Influence of a Compatible Design on Physical Human-Robot Interaction Force: a Case Study of a Self-Adapting Lower-Limb Exoskeleton Mechanism

Li, Jianfeng; Zuo, Shuguang; Xu, Cheng-Hui; Zhang, Leiyu; Dong, Mingjie; Tao, Chunjing; Ji, Run

doi:10.1007/s10846-019-01063-5

Cited by 19 publications

(16 citation statements)

References 42 publications

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“…Literature on the effects of misalignments is scarce. Some studies investigated the effects of compensation mechanisms on forces at the skin-cuff interface [ 12 , 13 ] and one study introduced a misalignment to a lower limb exoskeleton to study the effects on gait [ 8 ]. Due to the limited amount of studies, there is an overall lack of knowledge regarding misalignments in wearable robots.…”

Section: Introductionmentioning

confidence: 99%

Assessing effects of exoskeleton misalignment on knee joint load during swing using an instrumented leg simulator

Bessler

Schaake

Prange-Lasonder

et al. 2022

J NeuroEngineering Rehabil

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Background Exoskeletons are working in parallel to the human body and can support human movement by exerting forces through cuffs or straps. They are prone to misalignments caused by simplified joint mechanics and incorrect fit or positioning. Those misalignments are a common safety concern as they can cause undesired interaction forces. However, the exact mechanisms and effects of misalignments on the joint load are not yet known. The aim of this study was therefore to investigate the influence of different directions and magnitudes of exoskeleton misalignment on the internal knee joint forces and torques of an artificial leg. Methods An instrumented leg simulator was used to quantify the changes in knee joint load during the swing phase caused by misalignments of a passive knee brace being manually flexed. This was achieved by an experimenter pulling on a rope attached to the distal end of the knee brace to create a flexion torque. The extension was not actuated but achieved through the weight of the instrumented leg simulator. The investigated types of misalignments are a rotation of the brace around the vertical axis and a translation in anteroposterior as well as proximal/distal direction. Results The amount of misalignment had a significant effect on several directions of knee joint load in the instrumented leg simulator. In general, load on the knee joint increased with increasing misalignment. Specifically, stronger rotational misalignment led to higher forces in mediolateral direction in the knee joint as well as higher ab-/adduction, flexion and internal/external rotation torques. Stronger anteroposterior translational misalignment led to higher mediolateral knee forces as well as higher abduction and flexion/extension torques. Stronger proximal/distal translational misalignment led to higher posterior and tension/compression forces. Conclusions Misalignments of a lower leg exoskeleton can increase internal knee forces and torques during swing to a multiple of those experienced in a well-aligned situation. Despite only taking swing into account, this is supporting the need for carefully considering hazards associated with not only translational but also rotational misalignments during wearable robot development and use. Also, this warrants investigation of misalignment effects in stance, as a target of many exoskeleton applications.

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Section: Introductionmentioning

confidence: 99%

Assessing effects of exoskeleton misalignment on knee joint load during swing using an instrumented leg simulator

Bessler

Schaake

Prange-Lasonder

et al. 2022

J NeuroEngineering Rehabil

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“…In the design, the upper arm and forearm cuffs are fitted with strain gauge-based force sensors (see Figure 8(a)) to measure interaction forces, noted by F int , between the human and UB-AXO. It is noted that there are many different ways to measure the interaction force, either using commercial standard load cell, such as ATI six-DoF force sensor, 44 or design special ones to meeting specific requirements. 45 In this system, we designed our own force measuring device to meet space constraints to achieve a compact and portable system.…”

Section: Ub-axo Adjustments and Attachmentsmentioning

confidence: 99%

Design of a powered full-body exoskeleton for physical assistance of elderly people

