Time Response of Control Systems

No Thumbnail Available
Mustafa, Murtada Babiker
Journal Title
Journal ISSN
Volume Title
Historically the design of linear control systems was developed with a wealth of graphical tools such as Bode plot, Nyquist plot, gain-phase plot, and Nichols chart, which are all carried out in the frequency domain. The advantage of these tools is that they can all be sketched by following approximation methods without detailed plotting. There for, the designer can carry out designs using frequency domain specifications such as gain margin, phase margin, and so on. High-order systems generally do not pose any particular problem. For certain types of controller design procedures in the frequency domain are available which reduce the trial-and-error effort to a minimum. Design in the time domain using such performance specifications as rise time, delay time, settling time, maximum overshoot, and so on, is feasible analytically only for second-order systems, or systems that can be approximated by second-order systems. General design procedures using time-domain specifications are difficult to establish for systems with order higher than the second. The development and availability of high-powered and user-friendly computer software is rapidly changing the practice of control system design. With modern computer software tools, the designer can go through a large number of design runs using the time-domain specifications within a matter of minutes. State equations have the ability to represent linear and nonlinear control system with constant coefficients and those varying with time. Analysis in the frequency domain depends on the Laplace transform, which is capable of representing only linear time invariant systems. Since differential equations representing nonlinear-time variant systems are very difficult to solve analytically, we need a powerful tool to solve them, numerically. (MATLAB offers this tool). Thus the system (Linear time invariant, nonlinear time invariant, linear time varying, nonlinear time varying) response in the time domain can be obtained. Discrete systems can also be analyzed.
Time,Response, Control,Systems