Speed Vector Research Articles

Saturated PI Optimization Induction Motor with Integral

A high precision feedback control system with a given excitation current speed vector modulation and an integral saturated PI regulator is proposed for multi-scenario application of induction motor with wide speed and load in machine tool processing. Considering the characteristics of the variable range of voltage and current of the induction motor, the constraints of the excitation current of the motor and the slip frequency and other factors, the angular velocity vector of the induction motor, the given excitation current and the given speed variable are extracted as the adjusting variables of the feedback speed loop, and the transformation is carried out in combination with the relationship between the speed and the voltage of the modulation vector. The speed, torque, flux and three-phase stator current variables of the induction motor under the condition of constant torque, constant speed and torque and speed variables change were observed. By comparing the performance improvement of the proposed method with that of the conventional method, the effectiveness of the proposed method and the optimization characteristics of parameters were verified.

Magnetic cloud prediction model for forecasting space weather relevant properties of Earth-directed coronal mass ejections

Context.Coronal mass ejections (CMEs) are major eruptive events on the Sun that result in the ejection of large-scale magnetic clouds (MCs) in interplanetary space, consisting of plasma with enhanced magnetic fields whose direction changes coherently when measured in situ. The severity of CME-induced geomagnetic perturbations and space weather impacts depends on the direction and strength of the interplanetary magnetic field (IMF), as well as on the speed and duration of the passage of the magnetic cloud associated with the storm. The coupling between the heliospheric environment and Earth’s magnetosphere is strongest when the IMF direction is persistently southward (i.e. negativeBz) for a prolonged period. Predicting the magnetic profile of such Earth-directed CMEs is therefore critical for estimating their space weather consequences; this remains an outstanding challenge, however.Aims.Our aim is to build upon and integrate diverse techniques towards the development of a comprehensive magnetic cloud prediction (MCP) model that can forecast the magnetic field vectors, Earth-impact time, speed, and duration of passage of solar storms.Methods.The configuration of a CME is approximated as a radially expanding force-free cylindrical structure. Combining near-Sun geometrical, magnetic, and kinematic properties of CMEs with the probabilistic drag-based model and cylindrical force-free model, we propose a method for predicting the Earth-arrival time, propagation speed, and magnetic vectors of MCs during their passage through 1 AU. Our model is able to predict the passage duration of the storm without recourse to computationally intensive time-dependent dynamical equations.Results.Our method is validated by comparing the MCP model output with observations of ten MCs at 1 AU. In our sample, we find that eight MCs show a root mean square (rms) deviation smaller than 0.1 between the predicted and observed magnetic profiles, and the passage durations of seven MCs fall within the predicted range.Conclusions.Based on the success of this approach, we conclude that predicting the near-Earth properties of MCs based on an analysis and modelling of near-Sun CME observations is a viable endeavour with potential applications for the development of early-warning systems for space weather and enabling mitigation strategies.

Bi-objective unrelated parallel machine joint scheduling of jobs and preventive maintenance with a dynamic speed-scaling technique

Nowadays, industries contribute to a substantial consumption of energy. This consumption leads to significant greenhouse gas emissions, energy dependence and ever-increasing costs for manufacturers. Controlling consumption and improving energy efficiency in industry are therefore major challenges in terms of environmental issues. In this context, this article examines an energy-efficient bi-objective unrelated parallel machine joint scheduling of jobs and preventive maintenance activities problem to minimize both makespan and total energy consumption. The parallel machines are speed-scaling. To solve the problem, we propose a bi-objective mixed integer linear programming (MILP) model. Since the problem involves assigning jobs to machines and selecting an appropriate processing speed level for each job, we characterize each individual by two vectors: a job-machine assignment vector and a speed vector. To the best of our knowledge, no papers considering both production scheduling and Preventive Maintenance periods with minimizing the bi-objective makespan and the total of energy consumption. The gap between theory and practice prevents the satisfying performance of the schedules in industry. The purpose of this paper is to establish a joint model for integrating the production and PM scheduling to optimize the bi-objective of the total of energy consumption (TEC) and makespan (Cmax) simultaneously; and to make the theory applied in practice more efficaciously. The performance of the proposed mixed binary integer programming model is evaluated based on the exact method of Branch and Bound integrated on the CPLEX solver plus analyses using MATLAB software. A study of the results proved the performance of the model developed.

