Motion Analysis And Optimum Design Of Manipulator Flexible Wrist Or Feeding And Unloading

This paper is to configurate a feeding and unloading manipulator for NC gear grindingmachine at the request of some machine tool plant in Shanxi province. It is very important toensure the accuracy, reliability and efficiency in the assembly process. In the assemblyprocess, the exists of all kinds of errors make it difficult to assemble the work piece. It isdifficult to solve this problem in technology and economy, only depending on improving theprecision of the robot’s and the peripheral’s equipment. The practical way for effective preciseassembly in real reality and economic is to make the robot have a certain of the flexible ability.The flexible ability can adjust the pose between the assembly body initially or passivity,compensate assembly error in order to assemble the work piece smoothly. Usually it uses theflexible wrist to achieve compliant assemble.This paper proposes a new kind of flexible wrist according to the requirements of themanipulator’s task. It can compensate the position error by the compliance of the wrist, so thatthe assembly process can go smoothly. This wrist can reduce the centrifugal force’s impact tothe manipulator when the arm rotates, to avoid the throw out danger of gear.Firstly this paper presents the general structure scheme of the manipulator, hand and thewrist. It also introduces the matters need attention to design the hand and wrist, to providetheoretical basis for subsequent analyses.Secondly it detailed analyses and calculate the compensation error range of the doublependulum flexible wrist in the assemble process. Based on the analysis, it calculates thewrist’s allowing mix angle error and mix radius error. It also analyzes the influence factors ofthe mix angle error and mix radius error.Using the theoretical mechanics, it makes the mechanical analysis when the manipulatorin the still, rotating and assembly process. It calculates the pulling force of the wrist pulls thegear in the error compensation. It also analyzes the influence factors of the pull force.Finally it optimizes the parameter of the wrist’s swing finger. According to the structurecharacteristics of the wrist, the parameter of the wrist’s swing finger influences the ability ofthe wrist’s error compensation and the pulling force directly, so that it selects the maximumtension to achieve minimum and the compensation error to achieve maximum as the objectivefunction to optimize the parameter of the wrist’s swing finger.