Mechanical Design And Control Method Of The Compliant Tip-tilt Micropositioning Stage

The micropositioning and the micromanipulation systems are one of the fundamental parts of many advanced instruments and equipment,in which the mechanisms that can realize motions with ultra-high resolution and accuracy are the key components.The tip-tilt type micropositioning stages can realize precise pointing and alignment which is essential in the area of semiconductor manufacturing,laser engineering,quantum electronics,micro assemblage and optical microscope,etc.In recent years,the tip-tilt stages are requiring a resolution and accuracy of micrometer level,hence the flexure-based compliant mechanisms have become one of the main path for developing such precise equipment.Thanks to the support of NSFC and the Scientific and Technological Project of Jiangsu Province,aiming at improving the accuracy and stability of the tip-tilt type micropositioning stage,a novel type of flexure hinge has been developed,the displacement amplification mechanisms have been optimized,the modular design method of the tip-tilt stage based on the planar compliant mechanisms has been studied,then the static and dynamic modelling methods have been focused on,the control system for the tip-tilt type micropositioning stage has been established,the method of decoupled control and hysteresis compensation has been examined,the precise positioning control of the tip-tilt stage has been finally accomplished.The main topics in this dissertation can been concluded as:1.The modular design and development technique for the compliant tip-tilt type micropositioning stage utilizing the planar compliant mechanisms have been investigated.By utilizing the strip type and curved type flexure elements with rectangular cross-section,the concept of planar multi-DOF(degrees of freedom)flexure hinges has been presented.The three dimensional compliance model of the planar multi-DOF flexure hinges has been established,analysed and verified.The general analytical equation for the compliant bridge mechanism has been established.The configuration optimization of the bridge mechanisms has been realized.The prototypes of the tip-tilt type micropositioning stage have been developed by employing the modules of the multi-DOF flexure hinges and the displacement amplification mechanisms.2.The static analysis techniques for the spatial compliant tip-tilt micropositioning stages have been investigated.The quasi-static analyses of a compliant tip-tilt stage based on the compliant lever mechanisms and the cylindrical flexure hinges has been accomplished utilizing the Castiglione's displacement theory,where the planar model of the spatial compliant mechanism has been employed and the three dimensional quasi-static kinematics of the stage has been studied.Furthermore,the compliance matrix method has been employed to analyze a compliant tip-tilt stage based on the compliant bridge mechanisms and the planar multi-DOF flexure hinges.The three dimensional kinematics of the stage with multi-inputs and multi-outputs has been established.The verification of these methods by means of finite element analyses and experimental studies has been detailed.3.The dynamic modelling techniques for the compliant tip-tilt micropositioning stages have been investigated.The lumped-parameter modelling method for the spatial compliant mechanisms was presented,the equations of the kinematic energy and the potential energy of the mechanism under micro motions were obtained,the equations of the three dimensional motion of the system has then been established by means of the Lagrange's equations.The dynamic models of the compliant bridge mechanisms and the compliant tip-tilt micropositioning stage has been established,analysed,and verified by finite element analysis.4.The precision positioning control method of the compliant tip-tilt micropositioning stage has been investigated.The parameters of the kinematic model of the compliant stage and the Bouc-wen hysteresis model of the piezo actuator have been identified utilizing least square method simultaneously.A feedward-feedback compound control method based on the inverse kinematic model of the mechanism and the inverse hysteresis model of the piezo actuator has been established.The control system for the tip-tilt micropositioning stage has been set up.The three dimensional micropositioning of the tip-tilt stage has been realized.