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VESC Tool speed control overshoot

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PKmita
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Joined: 2022-04-21 12:13
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VESC Tool speed control overshoot

Hello everyone,

I am trying to control my outrunner AXI 2814/28 motor with the Flipsky Fsesc 6.7 70A controller using Vesc tool 3.01 under Windows (in sensorless FOC mode, BLDC mode is too noisy, which is crucial in this application). What I want to do is set electrical RPM here (via USB) and get the motor reaching smoothly this speed (the motor load is a propeller 11x5):

Ofc, first of all I am carrying the motor wizard and R,L, Flux Linkage, Current regulator gains and observer gain autosetting. 

Steady state current and speed seems fine (the motor isn't overloaded, its speed is constant enough and  there is almost no difference between the set and measured value).

Unfortunately I am getting this high speed (and current) overshoot during startup, no matter how I tweak the current regulator gains and current observer gain (as I have found in another topic on the forum): 

Current looks even worse. There is high spike to the set limit.

Moreover, I tried setting lower battery current limit (all I need to do here is to set constant motor speed - 5k RPM, so I set the current limit a little above the value the motor consumes then), which is kinda working, but motor still gets little overshoot, that fades only after few seconds (when speed comes back to preset value). Speed overshot is not allowed in this application. I could even accept little longer raise time (current and speed) but without overshoot.  

Does anybody know which parameters in VESC Tool are responsible for such overshot during startup? Is this because of sensorless control mode is used? What to do in order to get smoother step response without overshot?

Thank you if you get till this point :) 

Best regards,

Paul