Analytical method for determining the “active” speed of the spindle cotton harvester

The efficiency of the spindle harvester is determined by the activity of the spindle teeth located on the drums. The well-known M V Sablikov theory of cotton harvesting technology says that the capability of capturing cotton by the spindle depends on the correspondence between the directions of the tip and the speed vector of the tooth point. The article is devoted to the development of an analytical method for determining the active component of the absolute velocity of the tooth point of the spindle in the working chamber of the picking apparatus. The method is characterized by studying the orientation of the absolute velocity vector relative to the tangent to the circle of the section and the bisector of the spindle tooth wedge angle. Having located the centers of the coordinate axes along the tangent and the bisector at the tooth point, the oblique directing angles of the velocity vector were determined, and its active component was calculated. Graphs of changes in velocity during the time the spindle was in the working chamber were plotted, and an assessment was made of the capability of cotton capturing by the working body.

PEMYH için COMSOL'da Üç Boyutlu Çoklu Akış Modeliyle Altın Oran Yöntemi ile Oksijen ve Hidrojen Giriş Hızlarının Optimizasyonu

A three dimensional (3D), gas-liquid multi-phase flow and transport model in COMSOL Multiphysics has been developed to simulate flow and transport phenomena in a proton exchange membrane fuel cell (PEMFC) with several operational parameters. The effects of changes in oxygen and hydrogen input velocities on concentration change at electrodes, current density in polymeric membrane and cell performance have been investigated in PEMFC. The simulations, made in COMSOL for numerical method, were presented with an emphasis on the physical and fundamental insight afforded by distributions of velocity vector, local current density, overpotential, oxygen and water concentrations. Using Golden Section Method, optimization of the change in the speed vector was made based on the numerical models for velocity values. Results showed that computational and numerical methods are in great harmony. The polarization curve, which is used as a measure of efficiency in cell performance, were supportive with results. The data show that the power density obtained for the optimum model is higher, with such a model performance of 92.87%. Compared to the currently used PEMFC, while hydrogen saving achieved between 4.2% and 7.1%, electrical efficiency increase were between 1% and 2.4%.

THE ORIENTATION ANGLE OF REINFORCING ELEMENTS INFLUENCE ON TOOL WEAR INTENSITY IN PROCESSING POLYMER COMPOSITES

The relative angle between the direction of the reinforcing fibers and the cutting speed vector, defined as the angle of the reinforcing elements orientation, has a significant impact on the chip formation mode, cutting forces and the final surface quality. During machining of polymer composite materials, high-intensity wear occurs along the flank surface. This paper presents an analysis of the problem of the orientation fibers angle influence in a polymer composite on the cutting tool wear rate. For the previously proposed hereditary-aging model of tool weight loss due to wear, it is proposed to take into account the influence of the reinforcement angle through the dependence of the contact pressure and friction coefficient on this parameter. The article develops a generalizing model for practical consideration of the known in advance angle of reinforcement to predict tool wear and tool life during of polymer composite materials machining.

Analysis of trends of meteoclimatic characteristics at Enderby Land, East Antarctica based on land observations data and reanalysis

