scholarly journals Increasing the operating depth of an autonomous underwater vehicle using an intelligent magnetic field

Author(s):  
Ali Jebelli ◽  
Arezoo Mahabadi ◽  
Mustapha C. E. Yagoub

<p>Designing and manufacturing a suitable body is one of the most effective factors in increasing the efficiency of autonomous underwater vehicles (AUVs). In fact, increasing the propulsive power of an AUV by reducing the frictional drag on its body and incre asing its maneuverability will positively affect key parts of the AUV’s hardware and software such as control system, sensors, AUV vision, batteries and thrusters. On the other hand, a suitable body should have features such as lightness, underwater vehicl e’s balance, high mechanical strength, and enough space for equipment. Therefore, the design and manufacture of the body requires a lot of analysis in terms of body material, aerodynamic calculations, etc., increases the overall cost. This paper aims to re duce the stress in the body of a Polytetrafluoroethylene ( PTFE ) underwater robot and to increase its operating depth without changing the body’s structure by using fuzzy logic to intelligently controlling the magnetic force generated by the repulsion betwe en the coil and the cylindrical magnet, which saves energy, reduces battery consumption, and increases system performance. The results show that the robot performance depth increases by more than 50% without changing the robot body structure.</p>

2013 ◽  
Vol 437 ◽  
pp. 42-46
Author(s):  
Jian Min Ju

The design and manufacture of the vehicle structure determines of the safety and suitability during operation. For most designers, the bearing capacity of the vehicle body is not completely understood. The initial estimate of the vehicle is simply a uniform simply supported overhang beam structure. With the development of computer technology, people can use more complex and closer to the actual body computational model, but it generally requires a lot of work, and designers are often only able to see the final result. It is not clear that the factors affect Load-carrying properties of the body structure. Designers often can not look find a process of improving the design. This method to scan the body structure by a computer calculation and analysis, the geometry, mechanical properties of parameters of the body cross-section has been plotted map. You can quickly and accurately understand the overall performance of the body, analysis the performance difference of different body cross-section. Reasonableness and balance of the body can be measured and awarded. In general, it is very important for the designer of the vehicle.


Author(s):  
Majid Alijani ◽  
Marhamat Zeinali ◽  
Nowrouz Mohammad Nouri

The process of designing autonomous underwater vehicles comprises several steps, including the designing of the body shape. The hydrodynamic designing of the body shape is a major step in designing the body of an underwater vehicle. The effective parameters in the hydrodynamic design of body shape include the lengths of nose and tail, nose and tail profiles, and also the dimensions of the blunt sections in front of the nose and behind the tail. In the present study, the design of experiments method has been employed to investigate the effect of each of the above parameters on the drag coefficient of an autonomous underwater vehicle body. For this purpose, in addition to introducing the body classes of the Hydrolab family of underwater vehicles, the numerical simulation results of fluid flow over the body of a Hydrolab500 AUV have been used for the design of experiments. In the first step, an experiment has been performed in water tunnel on a test model in order to validate the pressure profile for the body of Hydrolab500. The comparison between the empirical and numerical results related to Hydrolab500 body confirms the validity of the numerical approach used in this paper. The results of the present work show that the drag coefficient of an autonomous submersible in the final design can be accurately estimated with the help of the presented method.


2017 ◽  
Vol 1 (1) ◽  
pp. 115
Author(s):  
Sudar Kajin

Growth and development of the child have the nature of a thorough and intertwined relationships between components (health, nutrition, and environment). In general, child development can be grouped into three areas, namely cognitive, affective, and psychomotor, whereas biological growth which includes a change in the body structure. Body structure regarding the changes in bone structure, especially the long bones that have an impact on changes in body size, whereas changes in bodily functions is a result of hormonal changes that affect the physiological function .. The purpose of this development are: 1) Describe the product feasibility study التربية الجسمية for grade XI IPA at MAN I Mojokerto 2) Describe the development of learning tools using process skills can improve learning outcomes subjects التربية الجسمية class XI IPA at MAN I Mojokerto From the results of this development can be concluded: 1) results of expert validation and testing, the model approach process skills is fit for use for subjects of Physical Education, Sport and Health, because the products developed are not revised by experts but from the results of questionnaire of students stated that require revision are: (a) Improve the look model or change the learning strategy, and (b) improve the use of resources in implementing the model. 2) Product development learning tools using process skills can improve learning outcomes subjects التربية الجسمية class XI IPA at MAN I Mojokerto. From the class of the test increased learning completeness of Pre and Post Tests Tests are respectively 77.78% increase to 91.67%.


