Research On The Active-passive Hybrid Vibration Control Using Negative Capacitance Branch Circuit

The negative capacitance controller uses a negative capacitance to counteract the capacitance ofthe piezoelectric patch. So the control effect is not associated with frequency, and less vulnerable toexternal interference. The multiple modal can be controled using a piezoelectric patch. It brings greatconvenience for the engineering application. Active-passive hybrid control is a novel control strategywhich is the comprehensive utilization of passive control and active control. In the active-passivehybrid control, the active control system and passive damping system are integrated with the samesystem, which can make the active control and passive control complement each other.In the paper, the relation of the circuit parameters of the piezoelectric vibration damping systemwith a negative capacitance circuit with the stability and vibration amplitude of system is studied. Inorder to solve their problems, the two active-passive hybrid control method are proposed, which canmake up the shortage of the negative capacitance piezoelectric damping method in vibration control.Considering the practical application, the active-passive hybrid control methods are deeply studied.The active-passive hybrid control method based on the negative capacitance piezoelectric shuntdamping circuit and the wavelet transform adaptive algorithm is proposed, which can improve theadaptive ability of the system. In order to make the negative capacitance circuit be better applied, theactive-passive hybrid control method is further studied. The equivalent circuit of the negativecapacitance is redesigned based on the charge equivalent. The active-passive hybrid control methodbased on the voltage controlled charge source and the wavelet transform adaptive algorithm isproposed.The main works and novel researched performed in this dissertation include:(1) The piezoelectric shunt damping model is establised based on the piezoelectric materialcharacteristics. The control principle of the piezoelectric shunt damping passive vibration controlsystem using a negative capacitance circuit is described, and the parameters of the negativecapacitance shunt circuit on the system damping effect is analyzed.(2) In the piezoelectric vibration damping system with a negative capacitance circuit, the negativecapacitance is used to counteract the capacitance of the piezoelectric patch. In theory, the controleffect is better when the negative capacitance is closer to the capacitance of the piezoelectricpatch. But experiments show that the piezoelectric vibration damping system with a negativecapacitance circuit will become unstable when the negative capacitance is smaller or slightly larger than the capacitance of the piezoelectric patch. Aiming at this problem, the stability of thepiezoelectric shunt damping vibration system with a negative capacitance or an inductancecircuit is analyzed and compared on the basis of the feedback control theory in the paper. Inorder to improve the stability of piezoelectric shunt damping vibration system with a negativecapacitance circuit, an active-passive hybrid control method is proposed. And the validity of thismethod is verified by the theory and experimental results.(5) The relation between the vibration amplitude of the negative capacitance shunt damping ofpiezoelectric vibration control system and the circuit parameters of the negative capacitancecontroller is derived. To optimize circuit parameters of the controller, an active-passive hybridcontrol method is proposed, which can transform the adjustive problem of the negativecapacitance circuit parameters to the active control algorithm. The paper gives the controlprinciple of the active-passive control method. And the theoretical simulation and experimentalresults prove the validity of this method.(4) In the active piezoelectric vibration control fields, LMS algorithm does exist slow convergencespeed and appear even to diffuse condition. Combining the Wavelets and LMS algorithm, thepaper does adaptive vibration control to sheet metal using decomposition LMS algorithm. Inorder to realize the real-time of Wavelets adaptive algorithm, the fast MALLAT algorithm is usedin the paper. Finally, the theoretical simulation and experimental results prove the validity of thismethod.(5) Considering the practical application, the active-passive hybrid control methods based on thenegative capacitance piezoelectric shunt damping circuit is deeply studied. Combining the activevibration control based on the LMS algorithm in the wavelet transform domain, the new methodwhich is the active-passive hybrid control method based on the negative capacitancepiezoelectric shunt damping circuit and the wavelet transform adaptive algorithm is proposed.The method can well solve the problem of the active controller parameters need to be adjustedmanually in the aforementioned active-passive hybrid control method. In this paper, according tothe Hamilton principle, the mathematical model of the active-passive hybrid control is deduced.And the relation of the negative capacitance with the passive control effect and the active controlvoltage is analysed. Finally, the theoretical simulation and experimental results prove the validityof this method.(6) The active-passive hybrid control method based on the negative capacitance piezoelectric shuntdamping circuit is further studied. According to the equivalent circuit of piezoelectric film, the equivalent circuit of the negative capacitance is redesigned.The circuit is a voltage controlledcharge source. Its output is charge which is used to offset the charge of the piezoelectric patch.Its input is the control voltage.In order to make the negative capacitance circuit be better applied,The new active-passive hybrid control method based on the voltage controlled charge source andthe wavelet transform adaptive algorithm is proposed. Firstly, the voltage controlled chargesource is designed according to the equivalent circuit of piezoelectric film, and the principle ofthe active-passive control method is described detailedly. Finally, in order to verify the proposedactive-passive method, the experimental platform which is an alloy rectangular thin plateclamped with stiff base is set-up using the dSPACE real-time simulation system and the elementsof analog circuit and piezoelectric. The active-passive method experiment is carried in sinusoidaland white noise excitation. The experimental results show the proposed control method not onlycan suppress effectively the single mode and multimode vibration produced by sinusoidal signal,and also can suppress effectively the vibration produced by white noise signal. The experimentalresults prove that the proposed method is feasible and superior.