2DOF motion simulator build

A video of the operation

@André Vasconcelos I'll post a video when I get the new H-bridge and I get both of the motors running and sort out all the other problems.

I'm having a problem with the sim. There's a little slack on the gearbox:


When I get on the sim and it becomes balanced, it starts to oscillate.


The motors were like this when I got them, atleast I think they were. I'm guessing that there should not be any slack in the gears?
I set the Deadzone to 2 in SMC3 and the oscillation stopped while only SMC3 is connected to the sim. But when I tried Asetto Corsa the oscillation was back.

Is there any way to fix this or do I have to go gear shopping?

@Ville Pesonen what values do you have in SMC3 utils ? can you post some screenshot with yours settings.

Here's my settings:

Only way I could get the oscillation to stop was by increasing the deadzone value to 3.

I lowered the PWMmin to 50 and it got rid of the oscillation!

also I got this off

I'll check here too

thats what i did too at my sim, lowered PWMmin, as i had the same trouble. good you got it working

The H-bridges already had coolers on them but I added another one just to be sure. Now it's sandwiched between two coolers. The original was under the board and I added the new one directly on top of the two half bridges. I also added a fan to keep it from heating. The sim still stops. The problem seems like it is not related to heating of the H-bridges


I can keep the sim moving as long as I keep the PWM-Max under 130 in the SMC3 but that makes it a "bit" sluggish.


when I have the PWM-Max value higher the sim moves for a while and then stops (around 30 seconds).

I tried several different things to troubleshoot this but none has worked so far.

I have the power supply plus connected to a diode to stop the "backlash" voltage from reaching the power supply and shutting it down. After that I have a capacitor connected to provide the high current peaks and last the Chinese H-bridge.

diode
+ ------>----|-----------------| H
CAP | BRIDGE
- -------------|-----------------|

1. I tried adding another psu to provide current
2. I removed the capacitor
3 I removed the diode
4 Added the capacitor without the diode

nothing helped. The sim still stops after a while, thinks about the world problems, and then continues its work. If I turn off the PSUs and then back on, the sim starts to move.
I measured the voltage on the H-Bridge while it was not moving and it showed 12 volts, so it is getting electricity. Also the fan that is connected to the PSUs does not stop moving. I have no idea what is causing this. Does anybody have any ideas what I could try to do to get the sim moving?

Here's a video showing the behavior.

Sorry it was my error probably not talking about the correct motor driver. You could reduce the Kp value down to 250 while raising the PWMmax, but the limit is the motor driver which has to operate under a certain load and is seems it is not able to handle such a high demand of current. One year ago I tested two Chinese bridges and both were failing after a short while.

Thank you for the info. I'll try to lower the Kp value when I get home and see if that makes any difference. I also ordered couple of monster motos to see if they can handle the currents. I'm planning to use one monster moto per motor. We'll see how it goes when they arrive.

hopefully they are not DOA...good luck.

Hello,
maybe you remember you postet in my thread at the beginning and we build nearly the same rig. I use these Motors with one MM per motor with good success.

One thing iI noticed in your video with the gear slack is that at the end where you put your hands off the upper platform is shaking very much. I don't know if there is something loose but if this is normal you maybe should think about some extra tubes to get more stability. I also had this problem and get those oszillations. After more stabilisation they are gone.

Also i have these slack in my Gearboxes. But i had this before on my wipers too.

If you got problems with MM try this seller http://www.ebay.de/itm/Dual-VNH2SP3...584?pt=LH_DefaultDomain_0&hash=item485bfc7368
Orderd many times always working.

Dead link, please can you add the the ebay dealer? Thanks.

It's good to hear that motomonsters can drive those motors! Now I'll only have to wait for them to arrive. I bought them from Deal Extreme so hopefully they're not DOA. I should get them in a weeks time.
The shaking you saw in the video happens because I have a steering wheel column universal joint and it is pretty flimsy. I'm planning on upgrading to a bigger u-joint to make it more rigid.

I tried lowering the Kp to 250 and upped the PWMmax little bit. Now it seems to stay on without problem. Thank you!

I redid the electronics and added a 140mm fan to keep things cool.

http://www.ebay.com/usr/satisfyelectronics?_trksid=p2060353.m2763.l2754
ordered twice from these people. 2 out of 11 were doa but got refunded within 24hrs.
again no guarantees, but you'll get your money back.

Sorry for the dead link.
http://www.ebay.de/itm/Dual-VNH2SP3...584?pt=LH_DefaultDomain_0&hash=item485bfc7368

Ebay seller name: alice1101983

For a bigger ujoint i can recommend you a bmw rear cardan joint. They are very stable and good to weld.

Thank you for the link. If the ones that I ordered does not work I'll order from there.
I've been planning to visit some scrapyards to find a cardan joint. maybe after I get everything working.

Today I got Lepai LP-268 mini amplifier that I ordered last week to drive my bass shaker. I tried it briefly and it seems like it's doing its job. The bass shaker is attached to the bottom of the seat.


Now I'm only waiting for MMs to arrive so I can get the thing moving. They can not arrive soon enough.

Good luck with the MM's !!!! Hope they all work and you ordered more than you need , just in case they are faulty.

I also tried the Chinese H-Bridges they are pathetic IMHO about as much power as one of my wet farts

Don't forget a cooling solution for the monsters. They can overheat quickly.