Winch Motors and Pot Position

I have just got my first Winch Motor and Im a little bit confused where to put the POT.

I am looking at Aldoz sim, and my winch seems pretty much identical to it. However on his, (See picture) it looks like the POT is connected to a cog and that cog is connected to the cog that is directly connected to the Motor.. This cog does 1 entire turn just to move the cog where the arm is connected to about 2mm.. Therefor it would need to do like 100 turns (may be an exageration) So If i connect a POT to that cog it will go way out of range.

How does this work, and cna you get pots that can turn indefinitely (they over turn)

and on a side note, for those aussie out there *bsft* where did you buy the cog that can connect to the POT that connects to the winch..

ok mate the cog came from a hobbie radio control shop, about $9.(heli spinal gear)
In relation to position it is driven from the gear off the main spidle as in pic it allows you to track position alot better i use a 5 turn pot.

alright

thanks and thanks. I think I have it all under control now..

I didnt know 5 turn pots exist.. I assume it means it takes 5 spins to get from 0 to max.. which would probably be about right

Hi! I am not longer using the rc hely gear way. Now I am using another way.
I weld a little lattice in the winch in a way that my pot is connected to the winch gear and when the gear is turning so my pot turn too.
was not a easy build.. but with using many precision the result is good.

I not longer using the rc hely gear from eaorobbie cause with full turn speed of the winch gear so my rc hely was losing coordination with the winch gear..

Where did yo ubuy the 5 turn pot? Im looking for 5 turn or 10 turn and they are bloody expensive in australia (expensive being like $30) Futurelec has pots for like 80cents but they are all single turns.

If possible, could you post some pictures?

sure, later when I back to home I will shot some pics about.
However I am using 10turn pots 'cause my platform legs run is 35cm so I mechanically need a lot of available turns in my pot to afford all the legs run.
price 13€ for one 10turn pot

Hi sirnoname, I can just tell you that when I make rotate my pot so I get a precise and fast response.
I can't considering myself too expert about to give you a precise answer..

I can tell you that when I use the jrk config utility and I start to turn the pot I get a very precise measurement in the jrk config utility (the jrk config utility can show to you a graph rapresentation of the turn movement with a line that tilt much if you make fast turn and tilt less if you make a slow movement) .

Example : If I slowly turn the pot, so I get a slowly and precise graph rapresentation of the turn.
When I turn fast the pot so I get a fast, precise and NOT jerking graph rapresentation of the movement.
I have not the experience and skills to give you a precise and professional answer but I think you can obtain really more precision using (for your platform legs run) a 10 turn instead a 5 turn.
More turn for same lenght of movement = more precision. I am really near to be really sure about it! :yes:

I can tell you too that I can't use 5 turn pot for my 35cm legs run. I need 10pots.

Well when I first set the winch up with a single turn pot complete with a simple lever between the pot and arm. I found that the scaledback feedback value in the pololu setup software was fluxuating and wouldn't sit still. Because of this i had to use an aggressive pid setting to calm the motor movement, because of the feedback value changing causing the lever to follow it.



This could be sorted out by increasing the I value in the pid and as well as increasing the deadzone , but his resulted in slowish motion that seem to lag with no fine road surface feeling in the seat.

So I found a 5 Turn Pot at my local RS Components store for $68 each, ya expect gold plated at that price, well gold contacts and internals to be right.

Well just talking about them i found last weekend ones finially playing up 2 years of simming, not too bad but looking for a alternative.

Yes Aldoz i had that problem once but im not spinning as fast or far as you. Would love to see pics.

Once installed all values stayed steady and I can now move the motor one step at a time from 0 -4095 in the pololu software. Where as before it was more like 10-15, so paying for a better pot and using more turn to gain resolution resulted in my sim motion being more refined and more responsive to xsim.

But ya only find this out by giving it a go with a test unit. So buy a cheap pot and a better one and see what gunna work for you.

Ps in a little trick re: attaching a lever or cog to a pot, simple by a large knob to fit ya pot and screw the lever or cog to it. $2

Hi dudes, here the pic showing you how I put my pot in my winch.
The main difficulty is to make right measurement to obtain the center of rotation of the pot perfectly coincident with the center of the winch gear.

If you don't do a perfect precision you can get the pot effort on his turnable part and you can get damage inside the pot in the wire spiral (1 pot damaged before obtain good precision..)

I weld a steel lattice in the winch body, I mount the pot in one side of this lattice and I use iron glue to weld the steel support that have to mantain the cap. This cap is blocked in the pot turning part so the game is done!

very interesting.. I wouldnt have thought that would be better precision but I guess i would be wrong.

Is it possible to use a Hall Sensor to sense the movement in the gears instead?

I drilled a hole in the steel frame of my winch and installed a 10x turn 50 kΩ potensiometer with a home made 16 tooth aluminum gear on it. It can be adjusted so that there is no backlash what so ever. Gears can be bought from sdp-si.com if you can't make them yourself. They need to be module 2.0 gears. The closer the feedback potensiometer is to the output gear, the better, I would think.

I bought these pots: http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... OU:US:1123

thanks very much for all the resposne.

Why dont you connect the Pot directly to the cog that the arm is connected to?

(ie see picture)

Because that won't give enough turns to achieve a good resolution. 1/2 turn of the output shaft with my configuration gives 9,69 turns of the potensiometer.

BTW, those white plastic gears many are using are Module 1.0 Century helicopter gears. I have several of those for my Century Swift helicopter and home made helicopters: http://www.fxaeromodels.com/product_inf ... dvlacd0594

Have you ever guys think of using magnetic sensors??? SS490 + neodymium magnet = precision contact less sensor!!

Hi tronicgr, in first I want to take this opportunity to congratulate to you for your work on motion systems!. If today I have a 3dof near to be finished it's just because time ago I watched your vids of your motion system! (and sure a very lot of help in this great forum!) Pure inspiration and really a star to follow! :clap:

To back to the thread, many times I thought about to use sensors instead potentiometers for the feedback position but the matter is a bit far from my experience... : Can you tell us something about these sensors? Have these sensors the same wire connection of a pot?
Thank you!

Here is a link that explains it all: http://www.mycockpit.org/forums/content ... a-joystick

I suppose you can figure out the rest ;-)

Thanos

The reason I didnt go for hall sensors is because I think you have to put a magnet attached to the center of hte gear cog, then put the sensor over the top of that.. But the gears we use, the center doesnt spin..

So Im not sure how it would work, you could put a magnet on the outside, but wouldnt it just go out of range when it was too far away from the sesnor?

Not a problem. Put the magnet on the end of the output shaft and make a little bracket to hold the sensor. I have a bunch of Allegro hall sensors that I'm going to use in my helicopter inceptors when I finish making them. I bought them with a Leo Bodnar card a while back, and they worked fine when I tested. I thought it would be easier to use a pot in the winch units though as I could just drill a hole and have a compact and robust unit. Perhaps I should change to hall sensors.

The hall sensors wil wire directly to the FB, 5v and ground connections on the JRk, right?

correct mate looking at them myself for my unit had another pot drop out but 2 years of use not too bad execpt it $68 for a new one.