Question my engine loses power

my motor loses power and falls when i sit on the bench, can someone help me, they are wheelchair motors, 24v/70a source, ibt2 h bridge, arduino uno

It works perfectly, when the weight of the body is placed, it stops working, as if the engine turns off.

Is the rig balanced with you on it?
Maybe that would take some load of the motors.

What is the power (Watts) of the motors?
Sounds like it draws to much currant( amperage) .

The motors are around 300 watts with a reduction of 32/1 each, I use a 24v 70a source, I put car batteries for testing but it was the same thing, it could be the SMC3 configuration, it works well but suddenly it falls apart

Motors should be powerfull enough.

Can you give more detail on "it works well but suddenly it falls apart"
maybe share video to see what is happening.

Set things up from the start
https://www.xsimulator.net/communit...3dof-motor-driver-and-windows-utilities.4957/
Does it work with one motor with sine movement? Does the blue and green line follow each other?

Yes it follows the sinusoid perfectly for a while, at some point I notice as if the motor stops and loses the reference, could it be the ibt2 h bridge heating up? , when the bridge h warms up could it stop sending pwm ? , I'm using b10k potentiometers. I will make a video

Ibt-2 can handle up to 27V , but if they getting hot that is not a good sign,
I reduced voltage to my ibt-2 to 21V
This minimalizes the heat generation , mine are not warm at all.

I think the potentiometers are not the problem.
You can check the pots:
no power to the motors and rotating motor by hand , check their movement in SNC3.

Maybe change an ibt2 or the arduino see if that makes any difference.
and meassure the load (amperage) of the motor.

I did a new test, my power supply works at least at 24v, I put a fan on the ibt2 bridges, in the ammeter test it reaches 3 amps and the motor is turned off, in theory the bridges are 43 amps and my supply 70 amps, it shouldn't there is this stop in the engine

Could be that the PSU is shutting down because of voltage received from motors when slowing down. This can easily exceed the supply voltage voltage. Some PSU can't handle that well. The bts7960 also doesn't like it much from what I read. A battery can handle this. Maybe the USB cable wich is pretty close to to the PSU lines, emi? Bad ground connection somewhere so could be a ground loop. I don't know exactly what the switch between the PSU line is. Looks like a 230v 16a breaker. Maybe it's faulty. Try to use one moter with the PSU so you know that it isn't the motors back emf that is working against each other. Just my 2 cents.

good morning, it could be the weight of the whole body on top of the motors, the chair needs to be at a well balanced angle, when I did my project the same thing happened, then I changed the angle of the chair so that all body weight would not be on the motor and it worked, I hope could have helped

You could try some light weight gas struts to help hold you up during static time. dont go too strong tho or you sim wont be able to move lol. I think Im using 40 pounders on my 6 d0f and that seems right on the brink, but I havent tested with me in it yet tho either.
also. your Ibt-2's could be going out. Im having a hell of a time with thos burnin out on me. Im swithing to the 30A cytron motor drivers myself. They are packed with features and never need cooling.[/QUO

I already changed everything, checked everything, and I don't find the problem, the 2dof works but suddenly I have to restart and it starts working again, the motors generate reverse energy could this be the problem, it would be as if the ibt2 h bridge goes into protection and turns off, closing smc3 and starting again the system works again.

HELLO EVERYONE, I HAD THIS PLOBLEM ALSO YOU NEED TO LOWER THE POWER OF THE ENGINE IN THE SMC3, IN CASE WHAT IS TURNING OFF, I HOPE I COULD HAVE HELPED.

how can i lower the engine power in smc3? what configuration did you use?

Hi nmk ,
could you tell me your smc3 settings?

good morning to all of the forum, my friend my configuration is like this Kp=50,Ki=50,Kd=50,Ks=1, PWMin=70,PWMmax=110,PWMrev=70 ,Max Limits=0 ,Clip Input=200 , Deadzone=0 , this is my configuration , depending on the engine it changes , so you need to do your configuration, hope I helped .

Hello everyone on the forum, yes I will correct it, thank you very much for the tip.

I don't know if your problem is solved.
If not, then try to decrease your Fpwm to increase the power to your engines.
I had the case, the motors ran normally no load and when I put weight on they went to safety.