Two Multiarticulated Hydraulic Hand Prostheses

Abstract

Two different designs of lightweight experimental prosthetic hand are presented. The weight of the first hand is reduced by 50% compared to a conventional prosthetic hand, whereas the functionality of the second hand is increased by additional prehension types. Optionally, a tactile feedback system can be integrated. Due to multiple articulated digits and flexible materials, both hands are able to conform to the shape of an object held. This significantly reduces the necessary grip force and results in stable holding of an object. For a natural appearance, the hands are covered with a cosmetic silicone rubber glove.

Dielectric elastomers as actuators for upper limb prosthetics: Challenges and opportunities

“…Creative invention in upper limb prosthetics has not been lacking over the past decade with designs based on a large variety of actuator technologies from conventional dc motors and micromotors [11,12] to more exotic shape memory alloys [11,[13][14][15][16], ultrasonic motors [17], and pneumatic artificial muscles [18][19][20]. Del Cura et al provide an excellent review of these technologies for prosthetic applications, concluding that micro-, ultrasonic, or piezoelectric motors are most promising when compared with hydraulic actuators, shape memory alloys, and contractile polymer gels with regards to size, weight, applicability, precision, hysteresis and non-repeatability, energy consumption, operating frequency, efficiency, power density, anthropomorphism, and cost [9].…”

The DEKA Arm

“…Most powered multifunctional hands have between 1 and 6 actuators and between 8 and 16 joints. [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] Most of these hands are underactuated, have conforming grips, can perform several grasp patterns, and are designed with 5 digits, although several designs have only 3 digits. 10 Although a complete review of the state of the art of research prosthetic terminal devices is beyond the scope of this article, a comparison of the digits, joints, number of actuators and actuation methods was provided by Dailey et al in 2010.…”

“…13 One device, not included in Dailey et al's review, has 22 joints and additional actuators for control of individual digits. 24 Some of the multifunction terminal devices can perform 6 or more grasping patterns as well as additional hand postures, 19,[24][25][26] offering potential functionality that is similar to or exceeds that of the DEKA hand.…”

Development of a multifingered robotic hand

“…The actuation method of this hand is done by pumping oil into joint chambers and the flexible joint chambers expand and bend the fingers [8]. It is an innovative design as it expands on the idea of using one pump to supply all joints to achieve maneuverability and light weight.…”