Kinematic and dynamic characteristics' analysis of a scissor multi-rod ring deployable mechanism

In this paper, the authors developed a double-layer ring truss deployable antenna mechanism (RTDAM) based on a scissor unit, which can be used as the deployment and support mechanism in large-aperture satellite antenna. Firstly, three configuration state diagrams of the scissor multi-rod RTDAM were displayed: folded, half-deployed, and deployed. The mechanism was decomposed into a closed-ring deployable mechanism unit and several non-closed-ring deployable mechanism units. The screw constraint topological diagram of the closed-ring deployable mechanism unit was drawn, and the number of degrees of freedom (DOFs) was calculated via the screw theory method. Then, the expressions for screw velocity and screw acceleration of each component in the resultant mechanism were analyzed, calculated, and solved. The screw velocity and screw acceleration of each component were obtained, and the six-dimensional velocity and acceleration of each component were obtained through screw conversion and recursion. Finally, using the Newton-Euler equation and virtual work principle, the dynamic equation of the RTDAM with an integral scissor multi-rod ring truss mechanism was established, and the theoretical analysis was validated through numerical calculation and simulation results. The RTDAM of the scissor multi-rod ring truss proposed in this paper has a single DOF and can be well applied to the large-aperture satellite antenna.