Development of a method to determine operator location using electromagnetic proximity detection

Researchers at the National Institute for Occupational Safety and Health (NIOSH) are advancing the emerging technology of electromagnetic proximity detection, which provides a promising means of protecting workers around any machinery that presents striking, pinning or entanglement hazards. This technology is particularly applicable to mobile underground mining equipment such as remote-control continuous mining machines, which offer perhaps the most difficult safety challenges in the mining industry. Other industries have effectively implemented proximity detection technology, with successful test cases at surface and underground mines. However, applying this technology to remote-control continuous mining machines presents uniquely difficult challenges. These machines typically weigh close to 100,000 pounds and have heavy, articulated parts. Due to visibility and space limitations, machine operators often work in very close proximity to the machine despite the clear hazards that this proximity creates. To protect miners without preventing them from doing their jobs or causing nuisance alarms, intelligent electromagnetic proximity detection technology is now being developed at the NIOSH research facility in Pittsburgh. At the heart of this technology are a number of electromagnetic field generators mounted on a mining machine and magnetic flux density sensors built into a Personal Alarm Device (PAD) worn by the operator. In this paper, the authors present a novel algorithm created to calculate an accurate position based on PAD readings from multiple field generators coupled with a previously developed model of the generated magnetic field. The use of this algorithm allows for the calculation of an accurate PAD location relative to the mining machine. A prototype of this intelligent proximity detection system has been successfully implemented and demonstrated on a Joy 14CM continuous mining machine at the NIOSH research facility in Pittsburgh. This technology has the - - potential to significantly affect the mining industry by greatly advancing the current state-of-the-art in proximity detection technology, leading to increased operator safety and preventing serious injuries and fatalities.