Study On Torsional Vibration Control Of A Flexible Bar Using Piezoelectric Torsional Actuator

Aiming at the active vibration control of space flexible bar and combined with the National Natural Science Foundation Project, the active torsional vibration control of a space flexible bar were investigated theoretically and experimentally in this dissertation. A piezoelectric torsional actuator was designed, and optimal placement position of the actuator/sensor was carried out using particle swarm optimization. The experimental system of the flexible bar system was founded, the simulations and experiments were carried out, the results show the proposed method of active torsional vibration control of the flexible bar system is effective and feasible.In chapter one, the research significance and background information of torsional vibration control were presented. Then the torsional sensor, torsional actuator, conventional control algorithms in active vibration control and the main research status home and abroad were all introduced. At last, the main research content of this dissertation was presented.In chapter two, the piezoelectric effect and the piezoelectric constitutive equations were presented. A piezoelectric torsional actuator was designed using axial poling method, and the output torque of the actuator was derived. The fabrication method of the piezoelectric torsional actuator was discussed. The fundamental of the strain gauge in testing torsional vibration was investigated.In chapter three, a space flexible structure consisting of a flexible bar, a piezoelectric torsional actuator and strain gauges was proposed. Aiming at the optimization placement of the actuator/sensor, the dynamic governing equation of the system was derived, and the state-space expression of the dynamic system was developed. The optimization process of the actuator/sensor was carried out using particle swarm optimization based on the optimization algorithm of maximum energy consumed.In chapter four, the use of PID control algorithm in active vibration control was discussed, the result of vibration control was reviewed. Also an active control simulation was implemented when the actuator/sensor was placed in bottom position, middle position and end position respectively. The theory of the optimization placement was confirmed by the simulation result.In chapter five, experimental system of the flexible bar was founded, and the corresponding hard ware and soft ware of the experimental system was summarized. Active vibration control research of the flexible bar system was carried out in term of PID control. The theory of the optimization placement was confirmed by the experiment result.In chapter six, some conclusions were made, and the future work was proposed.