Study On Vibration Control Of System Of Piezoelectric Cantilever Beam

The use of flexible structures (such as the flexible beam, flexible boards, etc.) in the spacecraft is increasingly widespread. Low-stiffness characteristics of flexible structures make vibration damping very low. The structure vibration caused by a variety of reasons decays very slowly, which not only affects the spacecraft's useful life, but also results in structural fatigue damage. It is an effective way to adopt smart materials to control vibration of flexible structures in spacecraft. As the cantilever beam is a typical flexible space structure, and the piezoelectric material is currently a smart material to be used most widely, then the piezoelectric ceramics is pasted in the cantilever's surface to form a piezoelectric cantilever beam intelligent system in the paper. The piezoelectric patch is used as a self-sensing actuator in time-division decoupling method, and experiments are implemented to study active vibration control of the cantilever beam.Based on the theory of bilateral piezoelectric transducer, the principle of time-sharing approach is elaborated detailedly. According to transfer matrix of bilateral network, three equivalent circuits of piezoelectric ceramic element are derived, in which the controlled charge equivalent circuit is the main tool to analyze time-sharing approach. The piezoelectric self-sensing actuator in time-sharing approach is set, and the design of switch sequential pulse, switch circuit and the circuit of sensor signal conditioning are discussed.A piezoelectric cantilever beam system is established by pasting the PZT to the root of the cantilever beam and combining with the piezoelectric self-sensing actuator in time-division method. The natural frequency expression of the cantilever beam is derived from a modal analysis, and the theoretical value of the first-order modal frequency is calculated, which is consistent with the result of experiment.With the positive position feedback control algorithm, active control of the cantilever beam's first-order modal vibration is researched. Based on LabVIEW software platform, the virtual positive position feedback controller is designed. Active control experiments of sinusoidal excitation and free excitation vibration of the cantilever beam are conducted, which both reach better control effects. Experimental results show that the piezoelectric self-sensing actuators in time-division way can control well the cantilever beam's first-order modal vibration. In the sinusoidal excitation vibration experiments, the vibration amplitude of controlled cantilever beam reduces to 13% of the uncontrolled condition.