Elimination of position-dependent disturbances in constant-speed-rotation control systems - a nonlinear compensation approach

To eliminate position-dependent disturbances in a constant-speed-rotation system, we have proposed a very effective approach that introduces a new concept called the “position domain”. However, because the position domain model of a linear plant is in fact nonlinear, a linear control strategy may not meet the design requirements. To solve this problem, this paper proposes a nonlinear compensation approach. The procedure for designing a control system comprises two steps. First, an input-output linearization approach is used to linearize the input-output characteristics of the nonlinear plant in the position domain. Then, a repetitive controller is designed for the linearized plant to ensure good performance