Multi-axial dynamic structural testing system and its control strategies

A high-performance 3 Degrees of Freedom Dynamic Structural Testing System (3DOFs testing system) which is mainly built with MTS servo-hydraulic system was developed. Its prominent advantages are accurate control and comprehensive function. A two-loop feedback control strategy was introduced and extended to multiple actuators' coupled control. To demonstrate the performance of the proposed testing system and control strategies, a full-scale steel column was taken as a test specimen. It is concluded that, by using the coupled control strategy, the testing system can perform perfectly in quasi-static test, vertical force can be kept constant, and shear-mode loading can be achieved simultaneously. Furthermore, by applying α-OS method in hybrid test, it is proved that the 3DOFs testing system can accurately simulate the complex boundary conditions of column substructure, and the harmonious loading of multiple actuators can be successfully implemented. The results may give references to further studies on multi-axial testing system.