Control of Stewart Platform Using Nonlinear H∞ Control

Control a parallel manipulator is very challenging due to high nonlinearity in systems dynamics, system uncertainties, and complex Kinematics. In this paper presents a nonlinear H∞ control approach for the control of a Stewart platform. Control of the Stewart platform is formulated into a non-linear H∞ optimization problem, namely optimal tracking performance in the presence of modeling uncertainties and external disturbances. A nonlinear H∞ controller using energy dissipation is designed in the sense of L2-gain attenuation from a disturbance to performance and it is essential to find the solution of the Hamilton Jacobi inequality (HJI). We show that the proposed control strategy has a larger domain of attraction than the linear H∞ control. Simulation results demonstrating the advantages of the nonlinear H∞ controller over the linear H∞ control are presented.

Keywords:

nonlinear H∞ control , parallel manipulator , Hamilton Jacobi inequality.