ABSTRACT
The design objective is to guarantee that TR(s) = Y(syR(s) and TD(s)=Y(s)/D(s) are members of the sets of acceptable 3R and 3D, respectively, for all P e £?and all D e 3). In a feedback system, the principal challenge in the control system design is to relate the system performance specifications to the requirements on the loop transmission function L(s) = G(s)P(s) in order to achieve the desired benefits of feedback, i.e., the desired reduction in sensitivity to plant uncertainty and desired disturbance attenuation. The advantage of the frequency domain is that L(s) = G(s)P(s) is simply the multiplication of complex numbers. In the frequency domain it is possible to evaluate L<JOJ) at every coi separately, and thus, at each «$, the optimal bounds on L(J(o,) can be determined
3-3 DESIGN PROCEDURE OUTLINE
The basic design procedure which is to be followed in applying the QFT robust design technique is outlined in this section. This outline enables the reader to obtain an overall perspective of the QFT technique at the onset. The following sec-
lions present a detailed discussion which is intended to establish for the reader a firm understanding of the fundamentals of this technique.
