Development of a Multi-Fingered Hand with a Multi-Step Locking Mechanism for Carrying Heavy Objects by a Humanoid Robot

Along with the progress of robot technology, robots are expected to work at construction and disaster sites. At such sites, multi-fingered hands are required to have the ability to manipulate objects of various shapes and a high endurance for supporting heavy objects. In this study, we propose a multi-step locking mechanism using cams for finger joints and a strategy for switching between locking and non-locking depending on target motions. This mechanism enabled a hand with the high back drivability for flexible manipulation and the endurance to continuously exert high torque regardless of the actuator's torque limit. By mounting the developed hand on a high-power and high-degree-of-freedom humanoid, the robot was able to perform high-load manipulation, such as pull-ups and bar-hanging, and tasks that require dexterity, such as tank-carrying operations. Through these experiments, we demonstrated that by combining the switching of the hand-locking mechanism with the dual-arm manipulation, the robot can perform tasks that require high manipulation force and dexterity. We found that a locking mechanism that can be turned on and off for each arm or each task is important for a dual-armed high-power humanoid robot.