Monostructure touch sensor with multifunction for discrimination of material properties

This paper describes the development of a monostructure touch sensor that has three kinds of sensing functions for discriminating materials. The sensor consists of two spiral metallic lines on a thin insulating substrate and has four terminals. When the two lines are used as two coils, the sensor has the property of inductance. When the two lines are used as two parallel electrodes, the sensor has the property of capacitance. When one spiral metallic line is used as a heater and another is used as a resistor, the sensor has the property of a temperature sensor. The proposed sensor is used to discriminate typical materials such as iron, aluminum, copper, bronze, gum, wood, acrylic resin, styrene foam, etc. The experiments show that the sensor has considerably high potential in discriminating materials, indicating that the sensor would be a promising candidate for developing an artificial skin tactile sensing system in the future.