Abstract

This research work contributes to the practical issues of radiated Electromagnetic Interference (EMI) measurements, analysis, and filter design for wireless robotic control. Detailed procedures and hardware setup used for the EMI measurements conducted at the NRC-AMTC factory floor have been presented. Then, the measured radiated EMI levels have been compared to the regulated limits on radiated EMI for Class A industrial equipment. The mentioned radiated EMI level measurements determined the problematic frequencies where the USA Federal Communications Committee (FCC) radiated EMI levels have been exceeded. The second phase involved band stop filter (BSF) design at the problematic frequencies. Initial filter models were designed using Ansoft Designer, where the characteristic impedance of series and shunt stubs were proposed and calculated by the software. Next, the BSF models were realized using microstrip technology. The dimensions of transmission lines were calculated based on the substrate thickness and the cutoff frequency of interest. BSFs were designed to maximize frequency-selectivity at the cutoff frequencies. Finally, the built BSF prototypes were built for higher-than-680 MHz models on Rogers RT/duroid® 5880 high-frequency substrates. The S-parameters and phase responses of the BSF prototypes were measured using a network analyzer. The measured results were close to the simulated ones, with an emphasis on selectivity at the cutoff frequencies. BSFs designed at cutoff frequencies of 840 MHz or higher are used while the robot performs arc-welding and peen-forming, while BSFs with cutoff frequencies lower than 840 MHz will be used near the moving-gantry, and while friction stir-welding processes.