Research On Micromanipulation Technology And Experiment Based On Adhesion Control Of Compound Vibration

With micromanipulation techniques, three-dimensional MEMS devices, operating small biological objects or a mobile microrobot system can be processed and assembled by people easily to complete the appropriate practical activities. With the wide range of applications involving micromanipulation techniques to the microsystem manufacturer, micromedical, biomedical, optical and other important areas, and the characteristics size of the object are also constantly reducing. Then the scale effect caused by the size presents new challenges and demands to the microoperation methods and microdevice design. To connect micro- and macrosystem, the micromanipulation tools are key components. MEMS technology researches micromechanical systems, and can achieve very fine operations. With the rapid development of MEMS, automation technology, microrobot technology achieves corresponding development within the micro world and all-round development of microrobot for the microoperation is given.Sponsored by the National Science Fund for Distinguished Young Scholars—"Adhesion mechanism, operation and control theory and method of micro-nano-scale (project number - 50725518)"and the National Natural Science Foundation—"Research on the Mechanism and method of operation of micro-scale objects based on dynamic adhesion control (project number - 50805040)", the dissertation takes comprehensive analysis of domestic and international methods and tools based on micro-operations. Aimed at the microoperations trends and the adhesion problems in micro-scale operation, a micromanipulation method based on dynamic adhesion control is presented. Combined with MEMS technology, the driving, mechanism, measuring integrated micro manipulating tool is developed subsequently for the experimental studies. In this dissertation, an in-depth study is conducted on the aspects of operation mechanism of micro-scale and dynamic adhesion control, integrated MEMS microgripper structure design, the key process analysis and implementation method, and vibration microoperations based on compound control strategy and operating experiments.Aim at the micro-scale object manipulating and dynamic adhesion mechanism the dissertation firstly establishes dynamic adhesive contact model, and investigates generation, calculation and control methods of adhesive. Variation of micro-adhesion in the pickup and release process is analyzed. The dynamic adhesion model for the micromanipulation is established through simulation and calculation method. Based on the dynamic adhesion model, the advantages of gripping is combined to propose the compound vibration method for the micromanipulation. The relationship among vibration frequency, vibration acceleration and inertial force, adhesion force are investigated. The dissertation researches the relationship of vibration acceleration and the adhesive force. And the optimum matching relation of the vibration acceleration in the pickup and release manipulation is obtained for the dynamic adhesion control, on this basis, the precision positioning problem of released micro-scale object is analysed.In the aspects of integrated MEMS microgripper structure design, the key process analysis and implementation methods, an integrated micro-gripper is designed based on micro-structure, driving and test integrated design concept. Through the analysis of electrostatic comb drive theory, the driving part of microgripper is designed. Using the elasticity theory, the stiffness model of tilting "n" type flexible support beam is established. And the stable region is analyzed to increase the dynamic stability of microgripper. The Finite Element Analysis is used to design the key components of the structure. The amplification mechanism and the parameters of testing beam are determined through the theory of modeling and simulation method. To achieve closed-loop force feedback, the force sensors are integrated in the arms of microgripper based on the technology of sidewall piezoresistance. In order to fabricate the designed integrated microgripper, a set of process flows are brought forward and a series of important process experiments are carried out to optimize the process parameters and the process flows. A sidewall surface piezoresistive technique is proposed and Deep Reactive Ion Etching (DRIE) and ion implantation are depicted. With this process, the piezoresistor is located at the vertical sidewall surface of the testing beam to improve the sensitivity and displacement resolution of the displacement sensor.In the aspects of compound vibration microoperations strategy and operating experiments, the drive power of microgripper is studied aimed to the characteristics of electrostatic actuators. Taking into account the special requirements of microoperations, the vibration driver circuit and power detection circuit are designed. The compound vibration in the micromanipuliton is achieved by combined the microstage of piezoelectric ceramic with the vibration of microgripper. The pickup and release methods are presented through the microgripper system dynamic model and control strategy analysis.Finally the experiments system is established based on dynamic adhesion control. Firstly, the performance testing is carried out and the self-assembled modification process of hydrophobic adsorbent on the microgripper is used. Aimed to the microscale manipulation, the studies of steady pickup, effective release and accurate position are experimented with different environments and conditions, different sizes of microsamples. Contrasting the analysis and simulation results, the theory is improved further based on the experiments. Through the summary of the factors in the micromanipulation, the initiative on microoperation to avoid microscale force interference is analyzed and experimented. With the experiments, the theory and practice experience are provided for the design of micromanipulation system and the micromanipulation approach.