JointMotor for urdf robot franka_panda

Official Python bindings with a focus on reinforcement learning and robotics.
Post Reply
cutman2593
Posts: 1
Joined: Fri May 29, 2020 4:01 pm

JointMotor for urdf robot franka_panda

Post by cutman2593 »

Hello,

I'm working on a C++ project about a robotic arm and I chose Bullet to handle the IK/FK of the robot and some physics besides it.

I use python for my tests and my workspace corresponds to the panda_sim of the repository 'pybullet'. I tweaked it a little to apply a motor on the first joint using the function 'SetJointMotorControl2' and I also set the initial joint/rest positions for all links to 0. So in the method 'panda_sim.py::step', there is only one line used to apply the motor :

Code: Select all

self.bullet_client.setJointMotorControl2(self.panda, 0, self.bullet_client.VELOCITY_CONTROL, 
							targetVelocity=-1, force = 1000)
The motor starts alright and is steady, however when time passes by, the other joints starts to rotate as well and in the end, everything goes wrong and the motor doesn't rotate the first joint anymore. Is there a way to block revolute positions of other joints to allow the rotation movement joint by joint (which corresponds to simple FK) ?

Thanks for reading.
Johann NOVAK
User avatar
Erwin Coumans
Site Admin
Posts: 4221
Joined: Sun Jun 26, 2005 6:43 pm
Location: California, USA
Contact:

Re: JointMotor for urdf robot franka_panda

Post by Erwin Coumans »

It appears as if you are driving a strong motor against a joint limit, this won't work properly so try to avoid doing that.
Post Reply