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You searched for subject:(passive exoskeletons). Showing records 1 – 2 of 2 total matches.

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Colorado School of Mines

1. Saadatzi, Mohammadhossein. Combined simulation of musculoskeletal biomechanics and exoskeletons.

Degree: PhD, Mechanical Engineering, 2018, Colorado School of Mines

Wearable robots are becoming increasingly common, in both research laboratories and the industry, due to their significant potential benefits in rehabilitation engineering, assistive robotics, ergonomics, and power augmentation. Thus far, design and control of these devices have primarily relied on exhaustive experimental procedures. Alternatively, combined predictive simulations of device and human musculoskeletal mechanics offer a promising approach to decreasing necessary human subject experiment scenarios and cost. In simulation, the device parameter space can be explored to determine the most promising design solutions and parameter values, which, in turn, can inform the human subject experiment design. This dissertation focuses on building a framework for combined musculoskeletal and exoskeleton dynamics for walking. In the framework, the actuation profiles of body muscles are optimized using a single-shooting method. The single-shooting method facilitates convenient consideration of human musculoskeletal system models with varying levels of complexity, various exoskeletons and controllers, and different objective functions. High-throughput computing resources are employed for the computationally-intensive optimizations in this framework. The proposed framework is used for study and design of passive exoskeletons for reducing the metabolic energy expenditure during walking. The simulation results suggest that elastic elements acting in parallel with lower-limb uniarticular muscles can reduce the metabolic cost of walking by up to 28%. These results support the use of predictive simulations as a tool for the study and conceptual design of exoskeletons and can accelerate device and control development. Advisors/Committee Members: Silverman, Anne K. (advisor), Celik, Ozkan (committee member), Bach, Joel M. (committee member), Petrella, Anthony J. (committee member), Zhang, Hao (committee member).

Subjects/Keywords: bipedal walking; passive exoskeletons; wearable robots; metabolic energy expenditure; biomechanics; predictive simulation

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Saadatzi, M. (2018). Combined simulation of musculoskeletal biomechanics and exoskeletons. (Doctoral Dissertation). Colorado School of Mines. Retrieved from http://hdl.handle.net/11124/172541

Chicago Manual of Style (16th Edition):

Saadatzi, Mohammadhossein. “Combined simulation of musculoskeletal biomechanics and exoskeletons.” 2018. Doctoral Dissertation, Colorado School of Mines. Accessed April 16, 2021. http://hdl.handle.net/11124/172541.

MLA Handbook (7th Edition):

Saadatzi, Mohammadhossein. “Combined simulation of musculoskeletal biomechanics and exoskeletons.” 2018. Web. 16 Apr 2021.

Vancouver:

Saadatzi M. Combined simulation of musculoskeletal biomechanics and exoskeletons. [Internet] [Doctoral dissertation]. Colorado School of Mines; 2018. [cited 2021 Apr 16]. Available from: http://hdl.handle.net/11124/172541.

Council of Science Editors:

Saadatzi M. Combined simulation of musculoskeletal biomechanics and exoskeletons. [Doctoral Dissertation]. Colorado School of Mines; 2018. Available from: http://hdl.handle.net/11124/172541

2. Alemi, Mohammad Mehdi. Biomechanical Assessment and Metabolic Evaluation of Passive Lift-Assistive Exoskeletons During Repetitive Lifting Tasks.

