Second Spine: Upper Body Assistive Device for Human Load Carriage

2015 ◽  
Vol 7 (1) ◽  
Author(s):  
Joon-Hyuk Park ◽  
Xin Jin ◽  
Sunil K. Agrawal
Keyword(s):  
Human Motion ◽  
Musculoskeletal Injuries ◽  
Load Carriage ◽  
Assistive Device ◽  
Upper Body ◽  
Human Walking ◽  
Inertia Force ◽  
Concept Design ◽  
Test Bed ◽  
Heavy Load

This study presents the development of second spine, an upper body assistive device for human load carriage. The motivation comes from reducing musculoskeletal injuries caused by carrying a heavy load on the upper body. Our aim was to design a wearable upper body device that can prevent musculoskeletal injuries during human load carriage by providing a secondary load pathway—second spine—to transfer the loads from shoulders to pelvis while also allowing a good range of torso motion to the wearer. Static analysis of the backpack and the second spine was first performed to investigate the feasibility of our concept design. The development of second spine had two considerations: load distribution between shoulders and pelvis, and preserving the range of torso motion. The design was realized using load bearing columns between the shoulder support and hip belt, comprising multiple segments interconnected by cone-shaped joints. The performance of second spine was evaluated through experimental study, and its biomechanical effects on human loaded walking were also assessed. Based on the findings from second spine evaluation, we proposed the design of a motorized second spine which aims to compensate the inertia force of a backpack induced by human walking through active load modulation. This was achieved by real-time sensing of human motion and actuating the motors in a way that the backpack motion is kept nearly inertially fixed. Simulation study was carried out to determine the proper actuation of motors in response to the human walking kinematics. The performance of motorized second spine was evaluated through an instrumented test-bed using Instron machine. Results showed a good agreement with simulation. It was shown that the backpack motion can be made nearly stationary with respect to the ground which can further enhance the effectiveness of the device in assisting human load carriage.

Compensating Inertia Forces During Human Load Carrying Using a Motorized Second Spine

2014 ◽  
Author(s):  
Joon-Hyuk Park ◽  
Xin Jin ◽  
Sunil K. Agrawal
Keyword(s):  
Vertical Motion ◽  
Upper Body ◽  
Human Walking ◽  
Inertia Force ◽  
Vertical Acceleration ◽  
Test Bed ◽  
Alternate Pathway ◽  
Load Carrying ◽  
Inertia Forces ◽  
Good Agreement

This study focuses on how the inertia force of a backpack induced by human walking can be compensated by active load modulation through a Second Spine, a device that provides an alternate pathway to transfer loads from the shoulder to the pelvis. Human walking induces periodic vertical acceleration of the upper body. A backpack worn on the upper body undergoes this same acceleration. Inertia force is induced by this acceleration and the human body has to sustain this motion and provide necessary energy. Based on this knowledge and our previous studies on a passive Second Spine, we present studies on a motorized Second Spine that can actively modulate the vertical motion of a backpack such that the inertia forces can be reduced. This is realized by real-time sensing and actuation so that the backpack is kept inertially fixed. The performance of such a device was evaluated on an instrumented test-bed using an Instron machine, showing results in good agreement with simulation. It was shown that the backpack motion can be made nearly stationary with respect to the ground by active modulation using motors and the inertia force is reduced.

Reducing Dynamic Loads From a Backpack During Load Carriage Using an Upper Body Assistive Device

2016 ◽  
Vol 8 (5) ◽  
Author(s):  
Joon-Hyuk Park ◽  
Paul Stegall ◽  
Sunil K. Agrawal
Keyword(s):  
Dynamic Load ◽  
Controller Design ◽  
Load Carriage ◽  
Lower Limbs ◽  
Dynamic Loads ◽  
Assistive Device ◽  
Upper Body ◽  
Single Subject ◽  
Preliminary Evaluation ◽  
Heavy Loads

