Mobility Analysis of Space Deployable Truss Considering Joint Clearance and Friction

Truss is an important component in the spacecraft system, its smooth deployment is significant to ensure the normal operation of the spacecraft. The parts in truss are connected by joints and clearance inevitably exists in joints. As the scale of truss structure expands, the number of joints in truss increases, resulting clearance having significant effect on the mobility of the truss, then influencing the operation of spacecraft. Firstly, in this paper, the multi-rigid-body Cartesian method is adopted to establish the deployment dynamics model of truss system with ideal joint. Then we establish contact dynamics model for clearance joint, obtaining normal contact force and tangential friction force by applying Hertz contact theory and Coulomb friction model, respectively. Finally, the effects of clearance, driving force and friction force on the mobility of truss system are analyzed by numerical simulations. The simulation results show that, the reduction of joint clearance and driving force, and the increase of joint friction both decrease the mobility of truss system.