In recent years, many countries have intensified space development. A spacecraft remains tightly constrained by payload mass and volume. Therefore, a low-inertia robot arm that is compact during transportation and has a wide range of motion in space is desired. As a related research work, in the previous study, we developed Extension type Flexible Pneumatic Actuator (EFPA) and a tetrahedral-shaped soft actuator composed of three EFPAs. A Spring Supported pneumatic Flexible Actuator (SSFA) using a coil spring and EFPAs that could be used safty after buckling of their EFPAs was developed. Based on these studies, we aim to develop a flxible robot arm that can be stored compactly during transportation, and provide a wide workspace after when deployed． In this study, a flexible robot arm that consists of three cylindrical arranged long pillar type soft actuators and three short pillar type actuators, and ring-shaped ratraint plates was proposed and tested. The long pillar type actutator consists of two paralell arranged EFPAs inclined at 80° to undergo a repeat expand–contract–expand with restraint plates. The shorter one is two V-shaped arranged EFPAs with restraint plates. Each pillar type actauator is set alternatively every 60° on ring-shaped restraint plates. The driving test of the robot arm was also carried out. As a result, it could be confirmed that the tested robot arm can extend, bend toward various radial directions, and rotate around a central axis after when deployed. As the end effector, a wrap type robot hand that has three fingers using EFPAs with axial string constraints was also propsoed and tested. The hand could hold an object with mass of 400 g. The remote control system via Bluetooth was also deveoped. As a result, we confirmed that the tested robot can deploy from transportation mode, and pick up the object put on the floor and carry the object to other point.