This paper presents studies of an upper body assistive device designed to aid human load carriage. The two primary functions of the device are: (i) distributing the backpack load between the shoulders and the waist and (ii) reducing the dynamic load of a backpack on the human body during walking. These functions are targeted to relieve stress applied on the shoulders and the back, and also reduce the dynamic loads transferred to the lower limbs during walking. These functions are achieved by incorporating two modules—passive and active—within a custom fitted shirt integrated with motion/force sensors, actuators, and a real-time controller. The relevant modeling and controller design are presented for dynamic load compensation. Preliminary evaluation of the device was first performed on a single subject, followed by a pilot study with ten healthy subjects walking on a treadmill with a backpack. Results show that the device can effectively transfer the load from the shoulders to the waist and also reduce the dynamic loads induced by the backpack during walking. Reduction in peak and total normal ground reaction forces, leg muscle activations, and oxygen consumptions was observed with the device. This suggests that the device can potentially reduce the risk of musculoskeletal injuries and fatigue on the lower limbs associated with carrying heavy loads and provide some metabolic benefits.

Wearable Upper Body Suit for Assisting Human Load Carriage

2015 ◽  
Author(s):  
Joon-Hyuk Park ◽  
Paul Stegall ◽  
Sunil K. Agrawal ◽  
Shridhar Yarlagadda ◽  
John Tierney ◽  
...  
Keyword(s):  
Dynamic Load ◽  
Load Distribution ◽  
Vertical Motion ◽  
Load Carriage ◽  
Upper Body ◽  
Human Walking ◽  
System Response ◽  
Cable Tension ◽  
Load Bearing ◽  
Backpack Load

This paper presents a wearable upper body suit designed to assist in human load carriage. The two functions of the suit are: (i) load distribution between the shoulders and the waist, and (ii) reduction of the dynamic load on the waist during walking. These are achieved through two cable driven modules — passive and active — within a custom fitted shirt integrated with motion/force sensors, actuators, and a real time controller. The load distribution between the shoulders and the waist is achieved through the load bearing columns connecting the shoulder pads and the waist belt whose load bearing capacity is modulated by a nominal cable tension in the passive module via a ratchet mechanism. The dynamic load is reduced in addition in the active module by modulating the cable tension via external actuator. Mathematical model of the system is presented and a state feedback controller is designed. Simulation study was performed to investigate the system response under different disturbance conditions as a result of vertical motion of the waist during human walking. Experiment evaluation of the suit was performed with a subject walking on a treadmill while carrying a backpack load. The results show that the developed suit can transfer the load from the shoulders to the waist as well as reduce the dynamic load induced during human walking. This can potentially reduce the energy expenditure and the risk of musculoskeletal injuries associated with human load carriage.

scholarly journals Identical Limb Dynamics for Unilateral Impairments through Biomechanical Equivalence

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 705
Author(s):  
Fatemeh Rasouli ◽  
Kyle B. Reed
Keyword(s):  
Mathematical Model ◽  
Numerical Solution ◽  
Dynamic Models ◽  
Assistive Devices ◽  
Assistive Device ◽  
Human Walking ◽  
Physical Parameters ◽  
Gait Rehabilitation ◽  
And Performance ◽  
Two Sides

Dynamic models, such as double pendulums, can generate similar dynamics as human limbs. They are versatile tools for simulating and analyzing the human walking cycle and performance under various conditions. They include multiple links, hinges, and masses that represent physical parameters of a limb or an assistive device. This study develops a mathematical model of dissimilar double pendulums that mimics human walking with unilateral gait impairment and establishes identical dynamics between asymmetric limbs. It introduces new coefficients that create biomechanical equivalence between two sides of an asymmetric gait. The numerical solution demonstrates that dissimilar double pendulums can have symmetric kinematic and kinetic outcomes. Parallel solutions with different physical parameters but similar biomechanical coefficients enable interchangeable designs that could be incorporated into gait rehabilitation treatments or alternative prosthetic and ambulatory assistive devices.

scholarly journals A Secured Load Mitigation and Distribution Scheme for Securing SIP Server

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Vennila Ganesan ◽  
Manikandan MSK
Keyword(s):  
Load Distribution ◽  
Test Bed ◽  
Heavy Load ◽  
Server Selection ◽  
Distribution Scheme ◽  
The Mean ◽  
Sip Server ◽  
Second Tier ◽  
Termination Time

Managing the performance of the Session Initiation Protocol (SIP) server under heavy load conditions is a critical task in a Voice over Internet Protocol (VoIP) network. In this paper, a two-tier model is proposed for the security, load mitigation, and distribution issues of the SIP server. In the first tier, the proposed handler segregates and drops the malicious traffic. The second tier provides a uniform load of distribution, using the least session termination time (LSTT) algorithm. Besides, the mean session termination time is minimized by reducing the waiting time of the SIP messages. Efficiency of the LSTT algorithm is evaluated through the experimental test bed by considering with and without a handler. The experimental results establish that the proposed two-tier model improves the throughput and the CPU utilization. It also reduces the response time and error rate while preserving the quality of multimedia session delivery. This two-tier model provides robust security, dynamic load distribution, appropriate server selection, and session synchronization.

