Pybullet getJointState what are the units of joint velocity?

[lauren-lee-cooke]

Hi,

My question boils down to; what are the units of the values returned by getJointState? Specifically, what are the units of the joint velocity?

The reason I am asking this is that when looking at the values returned by this function, the joint position appears to be in radians while I am unsure about the joint velocity (rad/s pr degrees/s?). The joint positions appear to be in radians as when I load in my model, the joint positions returned by the function make sense with the robot model's initial pose and seem to make sense as the robot moves. However, as the robot moves the joint velocities seem to be unreasonably large, if they are in rad/s.

I am using the unitree a1 robot urdf model and the reason for these large joint velocity values could be the way I am loading in my model, or perhaps another issue somewhere else in my simulation. In the code below I have included how I load the object into my environment as well as I how extract and print the joint velocity in case these may be the cause of my high velocity values.

quadId = pybullet.loadURDF(fileName = fn, basePosition = (0, 0, 0.353), flags = pybullet.URDF_USE_SELF_COLLISION | pybullet.URDF_MAINTAIN_LINK_ORDER, physicsClientId = client)
Temp = p.getJointStates(quadId, jointIndices = joint_indicies, physicsClientId = client)
joint_velocity = [j[1] for j in Temp]

Identifying the exact units of the joint velocity will help me narrow down where issues could lie in my simulation so please assist if you can!

I am also sorry if this is not the correct place to post this question, I tried to register to log this question on the Pybullet forum but was unable to register. I am also sorry if the post is in the incorrect format or area as this is my first time posting. Please let me know if this should be posted elsewhere.