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Study On Piezoelectric Ceramic Self-sensing Actuators And The Control Method Of Micro-motion Worktable Driven By It

Posted on:2004-03-14Degree:DoctorType:Dissertation
Country:ChinaCandidate:Y G CuiFull Text:PDF
GTID:1118360122496921Subject:Mechanical and electrical engineering
Abstract/Summary:PDF Full Text Request
Piezoceramic actuator micro-positioning technology exhibits remarkable properties than other micro-positioning ones, so it is widely used. This paper employs piezoceramic actuator to a drive table to improve static and dynamic performance of the piezoceramic micro-positioning table. The following related aspects have been studied.On the basis of systematic analyses of electrostrictive effect, inverse piezoelectric effect, the displacement mechanism and displacement contribution by ferroelectric effect, the causes of hysteresis nonlinearity of piezoceramic actuators have been intensely studied from the viewpoint of rotation of ferroelectric domain and incomplete reversibility of the rotation. The results show that rotation of ferroelectric domain and incomplete reversibility of the rotation are the fundamental reason of. hysteresis nonlinearity of the piezoceramic actuator. The hysteresis nonlinearity of piezoceramic actuators under different conditions has been studied. It can be found: as the amplitude of driving voltage increases,the hysteresis and nonlinearity of the piezoceramic actuator also increase; as the frequency of drivubg voltage increases,the hysteresis and nonlinearity of the piezoceramic actuator only increase a little; with the increasing of driving repetition times,the hysteresis and nonlinearity of the piezoceramic actuator gradually decrease.Based on the similarity of the displacement-voltage curves when driving voltage increases and decreases, a method of coordinate transformation has been adopted to set up a new type of simple and applicable hysteresis nonlinearity model of piezoceramic actuator. In order to avoid solving morbid equations, the method of least squares, whose basing function are orthogonal polynomials, is used to fit the hysteresis nonlinearity modeling of the piezoceramic actuator. The experimental data show that under different amplitudes, different frequencies and different repetition times of driving voltage, the modeling can accurately track the measuring values.According to the basic piezoelectric equations, the displacement information that is contained in the free charge of the wafers of the piezoceramic actuator is deduced, and then a new piezoceramic actuator displacement self-sensing method based on integral device circuit is brought forward. It is convenient to adjust circuit and easy to acquire sensing signal. It also overcomes the difficulty of the self-sensing method based on bridge circuit. The experimental results indicate that with the conditions of the different wave forms of driving voltage, different driving frequencies anddifferent driving repetition times, the self sensing piezoceramic actuator based on integral device circuit can effectively measure displacement signal.Under the quasiostatic or low frequency conditions, we discuss the dynamic characteristics of the piezoelectric micro motion worktable, and obtain that it can be considered as the series of a first-order inertia element and a second-order surge element. We also analyze how the pre-force influence on the rigidity, natural frequency and output displacement. In order to increase the response speed of the micro piezoelectric table, two measures have been given. The first method is decreasing resistance of the limiting current resistance, preconditioning the piezoceramic actuator not to be broken-down; the second one is decreasing the mass of the movement components of the worktable, and increasing the rigidity of the double elastic parallel plank, but the integer rigidity should be kept. Also the influences of the pre-force to the worktable rigidity, the natural frequency and the output displacement have been analyzed. To maintain static and dynamic properties of the piezoelectric micro motion worktable, we choose the rational pre-force through experiments. We find the hysteresis nonlinearity model of piezoelectric micro motion worktable is similar in form to the hysteresis nonlinearity model of piezoelectric actuator without load, but its output displacement is smaller than that o...
Keywords/Search Tags:Micro-motion worktable, Piezoelectric ceramic actuators, Hysteresis nonlinearity, Hysteresis nonlinearity model, self-sensing, compound control
PDF Full Text Request
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