Design Of Micro-displacement Positioning Platform For Atomic Force Microscop

Piezoelectric ceramic driven micro positioning platforms are widely used in integrated circuit manufacturing,biochip technology,nanotechnology,electronic packaging technology,fiber docking and other fields due to their advantages of high motion accuracy and response speed.It has become a research hotspt and gotten much attention at home and abroad.In the field of nanobiology,systems are required to have nanoscale resolution,so micro displacement positioning platforms need to have technical requirements such as large travel,high accuracy,and fast response.In this thesis,according to the requirements of relevant micro displacement technical parameters of atomic force microscope in the field of nano biology,the scheme design of the micro displacement positioning platform is carried out.With high precision and large stroke as the design goal of the micro displacement positioning platform,the micro positioning platform has been studied in structural design,model analysis,parameter optimization,finite element simulation and PID control.The research contents are listed as follows:Firstly,the composition of the micro displacement system was introduced,and piezoelectric ceramics were selected as the driving device for the micro displacement positioning platform,while flexible hinges were selected as the transmission mechanism to connect the motion platform.Secondly,several different types of flexible hinges were introduced.since the semi circular flexible hinge has the characteristics of compact structure and high accuracy,and is widely used in fields such as precision machinery,precision measurement,and nanotechnology,becoming the preferred choice for structural design.Then,the bridge amplification mechanism and lever amplification mechanism were introduced,and a differential amplification mechanism was designed based on their micro displacement amplification mechanism,as well as a new type of amplification mechanism composed of two parallel bridge amplification mechanisms connected in series with a lever amplification mechanism.A pseudo rigid body model for the differential amplification mechanism,perform pose analysis on it was established.After thant the amplification factor of the differential amplification mechanism was obtained Secondly,a 3-PRR planar three degree of freedom micro displacement positioning platform and a new type of large stroke 3-PRR planar three degree of freedom micro displacement positioning platform were designed..The kinematics analysis of the performwas conducted.The stiffness of the flexible hinge was calculated using the integration algorithm and finite element method.Following that the equivalent mass and stiffness were obtained.The natural frequency of the micro displacement positioning platform has been calculated.Thirdly,the influence of parameter sizes of different structures on the output displacement of the motion platform was obtained through finite element simulation.The structure of the platform was optimized.The final stroke of the micro displacement positioning platform in each direction was 0.1204 mm in the x-axis direction,0.1390 mm in the y-direction,0.1284 ° in the z-axis rotation motion,with a motion accuracy of 2nm.he micro displacement positioning platform,The maxim difference between the theoretical calculation results and the simulation results is 9.14%.Finally,finite element analysis was conducted to optimize the micro displacement positioning platform.Finally,the transfer function of the micro displacement positioning platform for PID closed-loop control was established to improve system response speed and stability.