Single-chamber Inflatable Robot Arm with a Four-finger Gripper Driven by Built-in Pouch Muscles

Inflatable robots are a class of soft robots that are suitable for human robot interaction, but their control complexity and safety remain challenging. We propose a soft inflatable robot in which the exterior, continuously supplied with air by a blower, serves as the skin, and a pouch muscle embedded within the skin and actuated by air pressure serves as the muscle. This system, termed the "musculo-skin system," forms the basis for developing an inflatable robotic arm with six degrees of freedom, including the shoulder, elbow, and four-finger gripper. The angles of the shoulder and elbow joints were measured and the angles and motion speeds of the joints were evaluated using data from the time series of each joint. To evaluate the fingers, a Rock-Paper-Scissors gesture was performed, demonstrating the ability to execute complex finger movements without interference. The experimental results confirmed that the finger movements were smooth and capable of performing natural gestures. These results will contribute to enabling more complex motions in soft inflatable robots.