Exo-Wrist: A Soft Tendon-Driven Wrist-Wearable Robot With Active Anchor for Dart-Throwing Motion in Hemiplegic Patients

Choi, Hyung‐Min; Kang, Brian Byunghyun; Jung, Bong-Keun; Cho, Kyu-Jin

doi:10.1109/lra.2019.2931607

Cited by 44 publications

(51 citation statements)

References 29 publications

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“…One end of a steel wire was connected to the wearable robot, and the other end of the wire was connected to a load cell that measured the tension in the wire. The torque was estimated by multiplying the distance between the universal joint and the wire by the tension [45]. The simple equation for the estimation of the torque is described in Equation (2).…”

Section: Torque Evaluationmentioning

confidence: 99%

“…Applying soft robotic technologies is a great approach for a compact, lightweight, user-friendly and portable exoskeleton for the upper limb, since the soft actuators and sensors are lightweight, compact and have high DOFs [36][37][38][39][40][41][42][43][44][45]. Pneumatic actuators are widely used for wearable applications since they can produce high force compared to that of other soft actuators along with large deformations.…”

Section: Introductionmentioning

confidence: 99%

“…However, the systems that use the pneumatic actuators require compressors and regulators, which in turn makes it hard to be used as a portable robot. Tendon-driven systems are also generally employed for designing wearable robots [42][43][44][45]. The use of Bowden cables along with DC motors [42,43] or twisted coil actuators [44] allows locating the actuators away from the point of interest, reducing the weight on the wearer and mobilizing the external joints that were constrained using the rigid exoskeleton.…”

Section: Introductionmentioning

confidence: 99%

“…The use of Bowden cables along with DC motors [42,43] or twisted coil actuators [44] allows locating the actuators away from the point of interest, reducing the weight on the wearer and mobilizing the external joints that were constrained using the rigid exoskeleton. For example, Choi et al used a simple cable-driven wearable robot with flexible polymer structures and an active anchor to produce the dart-throwing motion of the wrist [45]. However, further improvement in the anchoring mechanism is needed to accomplish a precise and repetitive motion.…”

Section: Introductionmentioning

confidence: 99%

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Design of Shape Memory Alloy-Based Soft Wearable Robot for Assisting Wrist Motion

et al. 2019

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In this paper, we propose a shape memory alloy (SMA)-based wearable robot that assists the wrist motion for patients who have difficulties in manipulating the lower arm. Since SMA shows high contraction strain when it is designed as a form of coil spring shape, the proposed muscle-like actuator was designed after optimizing the spring parameters. The fabricated actuator shows a maximum force of 10 N and a maximum contraction ratio of 40%. The SMA-based wearable robot, named soft wrist assist (SWA), assists 2 degrees of freedom (DOF) wrist motions. In addition, the robot is totally flexible and weighs 151g for the wearable parts. A maximum torque of 1.32 Nm was measured for wrist flexion, and a torque of larger than 0.5 Nm was measured for the other motions. The robot showed the average range of motion (ROM) with 33.8, 30.4, 15.4, and 21.4 degrees for flexion, extension, ulnar, and radial deviation, respectively. Thanks to the soft feature of the SWA, time cost for wearing the device is shorter than 2 min as was also the case for patients when putting it on by themselves. From the experimental results, the SWA is expected to support wrist motion for diverse activities of daily living (ADL) routinely for patients.

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Section: Torque Evaluationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Design of Shape Memory Alloy-Based Soft Wearable Robot for Assisting Wrist Motion

et al. 2019

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“…Compared to the conventional rigid robotic manipulators, CDMs have advantages of large workspace, low moving mass, high payload-to-weight ratio, and variable stiffness. As such, they have been applied in inspection and repair [1][2][3], human-robot interaction [4][5][6], moving and lifting payloads [7][8][9] and wearable robots [10][11][12][13][14]. Since cables have unilateral driving properties, i.e., can pull but cannot push, the number of driving cables in a CDM is greater than the number of its Degree-of-Freedom (DOF), yielding redundant actuation.…”

Section: Introductionmentioning

confidence: 99%

Study on Stiffness-Oriented Cable Tension Distribution for a Symmetrical Cable-Driven Mechanism

Yang

Chen

et al. 2019

Symmetry

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In this paper, we focus on the issues pertaining to stiffness-oriented cable tension distributionfor a symmetrical 6-cable-driven spherical joint module (6-CSJM), which can be employed to constructmodular cable-driven manipulators. Due to the redundant actuation of the 6-CSJM, three cables areemployed for position regulation by adjusting the cable lengths, and the remaining three cables areutilized for stiffness regulation by adjusting the cable tensions, i.e., the position and stiffness can beregulated simultaneously. To increase the range of stiffness regulation, a variable stiffness device(VSD) is designed, which is serially connected to the driving cable. Since the stiffness model of the6-CSJM with VSDs is very complicated, it is difficult to directly solve the cable tensions from thedesired stiffness. The stiffness-oriented cable tension distribution issue is formulated as a nonlinearconstrained optimization problem, and the Complex method is employed to obtain optimal tensiondistributions. Furthermore, to significantly improve the computation efficiency, a decision variableelimination technique is proposed to deal with the equality constraints, which reduces decision variablesfrom 6 to 3. A comprehensive simulation study is conducted to verify the effectiveness of the proposedmethod, showing that the 6-CSJM can accurately achieve the desired stiffness through cable tensionoptimization.

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Textile Technology for Soft Robotic and Autonomous Garments

Sánchez¹,

Walsh²,

Wood³

2020

Adv Funct Materials

167

123

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Textiles have emerged as a promising class of materials for developing wearable robots that move and feel like everyday clothing. Textiles represent a favorable material platform for wearable robots due to their flexibility, low weight, breathability, and soft hand‐feel. Textiles also offer a unique level of programmability because of their inherent hierarchical nature, enabling researchers to modify and tune properties at several interdependent material scales. With these advantages and capabilities in mind, roboticists have begun to use textiles, not simply as substrates, but as functional components that program actuation and sensing. In parallel, materials scientists are developing new materials that respond to thermal, electrical, and hygroscopic stimuli by leveraging textile structures for function. Although textiles are one of humankind's oldest technologies, materials scientists and roboticists are just beginning to tap into their potential. This review provides a textile‐centric survey of the current state of the art in wearable robotic garments and highlights metrics that will guide materials development. Recent advances in textile materials for robotic components (i.e., as sensors, actuators, and integration components) are described with a focus on how these materials and technologies set the stage for wearable robots programmed at the material level.

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Exo-Wrist: A Soft Tendon-Driven Wrist-Wearable Robot With Active Anchor for Dart-Throwing Motion in Hemiplegic Patients

Cited by 44 publications

References 29 publications

Design of Shape Memory Alloy-Based Soft Wearable Robot for Assisting Wrist Motion

Design of Shape Memory Alloy-Based Soft Wearable Robot for Assisting Wrist Motion

Study on Stiffness-Oriented Cable Tension Distribution for a Symmetrical Cable-Driven Mechanism

Textile Technology for Soft Robotic and Autonomous Garments

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