Mimicking obesity and pregnancy by adding load mass elicits minor postural oscillations compared to backpack weight carrying.

2019 ◽  
Vol 16 ◽  
pp. 100129 ◽  
Author(s):  
Hanan Rkain ◽  
Bruno Vie ◽  
Yves Jammes
Keyword(s):  
Weight Carrying ◽  
Backpack Weight ◽  
Load Mass

Analysis of Muscle Activity Using Surface Electromyography for Muscle Performance in Manual Lifting Task

2014 ◽  
Vol 564 ◽  
pp. 644-649 ◽  
Author(s):  
Halim Isa ◽  
Rawaida ◽  
Seri Rahayu Kamat ◽  
A. Rohana ◽  
Adi Saptari ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Surface Electromyography ◽  
Biceps Brachii ◽  
Twist Angle ◽  
Erector Spinae ◽  
Manual Lifting ◽  
Experienced Fatigue ◽  
Left And Right ◽  
Lifting Task ◽  
Load Mass

In industries, manual lifting is commonly practiced even though mechanized material handling equipment are provided. Manual lifting is used to transport or move products and goods to a desired place.Improper lifting techniquescontribute to muscle fatigue and low back pain that can lead to work efficiency and low productivity.The objective of this study were to analyze muscle activity in the left and right Erector Spinae, and left and right Biceps Brachii of five female subjects while performing manual lifting taskwithdifferent load mass, lifting height and twist angle.The muscle activitywere measured and analyzed using surface electromyography (sEMG).This study found that the right Biceps Brachii, right and left Erector Spinae experienced fatigue while performingasymmetric lifting (twist angle = 90°) at lifting height of 75 cm and 140 cm with load mass of 5 kg and 10 kg. Meanwhile, the left Biceps Brachii experienced fatigue when the lifting task was set at lifting height of 75 cm, load mass of 5 kg and twist angle of 90°.The load mass and lifting height has a significant influence to Mean Power Frequency (MPF) for left Biceps Brachii, left and right Erector Spinae. This study concluded that reducing the load mass can increase the muscles performance which can extend the transition-to-fatigue stage in the left and right Biceps Brachii and Erector Spinae.

scholarly journals A biomechanical study of load carriage by two paired subjects in response to increased load mass

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Guillaume Fumery ◽  
Nicolas A. Turpin ◽  
Laetitia Claverie ◽  
Vincent Fourcassié ◽  
Pierre Moretto
Keyword(s):  
Recovery Rate ◽  
Energy Recovery ◽  
Mechanical Energy ◽  
Center Of Mass ◽  
Step Length ◽  
Biomechanical Study ◽  
Load Carriage ◽  
Joint Torque ◽  
Total Mechanical Energy ◽  
Load Mass

AbstractThe biomechanics of load carriage has been studied extensively with regards to single individuals, yet not so much with regards to collective transport. We investigated the biomechanics of walking in 10 paired individuals carrying a load that represented 20%, 30%, or 40% of the aggregated body-masses. We computed the energy recovery rate at the center of mass of the system consisting of the two individuals plus the carried load in order to test to what extent the pendulum-like behavior and the economy of the gait were affected. Joint torque was also computed to investigate the intra- and inter-subject strategies occurring in response to this. The ability of the subjects to move the whole system like a pendulum appeared rendered obvious through shortened step length and lowered vertical displacements at the center of mass of the system, while energy recovery rate and total mechanical energy remained constant. In parallel, an asymmetry of joint moment vertical amplitude and coupling among individuals in all pairs suggested the emergence of a leader/follower schema. Beyond the 30% threshold of increased load mass, the constraints at the joint level were balanced among individuals leading to a degraded pendulum-like behavior.

Quantitative Feedback Theory Velocity Control of a Single-rod Pump-controlled Actuator Using a Novel Flow Compensation Circuit

2020 ◽  
Author(s):  
Guangan Ren ◽  
Gustavo Koury Costa ◽  
Nariman Sepehri
Keyword(s):  
Load Force ◽  
Circuit Switching ◽  
Hydraulic Circuit ◽  
Velocity Control ◽  
Quantitative Feedback Theory ◽  
Compensation Circuit ◽  
Wide Range ◽  
Flow Compensation ◽  
Response Envelope ◽  
Load Mass

This paper employs the quantitative feedback theory (QFT) to design a robust fixed-gain linear velocity controller for a newly developed single-rod pump-controlled actuator. The actuator operates in four quadrants, with a load force becoming resistive or assistive alternatively. The controller also satisfies tracking, stability and sensitivity specifications in the presence of a wide range of system parametric uncertainties. Its performance is examined on an instrumented John Deere JD-48 backhoe. The experimental results show that the controller can maintain the actuator velocity within an acceptable response envelope, despite variation in load mass as high as 163 kg and the hydraulic circuit switching between operating quadrants.

