A novel magnetic type tactile sensor is proposed. This sensor can measure a three-axis force vector and detect a slip. The structure is simple, and this sensor consists of two layers, an elastic layer and a substrate layer. The elastic layer is made of an elastic material and has a cylindrical permanent magnet. The substrate layer is a glass epoxy board and has four GMR(giant magneto resistance) elements and four chip inductors. Each element outputs voltages as to a magnetic flux density when the elastic layer deforms by a contact. A force vector and a slip detection are calculated from these outputs. Laboratory experiments demonstrate the effectiveness of this tactile sensor.

A novel tactile sensor based on electromagnetic induction that can detect slippage in addition to three-axis force is proposed. The structure of this sensor is simple, and the sensor, which is essentially a displacement gauge, consists of a two-dimensional array of inductors and an elastic body containing a permanent magnet. Formulas to transform the output voltage of the proposed sensor into a force vector are derived, and analyses of both deformation of the proposed structure and magnetic field generated by a cylindrical permanent magnet are carried out to extract transformation parameters. In addition, it is shown that the sensor sensitivity can be designed using the aspect ratio of the cylindrical magnet. A prototype unit-cell of a tactile sensor is developed with four chip inductors, silicon gel as an elastic body and a neodymium magnet, and experiments are undertaken with a six-axis force/torque sensor as a reference. The contributions of inductors to sensor output are observed experimentally to be in agreement with analytical prediction and the reference sensor. Experimental results show that the proposed tactile sensor is useful for three-axis force measurement and slip detection.