Configuration Design and Mobility Analysis of the Scissors Overconstrained Double-Ring Truss Deployable Antenna Mechanism

Based on the overconstrained scissors mechanism unit, a scissors overconstrained double-ring truss deployable antenna mechanism is constructed as a support mechanism for the satellite antenna. Firstly, the configuration mechanism and overconstraint characteristics of the scissors overconstrained double-ring truss mechanism are analyzed, and the units of the whole truss mechanism are decomposed. Then, the geometric conditions for the ring structure of the scissors overconstrained double-ring truss mechanism are derived in consideration of the effects of joint size. Furthermore, the screw constraint topology of the decomposed mechanism units is drawn based on the graph theory and screw theory, and the mobilities of the closed-loop deployable mechanism unit and the double-ring truss mechanism are analyzed. The result shows that the mobility of the whole double-ring truss mechanism is the same as that of the closed-loop deployable mechanism, with only one mobility. Finally, a simulation model of the double-ring truss deployable antenna mechanism is built, the deploying process of the whole double-ring truss is simulated, and the deployable feature is verified. The proposed scissors overconstrained double-ring truss deployable antenna mechanism has only one mobility, its kinematic joints are all revolute joints, and the movement form is simple.