CoAxial Wheeled Balancing Robot
My other holy grail. The co-axial wheeled balancing robot. I've tried this several times. I didn't alwasy keep a photographic record, but here's one of my earlier ones. (And probably the one which came closest to working.)
Here is it stripped down. The two MFA motors are brilliant with their built in gearboxes, but they ain't cheap. Thay also work from an irritating 18V, so I controlled them by 3/4 PWM from a pair of 12V home alarm system batteries.
The two M8 threaded rods show how high up the centre of balance the batteries were located.
The chassis is made from bent sheet aluminium.
In the second photo, it has the PCBs and wheels added. There are two 2-layer PCBs here. One is teh MCU (the brains) and the other is the motor controller (298D based). As always, my PCBs are home-made. (Yes, fritzl, walkthrough to follow.)
At the bottom left of the PCBs ( at the top right of the leftmost tyre) you can see the accelerometer and gyroscope.
The accelerometer is one I speak about in http://letsmakerobots.com/node/100 and theComponentsentry for the R/C helicopter gyro will follow.
Since it never really balanced on its own (I think there was too much backlash in the drive train) I'm not sure if "completed" is the word I'd use, but I'm done with this version.