Heat Flow Measurement by Force and Thermal Sensor Stick with Nerve-net LSI Chip

Assistant robots need a tactile sensing system. We propose a tactile sensor head with a nerve-net sensing system which measures force, temperature and heat flow on robot fingers. For accurate heat flow measurements, it is necessary to stabilize contact conditions between the sensor head and objects. A sensor stick which consists of the sensor head and an actuator was fabricated to control applied force. Heat flow measurements in three materials of different thermal conductivities such as polyethylene, glass and aluminum were examined with the sensor stick. For the measurement, the sensor head was heated at 0.55W and brought into contact with the measurement object for 180s. Materials were discriminated clearly by temperature changes and heat flow changes. Finally, 13 kinds of materials with different thermal conductivities were measured. Under 10W/mK in thermal conductivities of measurement objects, heat flow peaks, heat flow saturations and heat flow time constants showed good correlations with the thermal conductivities. Over 10W/mK heat flow peaks, heat flow saturations and heat flow time constants were saturated to 0.7W, 0.4W and 40s, respectively. The tactile sensor stick with heat flow measurement and force control is useful to discriminate materials of objects as smart as a human being.