Thanks for the reply! This helps a lot with my understanding and makes a lot of sense why it was developed this way. I happen to have some CUI absolute encoders lying around from another robotics project - I may look into implementing these as well to maintain a closed loop through power cycles that could potentially negate the need for limit switches.

Was able to fix the hole with some sealing heat shrink, and now I've got a pressure holding system. Time for some programming!

I was able to get it to work with some messing around - turns out I didn't push the tubes past the o-rings. My first time working with pneumatics, so definitely educational! Also for the silicone tubes, I had to add a few wraps of teflon to get a seal to hold. After all this, found out there was a tiny hole in one of my tubes at the robot control box end :( so I'll have to figure out a good way to seal that. Hoping I don't have to rewire everything!

Update 3 :) Using AR4 software for calibration and movement right now, will be using Python ROS (https://github.com/ongdexter/ar3_core) and klampt (http://motion.cs.illinois.edu/software/klampt/latest/pyklampt_docs/) for control in the next month. Hope to show you some ex vivo surgical studies in the next couple months!

Figured out the problem. Thought the NEMA 17 motors were the same - found out I swapped the HG10 and HG50. Will swap and rewire, then update later today.

update 2 - turns out I didn't switch from 24V on the stepper drives. All axes are working now! Though I noticed that J3 seems to be too weak - and skips steps on upward motion, causing the arm to droop and collapse. There is nothing other than the pneumatic actuator attached to the effector- so I'm curious if I have a defective NEMA 17?

update - so I updated the wiring to include ENA+ and ENA-, and performing the calibration test works only on J4. I am able to jog J4 normally as well. Will continue digging to see if I can find a problem, but right now my thoughts are that the stepper drivers are the main problem.

Just realized now, ENA+ and ENA- are not wired, since I was still following the AR3 manual. Will jumper those in and see if it works!

Hi @Chris Annin, finally had some time away from school to work on the "AR3.5" project, and am currently in a holdup. I'm using a mega 2560 with the teensy 4.1, and as of now, none of the motors jog, though they all are receiving power and remain "rigid" when the steppers turn on. I've been checking through my wiring, unable to find a problem yet. I may remake my wiring harness for the pul+/dir+ if all else fails, but I'm curious if you think there might be an obvious problem I'm overlooking. I was able to put everything else together, and the encoders/limit switches test programs work great. Please let me know if you have any insights! Al