Impulse Response estimation, normal PWM vs. Oneshot125

This is an estimate of the roll and pitch rate impulse response functions for my 450 sized AquaCopter with Bl-Heli ESCs. Gyro rates and rate setpoints were logged at 400Hz, and impulse response calculated by fitting a second order model to the data. Fit quality was good, more than 95% of the gyro signal energy matched the model prediction. Switching from normal PWM to OneShot125 actually increased the rate control latency from 35 to 37 msec, but the undershoot amplitude was reduced slightly, and the transfer function magnitude is flatter within the passband.

Normal PWM impulse response plot:


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