Control of Dynamixel XM430-W210 with very low latency (< 1ms). Is that possible?

Hello to all,

I am currently writing my master thesis on an experimental setup using two Dynamixel XM430-W210 Servo Motors. The idea is to control a two link manipulator using torque/current control mode of the dynamixel Servos, which is already working.

  • 2x Dynamixel XM430-W210
  • Dynamixel SDK with Protocol 2.0
  • U2D2 Power Hub Board
  • Ubuntu 20.04

Now my question:
Is it possible to reduce the USB Latency when reading out the motor states to a value
significantly lower than 1 ms? I have already reduced the USB Latency of the port /dev/ttyUSB0
to 1 ms and used group_sync_read / group_sync_write, respectively, which works quite well.

Now I have measured the actual reading and writing times: Reading time max is now about 1.1 ms,
writing time is significantly lower than 0.1ms (for both motors each).

So, the bottleneck of the controller speed is actually the time needed to read out the Dynamixel motors.
I have tried to reduce the latency further to values lower than 1 ms, but this does not seem to be allowed by Ubuntu, at least by default. So my question is: What could be done to improve this??

Best regards,

Answered in the forum thread below.