switch to Impedence control mode using FRI

ahundt / grl

Robotics tools in C++11. Implements soft real time arm drivers for Kuka LBR iiwa plus V-REP, ROS, Constrained Optimization based planning, Hand Eye Calibration and Inverse Kinematics integration.

https://ahundt.github.io/grl/

BSD 2-Clause "Simplified" License

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switch to Impedence control mode using FRI #172

Closed ghost closed 4 years ago

ghost commented 6 years ago

Hello, currently, we use the FRI driver to directly control the joints of the IIWA via ROS. Is it possible to use the robot in impedence control mode and overlaying joint values via FRI? How should I do it?

Many thanks, Bruno

ahundt commented 5 years ago

Sorry for the delay, I didn't see this message until now. So are you saying you've been able to move the robot with the grl FRI code, or are you utilizing your own?

yes it is possible to do that, but I don't believe we have that implemented. We preferred to directly control the joints entirely from FRI.

gpldecha commented 5 years ago

@ahundt I have just started to work with the IIWA. I am interested in knowing if it is possible to change the stiffness parameters (JointImpedence Control mode) when using FRI and joint overlay. This your current package achieve this? If not would you have any suggestions on how to achieve this behaviour?

Thanks a lot for any advice,

Guillaume

ahundt commented 5 years ago

It isn't supported yet in my package, and if I recall correctly, as of the version we use (1.11 I think) joint impedance control is only possible in FRI if you implement it yourself. This may have changed with later versions. Enabling/Disabling FRI does work well in my API.

Also for 99% of applications smartservo/directservo is likely sufficient. We have an API for controlling the robot in that way from a PC in C++. If I recall correctly latency is ~100ms, which should also be sufficient for most applications, though it wouldn't work for some very specialized use cases.

jacknlliu commented 4 years ago

@ahundt Is it possible that using the smartservo interface to switch the control mode while the FRI session motion is running?

ahundt commented 4 years ago

I do change between several modes while it is running, but you might have to test those specific modes and add a few lines to the C++ and Java code to support the new modes.

On Sun, Aug 25, 2019 at 8:25 PM Jack Liu notifications@github.com wrote:

@ahundt https://github.com/ahundt Is it possible that using the smartservo interface to switch the control mode while the FRI session motion is running?

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Cheers! Andrew Hundt