The article studies the presence and possible direction of climate change in Enderby Land, East Antarctica, where from 1963 to 1999, the only meteorological station of the WMO network operated at the Molodezhnaya research station (now the summer field base of the RAE), and now an automatic meteorological station has been installed. The trends in surface air temperature, wind speed and direction for the period from the mid-1960s to the present have been analyzed. As initial data, we used the results of ground-based observations at the Molodezhnaya station, as well as reanalysis datasets, which made it possible to complete the instrumental series and evaluate the dynamics of temperature and wind characteristics for the last decades. Monthly values of climatic parameters were used as initial values, but for wind characteristics presented as the V and U components of the speed vector, single values were taken, according to which the average monthly wind speeds and wind distributions in directions were estimated. From different reanalysis systems, by comparison with ground-based observations, series were selected that showed the greatest similarity in the dynamics of the climatic characteristics studied. Good agreement was found between the temperature series of observations at the Molodezhnaya meteorological station and the datasets UDEL_AirT, ERA5, and GISS. The correlation between the wind observation series is less strong; ERA5 reanalysis data shows the wind speed dynamics slightly better. According to the analysis of the long-term dynamics of average annual and monthly temperatures in the region of Enderby Land, the warming trend has not been statistically confirmed, however, a progressive increase in the number of months of the year with positive temperature dynamics has been noted. Based on the analysis of wind characteristics, it is shown that only an increase in average annual wind speeds of 0,1–0,3 m/s/10 years is statistically significant.

Online Path Planning of Mobile Robots Based on African Vultures Optimization Algorithm in Unknown Environments

Autonomous mobile robots developed using metaheuristic algorithms are increasingly becoming a hot topic in control and computer sciences. Specifically, finding the shortest root to the goal and avoiding hurdles are current subjects of autonomous mobile robots. The main drawbacks of classic methods are the incapacity to move the robot in a dynamic and unknown environment, deadlock in a local minimum and complicated environments, and incapacity to foretell the speed vector of obstacles and non-optimality of the route. This article exhibits a recent path planning approach that utilizes the African Vultures Optimization (AVOA) for navigation of the mobile robot in static and dynamic unknown environments with a dynamic target. The proposed online optimization approach is used in three different environments including an environment with unknown static obstacles, an environment with unknown dynamic obstacles, and an environment with a dynamic target. The proposed approach can solve a local minima problem in the environment with static obstacles. The online optimization method is performed using two phases which are the sensors’ reading phase and the path calculation phase and the results are given based on computer simulation in different unknown environments. A comparative study was conducted between the suggested algorithm and two other algorithms and the results showed that the AVOA algorithm was better in avoiding obstacles successfully including the local minima situation. Finally, the average enhancement rates in the path length compared with the Adaptive Particle Swarm Optimization (APSO) and the Hybrid Fuzzy-Wind Driven Optimization (WDO) are 2.21% and 1.02207%, respectively.

Improved Synchronous Motion of Linear and Rotary Axes While Avoiding Torque Saturation Under a Constant Feed Speed Vector at the Endmilling Point – Investigation of Motion Error Under Numerical Control Commanded Motion –

A five-axis machining center is known for its synchronous control capability, allowing complicated three-dimensional surfaces, such as propellers and hypoid gears, to be quickly created. Prior research has shown that it is necessary to improve not only the machined shape accuracy but also the machined surface roughness of free-form surfaces. Therefore, in this research, we aimed to maintain the feed speed vector at the endmilling point by controlling two linear axes and a rotary axis with a five-axis machining center to improve the machined surface quality. In previous research, we suggested reducing the shape error of machined workpieces (referred to as shape error in this research) by considering the differences in the servo characteristics of the three axes in the machining method. The shape error was significantly decreased by applying the proposed method, which uses a parameter (referred to as precedent control coefficient in this research) determined by calculation, rather than trial and error. Moreover, to maintain the feed speed vector at the endmilling point when machining complex shapes, a rapid velocity change in each axis is required, causing inaccuracy owing to torque saturation. The results of the experiments and simulations of previous research indicated that torque saturation can be evaluated via simulation. In this research, to reduce the shape error while avoiding torque saturation when movement has high angular velocity, we developed a theoretical method to obtain the most suitable precedent control coefficient of each axis by using a block diagram that considers torque saturation. Therefore, both shape error reduction and torque saturation avoidance can be realized by using the proposed method.

