Production management system in an assembly plant by terrestrial magnetism sensors

In quality management in an assembly plant, it is very important to verify whether workers are following instructions or not. However, it has been considered there is no perfect way to do it. Generally, most assembly processes have steps to check quality and work in former processes. However, there are some cases which are difficult to be verified in later processes whether operations were done according to instructions or not. For example, to fasten some parts to other part with some screws, it is necessary to screw in diagonal order. However, it is not easy to judge from finished pieces whether operations were done in diagonal order. Thereupon, we have been developing a system to improve quality of industrial products. This system employs terrestrial magnetism sensors and accelerometers to oversee motions of workers, and these sensors are attached to their arm/hand or tools. We have done an experiment to measure workerspsila motions with them in an actual car assembly plant. In this paper, we discuss its result and how sensorpsilas output generated when operations were done in correct order differs the one generated when operations were done in incorrect order.