Computer-aided design of classical linear compensators with application to aerospace

A new Matlab function based on a versatile compensator design approach is developed. This function allows design of lead-lag, PID, proportional plus rate feedback, proportional-integral plus rate feedback, and nth order linear compensators. The primary inputs to this function are the plant transfer function and the desired closedloop behavior in terms of an nth order transfer function. The output is the particular compensator parameters. The unified design approach is primarily based on minimizing a mean-squared error type objective function. This minimization gives the compensator parameters in terms of a set of linear simultaneous algebraic equations. This solution method requires the user to input such parameters as the lower and upper limits of frequency range of interest; such parameters are automatically determined by the use of numerical optimization. The design method and the associated software are demonstrated by solving a flexible satellite problem, and the results are compared with those obtained by two other methods reported in the open literatures.