Research On 3D Printed Six-axis Micromanipulation Wrist Of Microrobots For Micro/Nano-manipulation

Microgripper is the end effector of micromanipulator of microrobots for micro/nanomanipulation.Generally,it can only achieve one-dimensional clamping motion in micro or nano scale.The micromanipulator is composed of a number of one-dimensional linear motion guides and a circular motion turntable in series,which can achieve the resolution of large stroke and multi-dimensional motion in micron scale.If the micromanipulator is viewed as the human trunk and arm,the microgripper can be viewed as the human hand.If the microgripper can be connected with the micromanipulator through a six-axis micromanipulation wrist with resolution from micron to nanometer,the function of the microgripper can be greatly enriched.In order to meet the application requirements of microrobots for micro/nano-manipulation,a 3D printed piezoelectric actuated compliant six-axis micromanipulation wrist based on Stewart platform is proposed and implemented.The main research work and achievements of this thesis are as follows:(1)In this thesis,a 3D printed six-axis micromanipulation wrist based on cubic Stewart platform is proposed and implemented,and an integrated structure suitable for3 D printed is proposed and designed.In order to facilitate 3D printed and system integration,the six-axis micromanipulation wrist adopts the cubic Stewart platform,and the elliptical mechanism is designed on each branch chain to embed the piezoelectric stack driving elements,and the ball hinge is designed at the upper and lower ends of each branch chain to connect the upper and lower platforms.The kinematics simulation and analysis of 3D printed six-axis micromanipulation wrist are carried out,and the functional relationship between the end pose and the stack elongation of piezoelectric ceramics is established.(2)Based on the stiffness analysis of 3D printed six-axis micromanipulation wrist,the relationship model between the structural parameters and stiffness of flexible spherical hinge,elliptical shell flexible moving pair and the whole is established.The correctness of the stiffness model and the rationality of the structural design are verified by finite element analysis.The structural size parameters are determined and the strength is checked.(3)The prototype of six-axis micromanipulation wrist is manufactured,and the sixaxis micromanipulation wrist system of 3D printed is realized.The test device is established,and the performance of the six-axis micromanipulation wrist of 3D printed is tested.The test results show that the displacement and rotation angle of the six-axis micromanipulation wrist can reach 8.3 ?m and 184 mrad,respectively,the resolution of displacement and angle can reach 105 nm and 1.86 ?rad,respectively,displacement and angle repeat positioning accuracy can reach 0.275 ?m and 2.73 ?rad,respectively,which proves the feasibility of 3D printed six-axis micromanipulation wrist.At the same time,the resonant frequency,step response,hysteresis and creep characteristics are tested,and the error analysis is carried out,which is convenient for the later control and improvement of the six-axis micromanipulation wrist.The work of this thesis provides guidance for the design and development of integrated 6-DOF parallel micromanipulator.