2017 ◽  
Vol 54 ◽  
pp. 112-119
Author(s):  
L. M. Khmelnychy

The estimation of the first-born cows of Ukrainian Black-and-White dairy breed by the exterior type in the leading breeding herds of Cherkassy region by the method of linear classification (n = 566) has been carried out. The results of the evaluated animals by the 100-score system indicate that within the group of traits, the average level of assessment is "good with the plus". The animals have been differed by the good development of group features characterizing the dairy type (82.4 score), body condition (83.5 score), limbs (82.8 score), udder (82.7 score) and overall score (82.8 score). The degree of development 18 descriptive traits of the exterior of cows, has been predicted by the method of linear classification, indicates their significant intraherd variability. Animals have the moderate height, deep body and angularity. The rump angle, the angle of hock joint and the teats length, according to the variability of scores in the range of 17.8–22.4%, have an average optimal development. The level of scores for the rear width (5.9 score), attachment of the fore (6.3 score) and the rear parts (6.0 score) of the udder testifies to their good development. The body structure of the cows-firstborn has a sufficient description of the type traits that determine their milk yield. At the present stage of selection and breeding work due to the use of bull-sires different origins and breeding value on the local population livestock with significant genotype diversity, the degree of influence each of the hereditary factors in the overall variability of linear features has a scientific and practical significance. In our studies, the force of influence conditional bloodiness of the Holstein mother's breed in the overall fraction of variability of linear type traits within the exterior complexes and the overall assessment takes a significant percentage - from 24.9 to 31.5 with a high degree of reliability according to Fischer's criterion. Among the descriptive traits, the proportion of influence the conditional bloodiness of mother, which is confirmed by high statistical confidence, ranges from 14.4 to 19.8%, and refers to the traits important for breeding. The level of coefficients of influence the father's breeding value in the total phenotypic variability for some of the linear traits is high and reliable. First of all it concerns group traits of the exterior, the development of which is determined by the pedigree value of father by 37.1–41.8%, and the overall assessment of type – by 46.6%. The coefficients of influence father's breeding value in most of the descriptive traits have high reliability (P < 0,001). The coefficients of the force of influence father, depending on the heredity of Holstein for the linear traits of almost the same level as his pedigree value. Since in this case the organized factor is purebreed Holstein and crossbreed bulls-sires of domestic selection, the positive role of Holstein heredity in improving the exterior type of cows has been traced realistically. The necessity of linear breeding, as an effective method in the system of dairy cattle breeding, has been substantiated by reliable values of the coefficients of the force of influence of father's line on the linear traits of offspring (3.4–29.5%). Despite the significant variability of coefficients of the force of influence on the linear traits, most of them have a high level of reliability within the evaluated body parts important for selection. The effect of cows belonging to the maternal line on the development of features of the body structure is insignificant and unreliable (5.3–9.2%). In the process of breeding aimed at improving cows of dairy herd by the exterior type, the pedigree value of parents has been assessed according to the method of linear classification of their daughters and their belonging to perspective genealogical formations.


Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2468
Author(s):  
Ri Lin ◽  
Feng Zhang ◽  
Dejun Li ◽  
Mingwei Lin ◽  
Gengli Zhou ◽  
...  

Docking technology for autonomous underwater vehicles (AUVs) involves energy supply, data exchange and navigation, and plays an important role to extend the endurance of the AUVs. The navigation method used in the transition between AUV homing and docking influences subsequent tasks. How to improve the accuracy of the navigation in this stage is important. However, when using ultra-short baseline (USBL), outliers and slow localization updating rates could possibly cause localization errors. Optical navigation methods using underwater lights and cameras are easily affected by the ambient light. All these may reduce the rate of successful docking. In this paper, research on an improved localization method based on multi-sensor information fusion is carried out. To improve the localization performance of AUVs under motion mutation and light variation conditions, an improved underwater simultaneous localization and mapping algorithm based on ORB features (IU-ORBSALM) is proposed. A nonlinear optimization method is proposed to optimize the scale of monocular visual odometry in IU-ORBSLAM and the AUV pose. Localization tests and five docking missions are executed in a swimming pool. The localization results indicate that the localization accuracy and update rate are both improved. The 100% successful docking rate achieved verifies the feasibility of the proposed localization method.


