AI , 07 December To enable high forces with sufficiently high actuation speed at each fingertip, bundles of welded actuated SMA wires are used.
In order to increase the compliance of each finger, flexible joints from superelastic SMA wires are inserted between each phalanx. The resulting system is a versatile hand prototype having intrinsically elastic fingers, which is capable to grasp several types of objects with a considerable force.
The paper starts with the description of the finger hand design, along with practical considerations for the optimal placement of the superelastic SMA in the soft joint. The maximum achievable displacement of each finger phalanx is measured together with the phalanxes dynamic responsiveness at different power stimuli. Several force measurement are also realized at each finger phalanx. The versatility of the prototype is finally demonstrated by presenting several possible hand configurations while handling objects with different sizes and shapes.
The design of a device able to reproduce all the functionalities of a human hand has been a challenge for many researchers since the late '. Up to date, the most performant prototypes in terms of force, speed, and versatility are designed with a rigid structure, and driven by electric motors. Despite the high performances achieved by these devices, they have encountered high rejection rates by users mainly due to the rigidity of the artificial hands, their heavy weight, and their noisy motion Kyberd et al.
Soft robotic hands represent a valuable alternative to this technology Dollar and Howe, The increased compliance of these devices confers an intrinsic robustness to manipulation and, at the same time, safe features which are highly desirable in human collaborative environments Cianchetti and Laschi, A first example of flexible and underactuated system is presented in Dollar and Howe In here, the authors introduce a two-finger gripper with reconfigurable joints, actuated by two DC motors.
