オブザーバを含む航空機の低感度パーフェクト・モデル追従制御系シンセシス

Abstract

In the design of a control system for a multivariable linear plant using the optimal control theory which minimizes a quadratic performance index, the optimal control law results in a linear combination of the state of the plant to be controlled. Although all the regulator and tracking problems which were formulated by the above procedure have the assumption that the complete state vector should be measured accurately, this assumption becomes often unrealistic. It is then required for the controller implementation to include the observers which reconstruct the state vector or find the approximation to the state vector from the observed variables.In this paper, perfect model following problems, in which the aircraft (Convair C-131 B) to be controlled follows a model aircraft (Boeing SST) satisfying a desired flying quality when angle of attack can not be measured, are discussed. The approaches employed in this study have the following two steps. The first is the design of an optimal control law for perfect model following assuming that all the state vector can be measured. The second is the synthesis of a scheme which reconstructs the unaccessible states from the measured input and output informations of the plant. Then model following controller can be implemented with on-line configurations. For the state reconstruction scheme, two approaches are considered, one is the full order observer which reconstructs all the state vector of the plant, and the other is the reduced order observer which estimates only the unaccessible state.Special considerations are given for synthesizing the observers with good response characteristics and for improving the closed-loop response of the whole system. Moreover, the problems of sensitivity reduction to the variation of plant parameters are investigated by including the integral feedback terms.Numerical computations are performed for the nontrivial aircraft flight control problem.