Study On The Modeling And Control Strategy Of Cell-Manipulation Micro-Stage Base On Piezo Actuator

With the development of the modern biomedical engineering, many cellular level manipulations such as cells isolating, capturing, microdissecting and microinjecting must be done by micromanipulator. The micro-stage which as the supporting table of microgripper, microinjector and culture dish and its displacement range, resolution and kinematic accuracy are the important factors effect the success of cell-manipulation.According to the characteristics and requirements of cell-manipulation, the micro-stage should have the characteristic of large stroke to millimeter and the displacement resolution to micron or submicron. Therefore, a large stroke two-dimension integrated micro-stage was established by employing piezo actuator as the driving component and the nested structure of amplification and parallel guiding mechanism. Then the dynamic hysteresis model of micro-stage was established and the experiments about the control strategy were performed. The experimental results proved that the large stroke two-dimension integrated micro-stage has the displacement of millimeter and the resolution reached to submicron, those features could meet the requirements of cell-manipulation.The displacement resolution and kinematic accuracy of piezo actuator are the most important factors which influence the output displacement performance of micro-stage. Then this dissertation analyzed the effect of capacitive load to driving power supply based on the load characteristic of piezo actuator and derived that the equivalent capacitance of piezo actuator can lead to phase lag even oscillation of the driving system. For this, a bridge type driving circuit was designed based on high voltage operational amplifier. Meanwhile, a lead lag controller was applied to corrected the frequency characteristic of the capacitive load system and obtain the better static and dynamic performance.Because the output displacement of piezo actuator could not meet the requirements of cell-manipulation, the right angle flexure hinge was adopted as transmission section based on the analysis of displacement and mechanical performance to various type flexure hinges. The effect of geometric parameters to kinetic and mechanical performance of bridge type amplification and U-type parallel guiding mechanism were studied. Then a large stroke two-dimension integrated micro-stage was established based on bridge type amplification and U-type parallel guiding mechanism with the nested structure. The output displacement and stress concentration characteristics were analyzed. Finally, the dynamic model of micro-stage was established and verified by the finite element method and experiment.of cell-manipulation because of the random motion of micro-stage according to the operation requirements. However, the different voltage regulation can lead to the change of hysteresis characteristic of the micro-stage. And the static modeling method based on Preisach-type model did not describe this dynamic hysteresis phenomenon. So the neural network identification theory was introduced into and a dynamic hysteresis model was established based on the morphological of turning point, rising and falling of multi-loop hysteresis curve proposed by Preisach model. Then, the generalization ability of the dynamic model was verified by experiments.The control performance of micro-stage was tested by experiments base on its dynamic hysteresis characteristic. Then the control performance for step response and sine response was studied by employing the dynamic hysteresis inverse model, classical PID and the neural network adaptive PID control strategy. Finally, the random displacement tracking performance was compared by employing different control method.There are 125 figures, 7 tables and 153 references in the dissertation.