Active Vibration Control Of A Simplified Platefrom Vehicle Body Structure Based On Magnetostrictive Actuator

Vehicle vibration always overlaps with noise in transmission paths. When vibration frequency couples with the Eigen frequency of the interior acoustic cavity, booming noise will occur inside of the cabin. Through vibration control, not only can vibration be suppressed, but also the caused low frequency radiated noise is reduced in addition. Active vibration control overcomes the shortage of passive control, rendering a method for engineers about low frequency vibration control. Actuators based on giant magnetostrictive material own such advantages as rapid response and large strain stroke, offering a large opportunity for active vibration control.A ceiling plate structure is researched in this article. The ceiling structure is simplified as a clamped rectangular plate according to its installation conditions and the key contents. Then active vibration control of the clamped rectangular plate is studied based on magnetotrictive actuator. Important parameters are optimized from the actuator mechanism, by which magnetic field intensity is analyzed and actuating model is established. The coupling vibration model between rectangular plate and actuator is set up through finite element method when the validity of the finite element program is verified from comparison between analytical solution and numeric results. In actual engineering, rotational freedoms are ignored as lateral bending vibration is the main factor of plate vibration. So rotational freedoms are condensed to lateral displacement by static condensation method, and the natural vibration is calculated. A combined optimization criteria for locations of actuators/sensors is proposed by comprehensively considering energy and structural modal response amplitude of the plate. The optimal location for one patch of actuator/sensor is optimized in Genetic algorithm. Precision and main dynamic characteristics can be kept when inner balanced method is used for model reduction. The system is truncated according to modal controllability and observability in the inner balanced space. Comprehensive optimal characteristics are obtained from optimal control as considering both structural response and actuator control current at the same time. Under engine idle excitation and pavement unevenness excitation, spectrum and time response are calculated in closed loop control system. The efficiency of active vibration control is proved apparent after response contrast between control system and un-control system.