An untethered cable-driven ankle exoskeleton with plantarflexion-dorsiflexion bidirectional movement assistance

Wang, Tianmiao; Pei, Xitong; Hou, Taogang; Fan, Yubo; Yang, Xuan; Herr, Hugh M.; Yang, Xingbang

doi:10.1631/fitee.1900455

Cited by 23 publications

(17 citation statements)

References 39 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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“…Electric actuators were the most popular actuators deployed in the reviewed PAEs. They were powered by on-board battery packs [37,41,56,57,61,[65][66][67][76][77][78][79][80][81][82][83][84]86,87,94,[100][101][102]112,113,115,[118][119][120]126,127,130,144,145,[156][157][158][159][160][172][173][174][175]177,184,187,189,234,235], DC off-board power supply units [10,…”

Section: Low-level Control and Machine-machine Sensorsmentioning

confidence: 99%

“…Cable/rope tension Tension sensor [53,182] force sensor [57] load cell [39,58,69,[108][109][110][122][123][124][125][126][127][128][129]180,183,204] strain gauge [72,113,181] Mechanical deflection Potentiometer [10,55,67,108,110,137,146,153,176] encoder [206,207,236] Pressure Pressure sensor [62,63,146,156,158,166,171,173,176,232] Pneumatic muscle force Load cell [11,38,49,50,…”

Section: Measured Parameter Sensormentioning

confidence: 99%

“…Phase-based control algorithms aim to track a desired ankle joint torque or angular movement based on the user’s gait phase and kinematic states, measured by a variety of mechanically intrinsic wearable sensors [ 10 , 37 , 38 , 39 , 40 , 41 , 43 , 49 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 , 94 , 95 , 96 ,…”

Section: Sensor Technologies Used In Control Hierarchy Of the Paesmentioning

confidence: 99%

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Application of Wearable Sensors in Actuation and Control of Powered Ankle Exoskeletons: A Comprehensive Review

kian

Widanapathirana

Joseph

et al. 2022

Sensors

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Powered ankle exoskeletons (PAEs) are robotic devices developed for gait assistance, rehabilitation, and augmentation. To fulfil their purposes, PAEs vastly rely heavily on their sensor systems. Human–machine interface sensors collect the biomechanical signals from the human user to inform the higher level of the control hierarchy about the user’s locomotion intention and requirement, whereas machine–machine interface sensors monitor the output of the actuation unit to ensure precise tracking of the high-level control commands via the low-level control scheme. The current article aims to provide a comprehensive review of how wearable sensor technology has contributed to the actuation and control of the PAEs developed over the past two decades. The control schemes and actuation principles employed in the reviewed PAEs, as well as their interaction with the integrated sensor systems, are investigated in this review. Further, the role of wearable sensors in overcoming the main challenges in developing fully autonomous portable PAEs is discussed. Finally, a brief discussion on how the recent technology advancements in wearable sensors, including environment—machine interface sensors, could promote the future generation of fully autonomous portable PAEs is provided.

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“…To reduce the mass of systems, it is an effective method to utilize the clockwise and counterclockwise rotation of the motor to realize the different movement. For example, the flexion and extension of the same joint are assisted by single motors in [ 13 , 14 , 15 ], or one motor to be used for hip flexion and knee extension on the same leg [ 16 ], or one motor to be used for the same joint on both legs, such as right ankle plantar flexion and left ankle plantar flexion [ 17 ]. However, as the walking speed increases, the assistive force profile becomes shorter or the peak decreases, because there is less time left for the motor to change direction of rotation.…”

Section: Introductionmentioning

confidence: 99%

A Time Division Multiplexing Inspired Lightweight Soft Exoskeleton for Hip and Ankle Joint Assistance

Chen

Shi

et al. 2021

Micromachines

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Exoskeleton robots are frequently applied to augment or assist the user’s natural motion. Generally, each assisted joint corresponds to at least one specific motor to ensure the independence of movement between joints. This means that as there are more joints to be assisted, more motors are required, resulting in increasing robot weight, decreasing motor utilization, and weakening exoskeleton robot assistance efficiency. To solve this problem, the design and control of a lightweight soft exoskeleton that assists hip-plantar flexion of both legs in different phases during a gait cycle with only one motor is presented in this paper. Inspired by time-division multiplexing and the symmetry of walking motion, an actuation scheme that uses different time-periods of the same motor to transfer different forces to different joints is formulated. An automatic winding device is designed to dynamically change the loading path of the assistive force at different phases of the gait cycle. The system is designed to assist hip flexion and plantar flexion of both legs with only one motor, since there is no overlap between the hip flexion movement and the toe-offs movement of the separate legs during walking. The weight of the whole system is only 2.24 kg. PD iterative control is accomplished by an algorithm that utilizes IMUs attached on the thigh recognizing the maximum hip extension angle to characterize toe-offs indirectly, and two load cells to monitor the cable tension. In the study of six subjects, muscle fatigue of the rectus femoris, vastus lateralis, gastrocnemius and soleus decreased by an average of 14.69%, 6.66%, 17.71%, and 8.15%, respectively, compared to scenarios without an exoskeleton.

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An untethered cable-driven ankle exoskeleton with plantarflexion-dorsiflexion bidirectional movement assistance

Cited by 23 publications

References 39 publications

A Wearable Soft Fabric Sleeve for Upper Limb Augmentation

A Wearable Soft Fabric Sleeve for Upper Limb Augmentation

Application of Wearable Sensors in Actuation and Control of Powered Ankle Exoskeletons: A Comprehensive Review

A Time Division Multiplexing Inspired Lightweight Soft Exoskeleton for Hip and Ankle Joint Assistance

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