Raw IMU data from helicopter flight

I put an IMU (Fabio Varesano’s FreeIMU with the MPU-6050 and HMC5883L) on the helicopter and flew it until I crashed. The y-axis on all the plots below are raw ADC output, not scaled to engineering units, but the obvious message is the sensors get noisy as soon as the rotor spools up. I was using both sensors’, or Fabio’s, default settings. I think both have a low pass filter feature that I can tune, and I’ll try some different mounting techniques. I tried to fly level passes back and forth: the magnetometer X-axis looks almost useful and you can kind of see my turns in the gyro Z-axis. All of the accel channels are garbage, and clipped for most of the record.

heliccoordsys

gyrosaccmag

I’m kind of re-inventing the wheel here, because the Blade SRX 200 has a really effective stabilization feature. When I opened up the receiver, it found it’s using an MPU-6050, and I suspect it’s using Invensense’s DMP. IMG_1131

The noise in the accelerometer and gyro is narrowband at 5.6 Hz (336 rpm). Magnetometer noise looks broadband, and by the shape of the amplitude, it looks like the LPF cutoff frequency is around 20-25 Hz.

ffts

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