The Dynamic Characteristics And Motion Reliability Analysis Of Controllable Spraying Manipulator With Clearances

Spraying manipulator is a kind of common industrial robot, which is widely used in modern manufacturing industries, such as automobiles, electrical appliance, toys and so on. The existing spraying manipulator mainly adopt series structure, in which the driving device is directly installed at the joint, such defects as large moment of inertia, low stiffness and accumulated error are generated. Based on the existing spraying manipulator, a kind of controllable spraying manipulator is put forward, in which part of the drive device is moved close to the frame by adding Assur groups to form planar closed chain, it can theoretically improve the defects of the existing spraying manipulator. But when the Assur groups were added, the number of kinematic pairs of controllable spraying manipulator increased. While due to processing, assembly, wear and some other reason, the existence of kinematic pairs clearance is inevitable, which will causes separation and collision between the kinematic pairs’ element, and finally affect the dynamic performance of the manipulator. In view of this problem, this paper will conduct a research on controllable spraying manipulator with clearances, the following is the main content:By using closed loop vector method and space coordinate geometry, the kinematics model of controllable spraying manipulator without clearance was established, and on the basis of it, a brief analysis of the manipulator’s singularity and workspace was done. All of these enhanced the understanding of basic movement law of the controllable spraying manipulator.In this paper, the theoretical analysis model for the analysis of the mechanism with clearance was introduced, and carried out the dynamic modeling with the appropriate model. On the basis of it, using the MATLAB/Simulink software as a platform, the controllable spraying manipulator was simulated and compared under the condition of with or without clearance, clearance of different radius and different driving speed. Eventually, the influence of the clearance radius and the driving speed on the dynamic characteristics of the controllable spraying manipulator was obtained, which provides a theoretical reference for the choice of the machining accuracy and the working speed of manipulator.This paper briefly introduced the basic theory of mechanism motion reliability and the probability analysis model of clearance. Based on the error analysis of controllable spraying manipulator considered clearance factor and rod length error, the reliability of the manipulator was analyzed by using Monte-Carlo method. By comparing the influence of the clearance factor and the length error of the rod on the motion reliability of the controllable spraying manipulator, it is concluded that the kinematic pair clearance is very important for the further improvement of the motion reliability of the controllable spraying manipulator.