Assessment criteria for evaluating the stability and position of the centre of gravity on a balance training platform: a simulation with Matlab®

2011 ◽  
Vol 35 (5) ◽  
pp. 239-245 ◽  
Author(s):  
C. Ambrozy ◽  
F. Rattay
Keyword(s):  
Balance Training ◽  
Assessment Criteria ◽  
Centre Of Gravity ◽  
The Stability

scholarly journals The two-dimensional hydrodynamical theory of moving aerofoils. IV

1947 ◽  
Vol 188 (1015) ◽  
pp. 439-463
Keyword(s):  
Stability Problem ◽  
Two Dimensional ◽  
Centre Of Gravity ◽  
First Approximation ◽  
Von Karman ◽  
Moving Cylinder ◽  
Period Equation ◽  
The Stability ◽  
Von Kármán ◽  
Hydrodynamical Theory

In the first part of this paper opportunity has been taken to make some adjustments in certain general formulae of previous papers, the necessity for which appeared in discussions with other workers on this subject. The general results thus amended are then applied to a general discussion of the stability problem including the effect of the trailing wake which was deliberately excluded in the previous paper. The general conclusion is that to a first approximation the wake, as usually assumed, has little or no effect on the reality of the roots of the period equation, but that it may introduce instability of the oscillations, if the centre of gravity of the element is not sufficiently far forward. During the discussion contact is made with certain partial results recently obtained by von Karman and Sears, which are shown to be particular cases of the general formulae. An Appendix is also added containing certain results on the motion of a vortex behind a moving cylinder, which were obtained to justify certain of the assumptions underlying the trail theory.

scholarly journals Multibody model of fruit harvesting trucks: comparison with experimental data and rollover analysis

2018 ◽  
Vol 49 (2) ◽  
pp. 92-99 ◽  
Author(s):  
Stefano Melzi ◽  
Edoardo Sabbioni ◽  
Michele Vignati ◽  
Maurizio Cutini ◽  
Massimo Brambilla ◽  
...  
Keyword(s):  
Experimental Tests ◽  
Soil Stiffness ◽  
Safety Issues ◽  
Multibody Model ◽  
Centre Of Gravity ◽  
Rollover Risk ◽  
Speed Up ◽  
The Stability ◽  
Italian National Institute ◽  
Comparison With Experimental Data

Fruit harvesting trucks are used to easy and speed-up the work of agricultural operators. These vehicles are provided with a moving cargo bed, which can be raised up to 3 meters from the ground so that workers are closer to the plants top. Due to factors like height of centre of gravity and operation on soft and irregular soil, these vehicles present several safety issues. This research, carried out inside a project funded by INAIL (Italian National Institute for Insurance against Accidents at Work), analysed the stability of fruit harvesting trucks with particular focus on rollover risk. Experimental tests were carried out to characterise the response of these vehicles. Multibody models of two trucks were then developed and used to determine the rollover angle along a generic direction considering the effect of vehicle configuration and of tire-soil stiffness.

The Research on Weighing Metering Systems of Beer Barrel Liquid Filling Machine

2013 ◽  
Vol 437 ◽  
pp. 787-792
Author(s):  
Chao Jun Chen ◽  
Zhen Zhou Fu
Keyword(s):  
Large Error ◽  
Measurement Circuit ◽  
Load Bearing ◽  
Centre Of Gravity ◽  
Connection Method ◽  
Shock Resistance ◽  
The Stability ◽  
Selection Of

This design is designing for metering system of the beer barrel liquid filling machine. It contains the selection of metering mode and the design of the weighing system mainly etc. The new connection method which is applied multiple weighing sensor constitute the half-bridge measurement circuit which can achieve measuring function of the full-bridge measurement circuit. Not only can this structure increase the stability and shock resistance of the load-bearing platform but also it can solve the problem that generated large error when a single weighing sensor was measuring the object which has different centre of gravity. And this can improve the filling accuracy greatly.

Sledge-boats

Polar Record ◽  
1958 ◽  
Vol 9 (58) ◽  
pp. 20-22
Author(s):  
J. A. Exley
Keyword(s):  
Sea Ice ◽  
Cross Section ◽  
Falkland Islands ◽  
Oxford University ◽  
Centre Of Gravity ◽  
Marguerite Bay ◽  
Ice Conditions ◽  
The Stability ◽  
Shaped Cross Section

Unstable sea ice conditions in 1955 and 1956 made it advisable to carry some form of boat during sledge journeys from the Falkland Islands Dependencies Survey (F.I.D.S.) station at Horseshoe Island, in Marguerite Bay, Graham Land. The account given of a sledge-boat in Hints to travellers (Vol. 2, 11th ed., 1938, p. 137) was followed, and a craft similar to that employed by the Oxford University Arctic Expedition of 1935-36 was constructed. When this boat was tested it was found to be unstable. This was due both to the saucer-shaped cross-section and to the fact that the whole load has to be placed on top of the sledge. These disadvantages were overcome by the incorporation into the design of a pair of skis, extended from the sledge outer longitudinal and runner on plywood struts. These widened the bottom of the boat and increased the stability. The new shape was intrinsically more stable, and it was also possible to place cargo in the bottom of the boat, thus lowering the centre of gravity.

