Tooling ball detecting method design for ABB welding robot in automatic TIG welding process

Abstract

This thesis provides the design process for a new tooling ball detection method to calibrate moulds in automatic TIG welding. A mechanical component is designed to locate the tooling ball and convert the position information into analog signals. An electrical component is designed to process signals from the mechanical component and achieve the signal communication process. Finally, the computational component is designed and programmed to receive bits from the electrical component and convert information into position values for the tooling ball. The homogeneous transformation process is mathematically modeled for position computation in a robot system. The method is significantly different from current methods that have been developed and applied. Firstly, it uses a mechanical-touch style operation to locate the tooling ball with only a one-time detection operation. Secondly, it introduces a new approach for utilizing the joystick. Rather than as a manually operated direction controller for mobile control of devices, the joystick is used as a passive detection angle sensor. In order to properly use the joystick as an angle sensor, the joystick calibration method is also designed and tested. The designs of the three components are all implemented and tested separately. The results of these tests prove the feasibility of the new detecting method; however, the accuracy of detection is not yet acceptable and further improvements need to be made. In addition, a vision-based detecting method is also discussed at the end of the thesis. Compared to mechanical touch-style detection, the vision-based detecting method is designed to obtain better performance in a high temperature environment and to automate the tooling ball detecting process.