Computer aided control system design via low order models

In this study, the algebraic method developed by Chen and Shieh for the design of closed loop control systems, is investigated. The design method makes use of the technique for the simplification of linear system models also developed by the same authors, as well as being suitable for computer usage. The design examples originally solved in explaining the usage of the method, has been solved also by the graphical Bode design method, and the results of these, two approaches are compared. Furthermore, some design examples on the application of the Bode method selected from well known literature have been redesigned according to the investigated method and the results are also compared. As it is observed that the success of the investigated method depends on the initial design specifications as well as the effectiveness of the model simplification technique, the methods effectiweness for a modified set of design specifications is also investigated. The overall results inticate that the method applies the simplification technique to system design quite successfully although the results it produces are not as goad as those obtained via the Bode method. This originates from the fact that, in many cases, the second order models employed in the application of the method can not approximate the higher order systems with sufficient closeness.