Universal Robots Forum

Brakes do not release when mounted on vibrating vehicle

We are using the ROS1 driver on several UR5e mounted on a vehicle. They are new arms as of May 2021 (not sure of the exact software versions.) We use the current binary release of the ROS1 driver.

The arms are mounted in an upside down, ceiling hang position. The vehicle vibrates a fair bit – sometimes enough to be visible.

When starting the robots with the ROS driver, we get “C281A3: … Base joint entered the fault state”. It can be other joints besides the base joint depending on the orientation of the arm at startup.

Some of the brakes on the joints can be heard starting to retract, but somewhere in the process something fails and the fault is thrown.

We can provide data from an onboard IMU if it would be useful.

We have seen the same issues on our UR3’s that hang upside down with very little vibration.

Try changing the safety settings to ‘least restricted’ and see if you are still having problems. If you are then there is probably nothing that can be done about this. The mounting of the robot needs to be as vibration free as possible and unfortunately we do not have a specification for ‘how much is too much’.