Effects of revolute clearance joint on the dynamic behavior of a planar space arm system

Space arm system is a typical multibody mechanical system requiring high operation stability and precision connected by kinematic joints. As joint clearance is inevitable during the manufacturing and mounting process, it turns into a critical problem affecting the dynamic characteristics and kinematic accuracy of the mechanism. A space arm system deploying stably and accurately is the prerequisite to guarantee the final satellite pointing accuracy once it is into its working state. Thus, the space arm system needs to have good dynamic characteristics and stability during its deploying process and to have accurate and reliable positioning characteristics during its locking process. For the deploying process, the mathematical model of a multibody system with clearance joint has been established as a foundation to study the influence of clearance properties, including clearance size, clearance joint locations, numbers of clearance joints and lubrication on the dynamic performance and motion stability of a two-degrees-of-freedom space arm system. The mathematical model of a locking mechanism has been established to study the clearance effects on the pointing accuracy of the space arm system during its locking process. The simulation results show that, the clearance has different effects on the dynamic characteristics of the space arm system during its different working processes.