Degree: PhD, Mechanical Engineering, 2019, Virginia Tech

Low back pain (LBP) due to overexertion is known as one of the most important sources of nonfatal occupational injuries especially for the workers or manual material handlers who are involved in frequent or repetitive lifting tasks. Every year, many workers are temporarily or permanently disabled due to overuse injuries at workplace. In the past several years, industrial exoskeletons have gained growing interest among biomechanist, roboticist, and other human factor researchers as potential assistive devices to reduce the risk of LBP. In general, the industrial exoskeletons are either “passive or “active”; Active exoskeletons are powered by mechanical/electrical motors and actuators, however, the passive exoskeletons often work using cheaper devices such as gas or metal springs, elastic elements, etc. The exoskeletons discussed in this dissertation are categorized as passive rigid lower-back exoskeletons and they function by storing energy in a spring when the wearer bends and returning the stored energy when the wearer lifts. This dissertation consists of three studies that attempt to provide comprehensive biomechanical evaluations and metabolic assessments of three passive lift-assistive exoskeletons (i.e., VT-Lowe’s Exoskeleton, Laevo and SuitX). The first study examined the efficacy of a novel lift-assistive exoskeleton, VT-Lowe’s exoskeleton, in reducing the peak and mean activity of back and leg muscles. The results of this study demonstrated that the exoskeleton reduced the peak and mean activity of back and leg muscles for symmetric and asymmetric lifting tasks. VT-Lowe’s exoskeleton also showed higher reduction in activity of back muscles compared to other passive lift-assistive exoskeletons available in the literature. In the second study, the metabolic cost reduction with VT-Lowe’s exoskeleton was theoretically modeled and the modeling outcomes were compared to metabolic costs measurements when the exoskeleton was worn. The experimental findings of this study supported the applicability of the exoskeleton by significantly reducing the metabolic cost and oxygen uptake during the freestyle repetitive lifting tasks. Moreover, the prediction metabolic cost model of the exoskeleton showed high accuracy as the absolute prediction errors were within 1.5%. In the third study, the biomechanical evaluation, energy expenditure and subjective assessments of two passive back-support exoskeletons (Laevo and SuitX) were examined in repetitive lifting tasks. The lifting tasks of this study were simulated in a laboratory environment for two different levels of lifting symmetry (symmetric vs. asymmetric) and lifting posture (standing vs. kneeling). Findings of this study showed that both exoskeleton significantly lowered the peak activity of back muscles during the dynamic lifting tasks. Moreover, using both exoskeletons provided metabolic cost savings in all of the studies conditions. Overall, results obtained from the three studies in this dissertation verified the capability of these passive lift- vi assistive… Advisors/Committee Members: Nussbaum, Maury A. (committeechair), Asbeck, Alan T. (committeechair), Queen, Robin M. (committee member), Sandu, Corina (committee member), Kim, Sun Wook (committee member), Leonessa, Alexander (committee member).

Subjects/Keywords: Passive Exoskeletons; Back-Support Exoskeleton (BSE); Soft Robotics; Lift-assistive Exoskeletons; Work Related Musculoskeletal Disorders (WMSDs); Low Back Pain Prevention; Electromyography (EMG); Metabolic Assessment; Discomfort and Muscle Exertion

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Alemi, M. M. (2019). Biomechanical Assessment and Metabolic Evaluation of Passive Lift-Assistive Exoskeletons During Repetitive Lifting Tasks. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/93725

Chicago Manual of Style (16th Edition):

Alemi, Mohammad Mehdi. “Biomechanical Assessment and Metabolic Evaluation of Passive Lift-Assistive Exoskeletons During Repetitive Lifting Tasks.” 2019. Doctoral Dissertation, Virginia Tech. Accessed April 16, 2021. http://hdl.handle.net/10919/93725.

MLA Handbook (7th Edition):

Alemi, Mohammad Mehdi. “Biomechanical Assessment and Metabolic Evaluation of Passive Lift-Assistive Exoskeletons During Repetitive Lifting Tasks.” 2019. Web. 16 Apr 2021.

Vancouver:

Alemi MM. Biomechanical Assessment and Metabolic Evaluation of Passive Lift-Assistive Exoskeletons During Repetitive Lifting Tasks. [Internet] [Doctoral dissertation]. Virginia Tech; 2019. [cited 2021 Apr 16]. Available from: http://hdl.handle.net/10919/93725.

Council of Science Editors:

Alemi MM. Biomechanical Assessment and Metabolic Evaluation of Passive Lift-Assistive Exoskeletons During Repetitive Lifting Tasks. [Doctoral Dissertation]. Virginia Tech; 2019. Available from: http://hdl.handle.net/10919/93725

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