Adaptive tracking of non-linear dynamic plants, using the U-model

Abstract

Adaptive tracking of non-linear dynamic plants is currently an important area of research. The main difficulty being felt by the research community is the lack of a general modelling framework that can facilitate synthesis of a simplistic control law while being capable of providing accurate approximation of non-linear systems. In this study a novel technique based on the control-oriented U-model is proposed for the adaptive tracking of a wide range of stable non-linear dynamic plants using only past data. The basic scheme is based on the robust internal model control (IMC) structure. An adaptive version of the U-model is introduced for the modelling of the plant, and a simplistic control law based on polynomial root-solving is synthesized. The proposed scheme has a more general appeal than other adaptive schemes based on models such as the polynomial NARMAX (Non-linear AutoRegressive Moving Average with exogenous inputs) model. Additionally, the control law is much simpler in nature. The effectiveness of the proposed adaptive scheme is demonstrated through simulations and real-time implementation.