Frequency effect on the hysteresis phenomenon and its control strategy
Date Issued
2016
Date
2016
Author(s)
Wu, Chi-Ju
Abstract
With high resolution and high dynamics response, piezo-actuator is widely used in precision position control system. However, there is nonlinear effect caused by hysteresis phenomenon between input voltage and displacement of the piezo-actuator which increase the difficulty for control, thus degrades the precision of control result. In this thesis, the nonlinearity caused by hysteresis phenomenon is decoupled with the linear mechanic system. And hysteresis compensation is implemented to linearize the hysteresis phenomenon for the sake of enhancing the control performance.Referring to the charge control structure proposed by L.S. Chen et al., it is shown that the relationship between charge flowing through the piezo-actuator and its elongation is linear. Therefore, by measuring the charge flowing through the piezo-actuator, the voltage consumption caused by the hysteresis can be obtained and the hysteresis compensator can be built to compensate the nonlinear effect. It is asserted that in this thesis that the differences of the hysteresis caused by different operating frequencies can be compensated by modifying the differences of the static hysteresis model. By this simple and fast method, the nonlinearity caused by the hysteresis phenomenon under different frequencies can be eliminated. The hysteresis compensation is only used for hysteresis linearization but not for position control. Therefore, the designs of tracking controller and hysteresis compensator are independent. While designing the tracking controller, the system can be regarded as a linear mechanic system after being compensated. By doing this, the complexity of control algorism can be reduced. For validity, a series of experiments under several frequencies are implemented in this thesis.
Subjects
piezo-actuator
hysteresis compensation
hysteresis model
Type
thesis
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