Development of a Pneumatically Driven Flexible Finger with Feedback Control of a Polyurethane Bend Sensor

A pneumatically-driven flexible finger equipped with a flexible sensor is realized for improving the performance of the soft robotic hand. First, we propose a flexible angle estimation sensor. This sensor measures the change in the amount of light passing through polyurethane material and estimates the angle with high repeatability. Next, we design a flexible finger that makes this sensor easy to incorporate. The flexible fingers are produced with a multi-material 3D printer that can use flexible material. The flexible finger can accommodate the proposed flexible sensor within it. It is possible to place the sensor's signal line in the air pressure pipeline. Because the flexible finger is produced with a 3D printer, variations in each model's characteristics are small as compared with manufacturing through molding. In this paper, we show an improvement of positional accuracy in the proposed flexible finger using angle feedback control from the proposed sensor. The effectiveness of this sensor is also shown to solve the problem of vibration problems for the flexible finger during high speed motion.