="0 0.35" type="slide"/> <geom fromto="0.0 0.0 0.0 0.0 0.0 -1.0" name="third_ankle_geom" size="0.08" type="capsule" rgba="0 0 1 1"/> </body> </body> </body> <body name="front_left_leg" pos="0 0 0"> <geom fromto="0.0 0.0 0.0 0.4242 -0.4242 0.0" name="aux_4_geom" size="0.08" type="capsule" rgba="1 0 1 1"/> <body name="aux_4" pos="0.42 -0.4242 0"> <joint axis="0 0 1" name="hip_4" pos="0.0 0.0 0.0" range="-90 90" type="hinge"/> <geom fromto="0.0 0.0 0.0 0.318 -0.318 0.0" name="rightback_leg_geom" size="0.08" type="capsule" rgba="0 1 0 1"/> <body pos="0.318 -0.318 0" name="right_back_foot"> <joint axis="0 0 1" name="ankle_4" pos="0.0 0.0 0.0" range="0 0.35" type="slide"/> <geom fromto="0.0 0.0 0.0 0.0 0.0 -1.0" name="fourth_ankle_geom" size="0.08" type="capsule" rgba="0 0 1 1"/> </body> </body> </body> </body> </worldbody> <actuator> <position ctrlctrlrange="-1.0 1.0" joint="hip_1" gear="1"/> <position ctrlctrlrange="-1.0 1.0" joint="ankle_1" gear="1"/> <position ctrlctrlrange="-1.0 1.0" joint="hip_2" gear="1"/> <position ctrlctrlrange="-1.0 1.0" joint="ankle_2" gear="1"/> <position ctrlctrlrange="-1.0 1.0" joint="hip_3" gear="1"/> <position ctrlctrlrange="-1.0 1.0" joint="ankle_3" gear="1"/> <position ctrlctrlrange="-1.0 1.0" joint="hip_4" gear="1"/> <position ctrlctrlrange="-1.0 1.0" joint="ankle_4" gear="1"/> </actuator> </mujoco>