Patent ID: 8650971

Claim:
A slippage detection device, comprising: a slippage detection member in which a pressure-sensitive conductive sheet, which is made by dispersing conductive particles in a flexible layer main body, is disposed on a contact receiving member, with a resistivity value of the pressure-sensitive conductive sheet determined by the state of contact of the dispersed conductive particles at a time when a tangential-direction force is applied to a surface of the flexible layer main body after a normal-direction force is applied thereto; a slippage detection signal formation circuit that forms a slippage detection signal containing a high-frequency oscillation waveform component that occurs right before the occurrence of slippage displacement of a contact member, on the basis of a change in resistivity of the pressure-sensitive conductive sheet that is caused by a change in the dispersion arrangement state of the conductive particles in the flexible layer main body right before the contact member starts slipping and becoming displaced with respect to the contact receiving member, at a time when the contact member is pushed against the contact receiving member via the pressure-sensitive conductive sheet and then the contact member is pushed against the contact receiving member in a direction of slippage; and a slippage detection calculation section that transmits a slippage confirmation signal indicating the occurrence of initial slippage right before the occurrence of the slippage displacement from the occurrence of the high-frequency oscillation waveform component and the magnitude thereof exceeding a predetermined threshold value.