A hip–knee–ankle exoskeleton emulator for studying gait assistance

2020 ◽  
pp. 027836492096145
Author(s):  
Gwendolyn M Bryan ◽  
Patrick W Franks ◽  
Stefan C Klein ◽  
Robert J Peuchen ◽  
Steven H Collins
Keyword(s):  
Computer Aided Design ◽  
Human Mobility ◽  
Knee Extension ◽  
Loop Optimization ◽  
Human In The Loop ◽  
Bill Of Materials ◽  
Wide Range ◽  
Ankle Exoskeleton ◽  
Hip Flexion ◽  
Aided Design

Lower-limb exoskeletons could improve the mobility of people with disabilities, older adults, workers, first responders, and military personnel. Despite recent advances, few products are commercially available and exoskeleton research is still often limited by hardware constraints. Many promising multi-joint assistance strategies, especially those with high-torque and high-power components, have yet to be tested because they are beyond the capabilities of current devices. To study these untested assistance strategies, we present a hip–knee–ankle exoskeleton emulator that can apply high torques and powers that match or exceed those observed in uphill running. The system has powerful off-board motors that actuate a 13.5 kg exoskeleton end effector worn by the user. It can apply up to 200 Nm of torque in hip flexion, hip extension, and ankle plantarflexion, 250 Nm of torque in knee extension, and 140 Nm of torque in knee flexion, with over 4.5 kW of power at each joint and a closed-loop torque bandwidth of at least 18 Hz in each direction of actuation. The exoskeleton is compliant in unactuated directions, adjustable for a wide range of users and comfortable during walking and running. When paired with human-in-the-loop optimization, we expect that this system will identify new assistance strategies to improve human mobility. A complete computer-aided design (CAD) model of the exoskeleton and a bill of materials are included and available for download.

scholarly journals Comparing optimized exoskeleton assistance of the hip, knee, and ankle in single and multi-joint configurations

2021 ◽  
Vol 2 ◽  
Author(s):  
Patrick W. Franks ◽  
Gwendolyn M. Bryan ◽  
Russell M. Martin ◽  
Ricardo Reyes ◽  
Ava C. Lakmazaheri ◽  
...  
Keyword(s):  
Human Mobility ◽  
Metabolic Cost ◽  
Metabolic Energy ◽  
Maximum Effect ◽  
Loop Optimization ◽  
Human In The Loop ◽  
Ankle Joints ◽  
Individual Effects ◽  
Single Well ◽  
Ankle Exoskeleton

Abstract Exoskeletons that assist the hip, knee, and ankle joints have begun to improve human mobility, particularly by reducing the metabolic cost of walking. However, direct comparisons of optimal assistance of these joints, or their combinations, have not yet been possible. Assisting multiple joints may be more beneficial than the sum of individual effects, because muscles often span multiple joints, or less effective, because single-joint assistance can indirectly aid other joints. In this study, we used a hip–knee–ankle exoskeleton emulator paired with human-in-the-loop optimization to find single-joint, two-joint, and whole-leg assistance that maximally reduced the metabolic cost of walking. Hip-only and ankle-only assistance reduced the metabolic cost of walking by 26 and 30% relative to walking in the device unassisted, confirming that both joints are good targets for assistance (N = 3). Knee-only assistance reduced the metabolic cost of walking by 13%, demonstrating that effective knee assistance is possible (N = 3). Two-joint assistance reduced the metabolic cost of walking by between 33 and 42%, with the largest improvements coming from hip-ankle assistance (N = 3). Assisting all three joints reduced the metabolic cost of walking by 50%, showing that at least half of the metabolic energy expended during walking can be saved through exoskeleton assistance (N = 4). Changes in kinematics and muscle activity indicate that single-joint assistance indirectly assisted muscles at other joints, such that the improvement from whole-leg assistance was smaller than the sum of its single-joint parts. Exoskeletons can assist the entire limb for maximum effect, but a single well-chosen joint can be more efficient when considering additional factors such as weight and cost.

scholarly journals Comparing optimized exoskeleton assistance of the hip, knee, and ankle in single and multi-joint configurations

2021 ◽  
Author(s):  
Patrick W. Franks ◽  
Gwendolyn M. Bryan ◽  
Russell M. Martin ◽  
Ricardo Reyes ◽  
Steven H. Collins
Keyword(s):  
Human Mobility ◽  
Metabolic Cost ◽  
Metabolic Energy ◽  
Maximum Effect ◽  
Loop Optimization ◽  
Human In The Loop ◽  
Ankle Joints ◽  
Individual Effects ◽  
Single Well ◽  
Ankle Exoskeleton

