Ur_rtde lags behind UR10e

Technical Questions Robot Communication
1

I am using the ur_rtde by SDU Robotics to query the position of a UR10e about 500 times per second. The UR’s tcp moves back and forth parallel to the UR’s y axis. I query the position and find the change in xyz position from the previous query and print the xyz change to the console. I would expect to see the console print positive y values, then when the robot changes direction, the console will show negative values. Instead, the y values change sign well after the UR changes direction, and the delay gets worse as the program runs. Has anyone else encountered this issue or something similar?

2

Not sure if this is relevant but:

“Real-time synchronization: The RTDE generally generates output messages on 125 Hz. However, the real-time loop in the controller has a higher priority than the RTDE interface. Therefore, if the controller lacks computational resources it will skip a number of output packages. The skipped packages will not be sent later, the controller will always send the most recent data. Input packages will always be processed in the control cycle they are received, so the load for the controller will vary depending on the number of received packages.”

3

Thanks but it is not

4

I see that you’ve raised it as an issue on their repository. Probably the right move. If someone there solves it for you, definitely post a solution back here :slight_smile:

5

We were running ur_rtde 1.4.7 and we have rolled back to 1.4.3 which seems to have remedied the issue. Our tests look good but we haven’t integrated 1.4.3 into our application yet so we can’t be sure this is a solution.

6

Using version 1.4.3 fixes the issue.

7

Great to hear, I’m going to post your colleague’s snippet here too in case anyone else has to troubleshoot something similar:

Anders, I work along side Calvin. We just ran a test to see what is going on, see below; We ran these tests with very simple code position = getActualTCPPose(); print(position[1]); Using - c++ project version 1.4.7 result: the current bug in this thread… latency with positional data being returned Using - python project version 1.4.3 result: no latency. working properly, returning exact positional data as UR moves back and forth along the y axis We then went ahead and pulled down the C++ project version 1.4.3 and compiled that. This works, so the issue is something in the later versions fyi.