I collected these diagnostics from a couple of indoor flights this morning. The flight is 7.s long:
- 1.5s to get the props spinning to hover speed on the ground
- 2s climb at 30cm/s
- 2s hover
- 2s descent at -30cm/s.
This was using the complementary filter with tau set to 5s but the GERMS stats were collected to get a better idea what’s going on.
This shows two things – there’s a lot of noise in the raw data blue line, and the red trend line cleary shows an oscillation which is hiding the peaks and troughs of net acceleration / deceleration at 1.5, 3.5 and 5.5 seconds.
This set show raw accelerometer values, and the measure of gravity that comes after the raw data has been passed through the butterworth filter. Three things of interest here:
- The grey line of raw acceleration is still noisy, but does show the peaks and troughs better at 1.5, 3.5 and 5.5s
- The green butterworth filter line is doing a lovely job of extracting gravity from the noisy accelerometer data
- There’s oscillation in both the X and Y accelerometer readings, best seen in the blue and orange trend lines.
The flights were perfect to look at – only these diagnostics show these subtle problems.
The next steps then are to sort increase the P gain and decrease the I gain to stop the oscillations. With those gone, it’ll hopefully allow the GERMS stats to show only the deviations from real gravity, and thereby filter it out from the angle calculation as the complementary filter does now.
One point in passing, I have to drop the hover speed PWM value from the long standing 1500ms to 1400ms PWM; The new 4S batteries are clearly showing that 3S is not enough.