Towards Untethered Soft Pneumatic Exosuits Using Low-Volume Inflatable Actuator Composites and a Portable Pneumatic Source

Sridar, Saivimal; Poddar, Souvik; Tong, Yida; Polygerinos, Panagiotis; Zhang, Wenlong

doi:10.1109/lra.2020.2986744

Cited by 24 publications

(18 citation statements)

References 30 publications

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“…The target population of such a soft exoskeleton has been identified to be individuals with some physical disability that needs assistance during activities of daily living (ADLs), such as drinking from a mug, combing the hair, eating with a spoon, or answering the phone. Therefore, future development of the current soft robotic sleeve must involve a portable hydraulic source that can be worn by the users, such as the works proposed by [68][69][70]. During the mannequin experiment, the device showed the ability of maintaining the arm posture and a smooth natural elbow flexion motion.…”

Section: Discussionmentioning

confidence: 99%

A Wearable Soft Fabric Sleeve for Upper Limb Augmentation

Hoang

Bussu

et al. 2021

Sensors

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Soft actuators (SAs) have been used in many compliant robotic structure and wearable devices, due to their safe interaction with the wearers. Despite advances, the capability of current SAs is limited by scalability, high hysteresis, and slow responses. In this paper, a new class of soft, scalable, and high-aspect ratio fiber-reinforced hydraulic SAs is introduced. The new SA uses a simple fabrication process of insertion where a hollow elastic rubber tube is directly inserted into a constrained hollow coil, eliminating the need for the manual wrapping of an inextensible fiber around a long elastic structure. To provide high adaptation to the user skin for wearable applications, the new SAs are integrated into flexible fabrics to form a wearable fabric sleeve. To monitor the SA elongation, a soft liquid metal-based fabric piezoresistive sensor is also developed. To capture the nonlinear hysteresis of the SA, a novel asymmetric hysteresis model which only requires five model parameters in its structure is developed and experimentally validated. The new SAs-driven wearable robotic sleeve is scalable, highly flexible, and lightweight. It can also produce a large amount of force of around 23 N per muscle at around 30% elongation, to provide useful assistance to the human upper limbs. Experimental results show that the soft fabric sleeve can augment a user’s performance when working against a load, evidenced by a significant reduction on the muscular effort, as monitored by electromyogram (EMG) signals. The performance of the developed SAs, soft fabric sleeve, soft liquid metal fabric sensor, and nonlinear hysteresis model reveal that they can effectively modulate the level of assistance for the wearer. The new technologies obtained from this work can be potentially implemented in emerging assistive applications, such as rehabilitation, defense, and industry.

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Section: Discussionmentioning

confidence: 99%

A Wearable Soft Fabric Sleeve for Upper Limb Augmentation

Hoang

Bussu

et al. 2021

Sensors

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“…Recently, portable pneumatic sources are developed and users are able to carry it on waist or back (Fig. 1c) [3]. Elastomer actuators have been applied in exosuits for shoulder (Fig.…”

Section: Fluid-driven Actuatorsmentioning

confidence: 99%

Human Assistance and Augmentation with Wearable Soft Robotics: a Literature Review and Perspectives

et al. 2021

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Purpose of ReviewWearable soft robotics has demonstrated many unique capabilities in human assistance and augmentation. This paper discusses the recent trends and remaining challenges in designing soft actuators, soft sensors, and controllers for wearable soft robots.Recent Findings Different actuation mechanisms for wearable systems were investigated in this review. We include a synopsis on the design of soft sensors and algorithms for sensor fusion and discuss the recent trends for sensing simultaneous deformations and implementing machine learning techniques for soft sensor fusion. We also present a discussion on layered controller design and the evaluation metrics for experiments with healthy and impaired subjects. SummaryWe review three commonly used soft actuation mechanisms and provide their characteristics, in which the balance between material stiffness and functionality is still a challenge. We present the advances in soft sensor design and discuss the challenges in fusion algorithms for wearable soft sensors, such as inter-subject adaptability and sensor location movement. We also discuss the model-based and model-free controller design together with the evaluation criteria for healthy and impaired users, in which autonomous operation for personalized assistance is still an open challenge for controller design.

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“…While useful, PAMs may be limited by stroke length, since their motion depends on contraction. A larger range of motion may be afforded by PRAs (pneumatic rotary actuators) ( Sridar et al, 2017 ; Chung et al, 2018 ; Tiana M. Miller-Jackson et al, 2019 ; Veale et al, 2019 ; Fang et al, 2020 ; Park et al, 2020 ; Sridar et al, 2020 ; Veale et al, 2021 ), a type of SPA which produces rotary motion. J. Chung et al presented the PRA-driven Exoboot for ankle motion assistance and reported a maximum torque of 39 Nm at a supply pressure of 483kPa and an ankle angle of 60° ( Chung et al, 2018 ).…”

Section: Introductionmentioning

confidence: 99%

A Wearable Soft Robotic Exoskeleton for Hip Flexion Rehabilitation

et al. 2022

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Leg motion is essential to everyday tasks, yet many face a daily struggle due to leg motion impairment. Traditional robotic solutions for lower limb rehabilitation have arisen, but they may bare some limitations due to their cost. Soft robotics utilizes soft, pliable materials which may afford a less costly robotic solution. This work presents a soft-pneumatic-actuator-driven exoskeleton for hip flexion rehabilitation. An array of soft pneumatic rotary actuators is used for torque generation. An analytical model of the actuators is validated and used to determine actuator parameters for the target application of hip flexion. The performance of the assembly is assessed, and it is found capable of the target torque for hip flexion, 19.8 Nm at 30°, requiring 86 kPa to reach that torque output. The assembly exhibits a maximum torque of 31 Nm under the conditions tested. The full exoskeleton assembly is then assessed with healthy human subjects as they perform a set of lower limb motions. For one motion, the Leg Raise, a muscle signal reduction of 43.5% is observed during device assistance, as compared to not wearing the device. This reduction in muscle effort indicates that the device is effective in providing hip flexion assistance and suggests that pneumatic-rotary-actuator-driven exoskeletons are a viable solution to realize more accessible options for those who suffer from lower limb immobility.

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Towards Untethered Soft Pneumatic Exosuits Using Low-Volume Inflatable Actuator Composites and a Portable Pneumatic Source

Cited by 24 publications

References 30 publications

A Wearable Soft Fabric Sleeve for Upper Limb Augmentation

A Wearable Soft Fabric Sleeve for Upper Limb Augmentation

Human Assistance and Augmentation with Wearable Soft Robotics: a Literature Review and Perspectives

A Wearable Soft Robotic Exoskeleton for Hip Flexion Rehabilitation

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