A gait simulator for a quadruped walking robot

Robotica ◽  
1992 ◽  
Vol 10 (1) ◽  
pp. 57-64 ◽  
Author(s):  
John Stoner ◽  
Robert H. Davis
Keyword(s):  
Programming Language ◽  
Gait Cycle ◽  
Complete System ◽  
Walking Robot ◽  
C Programming Language ◽  
Design And Implementation ◽  
Centre Of Gravity ◽  
C Programming ◽  
Quadruped Walking Robot ◽  
The Stability

SummaryThe description is provided for the design and implementation of a system capable of simulating the motions of a quadruped walking robot. The system aims to investigate the feasibility of the robot's walking cycle. This is achieved by considering the robot's stability and more specifically the position of its centre of gravity in relation to its supporting legs. The robot is modelled as a solid body connected to four jointed limbs which are moved through a series of gaits, their positions being calculated at a set of discrete intervals. The resulting information is displayed using a graphical module to present an image of the moving robot and indicate its centre of gravity and support pattern. The complete system indicates the stability of the robot throughout a user-defined gait cycle and is both portable and adaptable.The system is implemented on a HLH Orion and an Atari 1040ST in the C programming language and is aimed at providing support for the Department of Mechanical Engineering at Edinburgh University where the particular robot is being built.

scholarly journals The Effects of Short-Term Visual Feedback Training on the Stability of the Roundhouse Kicking Technique in Young Karatekas

2021 ◽  
Vol 18 (4) ◽  
pp. 1961
Author(s):  
Stefano Vando ◽  
Stefano Longo ◽  
Luca Cavaggioni ◽  
Lucio Maurino ◽  
Alin Larion ◽  
...  
Keyword(s):  
Real Time ◽  
Visual Feedback ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Balance Training ◽  
Young Male ◽  
Training Intervention ◽  
Leg Flexion ◽  
The Stability ◽  
And Control

The aim of this study was to assess the efficacy of using real-time visual feedback (VF) during a one-week balance training intervention on postural sway parameters in young karatekas. Twenty-six young male karatekas (age = 14.0 ± 2.3 years) were randomly divided into two groups: real-time VF training (VFT; n = 14) and control (CTRL; n = 12). Their center of pressure (COP) displacement (path length, COPpl; distance from origin, COPod) was assessed pre- and post-training on a Wii Balance Board platform in two positions (Flex: knee of the supporting leg slightly bent, maximum hip and leg flexion of the other leg; Kick: knee of the supporting leg slightly bent, mawashi-geri posture for the kicking leg). Both groups trained twice a day for seven days, performing a one-legged stance on the non-dominant limb in the Kick position. During the training, VFT received real-time VF of COP displacement, while CTRL looked at a fixed point. No interaction effect was found (p > 0.05). VFT exhibited greater changes pre- and post-training in Flex COPpl (−25.2%, g = 1.5), Kick COPpl (−24.1%, g = 1.3), and Kick COPod (−44.1%, g = 1.0) compared to CTRL (−0.9–−13.0%, g-range: 0.1–0.7). It is possible that superimposing real-time VF to a week-long balance training intervention could induce a greater sport-specific balance-training effect in young karatekas.

scholarly journals Methodology for Assessing the Stability of Drilling Rigs Based on Analytical Tests

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8588
Author(s):  
Łukasz Bołoz ◽  
Artur Kozłowski
Keyword(s):  
Computational Model ◽  
Design Process ◽  
Computational Models ◽  
Dynamic Models ◽  
Graphical Representation ◽  
Underground Mining ◽  
Drilling Rig ◽  
Centre Of Gravity ◽  
The Stability ◽  
Drilling Rigs

Underground mining machines, such as wheel-tyre drilling rigs, are articulated and equipped with booms that project far beyond the undercarriage. Such a structure makes these machines prone to losing stability. Hence, it is necessary to analyse the distribution of masses and geometry as well as their broadly understood stability during the entire design process, taking into account many factors resulting from the manner and conditions of their operation. However, there are no appropriate computational models that would enable analytical tests to be carried out for machines with this kind of construction. This article is concerned with the author’s computational model, which allows the stability of single- and twin-boom drilling rigs to be quickly assessed. The model makes it possible to perform analyses without having to solve differential equations that are present in dynamic models or using specialist software based on CAD and CAE tools. The developed model allows determination of the pressure of wheels and jacks as a function of many important parameters and variables. Additionally, the distances of the centre of gravity from the tipping edge are calculated. The developed computational model was verified by comparing the obtained results with the results of the full dynamic model, the results of model tests carried out in the CAD/CAE program, and the results of empirical tests of wheel and jack pressures on the ground for the selected drilling rig. The model was subjected to verification and validation, which proved that it was fully correct and useful. The model was used to prepare a practical and user-friendly calculation sheet. Apart from the numerical values, the calculation sheet contains a graphical representation of the machine, the location of the centre of gravity, the tipping edges, as well as graphs of the wheel and jack pressures. Next, analytical tests of the stability of the selected drilling rig were carried out. The obtained calculation results are consistent with the results of empirical research. The computational model and the spreadsheet provide handy tools used during the design process by one of the Polish company’s producing drilling rigs.

