scholarly journals Stiffening Behavior of Supine Humans during En Route Care Transport

Vibration ◽  
2021 ◽  
Vol 4 (1) ◽  
pp. 91-100
Author(s):  
Salam Rahmatalla ◽  
Guandong Qiao ◽  
Rachel Kinsler ◽  
Jonathan DeShaw ◽  
Andrew Mayer
Keyword(s):  
Inertial Sensors ◽  
Whole Body ◽  
Transport Systems ◽  
Human Response ◽  
Response Behavior ◽  
Response Data ◽  
Softening Behavior ◽  
Input Acceleration ◽  
Vibration Magnitude ◽  
Simulated Field

Previous studies of human response to whole-body vibration demonstrated nonlinear softening behaviors with increasing vibration magnitudes. Most of these studies were conducted at relatively low vibration magnitudes of less than 3 m/s2 root mean square (RMS), and not much knowledge is available to show if this softening behavior exists when humans are exposed to higher vibration magnitudes. In this work, 26 participants were transported in a supine position inside an army medical vehicle on a road that simulated field scenarios and were exposed to input acceleration magnitudes at 0.60, 0.98, 1.32, 3.25, 5.58, and 5.90 m/s2 RMS. Motion response data were collected at the head, torso, and pelvis of the participants using inertial sensors. Transmissibility and coherence graphs were used to investigate the type of nonlinearity induced under these transport conditions. Participant responses showed softening behavior when the vibration magnitude increased from 0.60 to 0.98 to 1.32 m/s2 RMS. However, this response behavior changed to stiffening when the vibration magnitude increased to 3.25, 5.58, and 5.90 m/s2 RMS. In the stiffening range, the transmissibility of the torso transformed from two dominant peaks to a single peak, which may indicate a tonic muscle behavior. The resulting stiffening behaviors may be considered in the design of transport systems subject to rough terrains.

scholarly journals Biodynamics of supine humans and interaction with transport systems during vibration and shocks

2017 ◽  
Vol 38 (2) ◽  
pp. 808-816 ◽  
Author(s):  
Salam Rahmatalla ◽  
Jonathan DeShaw ◽  
Khalid Barazanji
Keyword(s):  
Relative Motion ◽  
Random Vibration ◽  
Whole Body Vibration ◽  
Three Dimensional ◽  
Whole Body ◽  
Transport Systems ◽  
Biomechanical Response ◽  
Contact Surfaces ◽  
Vertical Accelerations ◽  
Human Transport

This work investigates the effect of the contact surfaces on the biomechanical response of supine humans during whole-body vibration and shocks. Twelve participants were exposed to three-dimensional random vibration and shocks and were tested with two types of contact surfaces: (i) litter only, and (ii) litter with spinal board. The two configurations were tested with and without body straps to secure the supine human. The addition of the spinal board reduced the involuntary motion of the supine humans in most directions. There were significant reductions in the relative vertical accelerations at the neck and torso areas, especially during shocks ( p < 0.01). The inclusion of body straps with the spinal board was more effective in reducing the relative motion in most directions when shocks were presented. This study shows that the ergonomic design of the human transport system and the underlying contacting surfaces should be studied during dynamic transport environments.

A Mobile Motion Capture System Based on Inertial Sensors and Smart Shoes

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Pyeong-Gook Jung ◽  
Sehoon Oh ◽  
Gukchan Lim ◽  
Kyoungchul Kong
Keyword(s):  
Motion Capture ◽  
Inertial Sensors ◽  
Kinematic Model ◽  
Three Dimensional ◽  
Health Condition ◽  
Body Motion ◽  
Whole Body ◽  
Motion Capture System ◽  
Outdoor Sports ◽  
Motion Capture Systems

Motion capture systems play an important role in health-care and sport-training systems. In particular, there exists a great demand on a mobile motion capture system that enables people to monitor their health condition and to practice sport postures anywhere at any time. The motion capture systems with infrared or vision cameras, however, require a special setting, which hinders their application to a mobile system. In this paper, a mobile three-dimensional motion capture system is developed based on inertial sensors and smart shoes. Sensor signals are measured and processed by a mobile computer; thus, the proposed system enables the analysis and diagnosis of postures during outdoor sports, as well as indoor activities. The measured signals are transformed into quaternion to avoid the Gimbal lock effect. In order to improve the precision of the proposed motion capture system in an open and outdoor space, a frequency-adaptive sensor fusion method and a kinematic model are utilized to construct the whole body motion in real-time. The reference point is continuously updated by smart shoes that measure the ground reaction forces.

A new method to reduce the noise of the miniaturised inertial sensors disposed in redundant linear configurations

2013 ◽  
Vol 117 (1188) ◽  
pp. 111-132 ◽  
Author(s):  
T. L. Grigorie ◽  
R. M. Botez
Keyword(s):  
Inertial Sensors ◽  
Inertial Sensor ◽  
Low Frequency ◽  
Minimum Variance ◽  
Measurement Unit ◽  
Time Step ◽  
Accelerometer Sensor ◽  
Sensor Model ◽  
Input Acceleration

