wptm's 2DOF arduino wiper sim

[wptm]

Please see here the progress of my simulator construction.
I've made a cockpit with real car parts from the junkyard. Please see here for information on the peripherals: http://www.x-sim.de/forum/viewtopic.php?f=40&t=799
It's been started to reshape into a 2 DOF wiper simulator driven by the Arduino controller solution.
Before the start it was look like:


So, it was time to remove the seat to see the possibilities how to mount the cardan shaft:


Let's start the welding :


After that, I mounted it into the seat, and then the seat into the frame. I use screws, so I can remove the stuff whenever it'd be needed to.


Let's have a look on the wipers. It's time to have now some nostalgia, who has knew what DDR (GDR in English) meant to be.
They're from 1989, the last full year of DDR. They're coming from a Wartburg car.


Ok, let's back to present time and continue the work. The frame needs to be extended to hold the wiper motors.


I have found later that the motors need to be higher positioned. So, I used its original holder from the car.


One rod to move the seat is connected to the motor:


When I connected the other one also, and tried out to move the seat using a switch powered by a car battery, my welding of the cardan shaft has simply broken after a while.

So now, I need to make a better welding and then I'm gonna continue... and will also * this post

[motiondave]

Nice setup there.
not sure what DDR or GDR means?
As for welding, dont panic, my welds are shocking but hold, just add more power/heat to the welding stick should be fine to hold it.

[wptm]

Thanks motiondave!

DDR was the short form of former East Germany. Yes, I've given more power to the welding. Now the two metals seems to be melt together also.
It looks like now:


And I've given power to one of the motors, to see what happens again. The welding is ok * It is very vibrating and loose. I need to make it more stable. I'll use some more metal. Here's how it looks:

[prodigy]

Maybe some springs on the sides to make stable the "looseness"

[motiondave]

the motor brackets are twisting something fierce, which wouldnt help. Try some bracing to stop them moving so much.

Springs should be a last resort as wipers are not that powerful and a spring will slow them too much if used for balancing.
Springs were used on mine as a help to create a light constant load on the wipers and the motors tended to backlash and wear out too fast from constant abuse.
I sold a wiper sim to a bloke over a year ago with springs to help the load against the motors, not for balance. He uses the sim regularly for up to a few hours each day and the wipers are still going.

[wptm]

Thanks for your advices! I did some improvements.

A frame was welded at the back of the seat. Now the rods are connected to this frame, instead of the back of the seat. The motor holder plates are now from thicker metal. Now, the vibrating is minimal with a person loaded maybe nothing. There's no more twisting at the motors. And the rod ends are now better connected to their axials.


When I sit down into, I feel that the motors are weak. They are ok, when the seat moves to forward. But very weak (struggling) when they need to move my body to backward. Motiondave, is this the situation when you advice the springs?
I'm testing it with a car battery. I've read in a post somewhere, that some overvoltage can make higher performance on the motors.
But not only this is the problem. At some positions my body weight forces the motor to turn. I suppose its gears are not good for this kind of usage. I'm really not a heavy person. I will disassemble them, to check if there's anything I can upgrade, to achieve better performance from them. Or, may the springs here can also help?
But if the motor is the problem, I should replace them. Some suitable springs would cost more than an other pair of junkyard wipers.

[motiondave]

Let me make this clear, I NEVER used springs to help maintain a balance point , NEVER!
I got the balance point right, but I found the backlash on the wiper motors got bad as the direction changes damaged them.
THE REASON I USED SPRINGS IS...........to create a light constant load on the gears in the wiper motors to help alleviate the damage caused by constant direction changes.
The springs were not very strong, maybe 2-3kg tension?

as you are using ards and h-bridges I am not sure what settings you are using.
Have you checked the balance point, best spot is where your belly button is for balance for a seat mover.
Just sit in the seat, run a straight edge across your belly and measure straight down and thats the balance point.
Wipers are not that strong, but check balance point and also the settings on the PID on the ard and the h-bridge power settings.
Post them here and another person like Bob or Prilad can check them.

If you are planning motor changes, realistically, consider big worm gear motors like the Motion Dynamics or Ebay daytons, Nice big strong motors.
I found wipers were very successful apart from damaged gearing, of which a LIGHT spring helped, but since going to big worm gears, I have never looked back.
So double check balance point, post the settings or ard and h-bridges, and if they are right, you can work on the next step, not sure what step....
Cheers, David.

[wptm]

Thanks David!

It's clear * It's really a good advice to help on the backlash.

I'll adjust the balancing point according to your description. The seat movement was generated by me, powering the motors with a switch. I'll take as next step to setup the arduino and h-bridge and x-sim software. Unfortunatelly the h-bridge is still not arrived. When the computer generated motion works, I'll have a better picture what would be needed to change.

I see now, that for best performance I should buy big worm gear motors. But before, I'll try the whole setup with the wipers.

bye, Tamas

[wptm]

I've burned my Chinese E-Bay H-Bridge, with the Arduino solution. I'm not sure if only the big Ampere, but that was one of the cause sure.
I've tried to repair the lines, but when I corrected one, an other burned again. At the end some transistors were smoking too.

Surprisingly, there were some time when it seemed to work. When I pushed Start HW Rescan the motor was turning a bit. The Arduino board seems ok, extractor.exe still get knows it.

So, I've decided to use some more robust h-bridge. The Pololu one is sure the best. Or simply the jrk12v is the all in one solution. But before, I want to give a try to make Thanos (Tronicgr)'s H-Bridge connected to the Arduino. I've started it from the scratch, just finished etching the PCB.

Am I right, that it's a good idea to try the Arduino (open source) solution with Tronicgr's H-Bridge?

[motiondave]

your choice........
read the tronic thread to make sure you get it right.