EXPERIMENTAL INVESTIGATION INTO THE EFFECTS OF REDUCED VERTICAL CENTRE OF GRAVITY OF AN ARTICULATED CONCRETE MATTRESS IN CURRENT FLOW

2021 ◽  
Vol 159 (A3) ◽  
Author(s):  
A Neville ◽  
R McLaren ◽  
J Weber ◽  
C Chin ◽  
J Binns ◽  
...  
Keyword(s):  
Current Flow ◽  
Experimental Testing ◽  
Force Sensor ◽  
Experimental Information ◽  
Centre Of Gravity ◽  
Stability Performance ◽  
Fluid Velocities ◽  
Uniform Current ◽  
The Stability ◽  
Six Degree Of Freedom

An articulated concrete mattress model has been utilised to investigate the effects of reduced vertical centre of gravity on the stability of a 400 series block. Experimental testing was conducted at the AMC CWC, Beauty Point. To determine the effects that a reduced centre of gravity has on stability, the 3 by 3 articulated concrete mattress model was subject to pure uniform current flow. The subsequent forces were analysed with a six degree of freedom underwater force sensor. In order to gain a range of real world scenarios, the experimental model was tested at six flow angles ranging from -15 degrees through to 60 degrees, at 15 degree increments. Additionally, five fluid velocities starting at 0.6 m/s through to 1.4 m/s, at 0.2 m/s increments were investigated. These results explain how the inversion of a 400 series block increases its hydrodynamic coefficients and subsequently decreases its stability performance in current flow. Ultimately, this study provides experimental information for the installation of 400 series articulated concrete mattresses in the inverted orientation.

scholarly journals IV. The variation of stability with draught of water in ships

1883 ◽  
Vol 36 (228-231) ◽  
pp. 434-436
Keyword(s):  
Royal Navy ◽  
Usual Practice ◽  
Amount Of Information ◽  
Centre Of Gravity ◽  
The Stability

Of all the properties possessed by a ship none is more vital to her safety and efficiency than that of stability. At the same time none is dependent for its existence and amount upon so many or such diverse and variable circumstances as it. The stability of a ship, both as regards moment and range, is affected not only by the position of her centre of gravity, which largely depends upon stowage, but also by draught of water. If the centre of gravity be kept fixed in position at various draughts of water, the stability will still vary very considerably with the draught, and often in a manner that contains elements of danger. The usual practice in investigating a ship’s stability is to calculate a curve of metacentres, and one or more curves of stability at certain fixed draughts of water and with given positions of centre of gravity. The curve of metacentres gives the height at all draughts of water above which the centre of gravity cannot be raised without making the ship unstable when upright, and causing hen to lie over more or less to one side. The ordinates of the curve of stability represent the lengths of the righting arms, which, multiplied by the weight of the ship, give the righting moments at all angles of inclination from the upright. The stability of numerous vessels, both of the Royal Navy and Mercantile Marine, have been investigated in this manner for certain draughts of water, and a great amount of information obtained respecting the variation of stability with inclination at such draughts, and the angle at which the stability vanishes in many classes of ships. The peculiar dangers attaching to low freeboard, especially when associated with a high centre of gravity, have been fully discussed and made known.

scholarly journals Analysis of hydraulic system for adjustable ground clearance mechanism

2020 ◽  
Vol 4 (3) ◽  
pp. 203-208
Author(s):  
Jithendra Sai Raja Chada ◽  
Venkat G Sandeep ◽  
Rajesh Chollaganti
Keyword(s):  
Hydraulic System ◽  
Shock Absorber ◽  
Suspension System ◽  
Working Fluid ◽  
Ground Clearance ◽  
Centre Of Gravity ◽  
Drag Forces ◽  
Clearance Mechanism ◽  
The Stability ◽  
Lift And Drag

The stability of a vehicle depends on many parameters.The Centre of Gravity is one of the most important in them. If the height of center of gravity from the ground decreases the stability of the vehicle increases. But when the ground clearance is too low it has a chance of collision vehicle and the ground while going on an uneven road or with speed brakes. So, to avoid the collision of a vehicle to ground and increase the stability a mechanism to adjust the ground clearance is to be attached. Also, the lift and drag forces can also be altered using this adjustable ground clearance mechanism. The designers usually fix ground clearance and they try to acquire this by the suspension system. The suspension system has tires, tire air, springs, shock absorber, and other parts to connect the vehicle with the wheels. The present paper describes the significance of using hydraulic oil as a working fluid in an adjustable ground clearance mechanism. Also describes the design and analysis of piston and cylinder rod.

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