Design of linear adaptive controller for nonlinear systems

An adaptive controller is designed using disturbance accommodating control (DAC) theory. A basic comparison between this controller and an adaptive controller designed using a technique known as parametric pure feedback linearization is performed. The controller designed using parametric pure feedback linearization; requires that the nonlinear system be transformed into parametric pure feedback form. An adaptive controller designed using DAC theory is generally applicable to a broad class of nonlinear systems. Therefore it is simple to design; since it does not require feedback linearization; also it does not require transformation of the nonlinear system into any other form. DAC based linear adaptive controllers automatically compensate for uncertain plant-parameter perturbations as well as uncertain external input disturbances. It is also capable of accommodating modeling errors. The DAC based controller is entirely linear in structure, which makes it attractive from the analysis and implementation point of view.