A novel versatile robotic palm inspired by human hand

Human palm plays a great role in object grasping and manipulation. However, most current robotic hand researches focused on finger designs, with very few efforts seen on robotic palm research. Here, we propose a novel robotic hand palm that is highly adaptive to object shape with variable stiffness and can be controlled actively. Our palm has one degree of freedom (DOF) mechanism and one particle sac that can be activated by vacuum. When the mechanism is actuated by a soft actuator, the particle sac is forced into contact with a target object, adapting to its shape. The particle sac can then be stiffened to freeze the current contact based on vacuum particle jamming. The stiffness is controlled by vacuum pressure. Embedded into a robotic hand, the proposed palm can coordinate its motion with the robotic fingers in grasping tasks. A more than three-fold holding force increase in pull-out experiments showed its superior functionality when compared with pure silicone rubber palm. Grasping of objects with different shapes and properties are also demonstrated. We believe that the proposed robotic palm design can provide new insight into more effective robotic hand design.