FPGA-Based Platform Development for Change Detection in GTAW Welding Process

This paper presents the development of an FPGA-based platform for on-line discontinuity detection in a Gas Tungsten Arc Welding (GTAW) process, through the monitoring its voltaic arc, using an optical infrared sensor. The FPGA-based platform uses a hardware/software co-design approach, in which the hardware part includes a change detection peripheral, apart from general purpose peripherals (e.g. UART, timer) and several customized ones such as memory for storing discontinuity data and an ADC driver. The change detection peripheral comprises the filtering stage and the stopping rule stage, which include a Kalman filter and a cumulative sum (CUSUM) modules, respectively. In order to validate the FPGA-based platform, several experimental tests in the field have been made by introducing intentional discontinuities in the weld bead. These experimental results have shown a suitable performance of the overall system in the on-line discontinuity detection task. In this paper the change detection peripheral is described as well as the synthesis results related to performance and resources consumption. In the overall co-design approach, the software part includes a Micro Blaze soft-processor to control and managing the overall platform, including the interface issues.