Active control of structural vibration transmission from a vibrating rigid body to a flexible panel using two active mounts

摘要

Several different active control strategies have been studied for the reduction of structural power transmission from a rigid source to a receiver via a number of active mounts. In particular the effects have been analysed of transducer errors and the problems created by the presence of an uncontrolled flanking excitation acting on the receiver. The effects of minimising the total power transmitted to the receiver through the mounts have been compared with more practical control strategies at the junctions connecting the mounts to the plate: (a) the cancellation of out-of-plane velocities, (b) the cancellation of out-of-plane forces, (c) the cancellation of the power due only to the out-of-plane velocities and forces and (d) the minimisation of out-of-plane velocities and forces. The control of total power gives the best results under ideal conditions, but for realistic cases, characterised by measurement errors and flanking paths, the cancellation of velocity or force is more effective than the active control of measured power. The minimisation of the sum of squared out-of-plane velocities and weighted sum of squared forces gives a particularly interesting result since the efficacy of the isolation is almost equal to the total power minimisation control strategy and this performance is not sensitive to measurement errors or flanking paths. Finally two alternative configurations for the velocity cancellation strategy have been analysed: first, the minimisation of out-of-plane velocities and transverse velocity measured respectively at the receiver junctions and at the rigid source; second, the cancellation of out-of-plane velocities measured at two positions of each receiver junction. The first of these strategies performs particularly well when the rigid body modes of the isolator are excited while the second ameliorate the control when the first few modes of the receiver system are excited. However the benefit produced in both cases are not as good as the performance achieved by controlling the sum of squared velocities and forces.