Reset calibration - Printable Version

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+--- Thread: Reset calibration (/showthread.php?tid=4176)

Reset calibration - ironman - 2022-08-11

The other day I found myself at sea with 'boat not level' and bad steering performance. I must have done something wrong, possibly whilst in the harbour: one of the roll or pitch values was 40 degrees off.

With sails down, I was able to report 'boat is level' and get suitable, near-zero values for roll and pitch, but sadly I was unable to redo my 2D calibration with the seastate I was in. Eventually I got into some shallows, but it took 5 full circles (in fact, I had already given up) before I got calibration age to reset. Even after that, even in flat water, the pypilot steered very badly, until after some time, and to my big relief, it suddenly all snapped into place and steered as smoothly as I have been used to for the last years. I was under the impression that a messed-up 3D calibration was preventing this procedure to succeed swiftly, and my question is now: how can I reset any calibration? What variables should I set to what value, to erase the 2D and 3D calibration if all is messed up? Thx!

RE: Reset calibration - seandepagnier - 2022-08-12

I really dont know but it could be a sensor glitch. This meaning the sensors for odd reason (cosmic ray? heh) start outputing strange values for a while.

Keep us posted, and for ultimate reliability have two systems that can swap... If you can take note of the raw calibration values for compass and accel, and maybe even the gyro bias. Then compare these over time. The results could help make the program smarter.

Already the driver has special logic to reset the sensors in cases where the data seems very wrong and this usually fixed the problem (so I thought) which was somewhat rare and difficult to reproduce but I was able to (by plugging/unplugging i2c enough times randomly), So although this problem should not actually ever occur.. it does but may be a different problem, or maybe the same but just not quite bad enough to trigger the reset.

RE: Reset calibration - ironman - 2022-11-04

Somewhat related - I seem to have problems with my sensor again. I brought pypilot service down and removed all imu settings from it, then tried to get my accelerometers calibrated, but on this (spare) system it looks crooked. Never had a bad sensor - does this denote I have one? See youtube clip: this was taken after I put the machine on all 6 sides, while I continued to do so:

RE: Reset calibration - Ebraball - 2022-11-04

Hello, I had the same problem at the beginning of my tests of Pypilot. I replaced the MPU (MPU-9250/6500/9255) and it is much better, the points are in the sphere during the calibration and the compass gives consistent values.

RE: Reset calibration - ironman - 2022-11-15

I replaced the IMU with another one and now all accelerator calibration points are on the sphere again and the compass calibration succeeds as well. So I have concluded that when the accelerator calibration points don't land on the sphere, the IMU is bad.