Showroom No-Weld 2DOF Seat Mover On Homebrew Ricmotech RS1 Clone

Fans mounted up, harness added, and a numpad as a button box added. Also started a little on some cable management and finishing work on the wood.

I am able to deliberately reproduce the motor controller shutdown issue described in an earlier post by forcibly pressing my back against the seat while the motors are trying to push forward at high power (braking or turning back and forth).

This happens with PWMmax set at 130 (as low as I tested) and 255, though it tries to push against me for a shorter time before shutting off when 255 is used. Happens regardless of axis dof settings totaling up to 90% or 140%.

Does anyone have advice here? Should I wire up an independent monster moto per motor, will that fix this? I don't want to reduce the pwm lower than 130, that's just ridiculous when it has so much power at other times and just fails from a split-second of overcurrent protection or something.

Is it possible this is an overheating issue? I am just using small heatsinks on the monstermoto with some light cooling from a case fan in the PSU enclosure. I just tested taking the heatsinks off and the motor went into the 'protect' (or so I'm calling it) mode almost as soon as I pulled out of the pits. - EDIT: Just tried it with insane fans blowing on it, same issue and the heatsink wasn't even warm to the touch; so I don't think it's heat related.

Edit again:
So I looked up the model of motors I have and they have a built in stall protection that only resets once power is cut and reapplied once triggered. This looks like it may be the culprit. Anyone know how to bypass stall protection??

Edit yet again....
I found a 1 micro-ohm diode(?) and a model 470n 63v capacitor and a coil on the motor that are all located between the power source and the brush for the normal factory (+) connection. On a spare motor I bypassed all of these and went straight to the brush and it all seems to work just fine without load. I will wait for someone to chime in with advice for a day until I do this modification to the in-use motor, I really don't want to replace another.

Interesting, I've never seen a motor with built in stall protection before. Can you sketch how the components were connected together or post a picture? Those alone don't sound like they'd provide any stall protection. Connecting straight to the brush shouldn't cause any problems I don't think, just post a pic to verify

Here are some pics of it. The center orange one is the one labeled 470n 63v which bridges the low speed and high speed factory connections. Then around to each side is the the 1 microohm whatever it is which connects from the factory (+) connection to ground in parallel.





I have my room all packed up for painting so I'll have a couple days before I do anything with the motors.

The capacitors and inductors are likely there to filter out the electrical noise caused by the motor brushes arcing, the micro-ohm thingy might be an overvoltage protection diode or resettable fuse of some sort, if you can get a part number from the packaging that'd be very helpful.
One thing you can do to rule out if it's a problem with the monster motor shield or not is to cause the fault, and then check the voltage levels of the EN1 and EN2 pins on the MM. During normal operation these two pins should always be high (5V), but if there's an overcurrent or overvoltage fault, one or two of them will be pulled low (0-1V) until the fault has been cleared by moving the motor to its "zero" position (changing the state of the INA/INB pins). If these pins are still high during your motor stall, you can rule out the MM being the problem. You're right about 130 being quite low for a PWM limit, something seems off here.

I think the only other identifier on the 1 microohm thing was "k63", I couldn't find anything on Google about it, but I did find that the company that made my motors brags about overcurrent protection trip breakers built into most of their models.

I'll check the voltages on EN1 and EN2 once I have it hooked back up, that's a good idea, thanks!

They're likely auto-resetting circuit breakers then (or something similar). If you find that the MM was not the problem, you should be able to bypass these, but they were put there for a reason, so just realise that you may run the risk of damaging the motors . But imho as long as you keep a close eye on the temperatures you'll most likely be fine. What current are the motors rated for?

edit: Are you sure the micro-ohm module is connected in parallel? If it really is a circuit breaker of some kind it'd likely be connected in series with the main power path

I'm not an expert, but I'm pretty sure the microohm module was in parallel, I was able to bend it back and forth until it broke off and the main circuit was still complete.
Here's a spec sheet that has a wiring diagram on it: http://www.partdeal.com/downloads/d...013/sprague_wiper_motor_e_008_230_drawing.pdf

And the parts page that says it has a "self-resetting circuit breaker to protect against stall loads" http://www.partdeal.com/sprague-wiper-motor-e-008-230.html

Its normal operating current is 6amp according to a different spec sheet, but I think it's pulling around 15 amps being used for this project - I've blown a 10 amp fuse for a single motor but haven't blown a 20amp yet.


