How to model an underactuated gripper
Posted: 15 May 2023, 15:27
Hello,
Context:
Working on a project that will use an underactuated gripper. I am right now doing some tests on how to model a RobotiQ gripper as https://github.com/deepmind/mujoco_mena ... botiq_2f85.
I want specifically to model it as it is in this project, using tendons to actuate the fingers and using equality constraints
If you look at the mjcf file in the mujoco menagerie project between the body right follower and right coupler (as described in the xml file) to do the close loop.
What I've done:
https://ibb.co/f8Pns0J
For the equality constraint, I created a dummy loop with an dynamic overlap constraint.
For the actuated tendon, I used a prismatic joint linked to the tendons, I specify the name of the joint in the xml file at joint proxy.
I modeled only the right part of the gripper for now.
Results:
When I move the joint from low to high value. The prismatic joint is not moving and this happens :
https://ibb.co/vDM5Pzb
The first joint is going off the gripper, I didn't expect that. Do you know how can I correct it ?
Besides when I add a body on the prismatic joint inside the model tree, t moves but it does not correct the joint going off.
Best regards,
Alexis
Context:
Working on a project that will use an underactuated gripper. I am right now doing some tests on how to model a RobotiQ gripper as https://github.com/deepmind/mujoco_mena ... botiq_2f85.
I want specifically to model it as it is in this project, using tendons to actuate the fingers and using equality constraints
If you look at the mjcf file in the mujoco menagerie project between the body right follower and right coupler (as described in the xml file) to do the close loop.
What I've done:
https://ibb.co/f8Pns0J
For the equality constraint, I created a dummy loop with an dynamic overlap constraint.
For the actuated tendon, I used a prismatic joint linked to the tendons, I specify the name of the joint in the xml file at joint proxy.
I modeled only the right part of the gripper for now.
Results:
When I move the joint from low to high value. The prismatic joint is not moving and this happens :
https://ibb.co/vDM5Pzb
The first joint is going off the gripper, I didn't expect that. Do you know how can I correct it ?
Besides when I add a body on the prismatic joint inside the model tree, t moves but it does not correct the joint going off.
Best regards,
Alexis