Bad Compass

[Vince]

Hi guys,

I have finally completed the installation of my Tinypilot AP + ST4000 wheel, and while the AP seems to works relatively well, I am having this message when I look at the calibration info:



I have tried to do more 180/360 turns with the boat but it has not improved.

Is it because my Tiny Hat is too close to the motor controller which might generate interferences?

As I said, the AP works relatively good at keeping its route, but I am wondering it will affect its performance with high wind.

[seandepagnier]

I'm not sure it will be different in high wind, if it works ok it should be the same.

If possible maybe try to move the dc-dc converter outside the box. If it works ok, then maybe the definition of "bad" should change...

[Vince]

I'm not sure it will be different in high wind, if it works ok it should be the same.

If possible maybe try to move the dc-dc converter outside the box.   If it works ok, then maybe the definition of "bad" should change...

Thanks I am going to try that!

[seandepagnier]

if possible maybe also move the motor controller further away. Your deviation of 0.07 is quite high, I would aim for 0.03 or lower, but as you said it steers a course so maybe you don't care. What you might find is the compass heading will be inaccurate. For example, if you turn 90 degrees it may only change by 80 degrees, then turn another 90 and it changes 100.

[Vince]

if possible maybe also move the motor controller further away.   Your deviation of 0.07 is quite high, I would aim for 0.03 or lower, but as you said it steers a course so maybe you don't care.    What you might find is the compass heading will be inaccurate.  For example, if you turn 90 degrees it may only change by 80 degrees, then turn another 90 and it changes 100.

I followed your advice and I got much better results! Thanks.

This was done from home where I got "poor" last time, I will reinstall everything on the boat tomorrow and hopefully I will get the same.

Vince

[Vince]

I put everything back on the boat and it worked much better! Now I get Good/0.02 and I sailed in moderate wind without any issue! Thanks

[seandepagnier]

Did it not work before in moderate wind? The main improvement you should see is more accurate compassing (turning 90 actually changes compass by 90)

It would be interesting to know if it was the controller or power supply that caused the deviations... I"m guessing the power supply

[CapnKernel]

I could be wrong here, but the problem might be the orientation of your IMU. The MPU board containing the IMU should be horizontal not vertical, and the yellow capacitor should face towards the front of the boat. I think the magnetic heading is only correct with this orientation.

(Would love to know if I'm wrong. My autopilot would be better mechanically if I could mount it vertically like you've done!)

[seandepagnier]

It doesn't matter how you mount it, but you need to level the sensors once mounted.

[Vince]

Did it not work before in moderate wind?   The main improvement you should see is more accurate compassing (turning 90 actually changes compass by 90)

It would be interesting to know if it was the controller or power supply that caused the deviations...   I"m guessing the power supply

Yes it did work before even with bad compass, but I feel that the course correction has improved. I sailed again today and I really felt the improvement when sailing close hauled, I used to get caught into the wind but this time I felt like the AP was able to hold the course better.

I am planning on changing the enclosure boxes with something smaller, I will try to reproduce the issue with the dc and motor controller to see what caused the issue

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I could be wrong here, but the problem might be the orientation of your IMU.  The MPU board containing the IMU should be horizontal not vertical, and the yellow capacitor should face towards the front of the boat.  I think the magnetic heading is only correct with this orientation.

(Would love to know if I'm wrong.  My autopilot would be better mechanically if I could mount it vertically like you've done!)

As said by Sean, it does not matter once you level the sensor. Also for the compass reading you can actually correct +/- the Heading so it matches your regular compass. I think it's in calibrate\heading