gain scheduling observer based control design with guaranteed stability and h∞ performance consideration

this paper proposes a new method of gain scheduling control design for a nonlinear system which is described as linear parameter varying form. a performance measure based on linear matrix inequality is introduced. to consider stability and performance measures in design process, the h∞ loop-shaping method is used to design the local controllers, which can be described as state feedback observer based structure. by introducing the stability and performance covering condition for the linear parameter varying system, a new interpolation law is proposed, and it is proofed that the resultant controller can preserve the performance measure for the observer based structure for all values of the scheduling parameter. also the closed loop stability is guaranteed. the method is successfully applied on the control of a well-known benchmark system, namely, the autopilot for a pitch-axis model of an air vehicle. the performance and effectiveness is evaluated against disturbances and parameter uncertainties using computer simulation.