A practical 3D-printed soft robotic prosthetic hand with multi-articulating capabilities

Abstract

Soft robotic hands with monolithic structure have shown great potential to be used as prostheses due to their advantages to yield light weight and compact designs as well as its ease of manufacture. However, existing soft prosthetic hands design were often not geared towards addressing some of the practical requirements highlighted in prosthetics research. The gap between the existing designs and the practical requirements significantly hampers the potential to transfer these designs to real-world applications. This work addressed these requirements with the consideration of the trade-off between practicality and performance. These requirements were achieved through exploiting the monolithic 3D printing of soft materials which incorporates membrane enclosed flexure joints in the finger designs, synergy-based thumb motion and cable-driven actuation system in the proposed hand prosthesis. Our systematic design (tentatively named X-Limb) achieves a weight of 253gr, three grasps types (with capability of individual finger movement), power-grip force of 21.5N, finger flexion speed of 1.3sec, a minimum grasping cycles of 45,000 (while maintaining its original functionality) and a bill of material cost of 200 USD (excluding quick disconnect wrist but without factoring in the cost reduction through mass production). A standard Activities Measure for Upper-Limb Amputees benchmark test was carried out to evaluate the capability of X-Limb in performing grasping task required for activities of daily living. The results show that all the practical design requirements are satisfied, and the proposed soft prosthetic hand is able to perform all the real-world grasping tasks of the benchmark tests, showing great potential in improving life quality of individuals with upper limb loss.

Can Prosthetic Hands Mimic a Healthy Human Hand?

“…There are several advantages of incorporating 3D printing technology in the production of artificial limbs, as prostheses require a highly individualized and versatile design approach and, if possible, low maintenance requirements and cost limitation [39]. In addition, for the 3D prosthetic hand, multiple control mechanisms are being incorporated to create a product with comparable features to the more advanced hands on the market, while at the same time ensuring that the hand remains cheaper than those currently available [40]. Unfortunately, through 3D printing alone, it is not yet feasible to get prostheses with the same degree of consistency as commercial ones.…”

A Single-Actuated, Cable-Driven, and Self-Contained Robotic Hand Designed for Adaptive Grasps

“…Through several research studies, the functionality of robotic hands has been improved by focusing on affordability, portability, weight, design simplicity, number of DOFs, number of actuators, and the ability to provide a safe, powerful, and robust grasp. The design requirements can be summarized in three basic design factors, namely anthropomorphic ( [1][2][3][4][5]), underactuated ([3,6-9]), and compliant ( [2,5,[10][11][12]) design. With an anthropomorphic design, hand DOFs and natural movements can be reproduced.…”

“…It is, therefore, evident that anthropomorphic design involves a balancing act between the design simplicity and capturing the human hand dexterity. Considering such tradeoff, others have implemented the hand biomechanics structure partially by focusing on replicating the joints' movement [3][4][5]. Although these latter designs are less similar to the human hand in appearance, they are simple, lightweight, and highly underactuated.…”

A New Approach of Soft Joint Based on a Cable-Driven Parallel Mechanism for Robotic Applications

“…Within the framework of soft servo-mechanical actuation, there are several examples, such as a cable-driven soft robot for cardiothoracic endoscopic surgery [23] or a practical 3D-printed soft robotic prosthetic hand [24]. In addition, servomechanically actuated soft limbs, which are closer to the proposal presented in this document, have been developed.…”