Exoskeletons that assist the hip, knee, and ankle joints have begun to improve human mobility, particularly by reducing the metabolic cost of walking. However, direct comparisons of optimal assistance of these joints, or their combinations, have not yet been possible. Assisting multiple joints may be more beneficial than the sum of individual effects, because muscles often span multiple joints, or less effective, because single-joint assistance can indirectly aid other joints. In this study, we used a hip-knee-ankle exoskeleton emulator paired with human-in-the-loop optimization to find single-joint, two-joint, and whole-leg assistance that maximally reduced the metabolic cost of walking for three participants. Hip-only and ankle-only assistance reduced the metabolic cost of walking by 26% and 30% relative to walking in the device unassisted, confirming that both joints are good targets for assistance. Knee-only assistance reduced the metabolic cost of walking by 13%, demonstrating that effective knee assistance is possible. Two-joint assistance reduced the metabolic cost of walking by between 34% and 42%, with the largest improvements coming from hip-ankle assistance. Assisting all three joints reduced the metabolic cost of walking by 50%, showing that at least half of the metabolic energy expended during walking can be saved through exoskeleton assistance. Changes in kinematics and muscle activity indicate that single-joint assistance indirectly assisted muscles at other joints, such that the improvement from whole-leg assistance was smaller than the sum of its single-joint parts. Exoskeletons can assist the entire limb for maximum effect, but a single well-chosen joint can be more efficient when considering additional factors such as weight and cost.

scholarly journals The Effects of Incline Level on Optimized Lower-Limb Exoskeleton Assistance

2021 ◽  
Author(s):  
Patrick W. Franks ◽  
Gwendolyn M. Bryan ◽  
Ricardo Reyes ◽  
Meghan P. O'Donovan ◽  
Karen N. Gregorczyk ◽  
...  
Keyword(s):  
Metabolic Cost ◽  
Knee Extension ◽  
Cost Of Transport ◽  
Loop Optimization ◽  
Human In The Loop ◽  
Lower Limb Exoskeleton ◽  
Walking Performance ◽  
Ankle Exoskeleton ◽  
The Cost ◽  
Hip Extension

For exoskeletons to be successful in real-world settings, they will need to be effective across a variety of terrains, including on inclines. While some single-joint exoskeletons have assisted incline walking, recent successes in level-ground assistance suggest that greater improvements may be possible by optimizing assistance of the whole leg. To understand how exoskeleton assistance should change with incline, we used human-in-the-loop optimization to find whole-leg exoskeleton assistance torques that minimized metabolic cost on a range of grades. We optimized assistance for three expert, able-bodied participants on 5 degree, 10 degree and 15 degree inclines using a hip-knee-ankle exoskeleton emulator. For all assisted conditions, the cost of transport was reduced by at least 50% relative to walking in the device with no assistance, a large improvement to walking that is comparable to the benefits of whole-leg assistance on level-ground. This corresponds to large absolute reductions in metabolic cost, with the most strenuous conditions reduced by 4.9 W/kg, more than twice the entire energy cost of level walking. Optimized extension torque magnitudes and exoskeleton power increased with incline, with hip extension, knee extension and ankle plantarflexion often growing as large as allowed by comfort-based limits. Applied powers on steep inclines were double the powers applied during level-ground walking, indicating that larger exoskeleton power may be optimal in scenarios where biological powers and costs are higher. Future exoskeleton devices can be expected to deliver large improvements in walking performance across a range of inclines, if they have sufficient torque and power capabilities.

Study on Application of CAD Used in Visual Advertising Design

2014 ◽  
Vol 571-572 ◽  
pp. 768-771
Author(s):  
Jun Liu
Keyword(s):  
Computer Aided Design ◽  
Television Advertising ◽  
Paper Study ◽  
Application Technology ◽  
Visual Effects ◽  
3D Technology ◽  
Wide Range ◽  
Computer Aided ◽  
Visual Impact ◽  
Aided Design

The 3D technology currently has in various engineering fields have a wide range of applications, all the 3D visual effects technology can bring us visual impact, the use of 3D technology produced by the television advertising more easily accepted by the audience, this paper study on the 3D computer-aided design advertising design application technology.

scholarly journals Optimized hip-knee-ankle exoskeleton assistance reduces the metabolic cost of walking with worn loads

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Gwendolyn M. Bryan ◽  
Patrick W. Franks ◽  
Seungmoon Song ◽  
Ricardo Reyes ◽  
Meghan P. O’Donovan ◽  
...  
Keyword(s):  
Body Weight ◽  
Muscle Activity ◽  
Metabolic Cost ◽  
Load Carriage ◽  
Heavy Load ◽  
Human In The Loop ◽  
Light Load ◽  
Wide Range ◽  
Ankle Exoskeleton ◽  
The Individual

