# Revision history [back]

### how to output velosity with ur_modern_driver

I am doing a project about robot-teleoperation now. By using ROS I have accomplished the position-control（even though there are time-delay between the master and slave）.I find that the position control is not flexible enough,so I want to control the robot with velosity-control .After reading the explaination about link text ,I learned that maybe it's possible to control the jointspeed. After I

 roslauch ur_modern_driver ur_driver


and

 rostopic echo /ur_driver/jointspeed


There is no response anywhere,what's failure and what I should do to control the jointspeed? Any help should be appreciated!