I'm new and currently working on my 6 Dof Arm project, right now I am try to simulate it using Mujoco but I don't really understand why and how it works, here is the problem: My 6 Dof Arm is always moving in the simulation.
I don't really know why, the position (home) I set it at 0 to all the joint but when I start the simulation the joint 3 and 6 (upperarm_joint and endeffector_joint) always moving so randomly, the log status so that joint 3 usually run from 0 to 0,9 and joint 6 usually run from 0 to 0.3 and not only that I can't control the any joint except the linear one.
I think is it because the servo do not have enough force, but when I create another file I change the force range to higher x100 but it's still not working, it only can move one time. How can I narrow down the problem?
Here is the link drive for all the robot asset you can download: https://drive.google.com/drive/folders/1D_i0oXhlEZeCfKm559ciYAL0cHJ87w60?usp=sharing
My code:
<mujoco model="robot"
<compiler angle="degree" meshdir="assets" autolimits="true"/>
<option integrator="implicitfast"/>
<default>
<default class="robot">
<material specular="0.5" shininess="0.25"/>
<default class="revolute">
<joint range="0 180"/>
<general gaintype="fixed" biastype="affine" ctrlrange="0 180"
gainprm="100 0 0" biasprm="0 0 0" forcerange="-1.5 1.5"/>
</default>
<default class="linear">
<joint range="0 540" type="slide"/>
<general gaintype="fixed" biastype="affine" ctrlrange="0 540"
gainprm="500 0 0" biasprm="0 -50 -100" forcerange="-200 200"/>
</default>
<default class="visual">
<geom type="mesh" contype="0" conaffinity="0" group="2"/>
</default>
<site size="0.001" rgba="0.5 0.5 0.5 0.3" group="4"/>
</default>
</default>
<asset>
<material class="robot" name="white" rgba="1 1 1 1"/>
<material class="robot" name="jointgray" rgba="0.278 0.278 0.278 1"/>
<material class="robot" name="linkgray" rgba="0.82 0.82 0.82 1"/>
<material class="robot" name="blue" rgba="0.49 0.678 0.8 1"/>
<mesh file="base.obj"/>
<mesh file="gantry.obj"/>
<mesh file="armbase.obj"/>
<mesh file="forearm.obj"/>
<mesh file="shoulder.obj"/>
<mesh file="upperarm.obj"/>
<mesh file="wrist.obj"/>
<mesh file="endeffector.obj"/>
</asset>
<worldbody>
<light name="spotlight" mode="targetbodycom" target="gantry" pos="0 -1 2"/>
<body name="base" zaxis="1 0 0" childclass="robot">
<inertial mass="4.0" pos="0 0 0" diaginertia="0.00443333156 0.00443333156 0.0072"/>
<geom mesh="base" material="white" class="visual"/>
<body name="gantry" pos="5 190 50 " euler="180 0 90">
<inertial mass="3.7" pos="0 0 0" diaginertia="0.0102675 0.0102675 0.00666"/>
<joint name="gantry_joint" class="linear" axis="-1 0 0" pos="0 0 0"/>
<geom mesh="gantry" material="blue" class="visual"/>
<geom mesh="armbase" material="white" class="visual" pos="-47 30 8"/>
<body name="forearm_link" pos="-47 30 8">
<inertial mass="3.7" pos="0 0 0" diaginertia="0.0102675 0.0102675 0.00666"/>
<joint name="forearm_joint" class="revolute" axis="0 1 0" pos="0 0 16"/>
<geom mesh="forearm" material="blue" class="visual"/>
<body name="shoulder_link" pos="0 0 0">
<inertial mass="8.393" pos="0 0 0.2125" diaginertia="0.133886 0.133886 0.0151074"/>
<joint name="shoulder_joint" class="revolute" axis="1 0 0" pos="0 141 -19"/>
<geom mesh="shoulder" material="linkgray" class="visual"/>
<body name="upperarm_link" pos="0 0 0">
<inertial mass="2.275" pos="0 0 0.196" diaginertia="0.0311796 0.0311796 0.004095"/>
<joint name="upperarm_joint" class="revolute" axis="1 0 0" pos="0 195 -180"/>
<geom mesh="upperarm" material="blue" class="visual"/>
<body name="wrist_link" pos="0 0 0.0" zaxis="0 0 1">
<inertial mass="1.219" pos="0 0.127 0" diaginertia="0.0025599 0.0025599 0.0021942"/>
<joint name="wrist_joint" class="revolute" axis="0 0.3 -1" pos="0 230 -300"/>
<geom mesh="wrist" material="white" class="visual"/>
<body name="endeffector_link" pos="0 0 0">
<inertial mass="0.1889" pos="0 0.0771683 0" quat="1 0 0 1"
diaginertia="0.000132134 9.90863e-05 9.90863e-05"/>
<joint name="endeffector_joint" class="revolute" axis="1 0 0" pos="-125 236.5 -342.7"/>
<geom material="linkgray" mesh="endeffector" class="visual"/>
<site name="attachment_site" pos="0 0.1 0" quat="-1 1 0 0"/>
</body>
</body>
</body>
</body>
</body>
</body>
</body>
</worldbody>
<actuator>
<position class="linear" name="gantry_act" joint="gantry_joint"
kp="500" kv="60" ctrlrange="0 540" forcerange="-200 200"/>
<position class="revolute" name="forearm_actuator" joint="forearm_joint"
kp="120" kv="12" ctrlrange="0 180" forcerange="-1.5 1.5"/>
<position class="revolute" name="shoulder_actuator" joint="shoulder_joint"
kp="180" kv="18" ctrlrange="0 180" forcerange="-1.5 1.5"/>
<position class="revolute" name="upperarm_actuator" joint="upperarm_joint"
kp="140" kv="30" ctrlrange="0 180" forcerange="-1.5 1.5"/>
<position class="revolute" name="wrist_actuator" joint="wrist_joint"
kp="100" kv="10" ctrlrange="0 180" forcerange="-1.5 1.5"/>
<position class="revolute" name="endeffector_actuator" joint="endeffector_joint"
kp="80" kv="8" ctrlrange="0 180" forcerange="-1.5 1.5"/>
</actuator>
<keyframe>
<key name="home" qpos="0 0 0 0 0 0" ctrl="0 0 0 0 0 0"/>
</keyframe>
</mujoco>
