Development of soft mechanisms with a pleated ELSA for robots contacting with humans

Recently, studies of entertainment and communication robots have been conducted. These robots require intrinsic safety features because of the many opportunities to contact humans. For example, conventional robot hands that can grasp an object often consist of metal frames, electrical motors, and gears in order to maintain accuracy. These mechanisms are inevitably complex, high weight, and stiff. If the robot hand heavy, the moment of the elementary part of the manipulator is increased. When these robots operate near people, it is also necessary to perform tasks at low speed to ensure the safety of the people. This has the potential of decreasing work efficiency. Therefore, it is desirable for robot hands to be lightweight and soft. We propose extremely lightweight and supple mechanisms using a pneumatic driven thin plastic-film actuator based on pleated structures. In this paper, the structure of a soft gripper with a bending type actuator and a soft parallel joint with a contraction/extension type actuator are proposed. As a basic characteristics of these mechanisms, generating force are experimentally shown. Although this mechanism is lightweight, high output can be expected.