Modern methods of preventing aircraft overrunning the runway

The landing of the aircraft has always been the most challenging and dangerous stage of the flight. In order to make a safe landing, the aircraft (A/C) requires reducing the vertical (at the stage of flare-out) and horizontal (prior to touchdown) components of the aircraft's flight speed vector, which in turn reduces the capabilities to increase lift and limits the crew's ability to perform maneuvers. At the same time, during landing the crew must align the aircraft with the runway (RW) and make a touchdown, subsequent A/C landing roll and stop within a rather limited area, which eventually and particularly, under the effect of contributing adverse factors (piloting errors, wind shear, icing, engine failure, aquaplaning, etc.) can cause the aircraft to overshoot and overrun the RW. Currently, as the analysis of aviation accidents statistics shows, the issue of preventing and alerting aircraft overrun is quite relevant. The search for a solution, in terms of preventing aircraft overrunning the runway (RW), is conducted as at the level of aviation authorities as among aircraft manufacturers, operators. Within the framework of this review, an attempt is made to identify and analyze the key factors affecting the dynamics of aircraft motion during landing, using information about aviation accidents that have occurred over the past few years. Notably, such aspects as a human factor and technical features of the operation of modern jet aircraft, influencing the A/C landing roll, are considered. In addition, special attention is paid to consider the methods of prevention and warning of A/C overrun with highlighting the approaches of passive and active protection. Within the framework of the analysis of active protection techniques, the principles of on-board avionic systems operation of the most major aircraft manufacturers, such as Boeing and Airbus, are considered. As an example of the passive protection, the experience of using special energy-absorbing destructible blocks installed next to the runway threshold, is analyzed.

Development of a numerical stochastic model of joint spatio-temporal fields of weather parameters for the south part of the Baikal natural territory

Abstract The paper is focused on the construction of a numerical stochastic model of the joint spatio-temporal fields of air temperature, wind speed vector with three-hour resolution, and semidiurnal precipitation amounts according to observation data at a group of weather stations located in the south of the Baikal natural territory. The model also takes into account the dependence of one-dimensional distributions on temporal and spatial coordinates. The heterogeneity of the field in spatial correlations and the periodical correlation in time are also taken into account. The results of calculations for verification of the model are presented. An example of using the developed model to study the properties of time series of the wind chill index is given.

A framework for mode classification in multimodal environments using radar-based sensors

Monitoring traffic at locations where bicyclists and pedestrians are present and studying their interactions with motorized vehicles has the potential to reveal underlying crash mechanisms and, in turn, guide the implementation of suitable countermeasures. Previous research has demonstrated the capabilities of vision-based systems in traffic monitoring; however, as these systems rely on video camera data, they remain constrained in adverse lighting and weather conditions. Although radar-based sensors can be used in traffic monitoring, they have not been tested in multimodal environments. To bridge this gap a novel framework to classify trajectories recorded by radar-based sensors in multimodal traffic environments is developed. The Support Vector Machine is used as the classifier and the following aspects allow to develop a robust, flexible, and transferable classification framework that can be applied in various traffic scenes. The SVM employs (1) a speed and length or speed and acceleration feature vector, (2) trajectory normalization scheme (i.e., select multiple measurements per trajectory), (3) training sample balancing strategy, and (4) cross-validation strategy. The framework is tested and validated using data from two different multimodal intersections. The results suggest that the mode type for every trajectory can be predicted with 95% accuracy using ten speed measurements and the vehicle’s mean length while accounting for the unequal number of observations per class. While these results are subject to change, i.e., both SVM’s input (feature vector and/or balancing approach) and performance may vary across different traffic scenes, the proposed framework is transferable and flexible.

Исследование кинематических параметров андроидного робота при автоматизированном синтезе движений по вектору скоростей

The modernization of the method of synthesis of motions of manipulators by speed vector allows to exclude motions the emergence of dead ends in the process of computer simulation. The developed algorithm is based on the use of a database characterising the values of kinematic parameters that specify the permissible instantaneous states of the mechanism of the manipulator at different positions. The graphical representation of the hypersurface of the reflective relationship of the specified parameters from the values of the generalized coordinates is made. On the basis of this, a method for determining the above kinematic parameters is proposed, which makes it possible to reduce the time for calculating intermediate configurations on a given trajectory of the output link and to eliminate the occurrence of deadlock situations.

