2 DOF Wiper-Sim + Pololu 12v12

Hello dear forum,

Now I got all needed parts and builded a first prototyp - the geometrie was tested in Catia v5 (3d simulation). It's a copy and paste of all great working sim's out here in the forum thanks everybody.



I use wipermotors of a volkswagen golf, potentiometers (10kohm) are connected via gearing. The motors are connected to Pololu 12v12. Power supply is Techtron SP6015 for now. So far everthing mechanically works great.


It's build of bosch aluminium profiles. There are two frames. One is attached to the seat the other is the base. The both frames are connected by a rubber-bonded metal bearing with 55shore exactly in center of gravity. To restrict the degrees of freedom i used two rod's connected to the seat- and baseframe. The sim has two degree's of freedom so far (to simulate braking; acceleration and cornering l/r + curbs....). In my Catia Simulation I got another dof ready for traction loss (with third wiper + 12v12) but one step after the other.
The movement of the seat is made (like said) by two wipermotor's of a Volkswagen Golf. The leverage arm length is 4,5cm. The rotation 120° for first test's. When somebody is sitting in the seat there is no heavy force needed to move it (because of center of gravity) - i can move the seat with my little finger (can't say exact [N]).
I use 10kohm Potentiometers with 300° for feedback. They are attached to the motor via gearwheels (gear ration 1/1,6).
Thats about the mechanic part - if I missed something important pls ask.

This is my power-supply. Techtron SP6015 - 13,5V 15-18A. Both Jrk are connected to this, hope it is strong enough. (I reduced the motors in configuration utility by 5A each for first test's). Do you think it is safe to use a car batterie (12V 45Ah 360A) parallel to power supply?

The electric part is connected as shown (pro motor):
18755

As using wiper's I have to solve the ground issue, right? I searched this forum and read all threads on it (I hope so). But I still got some questions. Would be nice if someone could help me, even I know that the answer is anywhere around here :
My goal is to reduce the electric noise of the motor as much as possible for not manipulate the jrk's.
Here some pic's of the inside of my wiper's:

That was my first try. Just connected a wire direct to the brush (which is normally case-connected). For (+) I used low speed of the wiper. With this test a got motormovement in both direction's - BUT I got alot of brushfire - and I think the Jrk don't like this easy solution.
I have to admit - I'm far away from electrically skilled.

Here is another look and what I have done next to the motor:
Before:
After:

before:
after:

I want to add antother capacitor like here:


Do you think this would be safe of electric noise? Any experience on dimension of the capacitor c1-c3? The ilustration uses motors like mabuchi 540 (or max class 600 size). The wiper's are alot bigger - so I think other dimensions are needed. Volkswagen original used two 1,0µF 63V from case to à brush.

Also do you think a ferrit core of 1-10mH with 4-6 windings near the motor or jrk's will help? see:


...................................................................................................................................................................................
For configuration of the two Jrk's I refer to the user bsft and his youtube vid's:
http://www.youtube.com/watch?v=rb5tK4oMQy8
Detail's for Pololu configuration Utility will follow up.

For the configuration of X-sim software:
http://www.x-sim.de/documents/X-Sim Quick Guide.pdf


I will add some better pic's and some vid's of the sim if anything is nice and pretty, promised.

Hope someone can help me on my questions - my jrk for spare will come tomorrow and I want to test with the motors and feedback a bit more (I'm just don't want to destroy something ^^).

Thanks and best regards Mirco

How quiet do you want the motors? :?
Granted I understand electrical feedback through the circuitry, but that has NEVER been an issue for any of the JRK sim builders. We use 5k pots as recommended by Pololu. I would be interested if you have found noise causing a problem with the jrks. No one else has.....
Myself and others have run the JRK down to 5ms response rate with a SMOOTH motion, so electrical noise is NO ISSUE.
Dont add capacitors on the motors anywhere, even that will cause an earth leakage and effectively destroy the jrks.
I found on the boat winch motors a little capacitor across the terminals to reduce noise in the car, but it had to be removed as the jrks were playing up.
If its mechanical noise, it may be the metal gears you have fitted.
Finding a silent motor, well good luck. Some motors make a bit of noise.
I've used wipers in the past, and some were a tad noisy, but nothing to write home about.
The big worm gears are very quiet, just a normal motor noise, but again all good.
I have heard the boat winches people use are noisy, but thats from the gearing, not the motor itself.

Otherwise, good job there.... :hi:

Hi bsft,

thanks for your reply. Unfortunatly my english is so bad, sry. With noise I mean electric noise http://en.wikipedia.org/wiki/Noise_(electronics). Not something I can hear with my ear's .

I know that other users don't have this problems but I have a mistake somewhere. When first testing the Jrk in Configuration Utility everthing was fine for a while. Anyway I had a Comport issue in X-sim.
After that I want to change some values in Configuration Utility but both boards have problems - one firmware not detected error - and the other led status error. I ordered one Jrk for spare but before I go one I want to know what's causing trouble. Otherwise I spent as much for Jrk's that I could have gone for SCN5 directly

I talked to Pololu support and they mentioned the electric noise problem... So I googeld on it and followed the instructions Pololu gave me. --> this is the result. (Pololu say's 3 capacitor and two elkos would be perfect).