Christensen

Rafique

Bai

2021

International Journal of Advanced Robotic Systems

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The development of full-body exoskeletons has been limited due to design complexities, mechanical integration intricacies, and heavier weight, among others. Consequently, very few full-body powered exoskeletons were developed to address these challenges, in spite of increasing demand for physical assistance at full-body level. This article presents an overall design and development of a powered full-body exoskeleton called “FB-AXO.” Primarily, FB-AXO consists of two main subsystems, a lower-body and an upper-body subsystem connected together through waist and spine modules. FB-AXO is developed for the support of weaker ageing adults so that they can continue functioning their daily activities. At the onset of the project, a set of functional and design requirements has been formulated with an extensive end-user involvement and then used in realizing the FB-AXO. The final FB-AXO design comprises of 27 degrees of freedom, of which 10 are active and 17 are passive, having a total system weight of 25 kg. Overall, the article elaborates comprehensively the design, construction, and preliminary testing of FB-AXO. The work effectively addresses design challenges including kinematic compatibility and modularity with innovative solutions. The details of the mechanics, sensors, and electronics of the two subsystems along with specifics of human-exoskeleton interfaces and ranges of motion are also provided. The FB-AXO exoskeleton effectively demonstrated to assist full-body motions such as normal walking, standing, bending as well as executing lifting and carrying tasks to meet the daily living demands of older users.

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“…The second group is intended for the user’s kinematics and kinetics commonly used to assess LLEs. Similarly, the device’s indicators are also evaluated through kinematic and kinetic outcomes [ 12 , 16 , 17 ]. Previous indicators analyzed the joints of interest (e.g., joint moments, joint kinematics, and kinetics) and the spatiotemporal parameters (e.g., cadence, step length, step width, walking speed, phase time), performing a specific task that induces a motor skill.…”

Section: Introductionmentioning

confidence: 99%

“…On the one hand, Li et al [ 16 ] presented the kinetic approach focused on the reaction forces between the physical interfaces and a passive exoskeleton. This study analyzed the kinetic differences, by allowing or restricting two degrees of freedom (DOF), as well as the internal forces and corresponding torques inside the physical interfaces.…”

Section: Introductionmentioning

confidence: 99%

“…This study analyzed the kinetic differences, by allowing or restricting two degrees of freedom (DOF), as well as the internal forces and corresponding torques inside the physical interfaces. The variables are also measured indirectly along the sagittal plane, varying between 0.403 N and 20.678 N and 0.025 N.m and 1.949 N.m, respectively [ 16 ]. Another approach deployed by Leal-Junior et al [ 26 ] embedded force sensors to identify the sinks of energy among the physical interfaces, in which the peak force varied between 5 N and 26 N. In this context, kinetic analysis quantifies the HRI on the physical interfaces; even so, a few studies have been deployed through more than one-dimensional (i.e., sagittal or transverse plane) approaches [ 24 ].…”

Section: Introductionmentioning

confidence: 99%

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Development of a 3D Relative Motion Method for Human–Robot Interaction Assessment

Ballén-Moreno

Bautista

Provot

et al. 2022

Sensors

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Exoskeletons have been assessed by qualitative and quantitative features known as performance indicators. Within these, the ergonomic indicators have been isolated, creating a lack of methodologies to analyze and assess physical interfaces. In this sense, this work presents a three-dimensional relative motion assessment method. This method quantifies the difference of orientation between the user’s limb and the exoskeleton link, providing a deeper understanding of the Human–Robot interaction. To this end, the AGoRA exoskeleton was configured in a resistive mode and assessed using an optoelectronic system. The interaction quantified a difference of orientation considerably at a maximum value of 41.1 degrees along the sagittal plane. It extended the understanding of the Human–Robot Interaction throughout the three principal human planes. Furthermore, the proposed method establishes a performance indicator of the physical interfaces of an exoskeleton.

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Influence of a Compatible Design on Physical Human-Robot Interaction Force: a Case Study of a Self-Adapting Lower-Limb Exoskeleton Mechanism

Cited by 19 publications

References 42 publications

Assessing effects of exoskeleton misalignment on knee joint load during swing using an instrumented leg simulator

Assessing effects of exoskeleton misalignment on knee joint load during swing using an instrumented leg simulator

Design of a powered full-body exoskeleton for physical assistance of elderly people

Development of a 3D Relative Motion Method for Human–Robot Interaction Assessment

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