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Pypilot working on my Nicholson 44
#61
(2021-06-03, 09:05 PM)Phil_Shotton Wrote:
(2021-06-01, 09:34 PM)Kris Wrote:
(2021-06-01, 08:23 PM)Phil_Shotton Wrote: Sean and Kris, I've been reading this thread with great interest. I have a Nicholson 38 ketch with a 12v Neco installation and have a Tinypilot with Sean's Pypilot motor controller ready to connect up to the existing Neco relays once I manage to get down to the boat for a prolonged period. I'm very interested in not using relays and benefiting from motor current sensing, reduced power etc, but I'm not experienced enough with this stuff to fully understand. Are you using the IBT-2 motor controller or the Pololu one? How is it connected to the Pypilot and to the Neco motor unit? Do you have any diagrams? Thanks in advance for any tips and pointers.

Hey Phil, I can only encourage you to install the Tinypilot, as it is a far superior solution to the Neco control unit. Current sensing is great, but I think controlling motor PWM is waaaay cooler, as it lets you drive to motor much more smoothly and efficiently. I am not sure if Sean·s motor controller lets you drive the Neco to the max as I do not remember the max current. My Neco takes 24 volts and peaks around 200-300watts, so that should be around 20 amps on your 12 volt system. I use the IBT2 that handles up to 44 amps. My Neco on 24 volt only takes around 10 amps max, so the IBT2 is ample strong and probably long lived.

The Neco has a motor that is a bit more complex. There is a diagram and a description that was done by Daniele Fua, a really cool guy who was of much help to the community. You can find the documents posted earlier here in this thread. If your Neco control unit does not work anymore, you can just convert to the Tinypilot. I am a liveaboard cruiser and I opted for a switch box to be able to use both controls for redundancy. If you go for the full conversion, you can relatively easily reuse the end switches and the rudder angle sensor integrated into the Neco drive unit.

With the relays the motor is controlled at 100% juice and then forced to a halt, as the relays short the coil of the motor, thus magnetically braking the movement of the motor. This is a reliable but power hungry solution. The H-Bridge in Sean·s driver can nicely start and stop the motor and does not brake the motor like using the relays does. On the other hand there is a voltage drop on the H-Bridge but given how little the motor controller heats up during use, I do not think there is much energy lost there.

At the moment I am just trying to implement the last update of Sean, and drive the clutch with a PWM signal instead of an always-on signal when engaged. My clutch coil takes around 30-40 watts. It stays engaged with around 33% PWM so there is around 20 last watts to be saved with this last update.

Thanks for the update Kris. I've had long email exchanges with Daniele Fua, a really helpful guy. I went with Sean's motor controller planning to use the Neco relays, but the lower current consumption and better control of direct motor control seems like a good idea. The Neco drive unit is fused at 25 amps and probably peaks at around 20, so I don't think the motor controller will handle that. I'm looking at a Pololu unit to handle the current. Any info on the best way to control it would be really helpful.

Hi Phil

there are some diferent types of Pololu. I use the G2  24v19. you might like the G2 18v25, but htere are others.
I gues you can wire them also in diferent ways to the arduin with the running motor.ino. I use the RC mode. as I statet in erlier posts.
There is also a shematic how I conected. I dont use any feedback to the arduino and have the end of travel switches directly conected to the pololu. You can program the pololu to start speed and stallpower and many others. I also added a large capacitor as described in the pololu manual.
I know that Sean also has done larger controllers for hydrolic, so if you want to benefit mor easy from all the Pypilot has to offer maybe it is better to talk to Sean.

Greetings and save sailing
Andreas
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#62
Pololu G2 18V17 here: pwm-style=2, D9 to PWM, D2 to DIR, D10 to SLP.