The Muscle Myogram as a Control Signal for Use in Powered Limb Orthosis

2006 ◽  
Author(s):  
M. Antonelli ◽  
P. Beomonte Zobel ◽  
J. Giacomin
Keyword(s):  
Lower Limb ◽  
Assistive Device ◽  
Sitting Position ◽  
Test Bed ◽  
Disabled People ◽  
Test Protocol ◽  
Prosthetic Devices ◽  
Specific Device ◽  
Definition Of

The choice of the command technique to be used in orthotic and prosthetic devices is very critical for the acceptance and, finally, the success of the specific device. Many variables influence this choice: the general characteristics of the signal, the quality of the correlation between signal and specific actions of the user and the algorithm that is derived, the acceptance of the technique, as applied to the specific device, from the user, etc. Among the command techniques, MMG signal seems to be promising to command an assistive device. In this paper a test protocol for studying MMG signal, to investigate the prospective for its use as a command technique of a powered lower limb orthosis capable of raising elderly and disabled people from the sitting position, is proposed. The definition of the test protocol, including the description of the test bed and the sensors application, is presented. Finally, the experimental results are showed and discussed.

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.

Biomechanics of human walking and stability descriptive parameters

2016 ◽  
Vol 2 (1) ◽  
pp. 4
Author(s):  
Arturo Bertomeu-Motos
Keyword(s):  
Human Body ◽  
Center Of Pressure ◽  
Body Movement ◽  
Human Motion ◽  
Human Walking ◽  
Dynamic Motion ◽  
Mechanical Aspect ◽  
Zero Moment

From the time of Aristotle onward, there have been countless books written on the topic of movement in animals and humans. However, research of human motion, especially walking mechanisms, has increased over the last fifty years. The study of human body movement and its stability during locomotion involves both neuronal and mechanical aspect. The mechanical aspect, which is in the scope of this thesis, requires knowledge in the field of biomechanics. Walking is the most common maneuver of displacement for humans and it is performed by a stable dynamic motion. In this article it is introduced the bases of the human walking in biomechanical terms. Furthermore, two stability descriptive parameters during walking are also explained - Center of Pressure (CoP) and Zero-Moment Pint (ZMP).

scholarly journals An Approach to Human Walking Analysis Based on Balance, Symmetry and Stability Using COG, ZMP and CP

2020 ◽  
Vol 10 (20) ◽  
pp. 7307
Author(s):  
Seonghye Kim ◽  
Toshiyuki Murakami
Keyword(s):  
Personal Characteristic ◽  
Center Of Gravity ◽  
Lower Limbs ◽  
Upper Body ◽  
Human Walking ◽  
Joint Rotation ◽  
Gait Parameters ◽  
Zero Moment ◽  
Crossing Point

The parameters of walking have been studied from the viewpoints of joint rotation and translation of body. The balance and symmetry of walking are indispensable features to understand for healthy walking, while also being a personal characteristic. However, quantification has not been easy to carry out in the case of the conventional gait parameters COG (center of gravity) and ZMP (zero moment point). In this approach, the CP (crossing point) is proposed to quantify the concept of symmetry and balance by comparing it to the COG and ZMP. The CP is estimated based on the intersection between the hip line and the ankle line. While the hip line is fixed on the upper body where the COG is, the ankle line is altered depending on the each footfall, where the ZMP is. Therefore, the values of COG, ZMP, and CP have similar or different tendencies in terms of whether balanced walking results in symmetry or not. The validity of this is verified by carrying out a simulation with robot walking, and an experiment using human walking. Through additional experiments, it was noticed that the CP was able to improve the role of COG and ZMP in terms of not only stability, but also its relationship with the movement range of the lower limbs.

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