Оценка влияния моделей турбулентности на описание процессов вихреобразования в ветроэнергетике

Проведено сравнение результатов математического моделирования внешнего обтекания горизонтально-осевой ветроэнергетической установки Siemens модели SWT-3.6-120 (профиль лопасти B52) с применением осредненных по Рейнольдсу уравнений Навье-Стокса, замкнутых моделями турбулентности $k{-}\varepsilon$, $k{-}\omega$ Shear Stress Transport и Eddy Viscosity Transport. Задача верного определения угла отклонения вектора скорости над гондолой ветроэнергетической установки обусловлена работой системы ориентации, от которой зависит эффективность всей установки. В качестве критерия сравнения выбрано число Струхаля, определенного для поперечного обтекания цилиндра, описывающего частоту формирования вихревой структуры за комлевой частью лопасти ветроэнергетической установки. Расчетная область состоит из трех миллионов тетраэдрических элементов с призматическим слоем на поверхности гондолы с применением локального измельчения. Место регистрации параметров направления потока расположено на высоте 3 м над гондолой и на расстоянии 8 м от комлевой части лопасти, что соответствует стандартному расположению анеморумбометра. Анализ полученных результатов показал, что модели турбулентности $k{-}\varepsilon$ и Eddy Viscosity Transport практически одинаково описывают параметры потока над гондолой ветроэнергетической установки, но модель Eddy Viscosity Transport имеет одно дифференциальное уравнение, тем самым ее применение является более предпочтительным по критерию вычислительных затрат. Преимущество модели Eddy Viscosity Transport также заключается в меньшем количестве замыкающих полуэмпирических констант, анализ которых позволяет расширить область применения инженерных методик описания турбулентных процессов для решения практических задач, связанных с проектированием систем управления ветроэнергетическими установками, повышающих коэффициент полезного действия таких установок.

Analysis of the speed and curvature of the trajectory in the problem of pursuing a set of targets

Introduction. A kinematic model of group pursuit of a set of targets on a plane is considered. Pursuers use a technique similar to parallel approach method to achieve goals. Unlike the parallel approach method, the speed vectors of pursuers and targets are directed arbitrarily. In the parallel approach method, the instantaneous directions of movement of the pursuer and the target intersect at a point belonging to the circle of Apollonius. In the group model of pursuing multiple goals, the pursuers try to adhere to a network of predictable trajectories.Materials and Methods. The model sets the task of achieving goals by pursuers at designated points in time. This problem is solved by the methods of multidimensional descriptive geometry using the Radishchev diagram. The predicted trajectory is a composite line that moves parallel to itself when the target moves. On the projection plane “Radius of curvature — speed value”, the permissible speed range of the pursuer is displayed in the form of level lines (these are straight lines parallel to one of the projection planes). Images of speed level lines are displayed on the projection plane “Radius of curvature — time to reach the goal”. The search for points of intersection of the speed line images and the appointed time level line is being conducted. Along the communication lines, the values of the intersection points are lowered to the plane “Radius of curvature — speed value”. Using the obtained points, we construct an approximating curve and look for the intersection point with the line of the assigned speed. As a result, we get values of the radius of the circle at the predicted line of the trajectory of the pursuer.Results. Based on the results of the conducted research, test programs have been created, and animated images have been made in the computer mathematics system.Discussion and Conclusions. This method of constructing trajectories of pursuers to achieve a variety of goals at a given time values can be in demand by developers of autonomous unmanned aerial vehicles.

Selective Simulated Annealing for Large Scale Airspace Congestion Mitigation

This paper presents a methodology to minimize the airspace congestion of aircraft trajectories based on slot allocation techniques. The traffic assignment problem is modeled as a combinatorial optimization problem for which a selective simulated annealing has been developed. Based on the congestion encountered by each aircraft in the airspace, this metaheuristic selects and changes the time of departure of the most critical flights in order to target the most relevant aircraft. The main objective of this approach is to minimize the aircraft speed vector disorder. The proposed algorithm was implemented and tested on simulated trajectories generated with real flight plans on a day of traffic over French airspace with 8800 flights.

