A novel internal model control scheme for adaptive tracking of nonlinear dynamic plants

Adaptive tracking of nonlinear dynamic plants is presently an active area of research. The design of on-line nonlinear controller for tracking of nonlinear plants has always been an inevitable computationally complex procedure. In this paper a novel method to facilitate controller design for output tracking of wide range of nonlinear plants based on a new control oriented model known as U-model is presented. The use of U-model alleviates the computational complexity of on-line nonlinear controller design that arises when using other modelling frame works such as NAR-MAX model. The U-model utilizes only past data for plant modelling and standard root solving algorithm for control law formulation. The control structure of the scheme contains two feedback loops. The inner-loop, where inverse of the plant is developed based on adaptive U-model. Outer-loop, which is designed using linear control theory to improve tracking and disturbance rejection properties of the overall system. The effectiveness of the proposed scheme is illustrated by simulating a nonlinear plant and by real-time speed control of a laboratory scale DC motor.