A Firmware Voltage Controller for a Robotic Arm

Educational table-top robotic arms are used for robotics instruction at many colleges and universities. One of the most popular educational robots is the Rhino XR-2, a five-axis articulated coordinate robotic manipulator which features closed-loop feedback control with dc servomotors and optical encoders. This paper describes some enhancements to the XR-2 controller, including a global form of speed control that is obtained through pulse-width modulation of the applied motor voltage. No changes to the original controller hardware are needed to implement the new features. Instead, the expanded command set is added by simply replacing the Intel 8748 controller chip with one containing new firmware.