Wireless Magnetic Position-Sensing System Using Optimized Pickup Coils for Higher Accuracy

With the aim of improving the detection accuracy of a wireless magnetic position-sensing system using an resonant magnetic marker, a pickup coil with an optimal size (10 mm in diameter x 1 mm thick), as calculated by a previous simulation study, was used and tested in this paper. Our study confirmed that positional errors were reduced to a submillimeter order in the area within y = 120 mm from the pickup coil array. On the contrary, in the area outside y = 130 mm from the pickup coil array, the errors increased by about 0.5-2 mm compared to the results for the previous pickup coil size (25 mm in diameter x 2 mm thick). Regardless of the size of the pickup coil, however, compensation can be made for these positional deviations, including the influence of the mutual inductance between the marker and the exciting coil. After application of the compensation process, the detection results were corrected approximately to the actual positions of the marker.