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@conghui Software 3.3 and newer it is possible to feed external force/torque measurements into the robot controller, and use this input as an alternative to the internal measurements in e.g. force mode. The feature is enabled and disabled with a special script command and the force/torque measurements can be streamed into the robot controller using the Real-Time Data Exchange (RTDE) interface, see this document. The functionality can be integrated in a URCap for easy installation of external F/T sensors on Universal Robots.

UR Script Function: 
enable_external_ft_sensor(enable, sensor_mass = 0.0, sensor_measuring_offset = [0.0, 0.0, 0.0], sensor_cog = [0.0, 0.0, 0.0])

This function is used for enabling and disabling the use of external F/T measurements in the controller.

If no other RTDE watchdog has been configured (using script function rtde_set_watchdog, a default watchdog will be set to a 10Hz minimum update frequency when the external F/T sensor functionality is enabled. If the update frequency is not met the robot program will pause.

enable: enable or disable feature (bool).
sensor_mass: mass of the sensor in kilograms (float).
sensor_measuring_offset: [x, y, z] measuring offset of the sensor in meters relative to the tool flange frame.
sensor_cog: [x, y, z] center of gravity of the sensor in meters relative to the tool flange frame.

@Samuel_Bouchard is Robotiq working on a URCap for this? Could be a great addition to the FT sensors. I know customers would be more comfortable using the sensor data in force mode rather than the +/- 10N force readings generated by the robot.


heingab said:
Hi, I'm currently trying to implement this on our system. I'm fairly new to the UR ecosystem so this may be a dumb question but I'm not seeing how to actually pipe the FT sensor readings into the system. I'm currently using the RTDE interface so I know the basics of how that works. I understand that "enable_external_ft_sensor" enables using an external sensor but where do you actually override the internal FT estimates with the sensor readings for use in force control mode?

I am having the same troubles and I could not find any instruction for this. Right now I am looking through  the files and reading but I do not see how to actually implement it.