That one might be a little lightweight for your purpose, but the 18V25 has the same interface. Sturdy little thing, worth the high price, but don't forget that the inputs are 5.5V max - I blew my first one on that.
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#63
Thanks guys. I've got a Pololu 18V25 on order. First plan is to get the Neco drive working using the relays and the standard motor controller, then experiment with the Pololu. At the moment I've got intermittent drive issues with the Neco, manually moving the relays drives the motor sometimes and not others so I think there's a bad connection probably in the relay control connector block. Boat taking a back seat to house renovations at the moment, and the drive unit is a real pig to access.
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#64
(2021-06-06, 07:20 PM)Phil_Shotton Wrote: Thanks guys. I've got a Pololu 18V25 on order. First plan is to get the Neco drive working using the relays and the standard motor controller, then experiment with the Pololu. At the moment I've got intermittent drive issues with the Neco, manually moving the relays drives the motor sometimes and not others so I think there's a bad connection probably in the relay control connector block. Boat taking a back seat to house renovations at the moment, and the drive unit is a real pig to access.
Hi Phil,
have you cheked the brushes and also the oil ?
could also be en error by the end switches of the unit ...
I took my unit out for the rebuild and testing

Save sailing
Andreas
Reply
#65
Hi Andreas
I suspect the brushes, although they are supposed to be pretty long-lasting. Could be the end switches, Daniele Fua thought that there might be a loose connection on the relay connector block. I need to get the unit out of the boat but it's pretty hard to get at. Too many things on my boat todo list and the house comes first!
Enjoy the water
Phil
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#66
Here a little video from today
sailing downwind in 25+ knots and waves.

https://www.dropbox.com/s/ndq4jqrqx69uuf...8.mp4?dl=0

I m verry happy with my pypilot running now for a long time without problems.

Thanks again to Sean

Save sailing

Andreas
Reply
#67
That's going really nicely andreas, I'm very envious. Looks like you had quite a bit of wind.
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#68
Major milestone today! I removed the Neco Drive Unit from the boat for examination, turns out one of the brushes was sticking. Having cleaned everything up it passed all Daniel Fua's tests. So now I've reinstalled in the boat, with Sean's motor controller driving the relays. Everything seems to be working fine but sea trials await!

Next step (after using it for a while) is to plan to drive the motor directly rather than through the Nico relays. I'm still wavering between a home-built Pololu-based driver and Sean's new high power driver.

Anyway, reason for the post was to thank Sean for his wonderful work and everyone on the group for their help and information. I was facing a multi-thousand pound bill to replace the Neco with a modern commercial drive; Tinypilot + motor controller + a few relays less than £200 for a far more capable (and adjustable) unit. Rock on open source!
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#69
(2021-11-20, 03:44 PM)Phil_Shotton Wrote: Major milestone today! I removed the Neco Drive Unit from the boat for examination, turns out one of the brushes was sticking. Having cleaned everything up it passed all Daniel Fua's tests. So now I've reinstalled in the boat, with Sean's motor controller driving the relays. Everything seems to be working fine but sea trials await!

Next step (after using it for a while) is to plan to drive the motor directly rather than through the Nico relays. I'm still wavering between a home-built Pololu-based driver and Sean's new high power driver.

Anyway, reason for the post was to thank Sean for his wonderful work and everyone on the group for their help and information. I was facing a multi-thousand pound bill to replace the Neco with a modern commercial drive; Tinypilot + motor controller + a few relays less than £200 for a far more capable (and adjustable) unit. Rock on open source!

Hi Phil,
great to hear .... 

I just completed a 500 NM singelhanded (with Dog) mainly on Autopilot.
I had only on little problem, that was that the AP stoped working once.
It was the pololu wich after connecting it to the Laptopp and playing a little arround
came back ....
Anyway I carry everything (pi-zero, arduino, polou, imu) as spare.

So please continue reporting your progress.
Save sailing 
Andreas
Reply
#70
First sea trial yesterday. Wind 15-20kn gusting 30, and a very lumpy sea. Was mainly hand-steering but engaged pypilot several times on different headings and was amazed how well it held course for how little steering input even when being kicked around by a following sea. It appears that the small rudder inputs with pauses between average out the movement due to sea state remarkably well.

This was just a short sail to check things worked; no real opportunity to tune parameters but even the defaults seem good. After 3 years with no autopilot it was an absolute joy to be able to press a button and then leave the wheel to attend to other stuff. Much more playing to do but so far I've got a big smile!

This is on a Nicholson 38 ketch, Neco 12v motor drive, using Sean's motor controller to drive the Neco relays.
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