A New Control Algorithm for Hydraulic Universal Testing Machine Based on Extenics

The purpose of this study is to investigate a new control algorithm for hydraulic universal testing machine based on extenics. As the variable stiffness of testing specimen affects load stiffness, the theoretical analysis and simulation study of the effect of variable load stiffness on the system were investigated. The degree and tendency of the effect of variable load stiffness on the control quality and accuracy are given. Furthermore, a new extension control algorithm for hydraulic universal testing machine was presented in this paper. The results show that this new control strategy can solve the problems of variable structure parameters of hydraulic universal testing machine, and can realize switch smoothly in variable control modes.