I have some ideas on how to resolve this in the future, but for 2016 my solution was to get the students off to a good start and then turn the show over to some of my kids from the high school FIRST robotics group. Its good to have Minions after all.
Progress on the last day of my nominal supervision:
We had the basic drive system running a week earlier. It is touchy, hope the kids can drive without crashing.
Arms are tricky. The best system mimics nature, with the linear actuator providing pull akin to a muscle, and the yellow towing strap being like a tendon. This is a "shoulder joint".
Here is an "elbow joint". This was a bit fussy, the actuator has to be perfectly lined up. And like a real elbow you should not hyper extend it. The metal part of the joint comes from a power wheel chair that was donated for our use almost 15 years ago. I keep reusing the parts again and again.
My goal for my last session with them was to have the robot wave good bye to me under radio control. We did not quite manage it but the joints do all work, they just need to be attached to their electronics. Running it straight off the batteries I did get a feeble salute:
My high school helpers will have three weeks to get the younger kids to finish off some power connections and a candy dispenser. They might pull it off, they might not. Sometimes kids learn more with less adult input, and can get as smart by seeing what does not work as by seeing what does.
I left the robot assembled but not fully powered, lurking in its storage closet. I hope it provides a few unexpected surprises for people who come across it unawares.