Analysis And Control Of Expansion Process For Hoop Truss Deployable Antenna

Various structural concepts have been proposed for space-borne large deployable antennas. Considering the stringent requirements on surface performance of a antennas to serve signal with high accuracy and high resolution, a large sized deployable antennas with wide frequency band width were in urgent demand. Since the synthesized performance, such as, large contract rate, light quality, large caliber and band width, and stable work performance, the hoop truss deployable antenna played an important role in deployable antennas.Based on hoop truss deployable antenna, a systematic methodology for analyzing and controlling the expansion process of the antenna was presented. Joint specific structure of truss element was considered exactly, especially the influence of parameters of pulleys in the expansion process of the system. Based on the kinematic relations between each node and expansion angle, a precise methodology for calculating the length of the rope in the system during the expansion process was proposed, which can be applied to a general rope-pulley system. Moreover, we also found the relations between the driving speed of the motor and the expansion angular velocity of the system, so that the expansion speed of the system can be controlled according to the design of the driving speed of the motor. Besides, based on practice, we modified the expansion angular velocity, so that the intermittent of the angular acceleration was eliminated, and the movement of each node and the driving force was calculated. Numerical examples prove the validity of the method, and the expansion process of hoop truss deployable antenna was simulated.