That sounds interesting but also

confuses me.

Please can you explain me once again what exactly you have done to your wipers and what would be the safest setup to go again on the Jrk's? (I guess you are working with other motors now)

Thank you so much! yoko

You should mention to pololu as to what you are building. Speak to David Grayson at Pololu .
Adding capacitors as per instructions by pololu is fine, because if you blow the boards, they are responsible. :thbup:
All of us have NEVER had noise issues at all and all motors, wipers, winches, have all been properly earth isolated, no capacitors. If pololu says use them, then blow the hell out of your jrks then! And then tell pololu what went wrong. :lol:
With home simulators, you are constantly changing direction very quickly on each motor.
With wiper motors, as they are from a car, most car stuff is earthed to the body of the car. Saves wiring I suppose. So with using wipers on jrks on a metals frame and NOT earth isolating the motors is bad. You will get 12v feedback through the frame, through the pot and cook the jrk.
Earth isolation can be tricky. When I used wipers, I cut the wires from the plug and tested each wire until I found what was the fast speed and what was the earth. I then tested the motor to see if I had found the earth wire, by putting power through the body of the motor and if it didnt run, earth isolated.
I never pulled a motor apart, too many issues putting brushes back in for me :tape:

here I cut the wires


once I found the right wires, I soldered new wires on.
If you are not sure how to do this, either take the motors to an auto electrician or buy proper 12v motors http://www.motiondynamics.com.au/worm-d ... orque.html
As for safest hookup of jrk, you already have the picture and have set up a pot on it. Apart from earth isolation of motors, theres nothing else.

You haven't mentioned how you are testing the motors because, depending on what you are doing may be causing the errors in comports.
Can you specifically explain as to what you are testing and how you are doing it? If you are messing with utility settings in jrk, you'd better tell us what yo have so we can advise.
Sounds like you are doing something amiss.

Hi,

- David Grayson is my contactperson at Pololu - here is the link http://forum.pololu.com/viewtopic.php?f=15&t=5835&p=27696#p27696. He knows everthing about the project and what I have done to the motors and Jrk's. At the moment it seems to me like they got no idea where is the mistake... :no: His advice was to look after motor noise and PID settings.

Might be, but I allready own 4 Jrk's and live in Germany... Pololu is somewhere around LA - for support and sending back it can't be more unpractical.

Sorry I don't understand this?

Do you have any links on this. I think - as your image of the wiper shows - you can't know whats inside your wiper if you haven't opened it. In my wiper are already 2 capacitors by Volkswagen. Other oem's might add them too. Any user's who removed everything on the inside of the wiper instead of the brushes???
When you say don't use them - are there users who removed everything from inside of the wiper instead of brushes?

I thought all electric motors will have to be supressed - while driving rc-car years ago, this was an issue too - there we used shotky diodes (but youst needed one motordirection).

For this reason I cutted the brush who was connected to case and soldered a wire directly on it.

I think that's the best idea to be sure for starting.

My plug got just two wire's (one high- one low speed) red and green.

I used this settings:
Just for Max-current I set to 5A. I applied settings to device.
Also I applied this to device (by learn-function):

After this in input settings I selected automatically set target and then moved the slider above set target while sitting in the seat of the sim. The motor was moving me when I used the slider of set target and if I go back to around 2048 it stopped.

Then in x-sim:
for left- and right axis (a01 a02). Here I refered to the manual of x-sim and your recommandations. I checked use automatic maximum adjust for effect 25,27. Intensity and co like in the quick start guide. Then I unpaused the game and drove one round. If i go back to game - the start button is a red stop button but on converter pc I got the COMport error. No movement in x-sim so far.

After that issue I wnated to change some values in Confi. Utility - there the firmware not detected and so on errors start.

Hope this helps to understand what I have done. Thank you very much for your continuing help!!!

OK, first problem I see is the max duty cycle while feedback is out of range is 1, try matching it to max accel, so move it to 500 or 600, not 1.
Can you please take a screen shot of PID in utility. Whats the PID used? are you using 2/2 0/3 1/1. This is the generic PID for wipers.
I dont have any links on capacitors on motors, just experience from myself and a counterpart.
He bought 12v boat winch motors, tested for earth isolation and that was good, but he still got issues in the jrk and had errors caused. He opened the motors to find 2 little capacitors. One on each brush going to the motor body. He removed the capacitors, and hey presto - stopped errors. The capacitors were to stop motor noise going through the car stereo when it is on and you are towing a boat out of the water.
I found the same issue when I also used the motors.
Capacitors may reduce noise but as said, no one that has used the JRK has had this issue.
Comport errors and setcomstate errors are more related to JRK utility settings.
Go back to JRK utility, please post ALL tabs as pics and I can advise.

I read the thread you posted.
As for stall current, sim motors run at stall nearly all the time, and its usually double the rated.
Your motors are not too big for JRKS. I have run bigger motors at 34-38amps continuous through the jrk. It handles it.
I am not going to comment further on capacitors on motors as I haven't tried and have seen the issues it can cause.