2DOF WiperSim+Pololu problem(solved)+traction loss

[yokoyoko]

Hi NeoTokyoNori,

Are you using 24volts?

No I am using a car battery for the two rear motors and a power supply for the TL motor. Both have around 13,8V - I regularly recharg the battery after every session.

Did you have any issues with fwd/reverse motor speed?

No issues but the speed fwd/reverse is not equal! I have no exact values ​​differed but would tap about 10 rpm. I use the faster rpm for moving the seat forward (braking). For the TL I have to live with this rpm difference. In the simulator during the ride you can feel this difference in speed also very low.

Did you use RC tuning skills?

if you have access to a lathe and you use used motors like me I would recommend to do this:

abdrehen-des-kollektors.jpg (57.57 KiB) Viewed 11154 times

Don't forget to remove all chopper chips from the slots.
Have a look on the brushes if they are ok too. If not I would exchange it. There are also those with higher silver share but higher wear. Let the motor "run" in at a lower speed until the brushes complet rest at the commutator before power them at full load.
I use the "lower" speed of the wipers - brushes confronting axially.
There are special tools to adjust the "brush slots" like here (just as example)

1.PNG (64.59 KiB) Viewed 11154 times

2.PNG (152.8 KiB) Viewed 11154 times

Also, the brush may well slide into the guide.

A good fitting PID is important too.

I see now you are using the rod to push against the lower chasis.

not really . The motor is bolted to the lower frame. The rod presses or pulls the upper movable frame on which I sit.

I am thinking of using my wiper motor to make the upper chasis "swing" just like a wiper - they should be good at that right?
Do you think there is a big difference between the methods ?
my motor will be positioned halfway between the front pivot point and the seat pivot, like yours.

See my post above. I think your suggestion is the way I use this?

Are you using a rubber bushing instead of a uni-joint? if so what type?

I tested both and like the motion with the rubber bushing more. I use a 50x50mm rubber bushing with M10 thread. At a static load of 95kg they set 6mm.

what type of bearing are they called? i have never seen that shape before.

http://www.motedis.com/shop/Dynamik/Rollenelemente/Rollenelement-ohne-Fuehrung::680.html

i am thinking of putting raw steel ball bearings directly along the aluminum slots !
and just have a bolt that acts as the front pivot - no swivel plate

First I wanted to use big steel balls direct in the grooves too but I never tested as the current sollution works quiet good. How you want to do this in the front without a bearing? Do you have a drawing?

what are they made of, carbon fiber?
why do they look like rope?

These are simple M10 threaded rods. To this I took a fabric hose.

I would be happy to see more longer videos, showing your traction loss mechanism at work!

I will upload another video of the TL - but not before the weekend I think.

Best reagrds
yokoyoko

[NeoTokyoNori]

Hi yokoyoko,

I am busy working on and dreaming about my sim design.

I tested both and like the motion with the rubber bushing more. I use a 50x50mm rubber bushing with M10 thread. At a static load of 95kg they set 6mm.

Since you say the bushing is good, i am considering using it.
Your rig it helping me reduce the costs quite a lot !
I think I can get it from here in Japan. I hope it is the right shape
www.monotaro.com/g/00138182/

I would like to know why you like them - does it feel more like real driving?
I was concerned because in the video, it looks like you have some "wobble" happening

About the Stabilizer bars
Do you think the Stabilizer bars are a "must have"? or are they just to be safe?
maybe you could show the difference in video, with bars and without?

I am hoping to use Arduino Open Source X-PID firmware by sirnoname
but I am not sure it this can handle 3dof traction loss

[yokoyoko]

I think I can get it from here in Japan. I hope it is the right shape
www.monotaro.com/g/00138182/

There are alot of different shapes of these bushings. Make sure you can find some infos on static load - this helps choosing the correct one.
But as you noticed the stabilzer bars are a "HAVE TO" if you use these rubber bushings. This is a big disadvantage.

I would like to know why you like them - does it feel more like real driving?
I was concerned because in the video, it looks like you have some "wobble" happening

It is hard to explain. With the rubber bushing I am kind of "preloaded" with about 5mm because of my weight. If you use a bump effects and the motors move on a short distance relatively quickly the seat can move even these few mm above. It is like a fake dof. On the other side the movement feel smoother with these bushings. There is no clearance and it hardens with the movement. The rubber-like always returns to its initial state.

What do you mean with wobble? Can you say the min/sec in the video?

About the Stabilizer bars
Do you think the Stabilizer bars are a "must have"? or are they just to be safe?
maybe you could show the difference in video, with bars and without?

