Trolling motor noise?

Hi everyone, this is my trolling motor. I’ve been testing it for some time but I still can’t calibrate it for the various GPS-guided functions. Meanwhile, a brief description. I emptied the upper part and inserted the fc CC3D (in the front), the rc receiver, and two brushed esc behind it. in the upper part and far from the esc the compass with the gps. Logically, one ESC will turn the trolling motor and the other will turn the propeller. I have done all the calibrations and the steering seems to work well even in ACRO mode. The main problem concerns the loiter mode. Once set initially the steering works but when the propeller motor starts there is noticeable steering vibration and the motor loses course. As soon as I disarm the trottle everything moves perfectly. I imagine this is due to engine disturbances… However I ask if there is anything I can do or any advice. I’m attaching a video and a file if anyone wants to take a look. In the meantime, thank you.
trollin motor.param (13.2 KB)

2024-06-19T22:00:00Z



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you need a servo that can have its position set for the steering, ardupilot doesn’t work with continuous rotation servos on the steering.

Thanks for the kind reply. I would agree with you if the fc was inside a boat. Maybe I’m wrong but the fc, being on axis, shouldn’t have any problems as it behaves like a servo. Let me explain. If the engine goes straight I imagine that the 1.5 ms pwm signal arrives at the esc. When steering the PWM increases (or decreases) but once the exact trajectory is reached the PWM returns to 1.5ms. In fact, in LOITER mode, if I turn the engine to the right the FC brings it back exactly in the desired direction. It looks good from the video but I don’t know how to publish it.

PS: activate the subtitles in the YouTube video

A tipical log file, if someone can help me, please :thinking: :thinking:

I add a further detail that makes me think of the excessive disturbance generated by the engine noise. If I try the steering in acro mode this works perfectly if the engine is disarmed. As soon as I arm the propeller motor the steering behaves senselessly. It turns in the opposite direction to the desired speed and often vibrates. Unfortunately I see that no one can help me…

Hi @will75,

Looking good!

With manual mode looking OK I think the next step is to actually put it on a boat. It won’t be possible to really test it probably in Acro or Loiter mode while the vehicle can’t move

Re the shaking, I would guess that this could be feedback from the servo moving the motor. So perhaps as the servo moves, the autopilot is shaking a bit. I suspect if you set ATC_STR_RAT_P and ATC_STR_RAT_I to zero the shaking will go away because the steering controller will only be using feedforward (which comes from the target direction and doesn’t use the “error”). Once it’s on a boat you’ll likely need to restore those P and I values to something higher but maybe by then the setup will be more stable.

One small thing i’ve noticed is ARMING_CHECK = 0. Clearly it’s not dangerous at the moment but the arming checks will warn of various setup issues so I think changing this param back to 1 would be a good idea

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Thanks so much RMackay. I take this opportunity to ask two questions.
1- Can you confirm that the use of continuous steering can be used in my case? (see the answer I gave to geofrancis)
2-I set the values ​​of ATC_STR_RAT_P and ATC_STR_RAT_I to 0 but the shaking (ACRO mode) does not go away and sometimes it turns in the desired direction, other times in the opposite direction. In LOITER mode it keeps changing direction (sometimes it tends to go in the opposite direction from the anchor point). The strange thing is that when I disarm it turns in the precise direction. At this point I wonder if the reason for all this is to be found in the ESC. Since it runs a 30 lb brushed motor and is not of quality,(https://it.aliexpress.com/item/1005005866547271.html?spm=a2g0o.order_list.order_list_main.199.914c3696Tj7igy&gatewayAdapt=glo2ita) would you advise me to change it ? Is it possible to check if it actually creates noise to the FC?
I will try it on a boat as soon as possible.
I thank you in advance for the time you dedicated to me.

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Hi @will75,

No troubles, happy to help.

I suspect that @geofrancis is correct. A given PWM output from the autopilot should cause the motor to move to a given angle. If instead a PWM output causes the servo to rotate at a particular speed (and not stop) then it won’t work I’m afraid.

I think I’ll hold off on thinking about item 2 because if the above is true then we’re pretty stuck.

ok. but then in this application not even a servo motor would work… in fact my trilling motor must be mounted in the bow of the boat. as mentioned previously, the compass and fc are on axis with the motor, so as soon as the motor turns, the fc board and compass also turn. if I installed a servo motor the motor would turn towards the target but, as soon as they reach the turning angle (and therefore directed towards the target), it would set the steering motor back to neutral position but the boat would not have turned completely yet… tell me if I am correct explained. I’ll add a link to what I want to get. https://youtu.be/d-6Fm3_1qzk?si=LJIEpMwN_mI-O-9t

Hi @will75,

Couldn’t the FC be mounted on the boat frame separate from the motor?

I’ve never seen someone with this setup before but I think it may work with the FC mounted on the motor. I just think that we will need to take great care with the ATC_STR_RAT_XXX parameters. I would set ATC_STR_RAT_P, I and D to 0 and then focus on getting the ATC_STR_RAT_F to a value that seems to work.

There are instructions on the turn rate controller wiki page on how to use real-time tuning. I think testing in ACRO mode would be best and if you’re struggling to get the right parameters try setting LOG_DISARMED = 1 and move the steering around a bit in acro mode and send us a log.

The biggest issue I foresee is the autopilot will have no idea where the body of the boat is. It could get so bad that the FC turns the motor all the way around 180 degrees and ends up pushing the boat backwards. Anyway, it will at least be interesting to see what happens.

Why don’t you turn your trolling motor into a servo?

Take any servo and remove the gears and motor, and it leaves you with a position sensor with a DC motor control board.

Mount that servo to the trolling motor so it can detect the rotation

Connect the servo board motor output to the input of a 12v h bridge rectifier and use that to drive the 12v steering motor.

you could also replace the servo potentiometer with a multiturn potentiometer to get more turns.

Thank you again for the reply.
In fact, that’s exactly what should happen…FC shouldn’t have to worry about the position of the boat at all. What matters is the direction of the engine, the boat having the engine at the bow will simply follow it.
As soon as I try it installed in the boat (inflatable boat, 3 meters) I will try to obtain the LOG.

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yes, I could also do it but I would have to review the whole project. And then I have a hard head…

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It could be a good idea. But, in this case, I would have to move Fc into the boat. It’s still worth considering, thank you very much.

Not necessarily, you would keep the current setup and treat the boat hull as a rudder.