Konterror's 2 DOF Seatmover Project

So most are useing these kind of motors?
http://www.ebay.de/itm/12V-DC-Geare...371?pt=LH_DefaultDomain_3&hash=item58b2cd2323

Since I need a diffrent motor mount, I might just upgrade the motors as well. Would those be ok?

Could I use them with a longer lever for more speed (I can't find motors with 25:1 or 30:1 ratios in europe)? Something like 60mm for 195mm/s or 80mm lever for 260m/s?

Yes you could, just use a very sturdy lever. 65mm CTC should be long enough, and with fast settings on JRKS (will take time to get right) you should be looking at 250 ism mm per second linear speed.

Thanks bsft!
Would you consider 6mm steel as sturdy? Or do I need to look for something thicker?

How do i calculate the movement speed?
@bsft With 80 RPM on the gear shaft, so 4/3 turns per second, and a lever length of 65mm, which makes 408mm of circumference, I get 544mm/s with the motor at max speed and no load. Is load making such a huge difference, or am I missing something? Maybe the motors never reach max speed because the change direction too often?
Please do not get me wrong, I don't want to question what you wrote (to say you are more experienced than I would be vast understatement ) , just want to understand

@eaorobbie can explain that better than me

Since I have been very lazy for one year and a half, I thought I'll dig this out again. I did not update this thread because I did not do anything... There were some reasons, but mainly, I have been lazy
A couple weeks ago I thought it's a good time to finish the build, so I got back to building and since I have done some things since then I thought a little update would be nice.
What happend since the last post:

• got 2 bigger worm gear motors and new levers
• Put things together with the rest of the setup
• Started configuring simtools and JRKs

Right now I have 80mm CTC. I will punch in some more holes at 60mm or so and will fiddle with the geometry.

ToDos:

• Shorten lever length
• try some geometry changes
• build something to connect the motor mounts for more rigidity
• get something permament to put PSU and JRKs on
• Tidy everything up a little
• spend some more time in simtools

This is how far it is right now:

I wish you good luck! Where did you get the motor?
Servus
Choclo

These are the motors, more or less at least:
https://www.motioncontrolproducts.co.uk/products/8/166/dc-brushed-geared-motor-73zyt/

I got them of ebay, from the same vendor though.

Since my last post I changed the geometry a lot. I moved the cardan joint around to a better position, taking a lot of load off the motors. The pivot point I had before was a guesstimate, made during the building process and it has been of by about 12cm. With moving the cardan I reduced the load from about 35-40kg to basically 0 in neutral position. I changed the CTC to 50mm as well.

At the moment I run the JRKs with 400 for acceleration and max, whatever it is called because of the PSU problem I have ( explained below). Here is a Video of it runs:

I had some trouble with one of the motors. The JRK on that side was significantly hotter and the PSU shutdown from time to time. I opend the motors and turned the anchors by hand, with everything else (except power) attached. I did not feel any difference so I put them back together. One of them was easy to put together, something felt of with the other one. I saw there where two sping washers in the second motor and took one out. That solved the temepature difference problem
Sadly the one PSU still shuts down, I ordered a new one.

Right now I am fairly satisfied with how it works, and think I am done with building and geometry. I still need a lot of tuning in simtools I think. That is on the list as soon as I get the PSU problem fixed.


ToDos:

• Fix the PSU
• build something to connect the motor mounts for more rigidity
• get something permament to put PSU and JRKs on
• Tidy everything up a little
• spend some more time in simtools

You've had shut down's with those setting's seen in the video ?

Yes but only on the left side. For example when the motors go to the neutral position when starting the sim. Once it is in the neutral position it usually does not shut down during driving. I even put a 30A max in the JRKs. This only happens to the left side PSU never on the right side.
My thought was that one of the PSU phases is defective so the PSU can only put out 23,5 A maybe a little more and shuts down once it has to deliver more.

From the profile in the video, Your not pulling any where close to 20A+...let alone 30.

Im not a fan of trying to limit the JRK's amperage. It can and will handle 30+ spikes no problem.

can you consistently repeat the failure ?

@Nick Moxley while driving the PSU shut down more or less randomly. As soon as I set the duty cycles up and removed the amp limit it shut down the PSU at almost every movement.
Got the new PSU for the left motor. Turned max Duty Cycles and Max Acceleration to 600. Works well with the new PSU, problem fixed.
I changed some of the settings in simtools as well. It is less smooth and I can feel bumps and upshifts a lot more. I will post a new video later.
With these Settings it takes out the other PSU at times though. I got to test that more. I know it happens when I hit a wall, or flip. With a 35A limit everything runs without shutting off, even in a crash. My goal is to take all the limits out though.

As Promised, a new video.
I did edit the profile and set the JRK settings higher. I still might need to do some PID tuning...

The right PSU shuts down from time to time and I get motor driver fault errors. I need to investigate and maybe play around with PIDs a little more.
What is a safe temperature for the JRKs? On both sides the heatsinks get pretty hot.

This Problem is not on the side I replaced the PSU. That side runs fine with the more agressive PID settings, and I had no more trouble after replacing the PSU!
As soon as I use a little more agressive PIDs I get a lot of motor driver error, but only on one side. I guess that causes a short-circuit long engough for the PSU to shut of.
I need a little help here! What is usually the cause for this?
It is a symmetrical build and the problem exists only on one side.
Is it a bad/defective motor?
Any ideas?

You could change parts from one side to the other: PSUs, JRKs or perhaps the motors. Maybe the error then appears on the other side and so you can see which part is defective.

I still have a problem with motor driver errors. One Motor starts stuttering, than the PSU shuts down.

I changed the PSU and JRKs around. Error went from one side to the other, so I dicided to buy a new JRK. I put it in this week, and the error stayed. It ran ok for a few Laps with max duty cycles on 450 and max accel on 450 as well. I cranked it up to 550 and 600 and did not get out of the box. I had the luxury to take home two of the same HP PSUs I am already using, so chaning the PSU was no Problem. Still the same thing.
So the error wanderen with JRK and PSU. Both were replaced and the error still exists.

Am I too agressiv with the JRK setting?
It was running with Max Duty Cyles on 450 and Max Acceleration on 550. Is more too much for 60:1 worm gear motors?

I will try again with those setting and move them up bit by bit, but right now I am way too frustrated.
Maybe I changed it left to right and the error did not go side to side, and I just thought it did, so it could still be the motor. I start doubting myself... Will try that again as well, sometime.