AbstractThis paper proposes three kinds of state‐feedback controllers for the nonlinear rotational and translational actuator (RTAC) benchmark problem. Interpolating a nonlinear system into an LPV system associated with time‐varying and state‐dependent weighting functions allows one to apply various linear system theories and techniques for analysing and synthesizing nonlinear systems, and thus to generate LMI criteria to supply various stabilizers and guaranteed cost controllers. This approach is more flexible for this benchmark problem than existing approaches in the literature because the other controllers excessively depend on the structure of the nonlinear system. Simulation results show the performance of the resulting controllers. Copyright © 2001 John Wiley & Sons, Ltd.