Wheelchair-Portable Patient Lift

2018 ◽  
Vol 13 (1) ◽  
Author(s):  
Yoshikazu Mori ◽  
Akihiko Nakada
Keyword(s):  
Nursing Home ◽  
Flat Surface ◽  
Center Of Mass ◽  
Experimental Results ◽  
Assistive Device ◽  
Leaving Home ◽  
Sliding Mechanism ◽  
Small Force ◽  
Weight Carrying ◽  
Sufficient Strength

A patient lift is an assistive device for patients who lack sufficient strength or muscle control to be transferred between a wheelchair and a toilet or other places. Patient lifts of two kinds are commonly used: overhead lifts and mobile lifts. Nevertheless, because of its size and weight, carrying even a mobile lift with a wheelchair is difficult when leaving home. This study examined a novel portable patient lift that is small and light, sufficient to be carried using a wheelchair in a folded state. It is compact, light, and portable because it has no actuator. Moreover, its operation is simple. It is useful not only at home or in a nursing home but on any flat surface during daily excursions and activities, even in a conventional lavatory. A caregiver can transfer a user with a small force because this lift has a sliding mechanism that brings the fulcrum closer to the patient's center of mass. Experimental results underscore the effectiveness of the proposed patient lift.

Effects of Wall Thickness and Crush Initiators Position under Experimental Drop Test on Square Tubes

2017 ◽  
Vol 865 ◽  
pp. 612-618 ◽  
Author(s):  
M. Malawat ◽  
Jos Istiyanto ◽  
D.A. Sumarsono
Keyword(s):  
Energy Absorption ◽  
Tube Wall ◽  
Impact Load ◽  
Peak Load ◽  
Load Force ◽  
Drop Height ◽  
Thin Walled ◽  
The Impact ◽  
Initial Peak ◽  
Load Mass

Crush initiators are the weakest points to reduce initial peak load force with significant energy absorption ability. The objective of this paper is to study the effects of square tube thickness and crush initiators position for impact energy absorber (IEA) performance on thin-walled square tubes. Two square tubes having thickness about 0.6 mm (specimen code A) and 1 mm (specimen Code C) were tested under dynamic load. The crushing initiator is designed around the shape of the tube wall and has eight holes with a fixed diameter of 6.5 mm. In the experiment, the crushing initiator was determined at 5 different locations on the specimen wall. These locations are 10 mm, 20 mm. 30 mm, 40 mm, and 50 mm measured from the initial collision position of the specimen tested. The impact load mass was about 80 kg and had a drop height of about 1.5 m. Using the simulation program of the LabVIEW Professional Development System 2011 and National Instrument (NI) 9234 software equipped with data acquisition hardware NI cDAQ-9174 the signal from the load cell was sent to a computer. By controlling the thickness of the thin-walled square tube, the peak loading force can be decreased by approximately 56.75% and energy absorption ability of IEA can be increased approximately to 11.83%. By using different thin-walled square tube can produce different best crush initiators position with the lowest peak load force.

Linear Dynamics of an Elastic Beam Under Moving Loads

2000 ◽  
Vol 122 (3) ◽  
pp. 281-289 ◽  
Author(s):  
G. Visweswara Rao
Keyword(s):  
Internal Resonance ◽  
Multiple Scales ◽  
Moving Load ◽  
Mass Parameter ◽  
Equations Of Motion ◽  
Elastic Beam ◽  
Mass Effect ◽  
Moving Loads ◽  
Parameter Ratio ◽  
Load Mass

The dynamic response of an Euler-Bernoulli beam under moving loads is studied by mode superposition. The inertial effects of the moving load are included in the analysis. The time-dependent equations of motion in modal space are solved by the method of multiple scales. Instability regions of parametric resonance are identified and the moving mass effect is shown to significantly affect the transient response of the beam. Importance of modal interaction arising out of the possible internal resonance is highlighted. While the external resonance is due to the gravity effects of the moving load, the parametric and internal resonance solely depends on the load mass parameter—ratio of the moving load mass to the beam mass. Numerical results show the influence of the load inertia terms on the beam response under either a single moving load or a series of moving loads. [S0739-3717(00)01703-7]

Wave-Based Control of a Crane System With Complex Loads

2017 ◽  
Vol 139 (8) ◽  
Author(s):  
Jiao Zhou ◽  
Kai Zhang ◽  
Gengkai Hu
Keyword(s):  
Wave Scattering ◽  
Control Method ◽  
Model Simulation ◽  
Double Pendulum ◽  
Time Varying ◽  
Pendulum Model ◽  
Simulation And Experiment ◽  
Special Case ◽  
Transmission And Reflection ◽  
Load Mass

In the framework of wave-based method, we have examined swing motion control for double-pendulum and load-hoist models. Emphases are placed on wave scattering by the middle load mass in the double-pendulum model and on time-varying configuration in the load-hoist model. By analyzing wave transmission and reflection, trolley's motion to alleviate swing is designed by absorbing reflected wave through adjusting the velocity of trolley. Simulation and experiment are also conducted to validate the proposed control method. The results show that with the designed trolley's motion swings of load can be significantly reduced for both double-pendulum model, suspended rod model which is demonstrated a special case of double-pendulum model, and load-hoist model. Simulation results agree well with the experimental measurement. Launch velocity profiles may have important impact on motion design, especially on force necessary to displace trolley. Finally, a wave-based feedback control is also discussed to demonstrate the flexibility of method.

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