Abstract This paper presents a new adaptive algorithm for the statistical filtering of miniaturised inertial sensor noise. The algorithm uses the minimum variance method to perform a best estimate calculation of the accelerations or angular speeds on each of the three axes of an Inertial Measurement Unit (IMU) by using the information from some accelerometers and gyros arrays placed along the IMU axes. Also, the proposed algorithm allows the reduction of both components of the sensors’ noise (long term and short term) by using redundant linear configurations for the sensors dispositions. A numerical simulation is performed to illustrate how the algorithm works, using an accelerometer sensor model and a four-sensor array (unbiased and with different noise densities). Three cases of ideal input acceleration are considered: 1) a null signal; 2) a step signal with a no-null time step; and 3) a low frequency sinusoidal signal. To experimentally validate the proposed algorithm, some bench tests are performed. In this way, two sensors configurations are used: 1) one accelerometers array with four miniaturised sensors (n = 4); and 2) one accelerometers array with nine miniaturised sensors (n = 9). Each of the two configurations are tested for three cases of input accelerations: 0ms−1, 9·80655m/s2 and 9·80655m/s2.

Human response of vertical and pitch motion to vertical vibration on whole body according to sitting posture

2012 ◽  
Vol 26 (8) ◽  
pp. 2477-2484 ◽  
Author(s):  
Min-Seok Kim ◽  
Gyeoung-Jin Jeon ◽  
Jae-Young Lee ◽  
Se-Jin Ahn ◽  
Wan-Suk Yoo ◽  
...  
Keyword(s):  
Vertical Vibration ◽  
Whole Body ◽  
Human Response ◽  
Sitting Posture ◽  
Pitch Motion

Non-Linear Characteristics in the Dynamic Responses of Seated Subjects Exposed to Vertical Whole-Body Vibration

2002 ◽  
Vol 124 (5) ◽  
pp. 527-532 ◽  
Author(s):  
Yasunao Matsumoto ◽  
Michael J. Griffin
Keyword(s):  
Frequency Response ◽  
The Body ◽  
Dynamic Responses ◽  
Whole Body ◽  
Apparent Mass ◽  
Response Functions ◽  
Frequency Response Functions ◽  
Resonance Frequencies ◽  
Non Linear ◽  
Vibration Magnitude

The effect of the magnitude of vertical vibration on the dynamic response of the seated human body has been investigated. Eight male subjects were exposed to random vibration in the 0.5 to 20 Hz frequency range at five magnitudes: 0.125, 0.25, 0.5, 1.0 and 2.0 ms−2 r.m.s. The dynamic responses of the body were measured at eight locations: at the first, fifth, and tenth thoracic vertebrae (T1, T5, T10), at the first, third, and fifth lumbar vertebrae (L1, L3, L5) and at the pelvis (the posterior-superior iliac spine). At each location, the motions on the body surface were measured in the three orthogonal axes within the sagittal plane (i.e., the vertical, fore-and-aft, and pitch axes). The force at the seat surface was also measured. Frequency response functions (i.e., transmissibilities and apparent mass) were used to represent the responses of the body. Non-linear characteristics were observed in the apparent mass and in the transmissibilities to most measurement locations. Resonance frequencies in the frequency response functions decreased with increases in the vibration magnitude (e.g. for the vertical transmissibility to L3, a reduction from 6.25 to 4.75 Hz when the vibration magnitude increased from 0.125 to 2.0 ms−2 r.m.s.). The transmission of vibration within the spine also showed some evidence of a non-linear characteristic. It can be concluded from this study that the dynamic responses of seated subjects are clearly non-linear with respect to vibration magnitude, whereas previous studies have reported inconsistent conclusions. More understanding of the dependence on vibration magnitude of both the dynamic responses of the soft tissues of the body and the muscle activity (voluntary and involuntary) is required to identify the causes of the non-linear characteristics observed in this study.

Variation in human response to whole-body vibration

Ergonomics ◽  
1981 ◽  
Vol 24 (4) ◽  
pp. 301-313 ◽  
Author(s):  
D. J. OBORNE ◽  
T. O. HEATH ◽  
P. BOARER
Keyword(s):  
Whole Body Vibration ◽  
Whole Body ◽  
Human Response ◽  
Body Vibration

Investigation of Whole Body Vibration on Urban Midi Bus

2014 ◽  
Vol 592-594 ◽  
pp. 2066-2070 ◽  
Author(s):  
M. Rao Jaganmohan ◽  
S.P. Sivapirakasham ◽  
K.R. Balasubramanian ◽  
K.T. Sreenath
Keyword(s):  
Resonance Effect ◽  
Whole Body Vibration ◽  
Dynamic Test ◽  
Rear Seat ◽  
Operating Conditions ◽  
Whole Body ◽  
Static Test ◽  
Body Vibration ◽  
Exposure Limit ◽  
Vibration Magnitude

The objective of the study is to measure the whole body vibration (WBV) transmitted to the driver as well as the passengers during the operation of bus and to compare results with ISO 2631-1(1997) comfort chart and health guidance criteria. In this study, vibration exposure of the driver, passenger in the mid row seat and passenger in the rear row seat were measured at different operating conditions (static and dynamic). The BMI (Body Mass Index) was maintained for driver and passengers. The results of static test showed that the driver seat produced more vibrations compared to the passenger's mid row and rear row seat. This is due to the fact that driver seat was positioned close to the engine cabin. The results of dynamic test showed that, in all cases, the rear seat produced maximum vibrations. At 40 km/h speed the vibration magnitude exceeded the exposure limit at all tested seats. This high vibration magnitude might be due to the resonance effect caused between engine and chassis vibrations.

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