Characterization of Pneumatic Touch Sensors for a Prosthetic Hand

This paper presents the results from the characterization of pneumatic touch sensors (sensing bulbs) designed to be integrated into myoelectric prostheses and body-powered prostheses. The sensing bulbs, made of silicone, were characterized individually (single sensing bulb) and as a set of five sensors integrated into a silicone glove. We looked into the sensing bulb response when applying pressure at different angles, and also studied characteristics such as repeatability, hysteresis, and frequency response. The results showed that the sensing bulbs have the advantage of responding consistently to pressure coming from different angles. Additionally, the output (pneumatic pressure) is dependent on the size of interacting object applied to the sensing bulb. This means that the sensing bulb will give higher sensation when picking up sharper objects than blunt objects. Furthermore, the sensing bulb has good repeatability, linearity with an error of 2.95± 0.40%, and maximum hysteresis error of 2.39± 0.17% on the sensing bulb. This well exceeds the required sensitivity range of a touch sensor. In summary, the sensing bulb shows potential for use in prosthetic hands.