Evaluation of gripping sensor using polyurethane with high photoelastic constant

Abstract

Abstract In this study, the measurement of the gripping force on an object using a photoelastic polyurethane sensor is reported. A small amount of force (0.1–10 N) is detected using polyurethane with a high photoelastic constant of 1000–10 000 (×10 –12 Pa −1 ). The force is detected based on the change in the optical path difference due to birefringence when stress is applied to the polyurethane. The value after correction processing for light-receiving intensity that periodically changed with respect to stress is used to determine the force. This corrected value is obtained from the sum of the absolute values of the time difference of the received voltage. The sensor, installed at the fingertips of the robot hand, is used to lift hard and soft imitation eggs, both of which were successfully lifted using a force of approximately 1 N, as detected by the sensor.