Solution of almost disturbance decoupling problem for nonlinear systems based on fuzzy feedback linearization control

This paper studies the output tracking and almost disturbance decoupling problem for some class of nonlinear systems via fuzzy logic control and feedback linearization approach. The main contribution of this study is to construct a controller, under appropriate conditions, such that the resulting closed-loop system enjoys for any initial condition and bounded tracking signal the following characteristics: input-to-state stability with respect to disturbance inputs and almost disturbance decoupling, i.e., the influence of disturbances on the L₂ norm of the output tracking error can be arbitrarily attenuated by increasing some adjustable parameters. The underlying theoretical approaches are the differential geometry approach and the composite Lyapunov approach. In order to demonstrate the practical applicability, the paper has investigated a ball and beam control system.