The Rolling Stone
A Spherical Wheel Drive Mechanism
Software, Control and Electronics
The Build
-Structure
-Friction Drive
-Tension Wheel
-Electronics
-Assembly
Software, Control and Electronics
The overall process flow to control the spherical wheel is shown above. We used a joystick to send a signal to the DSP for the desired velocity. The DSP calculated the desired actuation and sends it to the controller which then controls the motor actuation through a PWM duty cycle.
The software flow is shown above. Main.c controlled when the controller and input functions are run and holds the on/off functionality. xRCinput.c and yRCinput.c are the functions that read in from the joysticks and calculates the desired direction of actuation. This signal coming from the joystick needed to be decomposed based on signal duty cycle. The controller was a PID controller which takes in the desired direction and speed from main.c and actuates the motors to ensure smooth motion.
Electronics Wiring Diagram
The wiring diagram is how all of the chips were wired up on the bread board and the inputs and outputs lines that fed to the DSP, encoders, and H-bridges. This saved as a lot of time and confusion by planning the wiring from the beginning.