I am hoping to use Arduino Open Source X-PID firmware by sirnoname
but I am not sure it this can handle 3dof traction loss

Bob answered these topics perfect. Thx.

I agree that the arduinos are a clever option!

This weekend I will try to show the TL with an other video a bit better.

[NeoTokyoNori]

Yes but you need to run 2 Ard uno's , one controls 2dof and the other will only utilize one side and can control the traction loss, and as cheap as the Ard's are its quite a clever option, I believe this has been stated in the post following Sir's and is good for running up to 32 units on one pc, would like too but handy to have the expansion, if done with Jrks you need to buy 3 jrks, with an AMC you either need his addon card or 2 AMC's or with the K8055 you need two K8055 but under windows 7 that becomes too much of a hassle as sometimes the second k8055 disappears.

Thanks for the tips BobBuilt ! I am really glad that it is possible.
Now that you mention it, I did read that part, but it is like trying to drink water from a jet hose right now! so I have trouble taking it all in at once

I just got my 60Amp Motor drivers from china today, so I am thirsty to get them working with the arduino and x-sim.
But I am being blocked from progressing by this odd "SimForceGT access violation" error - I have posted a bug report about it.

I see your point about the stab bars, and I will keep it in mind.

In the meantime WRC Mexico starts today, so I will be tuning in for some major traction loss action!!!
http://www.wrc.com/video/

Do ya'll enjoy some rally too downunda

[yokoyoko]

I just got my 60Amp Motor drivers from china today

I hope you ordered enough to power 3 motors
Buy two Arduino, a Power supply or Battery, 3 pot's, 3 motors and some wires and you are ready to go.

But I am being blocked from progressing by this odd "SimForceGT access violation" error - I have posted a bug report about it.

Why do you want to do with this? Have you tried the "older" version of x-sim. I think it should work there.

[NeoTokyoNori]

It is hard to explain. With the rubber bushing I am kind of "preloaded" with about 5mm because of my weight. If you use a bump effects and the motors move on a short distance relatively quickly the seat can move even these few mm above. It is like a fake dof. On the other side the movement feel smoother with these bushings. There is no clearance and it hardens with the movement. The rubber-like always returns to its initial state.
What do you mean with wobble? Can you say the min/sec in the video?

As you say, I think the "damping" is a good thing to have.
Of course you have a lot of movement in the video
so I cannot be sure what movement is due to the bushing, but as long as it is not something
that feels too "squishy" or "bad" then there is not a problem

But as you noticed the stabilzer bars are a "HAVE TO" if you use these rubber bushings. This is a big disadvantage. Bob answered these topics perfect. Thx.

I will keep the stab bars in mind, but actually my sim is going to be a floriske style configuration,
so my estimate is that the 2 motor brackets will keep the seat from being able to yaw in any major way,
so I think i will try it first without, and can add them on later if it really yaws like crazy.

Do you watch WRC? Volkswagen is really doing great ! I love the WRC Polo

[yokoyoko]

I actual get an error from this too :

Zugriffsverletzung bei adresse 005FB428 in Modul 'SimForceGT.exe'.
Lesen von Adresse 000001E0.

Yes - that should have been seen during the beta-tests sry
I think it is a problem related to "

partly builded with new compiler of Visual Studio 2010 SP1

"

[NeoTokyoNori]

I actual get an error from this too :
Zugriffsverletzung bei adresse 005FB428 in Modul 'SimForceGT.exe'.
Lesen von Adresse 000001E0.

So I guess using SimForceGT is not an essential part of getting things to work?
It is just to test things right?

I guess will have to skip it for *
I am trying to wire my arduino and the new driver as we speak...

[NeoTokyoNori]

Hi,
Sorry, I 've been catching up on my WRC !

I have been working on my build in CAD, but for some reason the software I am using (provided by the aluminum profile supplier here) does not allow me to take any screencaptures . I wonder if this is a 3D driver issue or something...
It also does not export to any image formats.. yes it sucks.
I also lost my smartphone/camera recently , so please hold on while I figure out how to show it.

The good news is I managed get xpid/xsim/arduino to get the driver to drive one of the motors
It sure heats up the mosfets !! So I have to get some heatsinks asap.

I need to figure out how to setup and attach the pots to the motor arm..
Gears seem to be really difficult to get the right size (shaft diamaters, modules,etc.)
Arms are ok, but they seem to lack the range of rotation...
So I am thinking of going with a pulley for this, as it offers the rotation without the gear matching issues.

So many things to figure out, I need heatsinks for my forehead!!

[motiondave]

maybe use lego gears http://www.spareblocks.com/buy_replacem ... heels.html , and use these for feedback pots