4 ms·

Great improvement since the last video! Are you just using Jacobian transpose for force control on the neck? I ask because it seems a bit stiff, the red marks

Great improvement since the last video! Are you just using Jacobian transpose for force control on the neck? I ask because it seems a bit stiff, the red marks on the neck of the test subject suggested to me that maybe there's a lot of noise in your force sensing, or at least unmodeled behavior. Due to the slow growth of test subject hair, have you found 6$ to be cheap enough to keep your test cycles short enough? The kinematic configuration of the arm looks odd, did you pick this to maximize rank of the Jacobian or the manipulability matrix?

dopeboy 7y ago
Awesome questions, I appreciate the curiosity. We're using the stock force control software and plan to tweak it soon. I couldn't tell you how it works under the hood. We use mannequin to test and then, other body parts [0]. Long term, we want to invest in a better testing harness. Open to ideas on how to do that. [0] - https://twitter.com/manishsinhaha/status/1202078849619513345 https://twitter.com/manishsinhaha/status/1202078849619513345
- cbames89 7y ago
  UR website[0] seems to suggest +- 10N (a kilo resting on your neck) with their stock implementation. I imagine you're going to want something better than that. What Force/Torque sensor do you use? Some of them are temperature sensitive and require a good warm-up period before they can be used to achieve good performance. [0]https://www.universal-robots.com/how-tos-and-faqs/how-to/ur-how-tos/urscript-dynamic-force-control-20571/ https://www.universal-robots.com/how-tos-and-faqs/how-to/ur-...
  - ladberg 7y ago
    Not OP but I've written custom force control code for a UR5e. There's a six axis force sensor on the end effector for the e model which has a pretty noisy raw output. After some filtering we were able to get a pretty sensitive controller. I didn't measure it, but far less than 10N.
    - cbames89 7y ago
      Sweet, thanks for sharing your experience!

dopeboy 7y ago

Awesome questions, I appreciate the curiosity. We're using the stock force control software and plan to tweak it soon. I couldn't tell you how it works under the hood. We use mannequin to test and then, other body parts [0]. Long term, we want to invest in a better testing harness. Open to ideas on how to do that. [0] - https://twitter.com/manishsinhaha/status/1202078849619513345 https://twitter.com/manishsinhaha/status/1202078849619513345

cbames89 7y ago
UR website[0] seems to suggest +- 10N (a kilo resting on your neck) with their stock implementation. I imagine you're going to want something better than that. What Force/Torque sensor do you use? Some of them are temperature sensitive and require a good warm-up period before they can be used to achieve good performance. [0]https://www.universal-robots.com/how-tos-and-faqs/how-to/ur-how-tos/urscript-dynamic-force-control-20571/ https://www.universal-robots.com/how-tos-and-faqs/how-to/ur-...
- ladberg 7y ago
  Not OP but I've written custom force control code for a UR5e. There's a six axis force sensor on the end effector for the e model which has a pretty noisy raw output. After some filtering we were able to get a pretty sensitive controller. I didn't measure it, but far less than 10N.
  - cbames89 7y ago
    Sweet, thanks for sharing your experience!