Date of Defense
Electrical and Computer Engineering
Dr. Frank Severance
Dr. John Gesink
A dual channel servo amplifier has been developed which is smaller, less costly, and simpler than similar amplifiers available on the market. The dual channel amplifier uses pulse width modulation (PWM) techniques to control the current through DC permanent magnet brush-type motors. The complexity is reduced by replacing much of the analog circuitry found in other amplifier designs with an Intel 87C196KD-20 16-bit microcontroller. This results in a significant reduction in the number of components used and provides greater flexibility in making future custom design changes. The microcontroller is fast enough and has sufficient I/O to control both amplifier channels.
Recent advances in metal oxide semiconductor field effect transistor (MOSFET) technology make it possible to use fewer MOSFETs than other amplifiers presently use. Combining this with integrated circuit MOSFET driver circuitry, a reduction in component count results in the output section as well.
Only essential features are implemented in the dual channel amplifier. The amplifier operates in "current mode" only, i.e., the input command controls the current through the motor. Position or velocity feedback is returned to the host controller.
By combining these features in the dual channel amplifier, a 70 % to 83 % reduction in the number of components used over two similar single channel amplifiers is realized. The cost is reduced by 19 % to 38 %. Finally, the physical volume of the dual channel amplifier is reduced by 50 % to 83 %.
These results are accomplished without sacrificing other performance aspects. The dual channel amplifier's performance characteristics are similar to competing amplifiers. This makes it possible for manufacturers of automated guided vehicles and other similar electric vehicles to package vehicle electronics into smaller spaces and remain competitive.
Jansen, Douglas; Venero, José; and Jang, Chyuan-Horng, "Microcontroller Based Dual Channel Servo Amplifier" (1996). Honors Theses. 1564.
Honors Thesis-Campus Only