Author(s):  
K. Mendelssohn ◽  
J. D. Babbitt ◽  
Frederick Alexander Lindemann

Until a year ago it was generally accepted that if a body is made supraconducting while in a magnetic field the lines of magnetic force were "frozen in," i. e ., whatever lines of force passed through the body at the time when it became supraconducting remained there afterwards, unaffected by any change in the external field, so long as the body was supraconducting. Meissner and Ochsenfeld, however, showed that this supposition was not true. They measured field strengths in the immediate neighbourhood of cylinders which had been cooled to supraconductivity in an external magnetic field, and found that the field of force was then of the same nature as that to be expected in the neighbourhood of perfectly diamagnetic bodies. Thus it appeared that when a body becomes supraconducting in a magnetic field the lines of force are all pressed out of the body, and the induction inside the body falls to zero. At the same time, however, these authors report on another experiment, the result of which appears to us not entirely in accordance with the assumption that the induction in the whole body became zero. They measured the field strengths inside and outside a hollow cylinder, after it had become supraconducting in a field perpendicular to its axis, and found again that the field strength outside was as if the cylinder were almost perfectly diamagnetic, but the field inside was appreciably the same as if the cylinder were non-supraconducting. We therefore made a number of experiments, hoping to find out more exactly the nature of the phenomenon.


1970 ◽  
Vol 67 (3) ◽  
pp. 671-676
Author(s):  
E. R. D'sa

In (1) the velocity and magnetic fields were studied in the stagnation point region of a magnetized blunt body rotating with angular speed Ω. Some familiarity with this paper is assumed here: briefly, the nose section of the body was approximated by a disc of thickness t and conductivity σ′ and a perturbation solution was derived for small values of the diffusivity ratio ε (= ν/λ) and of the magnetic force coefficient N = σB2/4ρa. B is the uniform normal field component at the upperside (z = 0) of the disc, a is the strength of the external flow, p and σ are the density and conductivity of the fluid. The other two governing parameters are ω = Ω/a and β = σ′/σL, where L = (λ/a)½.


Author(s):  
Mohammad Saghafi ◽  
Roham Lavimi

In this research, the flow around the autonomous underwater vehicles with symmetrical bodies is numerically investigated. Increasing the drag force in autonomous underwater vehicles increases the energy consumption and decreases the duration of underwater exploration and operations. Therefore, the main objective of this research is to decrease drag force with the change in geometry to reduce energy consumption. In this study, the decreasing or increasing trends of the drag force of axisymmetric bare hulls have been studied by making alterations in the curve equations and creating the optimal geometric shapes in terms of hydrodynamics for the noses and tails of autonomous underwater vehicles. The incompressible, three-dimensional, and steady Navier–Stokes equations have been used to simulate the flow. Also, k-ε Realizable with enhanced wall treatment was used for turbulence modeling. Validation results were acceptable with respect to the 3.6% and 1.4% difference with numerical and experimental results. The results showed that all the autonomous underwater vehicle hulls designed in this study, at an attack angle of 0°, had a lower drag force than the autonomous underwater vehicle hull used for validation except geometry no. 1. In addition, nose no. 3 has been selected as the best nose according to the lowest value of stagnation pressure, and also tail no. 3 has been chosen as the best tail due to the production of the lowest vortex. Therefore, geometry no. 5 has been designed using nose and tail no. 3. The comparison made here showed that the maximum drag reduction in geometry no. 5 was equal to 26%, and therefore, it has been selected as the best bare hull in terms of hydrodynamics.


2018 ◽  
Vol 212 (1) ◽  
pp. 105-123
Author(s):  
Tomasz Praczyk ◽  
Piotr Szymak ◽  
Krzysztof Naus ◽  
Leszek Pietrukaniec ◽  
Stanisław Hożyń

Abstract The paper presents the first part of the final report on all the experiments with biomimetic autono-mous underwater vehicle (BAUV) performed within the confines of the project entitled ‘Autonomous underwater vehicles with silent undulating propulsion for underwater ISR’, financed by Polish National Center of Research and Development. The report includes experiments in the swimming pool as well as in real conditions, that is, both in a lake and in the sea. The tests presented in this part of the final report were focused on low-level control.


2018 ◽  
Vol 213 (2) ◽  
pp. 53-67 ◽  
Author(s):  
Tomasz Praczyk ◽  
Piotr Szymak ◽  
Krzysztof Naus ◽  
Leszek Pietrukaniec ◽  
Stanisław Hożyń

Abstract The paper presents the second part of the final report on all the experiments with biomimetic autonomous underwater vehicle (BAUV) performed within the confines of the project entitled ‘Autonomous underwater vehicles with silent undulating propulsion for underwater ISR’, financed by Polish National Center of Research and Development. The report includes experiments on the swimming pool as well as in real conditions, that is, both in a lake and in the sea. The tests presented in this part of the final report were focused on navigation and autonomous operation.


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