Study on Improving the Dead Zone Character of Electro-Hydraulic Servo System with Dither

A novel approach to improve the character of nonlinearity is proposed with adding dither signal which has high frequency and small amplitude. The mathematics model of the dither signal effect on dead zone element is established using the equivalent gain, the principle how to eliminate dead zone is discussed particularly. A simulation example of electro-hydraulic servo vibration table is implemented, and the result demonstrates that the dither signal can eliminate dead zone effectively, enhance the control character obviously, and this study has practical significance in engineering.