Analysis of the mutual inductance of energy-transferring component for a novel electromagnetic tactile sensor

Recent developments of a novel electromagnetic tactile sensors have prompted requirements to investigate the mutual inductance between a micro planar coil and a non-coaxial planar coil. To realize miniaturization design for robot applications, the ratio of pitch to radius for planar spiral coil is over 20%. In this paper, an extended formula is proposed for mutual inductance calculation of energy-transferring component which consists of two micro planar spiral coils sandwiched between two substrates for tactile sensor. The calculated results have higher accuracy than previous methods and it can quickly determine the mutual coupling of two planar coils that have different relative positions and distance between them. This new calculation method provides a convenient and useful tool for determining the mutual inductance of micro planar spiral coil with high ratio of pitch to radius. The theory has been favorably tested by finite-element analysis and compared with predecessors' research.