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Current control performance & best way to tune Kp and Ki

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jinwonchung
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VESC Free
Joined: 2024-10-07 19:06
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Current control performance & best way to tune Kp and Ki

Hi,

I am relatively new to vesc and I want to hear expert opinions about the best way to tune current controller.

For your context, I've been using ELMO gold tweeter motor controllers for a while and I just started playing with vesc. My plan is to replace ELMO with VESC for my force controlled robot. I am using this motor (https://store.tmotor.com/product/u7-v2-motor-u-power-kv280.html) with 28V batteries.

With ELMO in current control mode, rise time of current was about 1ms and the error was pretty small (RMSE ~0.08A). I achieved this performance after some tuning off of its identified Kp, Ki.

With VESC in FOC current control mode, rise time was about 10ms & the error is much bigger (~0.8A) with detected Kp and Ki after running R, L and flux linkage measurements. I believe VESC should be able to achieve current control performance comparable to ELMO as it has similar hardware components and uses comparable control algorithms.

 

So, I have two main questions:

1) What would be the best current control performance (current (iq) rise time & rough RMSE) I can expect from VESC?

2) What would be the best way to tune Ki and Kp?

- In ELMO software, there is a tool that I can plot square wave current command (5ms period) and current measurement while tuning Kp and Ki in real time. The sample rate was pretty high, like 10kHz, and I could easily tune parameters within an hour.

- In VESC tool, it seems like there are many tools/functionalities that I can potentially do similar things. I found Realtime and Experiment Data plots are a little too slow for this, but it may be my fault not to use the best configuration. Sampled data plot seems pretty fast but it's been hard to figure out the timing of sampling.

 

I would really appreciate any help for this!