General approach to control-configured-plant (CCP) design/redesign

The performance of a multivariable control system is limited by intrinsic properties (such as right-half-plane poles/zeros and condition number) of a plant, hence a required performance of a control system is achievable only when a plant is properly designed to fit the need of a control engineer. Such a plant is sometimes referred to as an `(input-output) controllable plant´, and is referred to as a control-configured-plant (CCP) in the paper. However, due to the lack of a systematic approach, existing CCPs (such as the T2-CCV and the AO-IAF `Mohawk´ airplanes) are highly ill-conditioned with lightly damped RHP poles/zeros. As a result, it is extremely difficult to achieve a good control performance with such plants. Motivated by these facts, the paper presents a general approach to the design/redesign of a multivariable CCP, which attempts at a plant S(A,B,C) which satisfies constraints on its pole/zero locations and conditioning numbers of C(s)=C(sI-A)^-1B in a frequency range, while the H₂ norm of G(S) is maximised. An illustrative example is given to show that a CCP resulting from the present approach can achieve a much better control performance than an `ordinary´ multivariable plant