DYNAMIC ANALYSIS OF FLEXIBLE TRUSS WITH CLEARANCE JOINTS AND VIBRATION CONTROL BASED ON PIEZOELECTRIC ACTIVE STRUT

In this paper, a rigid-flexible coupling model of the truss with clearance joints in post-lock phase is established based on the finite element method and multi-body dynamics theory. The impact force model and the modified friction model are developed to describe the dynamic behavior of clearance joint. In order to simulate the real condition of post-locked phase, a stiffness-damper spring with pretightening force is applied to simulate the deployment cable. Furthermore, the influences of clearance size and friction coefficient on the dynamic characteristics of the truss are analyzed, and study the effects of a pulse disturbance. The results show that the degree of equilibrium position deviation has little effect on the dynamic characteristics of the truss structure, and the greater the friction coefficient of the joint will cause the faster the vibration attenuation speed of the truss. Finally, to suppression the vibrations caused by the pulse disturbance, a piezoelectric stack actuator is embedded into one flexible rod of the truss to form the piezoelectric active strut, and a controller is designed to control the truss vibration, which is quickly suppressed by axial force of the piezoelectric active strut.