Adaptive nonlinear gain based composite nonlinear feedback controller with input saturation

Abstract

This article proposes for the first time a novel adaptive nonlinear gain based composite feedback controller. In the proposed method an adaptive nonlinear gain is introduced in the composite feedback controller to improve the system dynamic response. Using the Lyapunov analysis and the adaptive law for the nonlinear gain, it is shown that all the closed loop signals of the system are bounded. Finally, we use a double integrator single-input single-output system and twin rotor multi-input multi-output (MIMO) system to demonstrate the application of the proposed scheme. In both the applications, the improvement in settling time and root mean square error is scalable by the adaptive nonlinear gain based composite feedback control. Further the controller is successfully tested for a set of desired set points for MIMO system example which will create large initial errors.