A new hand rehabilitation system based on the cable-driven mechanism and dielectric elastomer actuator

Abstract

Abstract. The increasing number of patients with hand disabilities after strokes or peripheral nerve injuries necessitates the continuous development of rehabilitation system devices to accelerate muscle recovery and to help patients regain the motor functions of their hands. This paper introduces the design of a hand rehabilitation system for patients who have a solitary impairment of their hand extension. The system was designed to be portable, simple, and cheap. Using a system based on a cable-driven mechanism instead of traditional rigid links reduces the degrees of freedom of the finger to one. The dielectric elastomer actuator was designed and fabricated as a smart actuator for the system, which supports the low cost of the system. A kinematic analysis of the cable-driven mechanism has been done. Parameters of the actuator were optimized to reach the required output. In order to characterize the performance of the actuator, a uniaxial tension test, isotonic test, and isometric test have been implemented.

Modeling dynamic behavior of dielectric elastomer muscle for robotic applications

“…Recently, another free energy modeling method of the spring-rolled DEA was reported, which describes the strain energy of the material with the Yeoh form. This model was also verified by comparing theoretical data with the experiment (Amin et al, 2020). However, although both hyperelastic modeling approaches contributed to improving modeling capability, the models still could allow accurate estimation of the actuation performance in the specific condition only.…”

“…• Robotic kinematic application: DE muscles have been utilized to operate robotic systems. A robotic hand, where DE muscles move fingers through a pulley mechanism (Jung et al, 2006), and a cabledriven hand exoskeleton for rehabilitation, where DE muscles assist finger extension (Amin et al, 2020), have been proposed. In such robotic kinematic applications, it is important to amplify the DE muscle's mechanical strength and/or its displacement.…”

Dielectric elastomer actuators as artificial muscles for wearable robots

“…Later, Carpi et al (2014) studied the feasibility of applying linear expanding DEAs (with corrugated metal electrodes) as variable stiffness elements to such type of orthosis and verified that the stiffness can be continuously modulated during the finger flexion/extension. Amin et al (2020) also assessed the application of dielectric elastomers (spring-roll actuators) for hand rehabilitation devices (Figure 12(b)) and their results support that DEAs enable portable, simple, and low-cost rehabilitation systems.…”

“…The actuator is placed on the back of the hand, inside the transparent case (Reprinted from Carpi et al (2008), with permission from the authors). (b) Hand orthosis with spring-roll DEAs (inside the yellow structure in the back of the forearm) (Amin et al, 2020) (Reprinted from Amin et al (2020)).…”

Low‐Voltage Soft Actuators for Interactive Human–Machine Interfaces

“…[269,270] Also, a hand rehabilitation system that utilizes DEAs as a smart actuator has been reported. [273] In this system, cables and spring-rolled DEAs are used, resembling natural tendons and muscles, respectively, where voltage application causes finger flexion while voltage removal returns the finger to the extended state. Similarly, the complaint nature of DEAs has led to the development of active compression bandages (ACB) that targets venous pooling disorders at the body's lower extremities.…”