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Pypilot working on my Nicholson 44
#31
The clutch output can supply 1-2 amps (maybe 3) just fine. Does your clutch use significantly more that you need a relay?
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#32
(2020-07-02, 05:53 PM)seandepagnier Wrote: The clutch output can supply 1-2 amps (maybe 3) just fine.   Does your clutch use significantly more that you need a relay?

Sean ==>  Again, my big boat (42 ft Solaris cat)_to which this all applies, is enroute from St John, USVI to the States as we speak.   My intention is to have all ready to install the new autopilot and OpenPlotter RPI all-in-one nav computer when it arrives in a month or so.

All in all, I think that having the Motor Controller operate relays or SSRs may ensure that the cumulative load on the Motor Controller is limited to driving low amperage loads.   Just seems more reasonable - allowing smaller gauge control wiring to a relay box at the Neco (which sits just above (8 inches) the battery banks. 

Once the boa is here and I am knee deep in details, I'll check back with you.

Thanks for your help and all else you do,

Kip
Kip Hansen
S/V Golden Dawn
S/V Merlin
kip@i4.net

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#33
Using relays has advantages, but the disadvantage:

1) no speed control, no way to make the movements of the motor smooth with soft start/stop
2) more power consumption
3) eventually wear out if mechanical relays.
4) no current feedback to prevent stalls. You will have to use end of travel switches or rudder feedback.

Otherwise, it should be ok to use relays if you accept the tradeoffs.
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#34
A little update video ....

Sailing with the assymetrical for 70NM with mode on wind:

Conditions: Wind 13-16 kt true, little waves.

Gains: D=0,1 DD=0,17 FF=0,7 P=0,0032 all other =0
servo.gain=1,5
servo.period=0,2 ( I usaly have this on 0,4 but the reaction time improoved much by changing to 0,2)

So the conclusion for me is: For downwind with waves reducing servo.period was essential.

Here is the link to the video:
https://www.dropbox.com/s/qsxpjxdui4mrob...0.mp4?dl=0 

Save sailing
Andreas
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#35
Great to see it working in wind mode!

You might also get faster reaction times by increasing the servo.slew.speed and servo.slew.slow, but this will also stress the drive a little more.
The new version of pypilot improves reaction times by making everything run at 20hz (uses more cpu but there was enough spare) and also this gives a finer resolution to timing. I improved reaction in a few other was as well. I'm trying to fix a few minor details and make a new release soon.
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#36
I’m curious how wind mode works? I’m not a sailor but my most challenging days fishing using pypilot is when it’s windy. Down wind is no problem but any heading into the wind.. such as a heading similar to a broad reach in 10 knots of wind or greater is very challenging to hold a heading. Would wind mode work under engine power as well?
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#37
pypilot does not know what is powering the boat, but the dynamics under sail are completely different. Most sailboats tend to be balanced going into the wind which really helps the autopilot a lot. A lot of boats can lock the rudder and hold course upwind although the efficiency especially with waves is a compromise because you tend to oversheet the head sail to get this to work closer to a reach. So without sails providing this natural balance the autopilot may have to work a lot harder.
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#38
(2020-09-25, 11:21 PM)rastam4n Wrote: I’m curious how wind mode works? I’m not a sailor but my most challenging days fishing using pypilot is when it’s windy. Down wind is no problem but any heading into the wind.. such as a heading similar to a broad reach in 10 knots of wind or greater is very challenging to hold a heading. Would wind mode work under engine power as well?

I guess it will work well. Just put the pilot in Wind Mode and activate it when you into the wind. You want loose anyrhing by giving it a try. Of course you will need to have the wind instrument connected so pypilot receives this data.
Good fishing !
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#39
Bug 
(2020-01-30, 11:52 PM)seandepagnier Wrote: You can adjust the acceleration and deceleration limits as well as minimum and maximum motor speeds though the servo parameters for speed and slew speed.

Hello everyone! Similarly to many others in this thread, I am building a Pypilot controller for the 24v Neco rotary drive on my Camper Nicholson 48. Enormous thank you goes to Sean for coding the Pypilot and making it available to others! I would not have entered the maker world if it weren't for the Pypilot. I am also very grateful to Daniele Fua who helped me a lot with the technical drawings and sent me a spare unit while we were in Italy. I strongly encourage everyone to turn to him concerning Neco drives.

I have the Pi 3B+, the 9255 IMU sensor, a Nano, the IBT2 motor controller and transistors. It was quite a learning curve to get to the point where it works fine now as this is the first time in my life I met Arduinos and the Pi.

I made a switch box to be able to switch back and forth between the Pypilot and the Neco CU. That part could also come in handy later in case of a lightning strike as the Neco unit seems quite indestructible.

Contrary to others, I drove the shunt coil with two diodes connected to the two low sides of the H-bridge (pin 2 and 3 I believe). They only turn on when the motor needs to move, so there is a substantial energy saving there. That I think outweighs the benefits of the brake function on the drive when the shunt coil is on and the armature is short circuited by the relays.

I want to spare a few watts still on the clutch coil as well. The clutch coil engages well when it receives the full 24 volts. It then only needs about a third or quarter of that current to remain engaged. I drive the clutch from the clutch pin 11 through an NPN transistor. The clutch pin is capable of PWM, I believe. I have tried altering Sean's code to change the digitalwrite to analogwrite as follows but that resulted in the clutch not turning on anymore.

   //digitalWrite(clutch_pin, LOW);
     analogWrite(clutch_pin, 254);


Could you sailor brothers and sisters share your thoughts on this?

[Image: 20201213-155452.jpg]
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#40
(2020-12-14, 10:31 AM)Kris Wrote:    //digitalWrite(clutch_pin, LOW);
     analogWrite(clutch_pin, 254);

Could you sailor brothers and sisters share your thoughts on this?

---------------------------

Hi Kris, 

great to hear that you also kept your "old" Neco and drive it through the Pypilot software from Sean.

I also have been thinking in using PWM for the clutch. But at the end I did not, as I dont understand realy what is necessary.  I also drive the series coil through the clutch and I would have to make here changes as well. I already bought a rectifier diode unit for this porpouse and I might start with this.

I guess you need a 100% PWM for a short time to engage the clutch and then mayby 50% to hold it.  I think one has to consider at this point the state of the battery while sailing so it would be a difference if your battary full is at 14V/28V or low 12v/24V so the PWM should be set high to hold the clutch in any state or change the PWM depending on battery state.

So there are some changes to make to motor.ino (or servo.py ??).

If you make any progress on this please let me know.

Save sailing
Andreas



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