Feedback Control System Design: Methodology
The design is an important part of engineering education. It is aimed at customer satisfaction. The design is a philosophy and as such depends on various factors. The following are various suggested steps involved in the design of feedback control systems.
1. Study the physical process or plant intended to perform the desired actions.
2. Select sensors and actuators.
3. Model the whole plant in terms of linear differential and/or difference equations.
4. Analyze the given plant for its performance in time and frequency domains (transient response, Routh-Hurwitz test, root locus, Nyquist criterion, Bode plot, Nichols chart).
5. Enumerate the performance characteristics or design specifications in both time and frequency domains, such as peak overshoot, rise time, settling time, steady state accuracy, relative stability (gain margin, phase margin, band width, and resonant peak value), disturbance rejection, and control effort.
6. List the desired design specifications or criteria in time or frequency domain.
7. Obtain phase-lag, phase-lead, lag-lead, PID, and/or state feedback design methodologies to meet the desired design specifications.
8. From the design, obtain compensator, or controller.
9. Realize or implement the controller using mechanical components or its electronic analog.
10. Finally, check the system with the controller for the given specifications. If they are not met, go to Step 7 and repeat until the design is within the required specifications or the customer is satisfied.