Theoretical bases of development and research of electronic sensor of small-sized aircraft speed vector parameters

Theoretical bases of development and research of electronic sensor of small-sized aircraft speed vector parameters

Development of the scheme and method for measuring the characteristics of the friction areas in the car wheel contact

The aim of the research is to develop and implement a scheme and method for measuring the characteristics of static and sliding friction areas in the contact patch of an elastic wheel with a solid support when they appear, exist and disappear. The characteristics are understood as: the relative location of static and sliding friction in relation to the vector of the translational speed of the wheel axis; their size and location in the contact patch when they appear, spread and disappear; the values of the moments on the wheel, corresponding to the appearance, spread and disappearance of static and sliding friction. A scheme and a method for measuring these characteristics have been developed and implemented. The measurements are indirect. It has been experimentally established that, in the general case, the geometric center of static friction in the contact patch moves towards the moment acting in the plane of the wheel rotation relative to the rotation axis by an amount proportional to the moment. The maximum value of this displacement according to the moment that is maximum in terms of sliding conditions, and is one third of the contact patch length for all types and conditions of a solid support. The research results are valid for elastic wheels with a radial stiffness not exceeding 12000000 N/m, the main plane of which is perpendicular to the reference plane. The research results can find application in design modeling of stability and controllability of vehicles.

Optimization of the trimming tilting angle of the electric tiltrotor propeller group

The paper examined the possibility of improving the energy efficient performance of an electric tiltrotor with a lift-propulsion propeller group for a steady flight mode by reducing the energy consumption of the propeller group per unit of time or per unit of the path traveled by the electric tiltrotor. This is achieved by selecting the optimal tilting angles of the electric tiltrotor total thrust vector. In the proposed approach, the trimming tilting angle of the propeller group is variable, depending on the aerodynamic characteristics of the electric tiltrotor, its propeller group. Since the propeller group is equipped with the drives for tilting them, this approach is easily implemented by the conventional facilities of the electric tiltrotor. The tilting of the total thrust vector, on the one hand, leads to an increase in the effective value of the aerodynamic lift coefficient and, on the other hand, it is accompanied by a decrease in the projection of the total thrust vector on the flight speed vector, a change in the drag and power required to create the thrust of the propeller group. This circumstance makes it necessary to solve the optimization problem in order to increase the maximum endurance and long-range capabilities in the cruise mode of the electric tiltrotor flight. The paper presents a method for calculating the optimal tilting angles of the total thrust vector based on the equations of steady motion of the electric tiltrotor in the cruise flight mode, the expression for the total power required for the rotation of the propellers of the propeller group. The analytical dependences for the optimal tilting angles of the total thrust vector are obtained depending on the ratio of the wing area to the total propeller-disk area of the propeller group and the aerodynamic quality of the electric tiltrotor.

Energy Efficient Localization Through Node Mobility and Propagation Delay Prediction in Underwater Wireless Sensor Network

In Underwater Wireless Sensor Network, for mobile target localization schemes, there exists long propagation delay of sensor nodes' messages. Further, the flexibility of node localization schemes to adapt in harsh underwater environment is the major issue. As propagation delay is one of the principal aspects that disturb the time harmonisation of underwater sensor nodes for communication. It must be adjusted to attain precise and accurate localization. In this article, we propose an energy-efficient localization scheme based on mobility and propagation delay prediction. Precise synchronization time is accomplished by forecasting the long propagation delay. Anchor node mobility prediction procedure is intended to analyse and record its speed at every localization period. Then, the propagation delay is compensated to attain rapid reporting of localization. The ordinary nodes make localization, utilizing the expected speed vectors obtained from the anchor nodes. The proposed scheme is tested in simulator NS-2.30 all-in-one with multiple runs and average of these runs is considered. The replicating outcomes exhibit, that the proposed method increases overall energy efficiency by 16%, localization cost by 26%, and delay by 28%, which are the major concern for localization scheme.