Computer aided laboratory in digital control

The availability of powerful PCs, and PC based computer aided control system design (CACSD) software packages such as MATLAB has enhanced the development of creative student centered learning activities in control system courses. This paper discusses a sequence of exercises that have been developed and used by the author for teaching an undergraduate course in digital control. At the outset of the course, an exercise involving time-domain analysis and simulation of a dc servomotor positioning system incorporating a digital controller is used as a vehicle to demonstrate the main features and limitations of digital control systems. A second exercise exposes students to digital controller hardware and programming; students develop and implement a PID control algorithm on a PC equipped with an inexpensive analog I/O interface board. This set up is later used as the controller of a bench-scale dc servomotor positioning system. The integrated approach ties together the various aspects of digital control system modeling, analysis, controller design, verification by instrumentation, programming, and finally, system implementation.