2022-09-30, 09:58 AM
Hello mgrouch and Sean, thank you very much for your answers. I will try to be a bit more precise. However, you should know that, despite this problem, Pypilot works wonderfully most of the time.
I didn't know that the "GPS" mode only works if the heading offset is zero, thanks for the info. My heading offset is always set to 0. I guess it's the `imu.heading_offset` key in `pypilot.conf`.
Regarding the IMU, I think it is the model that Sean considers to be less good (orange MPU-9250). I set it up as best I could and checked that no magnetic elements were interfering with it. At the beginning of the navigation it constantly "rotates" and then eventually stabilizes with a different course shift each time, which I don't bother to correct anymore. However I think I can still improve this setting.
Some details on hardware and software: I have an RPI3 with the latest version of openplotter, and pypilot installed manually from github sources, in May 2022 (then updated yesterday). There is nothing else on the RPI, the network and other software are managed by another computer. An Elegoo nano for the motor, an IMU MPU-9250 and a IBT-2. For information, I made this assembly with the components that I had on board, or that I could have quickly at the beginning of my trip. The GPS data are those of the AIS transponder via SignalK, used for pypilot, opencpn and all other software. It should also be noted that my boat is a fairly heavy cruising yacht (20T loaded for 47 feet), with a hydraulic system for steering.
I did not try to switch to compass mode because during this navigation, I did not achieve to have a good compass course calibration to have a stable heading, and thus be able to run the pilot without GPS mode. When I try the compass mode in these conditions, the pilot is at the mercy of a "crazy" compass and only the GPS mode allows to follow the route.
I confirm that, curiously and only in this particular situation, the pilot was turning the rudder in the wrong direction. There was a lot of swell, a cross-current and 20 kts of steady wind with occasional squalls. I had just the Genoa, broad reach, port tack. The COG provided by the GPS varied around 130°, which opencpn and the other instruments displayed well. But Pypilot displayed a heading value around 110°, whereas it usually displays the same value as the other software. I tried several gain values, especially quite high ones compared to usual, in order to maintain the heading... but even when I asked for 140°, it turned the rudder left. I restarted the system in the meantime, without success. Before and after this navigation, the pilot worked perfectly, with less swell and less wind.
It takes about 8 seconds for the pilot to move the rudder through its full range, a little longer when more effort is required. I don't have a rudder sensor (I removed it because it wasn't accurate enough).
I'm sorry I can't give more precision. Next time I will note more information and then share it with you. (is there a "record" option to send everything that happens to a file?)
In retrospect, it's possible that due to the swell and strong wind, the pilot is trying right and left movements and only the left movements are working... I put LEDs to visualize the signals sent to the rudder, which unfortunately I didn't have the reflex to look at... I just noticed that even with a lot of intensity, the rudder was making steps to the left and not to the right, for some unknown reason.
I didn't know that the "GPS" mode only works if the heading offset is zero, thanks for the info. My heading offset is always set to 0. I guess it's the `imu.heading_offset` key in `pypilot.conf`.
Regarding the IMU, I think it is the model that Sean considers to be less good (orange MPU-9250). I set it up as best I could and checked that no magnetic elements were interfering with it. At the beginning of the navigation it constantly "rotates" and then eventually stabilizes with a different course shift each time, which I don't bother to correct anymore. However I think I can still improve this setting.
Some details on hardware and software: I have an RPI3 with the latest version of openplotter, and pypilot installed manually from github sources, in May 2022 (then updated yesterday). There is nothing else on the RPI, the network and other software are managed by another computer. An Elegoo nano for the motor, an IMU MPU-9250 and a IBT-2. For information, I made this assembly with the components that I had on board, or that I could have quickly at the beginning of my trip. The GPS data are those of the AIS transponder via SignalK, used for pypilot, opencpn and all other software. It should also be noted that my boat is a fairly heavy cruising yacht (20T loaded for 47 feet), with a hydraulic system for steering.
I did not try to switch to compass mode because during this navigation, I did not achieve to have a good compass course calibration to have a stable heading, and thus be able to run the pilot without GPS mode. When I try the compass mode in these conditions, the pilot is at the mercy of a "crazy" compass and only the GPS mode allows to follow the route.
I confirm that, curiously and only in this particular situation, the pilot was turning the rudder in the wrong direction. There was a lot of swell, a cross-current and 20 kts of steady wind with occasional squalls. I had just the Genoa, broad reach, port tack. The COG provided by the GPS varied around 130°, which opencpn and the other instruments displayed well. But Pypilot displayed a heading value around 110°, whereas it usually displays the same value as the other software. I tried several gain values, especially quite high ones compared to usual, in order to maintain the heading... but even when I asked for 140°, it turned the rudder left. I restarted the system in the meantime, without success. Before and after this navigation, the pilot worked perfectly, with less swell and less wind.
It takes about 8 seconds for the pilot to move the rudder through its full range, a little longer when more effort is required. I don't have a rudder sensor (I removed it because it wasn't accurate enough).
I'm sorry I can't give more precision. Next time I will note more information and then share it with you. (is there a "record" option to send everything that happens to a file?)
In retrospect, it's possible that due to the swell and strong wind, the pilot is trying right and left movements and only the left movements are working... I put LEDs to visualize the signals sent to the rudder, which unfortunately I didn't have the reflex to look at... I just noticed that even with a lot of intensity, the rudder was making steps to the left and not to the right, for some unknown reason.