| In response to the requirements of large positioning,high precision,multiple degrees of freedom and output displacement decoupling proposed by the micro positioning technology on the micro motion platform,this paper used a piezoelectric ceramic actuator as the driving element and designed an XY based on a two-stage amplification mechanism.The two-degree-of-freedom bidirectional driving micro-motion platform has the advantages of large stroke,high precision,high resolution,and symmetrical bidirectional output characteristics.The main research work is as follows:Straight circular flexible hinge and leaf-shaped flexible hinge were selected as the basic unit of the compliant mechanism.An XY two-degree-of-freedom bidirectional driving micro-motion platform was designed.The platform consisted of a Scott-Russell mechanism and a lever mechanism in series to form a two-stage displacement amplification mechanism.There are two sets of secondary amplifiers in each direction to form a mirror and symmetrical arrangement,which can ensure the linear output of the output end of the amplification mechanism.The displacement guide mechanism composed of leaf-shaped flexible hinges connects the amplifying mechanism and the output platform to ensure that the linear output in the XY direction and the displacement are decoupled when the platform is working.There are two piezoelectric ceramic actuators symmetrically arranged in each direction of the platform.By controlling the piezoelectric ceramic actuators,the bidirectional driving of each degree of freedom of the platform can be realized.The designed micro-motion platform has a simple structure and a large working stroke.The overall size of the platform is 207.5mm × 207.5mm × 10 mm.The control variable method was used to optimize the design of the structure of the micro-motion platform with the help of finite element analysis software.The platform has good static and dynamic characteristics.Using the pseudo-rigid body modeling method,the kinematics analysis of the micro-motion platform was carried out.The flexibility matrix method was used for static analysis of the platform.According to the conversion relationship between force and displacement in different coordinate systems,combined with the relationship between the motion and force transmission of the series and parallel mechanisms,the flexibility of the compliance mechanism in the global coordinate system was derived the matrix,in turn,established the output flexibility model of the secondary amplification mechanism,the blade guide mechanism,and the mathematical model of the output and input of the platform,and obtained the output and input stiffness of the platform by solving the inverse of flexibility.Lagrange's equations were used to establish the platform dynamics model,and the natural frequency of the platform was analyzed based on the vibration theory and the dynamics model.With the help of finite element analysis software,the displacement,stress,stiffness,modal,and frequency response of the micro-motion platform were verified and analyzed.The corresponding experimental test system was built,and the static and dynamic characteristics of the micro-motion platform were tested.The test results showed that the maximum output displacement of the platform along the positive and negative directions of x is84.6?m and-84.2?m under the 150 V rated voltage drive,The corresponding coupling displacement is 0.70?m and 0.56?m respectively;the maximum displacement of the platform output along the positive and negative directions of y is 85.0?m and-84.5?m respectively,and the corresponding coupling displacement is 0.68?m and 0.59?m,respectively.Under the minimum driving voltage of 0.017 V,the resolution of the platform in the x and y directions is 10 nm.The natural frequencies of the platform along the x and y directions are 266.6Hz and 268.2Hz,respectively.The stiffness of the platform along the x and y directions are 0.347 N / ?m and 0.343 N / ?m,respectively. |
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