Robust backstepping control of active vibration isolation using a stewart platform

This paper focuses on deriving a robust backstepping control approach to solve the active vibration isolation problem using a Stewart platform. The dynamics of the Stewart platform driven by the linear voice coil motors is developed with the Newton-Euler method. By fully considering the characteristics of vibration isolation, the properties of the dynamics of the Stewart platform are applied to transform the coupled dynamics into six independent single-input single-output (SISO) channels. Furthermore, in the procedure of controller design, the influence factors of vibration isolation are taken into account, such as the parameter perturbation and the unmodeled dynamics, etc. Meanwhile, high-gain design method is employed to deal with the problem introduced by input unmodeled dynamics of the system. It is demonstrated that a sufficiently small L₂ gain from disturbance to output can be obtained in Lyapunov synthesis. The simulation results show that the controller can effectively attenuate low frequency vibrations in six degrees of freedom (DOFs) and a satisfactory vibration isolation performance can be achieved.