Smith Compensator on PID measurement #6900
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| #ifdef USE_SMITH_PREDICTOR | ||
| smithPredictorInit( |
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any reason you don't use a for loop here to get all three axis?
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At the end it's almost the same. Loop or 3 calls.
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do 3 calls use more memory than a loop? Thats what i've always thought and for init code we don't need to worry about performance. Maybe i'm wrong and the compiler will optimize for that anyway.
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| // filter the delayedGyro to help reduce the overall noise this prediction adds | ||
| float delayed = pt1FilterApply(&predictor->smithPredictorFilter, predictor->data[predictor->idx]); | ||
| float delayCompensatedSample = predictor->smithPredictorStrength * (sample - delayed); |
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Small note here, in EmuFlight I recently changed this code. I moved the pt1Filter to be on the delayCompensatedSample instead of the delayed data. Seems to fly a bit better that way.
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You've made other changes, but i'd still suggest this change.
float delayed = predictor->data[predictor->idx];
float delayCompensatedSample = pt1FilterApply(&predictor->smithPredictorFilter, predictor->smithPredictorStrength * (sample - delayed));
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I do like the idea of a separate file for the smith predictor. The original idea for the smith predictor came from dRonin actually. They used the smith predictor on the motor outputs, but doing it on the gyro is a lot simpler and I would guess give better results. Heres the dRonin code if you are interested. d-ronin/dRonin#2044 |
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Red - not compensated gyro tests show that it indeed works and the compensated signal is indeed around 4ms in front of the not-compensated one. Subjective flight results:
Cons: when working with a noisy gyro, can amplify noise. In those tests, both gyro LPF was off, only Matrix and Unicorn Filter were enabled |
Based on work in emuflight/EmuFlight
CC @Quick-Flash