Analytical and experimental studies on active vibration control of flexible thin-walled structure using multi-layer planar dielectric elastomer actuator

A multi-layer planar dielectric elastomer actuator (MPDEA), which contains multiple identical DE film actuators superimposed layer by layer, is proposed to realize active vibration control of flexible thin-walled structure in low driving voltage. To reveal theoretically the mechanism of driving capability enhancement for MPDEA and the effect of MPDEA on control voltage reduction and then facilitate control system design, an electromechanical coupling analytical model of flexible thin-walled plate structure with MPDEA is established based on the thermodynamic theory of dielectric elastomer and the constitutive relations of plate structure. Moreover, a nonlinear compensation model is proposed and combined with the proportional-derivative control algorithm in control strategy design to attenuate the frequency doubling force component resulting from nonlinear actuating force characteristics of MPDEA, which may cause control spillover and deteriorate distinctly overall control performance. Finally, simulated and experimental studies are conducted on the active vibration control of flexible thin-walled polycarbonate plate using MPDEAs with different layers. The experimental results are pretty consistent with the simulated results, which demonstrate the accuracy of the established analytical model for the control system and the effectiveness of the proposed control strategy. The vibrations of the flexible thin-walled polycarbonate plate under harmonic excitations are significantly suppressed under the control of MPDEA. The control spillovers caused by the frequency doubling force component of MPDEA are also entirely eliminated through the nonlinear compensation. More importantly, it is proved that MPDEA is effective in reducing control voltage, e.g. a three-layer MPDEA can decrease control voltage by 57.95 % in comparison with a single-layer planar dielectric elastomer actuator. This merit will greatly reduce the risk of electric breakdown of MPDEA and significantly improve reliability of flexible thin-walled structure vibration control system.