A new robotic hand capable of switching between multiple grippers using a single motor

Researchers at Kanazawa University have developed a prototype robotic hand with multiple grippers powered by one motor. The work was reported in IEEE Robotics and Automation Letters. Conventional robotic hands often rely on several motors or external tool changers to handle objects with differing shapes, sizes, weights, and rigidity. Those arrangements can add weight, cost, failure risk, and control complexity.

The new hand uses a MaGDri, or Magnetic and Gravity-based Driving, mechanism. Rather than adding actuators, it switches the motor's torque path among gripping units by using gravity. The researchers describe this as a design principle that turns gravity, commonly treated as a disturbance in robotics, into a source of mechanical action. In prototype experiments, the system selected suitable grippers for objects of different shapes and sizes.

Because multiple grippers share a single motor, the design could reduce the hand's weight, space requirements, and cost while retaining several grasping methods. The article says the approach may provide a relatively simple route to multifunctional robotic hands and may inform future research on hand mechanisms. It also suggests potential uses where robots must safely and reliably manage varied items, including factories, logistics, service work, households, stores, nursing care, social welfare, mobility, and disaster response.

The researchers expect that being able to change grasping methods within one hand could broaden the tasks robots support and give them greater flexibility in assisting people. The study does not claim to eliminate the need for object-specific grippers; instead, it demonstrates a mechanism for selecting among multiple installed gripping units.