The Design And Fundamental Property Research Of A 4-DOF 4-RRUR Parallel Micromanipulator

Micro-manipulating robot is currently one of the hot topics in the field of robotics. The Micromanipulator can implement fine movement, and positioning accuracy at the sub-micron or even nanometer level, with wide application prospect in biology, medical sciences, micro-machining, aerospace etc. Because of the advantages of compact structure, simple control, less error accumulation etc, the parallel mechanisms win a very good application in the structural design of Micro-manipulator. This paper designs a micromanipulator based on the 4-DOF 4-RRUR parallel mechanism, and focuses on the kinematics and static stiffness research of the micromanipulator.The performance of the flexible hinge directly affect the final operational performance of micromanipulator, so first, the optimum structural of flexible hinge is designed. Based on analyzing and comparing the maximal rotary angle of four types of flexible revolute joints, considering increasing the workspace of micromanipulator, we choose a right flexural revolute joints as motion pairs of the micromanipulator.Based on the input and singularity analyse of the 4-DOF 4-RRUR parallel robot, the 4-RRUR micromanipulator is designed by using the flexible hinge as a substitute for the general motion joint. Static analysis of the micro mechanism is achieved by using finite element analysis software, the optimal mechanism model is choosed by comparing the stress and displacement distribution map, and the variation relation between the center displacement of moving platform following and the driving force is drawed, and the displacement range to meet the strength is given.Considering the kinematics characteristic of micromanipulator, kinematics of the micromanipulator are solved by using differential method, the characteristic matrix about the relationship between the input and output displacement, velocity and acceleration is established. The evaluation index of velocity and acceleration is given, and the effects of the structural parameters of the mechanism on performance of velocity and acceleration is analyzed.According the correlation formula of mechanics of materials, the flexibility matrices of spatial deformation of flexible hinge is established. Then, by using flexibility matrices method of mechanism analysis, the flexibility matrix and stiffness matrix of 4-RRUR parallel micromanipulator is gained by recursive computation. The evaluation index of static stiffness related to the micromanipulator is set up, and the influence curve of the structural parameters of flexible hinge on stiffness of the micromanipulator is drawed.