I recently made a quick and dirty box boat to use as a test platform for Ardurover, with hopes of eventually making an autonomous solar powered boat. It’s working fairly well but I’m having a tough time getting it to track in a straight line. Maybe this is just because I was testing on a breezy day, or its just the nature of the box, but I thought I’d post a log to see if anyone has any tuning suggestions. It does much better going down wind than up wind. The files were too big to upload directly so I’m linking to them in google drive:
i tried to open the log but it seems to be completely full of 0s. May the logs can be downloaded again and perhaps try opening them in MP to be sure they seem OK.
It’s definitely true that a box boat does not work very well. The completely flat bow makes them very inefficient.
Seems like my Pixhawk might have stopped logging correctly when the SD card filled up. Here’s an older log from a quick tuning session. I was able to get it working a bit better after this point, but it was still at least able to navigate through waypoints.
For throttle/speed tuning it looks like the vehicle’s top speed is about 0.4m/s so it’s probably best to set the CRUISE_SPEED = 0.3 and CRUISE_THROTTLE = 80.
The maximum turn rate of the boat appears to be about 50deg/sec. So might as well reduce some of the maximum turn rate parameters:
ATC_STR_RAT_MAX to 60 (was 180)
ATC_STR_ACC_MAX to 120 (was 180)
ACRO_TURN_RATE to 50 (was 90)
Because the desired turn rates are so much higher than the vehicle’s abilities in this log, it’s hard to see what the turn rate gains should be but perhaps this will help:
Thanks so much for the help! The recommended parameters above definitely seem like an improvement.
I did another tuning session today with great results. In auto mode the performance was still terrible. The vehicle would just snake back and forth. I noticed that in steering mode the vehicle would track in a near perfect straight line. This made me realize that the poor performance in auto mode is not a steering tuning issue, but instead the result of GPS noise paired with the extremely slow speed of the vehicle. A cruise speed of 0.6 m/s and a GPS accuracy of ~1.5m is not ideal. I fixed this by increasing the NAVL1_Period to 45. That seemed to filter out all the GPS error and now it runs waypoints straight as an arrow.
The speed is still very inconsistent in auto mode and I’m assuming it’s also a result of GPS noise. Is there a parameter that can filter this out? I tried decreasing ATC_SPEED_P and ATC_SPEED_I to 0.2 and that seemed to help a bit.
Re the speed inconsistency… I’d check the CRUISE_SPEED and CRUISE_THROTTLE are correct… beyond that perhaps increasing the I or reducing the _FILT might help. But really this is just a guess and a dataflash log would help confirm where the issue is.
The _FILT parameter seems to help. Speed is very steady now. Thanks!
Another question came to mind: right now I’m using R/C car ESCs with reverse, so 1500us is neutral, above is forward and below is reverse. Is it possible to use cheaper RC plane ECSs with Ardurover? Would I have to recalibrate them so that 1500 is min throttle? Thanks!
BLHeli32 ESCs can be made to spin in reverse so those would be a good choice. Many other ESCs meant for use on planes and multicopters will only spin in one direction.
Got it. I don’t need reverse so I’m not concerned about that. I’m just wondering if its possible to use normal airplane ESCs with Ardurover? Or does it need ESCs where 1500ms = neutral?
@Daniel_Riley, that’s a great video! I really loved watching it and it seems very popular.
As I mentioned in the comments, it was interesting what you discovered re navigation tuning to deal with the boat’s low speed. … it also made me think that we need to revisit the automatic weed removal issue.
