Kinematics and dynamics characteristics analysis of a double-ring truss deployable mechanism based on rectangular scissors unit

In order to improve the low structural strength of single-ring truss deployable mechanism with large aperture, a double-ring truss deployable mechanism (DRTDM) based on rectangular scissors unit is proposed, which has higher utilization rate and aperture expansion rate. First, the configuration of proposed DRTDM is analyzed and the size relationships between the components are derived. Then, the degree of freedom (DOF) of DRTDM is analyzed based on screw theory, and the results show that DRTDM has only one DOF. Through the displacement vector method and screw constraint topology, the velocity, acceleration and angular velocity of each component are obtained. Additionally, a dynamics model of the whole DRTDM is established based on Lagrange equation. Finally, above conclusions are verified by ADMAS simulation and the mobility of DRTDM is verified by the principle prototype. The DRTDM proposed in this paper provides a theoretical reference for the research and design of spatial deployable mechanism, and has potential value in the application of large aperture deployable mechanism.