Nonzero joint velocities for static position
Hello everyone! I am using ROS Melodic with Gazebo 9 and working with Unitree A1 quadruped robot model. Recently I found that joint_states shows considerable non-zero joint velocities when robot stands on the ground in static position. When I plot joint velocities in Gazebo values are also non-zero. However when I hung up the robot and use the same servo velocities are zero. I use unitree_legged_control package as a servo controller.
Seeing this:
makes me believe this is a problem in Gazebo, not the ROS integration.
Gazebo is not a part of ROS, it's a stand-alone piece of software for which plugins are available which make it usable with ROS.
If Gazebo itself reports non-zero velocities, the plugins will just copy those over into ROS
JointState
messages.You should ask this question over at
answers.gazebosim.org
.If/when you do, please post a comment here with a link to your new question there so we keep things connected.