The more I think about this, the more I think it's the MM going into a short-circuit fault. I'll definitely be testing the MM outputs before doing anything with the motors.
If it ends up being the MM going into a fault, I wonder if I can modify the SMC code to detect the fault and reset that output when it happens.... That will be a fun (not being sarcastic) project to work on if I go that route

You can make out the circuit diagram at the bottom of the PDF. If it wasn't in series with the rest of the circuit then it likely wasn't a circuit breaker (unless they're breaking the circuit by shorting the power and ground together to force the motor to stop, which would be quite odd). Clearing it up with extra code would probably be quite doable actually, all you'd have to do is wire up one of the pins to detect whether or not the ENx pins had changed state (indicating a fault), and when that does happen just force the output of the INA/INB pins to change position for onc cycle so the fault clears. I'd recommend simply adding a second MM to your system before trying this though.
Something else I haven't asked, where did you source your MMs from? The chinese ones are hit or miss, you'll end up with some that work well and some that don't at all, I know some users on here have had bad luck with them (but they're so cheap that even if you have to throw out half of them it's leagues less expensive than an equivalent sabertooth driver).

That was the plan, detect fault and put it in a standby state. I know there's some time overhead with the standby state.

I sourced them from various sellers on ebay, finally got what appeared to be a good batch from a seller recommended on this forum. I have two that I believe are good, I'll look into hooking up one per motor IF the time overhead for the fault-detection standby reset is unacceptable.

I've painted and moved everything back in but its way too late at night to do any testing. I still need to verify that the MM is actually going into a fault state. I'll work more on it after work tomorrow(today??)

Since I love spamming this thread with pics, here's what my room now looks like:



And a bonus cat picture

I added a reset loop that puts both motors in a standby state for one tick instead of sending entering the normal PWM sending code for that tick once every 10 seconds just to test, and it does successfully bring the motor back online after it experiences the "protect mode" issue. I then dropped it down to recover every 100ms and I barely noticed that the motor controller ever entered a failed state, and I have no noticeable overhead during normal operation.

I'll be working to make this dynamic so that it can instantly be brought back up when it faults without forcing a standby mode every 100ms. I will be happy with this solution for this iteration of my rig. I know this is basically bypassing a 'protection' mode of the controller, but in the event this causes a burnout of the chip I'll THEN look into other options.

If I upgrade motors in the future I will go the dual MM route and hopefully this piece of fault recovery code won't be necessary.

Thanks for playing devil's advocate with me @Tim McGuire ! Saved me from unnecessarily tearing into a motor.

Devil's advocate is my favourite position to play
Glad to hear you've got something that's working for you!

Just got done putting down laps on Spa non-stop for about 2 hours, loving every second of it!
The motors were pretty warm but I think the cooling solution I have on them is enough, and the fault recovery code has proven to be completely functional!

If anyone has suggestions for noise/vibration dampening, I'd love to hear. My wife was downstairs and said the bumping noises were pretty bad and I actually knocked some things off a shelf in the garage... my room is upstairs and across the house from the garage, so.....

I was considering air compressor feet but I've read in other threads that these don't actually do much. I'm thinking a weight lifting mat may do the trick, but I'd love to find something a bit less expensive.

Thanks noorbeast, I'll look into some rubber feet like that


I decided to see how the setup would work for Dirt Rally. I went with a slightly tweaked version of my Assetto axis settings and spent just a little time in the tuning center. Pretty happy with the results, man this game is intense with motion! And I am NOT good at it

Still needs some tuning and I definitely need to dial down the motion.

My Sunday project was to take it all apart and put it back together:









Still working on a new seat mount bar made from a 2x6 instead of the two 2x4's and also designing a new shifter/handbrake mount

Just a bit of color, and it gets a really professional look.
So what is the grey stuff you added to the base? Some kind of fabric for sound dampening?

Thanks!

I wanted the base to give off a 'car floor carpet' vibe.
The plan was to get automotive speaker box carpet, but everywhere local was price hiking it and I didn't want to wait for any to ship.
I ended up going to a hobby store and got 6ftx9ft of some decently thick felt fabric that seemed like it'd fit the bill, it was tough to work with and the finish isn't perfect, but it looks a lot better than raw wood. It ran me just over $10 and I have plenty of extra left over.

It does seem to help with sound dampening a bit, just while moving it around my room getting it put back together it was much less clunky, looking forward to hearing if there's much difference when everything is back on it.

Hi, just wondering where did you get 12mmID Motor Hubs from.