Abstract Background Load carriage is common in a wide range of professions, but prolonged load carriage is associated with increased fatigue and overuse injuries. Exoskeletons could improve the quality of life of these professionals by reducing metabolic cost to combat fatigue and reducing muscle activity to prevent injuries. Current exoskeletons have reduced the metabolic cost of loaded walking by up to 22% relative to walking in the device with no assistance when assisting one or two joints. Greater metabolic reductions may be possible with optimized assistance of the entire leg. Methods We used human-in the-loop optimization to optimize hip-knee-ankle exoskeleton assistance with no additional load, a light load (15% of body weight), and a heavy load (30% of body weight) for three participants. All loads were applied through a weight vest with an attached waist belt. We measured metabolic cost, exoskeleton assistance, kinematics, and muscle activity. We performed Friedman’s tests to analyze trends across worn loads and paired t-tests to determine whether changes from the unassisted conditions to the assisted conditions were significant. Results Exoskeleton assistance reduced the metabolic cost of walking relative to walking in the device without assistance for all tested conditions. Exoskeleton assistance reduced the metabolic cost of walking by 48% with no load (p = 0.05), 41% with the light load (p = 0.01), and 43% with the heavy load (p = 0.04). The smaller metabolic reduction with the light load may be due to insufficient participant training or lack of optimizer convergence. The total applied positive power was similar for all tested conditions, and the positive knee power decreased slightly as load increased. Optimized torque timing parameters were consistent across participants and load conditions while optimized magnitude parameters varied. Conclusions Whole-leg exoskeleton assistance can reduce the metabolic cost of walking while carrying a range of loads. The consistent optimized timing parameters across participants and conditions suggest that metabolic cost reductions are sensitive to torque timing. The variable torque magnitude parameters could imply that torque magnitude should be customized to the individual, or that there is a range of useful torque magnitudes. Future work should test whether applying the load to the exoskeleton rather than the person’s torso results in larger benefits.

Towards Computer Aided Design and Analysis of Spatial Flexure Mechanisms

2016 ◽  
Author(s):  
Omer Anil Turkkan ◽  
Hai-Jun Su
Keyword(s):  
Computer Aided Design ◽  
Screw Theory ◽  
Design Tool ◽  
Future Design ◽  
Linear Elastic ◽  
Wide Range ◽  
Speed Up ◽  
System Equations ◽  
Compliance Matrices ◽  
Aided Design

Flexure mechanisms are the central part of numerous precision instruments and devices that are used in a wide range of science and engineering applications and currently, design of flexure mechanisms often heavily relies on designers’ previous hands-on experience. Therefore, a design tool that will speed up the design process is needed and this paper will introduce a systematic approach for building the necessary equations that are based on screw theory and linear elastic theory to analyze flexure mechanisms. A digital library of commonly used flexure elements must be available for a design tool and therefore, we first present the compliance matrices of commonly used flexure components. Motion twists and force wrenches of the screw theory can be related with these compliance matrices. Then, we introduce an algorithm that constructs the required linear system equations from individual compliance equations. This algorithm is applicable to flexure mechanisms with serial, parallel or hybrid chains. Finally, the algorithm is tested with a flexure mechanisms and it is shown that this approach can be the core of a future design tool.

Technology Education in the Middle Level School: Its Role and Purpose

1999 ◽  
Vol 83 (608) ◽  
pp. 34-44 ◽  
Author(s):  
Mark E. Sanders
Keyword(s):  
Technology Education ◽  
Computer Aided Design ◽  
World Wide ◽  
Magnetic Levitation ◽  
Education Technology ◽  
Middle Level ◽  
Digital Electronics ◽  
Flight Simulators ◽  
Wide Range ◽  
Aided Design

The curriculum and method of technology education remain one of the best-kept secrets in all education. Technology education engages students in a wide range of the very latest technologies: digital imaging, lasers, robotics, solar energy, World Wide Web development, magnetic levitation vehicles, analog and digital electronics, flight simulators, computer-aided design, and so forth.

Application of Advertising Based on Computer Aided Visual Design

2014 ◽  
Vol 889-890 ◽  
pp. 125-129
Author(s):  
Wei Xiao
Keyword(s):  
Computer Technology ◽  
Computer Aided Design ◽  
Paper Analysis ◽  
Visual Design ◽  
Visual Effects ◽  
Wide Range ◽  
Computer Aided ◽  
Visual Impact ◽  
Technical Features ◽  
Aided Design

The 3D computer technology has a wide range of applications currently, with various engineering fields. All 3D visual effects can bring us visual impact, the use of 3D computer technology produced by advertising more easily accepted by the audience, this paper discuss the 3D computer-aided design advertising and its application. The paper analysis 3D advertising purposes and applications range scale, the application of technical features and style.

Application of Computer-Aided Visual in Advertising Design

2013 ◽  
Vol 475-476 ◽  
pp. 1517-1521
Author(s):  
Qing Gang Yang ◽  
Meng Zhang ◽  
Chang Xiao
Keyword(s):  
Computer Technology ◽  
Computer Aided Design ◽  
Three Dimensional ◽  
Television Advertising ◽  
Application Technology ◽  
Visual Effects ◽  
Wide Range ◽  
Computer Aided ◽  
Visual Impact ◽  
Aided Design

The three-dimensional computer technology currently has in various engineering fields have a wide range of applications, all the three-dimensional visual effects technology can bring us visual impact, the use of three-dimensional computer technology produced by the television advertising more easily accepted by the audience, this thesis in the three-dimensional computer-aided design advertising design application technology.

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