This is currently a planar robot only with three joints (two slide joints and a hinge joint).
This repository includes:
- Required STL files to represent the shown robot.
- MuJoCo XML files to represent the robot in MuJoCo.
- A Python script that will convert UR5 joint values from degrees to MuJoCo body quaternions. An explanation about the need of this script is available under here.
MuJoCo UR5 Model was developed by the Robot Manipulation Lab in the School of Computing at the University of Leeds.
- Authors: Rafael Papallas, Wisdom Agboh
- Current maintainors: Rafael Papallas, Wisdom Agboh.
This work is licensed under GNU General Public License v3.0. The full license is available here.
Since we meant to use this robot model as a planar robot, we decided to remove the arm joints and just add three joints on Ridgeback (x, y, theta). Therefore, we had to apply some rotations to the bodies themselves to match the joint configuration of the actual robot.
The current model in this repository as defined includes some custom configurations such that the arm is set to the following:
- Base: -90.0 degrees
- Shoulder: -175.0 degrees
- Elbow: -5.0 degrees
- Wrist1: -180.0 degrees
- Wrist2: -90.0 degrees
- Wrist3: -180.0 degrees
If you want to change the configuration of the robot, then we recommend to start from the following original configuration of the arm (which is the home configuration of UR) and apply rotations as needed to the required bodies to match the UR5 joint values shown on the screen. With the following configuration you should just apply the required rotations of each joint from the UR5 screen to the existing quaternions of the configuration below (multiply the current quaternion of the XML with the desired rotation):
<body name="shoulder_link" pos="0.28 0 0.545159" quat="0.681998 0 0 -0.731354">
<inertial pos="0 0 0" mass="3.7" diaginertia="0.0102675 0.0102675 0.00666" />
<geom type="mesh" rgba="0.7 0.7 0.7 1" mesh="shoulder" />
<body name="upper_arm_link" pos="0 0.13585 0" quat="0.707107 0 0.707107 0">
<inertial pos="0 0 0.28" mass="8.393" diaginertia="0.226891 0.226891 0.0151074" />
<geom type="mesh" rgba="0.7 0.7 0.7 1" mesh="upperarm" />
<body name="forearm_link" pos="0 -0.1197 0.425">
<inertial pos="0 0 0.25" mass="2.275" diaginertia="0.0494433 0.0494433 0.004095" />
<geom type="mesh" rgba="0.7 0.7 0.7 1" mesh="forearm" />
<body name="wrist_1_link" pos="0 0 0.39225" quat="0.707107 0 0.707107 0">
<inertial pos="0 0 0" quat="0.5 0.5 -0.5 0.5" mass="1.219" diaginertia="0.21942 0.111173 0.111173" />
<geom type="mesh" rgba="0.7 0.7 0.7 1" mesh="wrist1" />
<body name="wrist_2_link" pos="0 0.093 0">
<inertial pos="0 0 0" quat="0.5 0.5 -0.5 0.5" mass="1.219" diaginertia="0.21942 0.111173 0.111173" />
<geom type="mesh" rgba="0.7 0.7 0.7 1" mesh="wrist2" />
<body name="wrist_3_link" pos="0 0 0.09465">
<inertial pos="0 0 0" quat="0.5 0.5 -0.5 0.5" mass="0.1879" diaginertia="0.033822 0.0171365 0.0171365" />
<geom type="mesh" rgba="0.7 0.7 0.7 1" friction="0.8 0.8 0.8" mesh="wrist3" />
</body>
</body>
</body>
</body>
</body>
</body>However, to make this easier, we wrote a simple Python script under scripts called
set_ur5_joints.py that will ask you to provide the joint values in degrees of the
robot as shown on the UR5 screen and the xml file you would like to modify and will
do the appropriate calculations and convertsions to set the model quaternions correctly.