Abstract: Large flexible antenna arm appears obviously low frequency vibration characteristics, for its light damp and feeble rigidity, caused by large scale. Meanwhile, this vibration cannot decay fast in a short time. Traditional passive control methods are mainly using the damping material, to implement the control by increasing damping, and the control effect of vibration problems on low-frequency flexible structures is limited. The vibration suppression problem on the flexible antennas arm structure of composite material with load is researched. Piezoelectric elements are used as the transducer and actuator, respectively, by sticking on the surface of the antennas arm structure. Vibration control on antennas arm is achieved, by using piezoelectric actuator drove by adaptive semi-active control method, based on synchronous switch damping technique. Simulation and analysis on flexible antenna arm is achieved. A test platform of switch damping semi-active control on antennas arm is built, on which the control circuit is designed and manufactured. In view of the need to control the first-order bending mode of the structure, a reasonable layout of the piezoelectric elements is set up. With the vibration control test under different excitation, the results show that the method has good inhibition to the antenna arm structure with load. For the case of transient excitation of a 100 mm initial displacement, the system equivalent damping ratio rises from 0.6% to 4.03%. For the case of steady state excitation with a 50 mm amplitude, the displacement at the end of the structures after control is reduced to 10 mm. The amplitude of steady state vibration decreases 16.843 dB. It has immense application prospect in large flexible structure.

Key words: synchronous switch damping technique, adaptive semi-active control method, flexible antennas arm structure, vibration suppression