On combining accelerometers, force/torque sensors, and electrical sensing for detecting contact errors during assembly

This paper considers detection of errors during assembly. The sensors used are a combination of accelerometers, a force/torque (F/T) sensor; and an electrical contact indicator. Preliminary experiments show that by combining the three types of sensing, both normal contact situations and defects on the parts can be identified. For example, ruts were not detected by the F/T sensor but by the accelerometer. On the other hand the acceleration impulse from a peg with a burr was weak while the F/T sensor combined with the electrical contact indication gave distinct output on the matter. The contact indicating current was fluctuating just after an impact, which shows how the peg bounces on the surface of the chamfer or hole. Using the full range of sensors in assembly of metal workpieces the nature of the error can be determined