Bumpy Stepping Motion (2 Dof Flight Chair)

Shortened the levers to 45mm and it's still quite rough. I can feel each single gear, if that's in fact what it is. I think I'll try to come up with some sort of dampener.

One last thought from my end would be to try the rig without you sitting in there.
Reason being, just to see if your current setup can handle all the weight that it is now bearing. Now sure how you'll feel the bumps without being on the chair though...


Also yes, Flypt can be tricky to setup, but you get used to it. I'll post some links which can be useful to you.

LeBois Racing shows the Flypt setup.


my own thread here as i was struggling with Flypt and got loads of help from the forum.
https://www.xsimulator.net/community/threads/2dof-all-controls-inverted-flypt.19143/

I also came across Departed Reality Sim Manager, which is supposedly simpler than Flypt. It has a demo which you can check out.

Much appreciated. I'll take a look at the video later today.

I've tried off the seat and it still steps. The video I posted earlier where you can see the stepping was without me on the chair.

I still am not 100% sold on the cogging possibility because I didn't notice it behaving this way when I used my first iteration of the chair. It felt kinda mushy and lumpy, but not like hard steps. I'm kind of wondering the motors or gears were damaged from some hard motions or something? I'm still coming up with a few more things to try before I start thinking about a different motor or gear solution. If anyone has any more ideas, please keep them coming. I'd hate to replace the motors only to find out it wasn't the problem.

You can always connect the motor directly to the 24v dc supply - that is without the IBT. Disconnect the linkages when you do that and you'll see the motor shaft turning, you'll have an idea whether the motor steps due to the gears and not due to the electronics.

I've disconnected the linkage and pot belt and let it spin at the slowest setting I could get it to go by adjusting the pot with my fingers and it felt smooth, but it was still quite a bit faster than what the flight sim would achieve in a gentle climb.

If I was a good programmer (which I am not), I could modify the smc3 code to send a constant low pwm signal to have the motor turn at a very slow speed. That could be very informative. Any idea how I would do that? I have experience with python, but just basic stuff.

IMHO I don't think what you're seeing is cogging. The movements look too rough. In my case the levers move smoothly I can't see any visible jerkiness. What I did feel was a series if micro-accelerations and decelerations, which I couldn't even feel in a not-sterile environment (in MSFS flight), not sop-and-goes as your video shows. that would be impossible to ignore.

I also think that there is plenty of power with those motors, especially for a 2DOF.
I see from your topic that you're struggling to get a slow movement for testing. It's easy with FlyPT Mover: just add a source of type "Loop" and choose Sine wave type, then just assign it to roll or pitch and you can control the speed and amplitude as you want. You can make it really slow.
One other thought is IBT2s are notoriously unreliable with 24V, that's the reason I'm not using them in my 6DOF (I used them in 2DOF with 12V PGSAW motors just fine). It's possible that the issue has something to do with IBT2s as well. Many people operate IBT2s around 19V because of their tendency to burn out at 24v. If you're doing that, the motor may not have enough power to move properly.
Also, your SMC3 calibration may be wrong. In theory, it can behave this way if it tries to move the motor too weakly and increases the PWM in steps until the motor finally moves to the desired angle...

I suggest you start with a sine wave in FlyPT Mover, and completely unload the motor - disconnect the arm. See what the motion is like. If it's smooth, the issue is definitely not cogging.
Oh, I just thought of another potential cause - somebody had an overheating problem with one of his Yalu motors and after disassembly of the gearbox saw a huge buildup of grease on the side of the gears, that made the large gears sticky. He removed it from the side and the motor stopped overheating. I guess the gears could be sticking and lead to your problem...

Thanks so much Ronan, I wasn't aware of that function in Flypt. I couldn't find ANY documentation on how to set it up however, other than the video that was posted previously here. I guess I need to start there.

I was also having the squishy sloppy motion as well, but was willing to live with it. However, now with this new problem which didn't occur before (or at least that I noticed), I just bought two of these NEMA17 motors which have a much higher ratio. They won't be here for a week though so I'll go ahead and try get get flypt to send a wave to an unloaded motor to see what I can see. Thanks again.

https://www.phidgets.com/?prodid=1080#Tab_Connection__Compatibility

Try zeroing kd. I know when I zeroed kd and ki things got ltos better and they were set to very low values.