No abstract

To solve the problem of unmanned plugging weld for the steam generator in high temperature gas cooled reactor, a new seven-degrees-of-freedom robot with 3-PSP and SCARA structure is designed based on the scheme of serial-parallel robot. In order to achieve simple and stable motion control, the D-H method and analytical method are used to study its serial-parallel kinematics and establish an accurate kinematics model. Based on MATLAB software and existing kinematic models, the Monte Carlo method is introduced to analyze the position and posture accessibility of the robot which has redundant degrees of freedom, and the rationality of the institutional design is verified. To ensure the high precision performance of the robot, the positional accuracy of the prototype is tested and analyzed under the different operating conditions by means of the standardized robot performance tests. In addition, in order to ensure the quality of plugging weld, through the T22 base material for several groups of TIG welding process experiments and mechanical properties testing to determine the reliable plugging welding process parameters. The results show that the robot can meet the requirements of plugging welding, and has accurate motion control, good reachability, high position and posture accuracy and strong expandability.