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PL
W artykule przedstawiono wyniki pomiarów, których celem było zbadanie możliwości zwiększenia efektywności działania modelu mikroelektrowni wiatrowej przez zastosowanie zmiennego kąta ustawienia łopat. Badania przeprowadzono na stanowisku pomiarowym zbudowanym do realizacji prac nad opracowywanymi wstępnie projektami mikroelektrowni wiatrowych. Stanowisko umożliwia przeprowadzenie pomiarów związanych z doborem optymalnej geometrii śmigła oraz opracowaniem i testowaniem działania algorytmów optymalnego sterowania pracą mikroelektrowni. Omówiono podstawy fizyczne działania turbiny wiatrowej i sposoby optymalnego jej sterowania. Zakres przeprowadzonych badań obejmuje wykonanie pomiarów dla przypadku wybranej geometrii łopaty śmigła z możliwością zmiany jej kąta ustawienia. Jako generator zastosowano prądnicę prądu stałego z obciążeniem o charakterystyce nieliniowej w postaci ogniwa akumulatora Li-Po. Przedstawiono wyniki działania prostego algorytmu sterowania MPPT. Brak układów optymalnego sterowania pracą mikroelektrowni podyktowany jest ogólnym przekonaniem, o wysokich kosztach jego wytworzenia w stosunku do możliwej poprawy efektywności mikroelektrowni. Ponadto stosowane w praktyce sposoby sterowania większymi turbinami wiatrowymi o mocach przekraczających wartość kilkuset kilowatów nie są optymalne dla mniejszych turbin o mocach do 1 kW. Przeprowadzone badania koncentrowały się na określeniu możliwości zastosowania w elektrowniach wiatrowych o mocach do 1 kW, turbin o zmiennym kącie ustawienia łopat w zależności od jej prędkości obrotowej. W większych elektrowniach wiatrowych zmianę kąta ustawienia łopat stosuje się głównie do ograniczenia mocy turbiny przy dużej prędkości wiatru. W mikroelektrowniach wiatrowych takie rozwiązania, ze względów ekonomicznych, nie są stosowane. Jednak zastosowanie prostego mechanizmu zmiany kąta ustawienia łopat w zależności od prędkości obrotowej śmigła może zwiększyć efektywność pracy turbiny w szerszym zakresie prędkości wiatru. Niewielkie wymiary modelu badawczego pozwalają na szybkie i tanie opracowywanie wstępnych prototypów łopat turbiny dzięki możliwości wykorzystania technologii druku 3D.
EN
The article presents the results of research into the operation of a model of a wind micropower plant with a variable blade angle. The research was carried out on a miniature model of a measuring stand built for the purpose of carrying out work on pre-developed projects of wind micro power plants. The stand allows to carry out measurements related to the selection of the optimal propeller geometry, as well as the development and testing of algorithms for optimal control of the micropower plant. The physical basics of wind turbine operation and the methods of its optimal control are presented. The results of the performed measurements for the selected propeller blade geometry with the possibility of changing its setting angle are presented. A DC generator with a load with a non-linear characteristic in the form of a Li-Po battery cell was used. The results of operation of a simple MPPT control algorithm are presented. The lack of optimal control systems for the operation of micropower plants is dictated by the general belief that the costs of its production are high in relation to the possible improvement of the efficiency of micropower plants. Moreover, the practical methods of controlling larger wind turbines are not optimal for small and very small turbines. The conducted research focused on determining the possibility of using turbines with variable blade angles depending on its rotational speed. In larger wind farms, changing the blade angle is mainly used to limit the power of the turbine at high wind speeds. In micro wind power plants such solutions are not used for economic reasons. However, the use of a simple mechanism for changing the angle of the blades depending on the rotational speed of the propeller can increase the efficiency of the turbine in a wider range of wind speeds. The small dimensions of the research model allow for quick and cheap development of preliminary prototypes of turbine blades thanks to the possibility of using 3D printing technology.
PL
Sukces uniknięcia kolizji z ruchomymi przeszkodami zależy od rozwiązania najistotniejszych problemów takich jak: szybkie wykrycie przeszkód, sprawdzenie czy stanowią zagrożenie oraz podjęcie właściwej decyzji o sposobie ich ominięcia. Do podjęcia tej decyzji niezbędna jest właściwa identyfikacja rodzaju zagrożenia, w tym między innymi czy wykryte przeszkody należy potraktować jako jedną zagregowaną grupę. Do typowych przypadków zalicza się agregację ruchomych przeszkód poruszających się blisko siebie. Opisano sytuacje, gdy dołączeniu do grupy podlegają obiekty przemieszczające się w większej odległości od siebie. Zaprezentowano algorytm podejmowania decyzji przypisania (zagregowania) ruchomych przeszkód do danej grupy. Przedstawiono sposób wyliczania jej charakterystycznych parametrów. Omawiane zagadnienia zostały zilustrowane wynikami symulacji manewrów omijania zagregowanej grupy ruchomych przeszkód dla wybranych scenariuszy.
EN
Successful avoidance of a mid air collision with moving obstacles depends on solutions of some most essential problems, e.g.: quick detection of an obstacle, verification whether detected obstacle is a critical one and making right decision on evasive manoeuvre. This decision-making process requires an appropriate identification of a threat’s nature, including whether detected obstacles should be treated as one aggregated group. Aggregation of obstacles moving in short distance one to the other is a typical case. The paper addresses also the case of inclusion the obstacle to the group objects moving in longer distances one to the other. The algorithm used for deciding whether a moving obstacle should be added to (aggregated with) a given group has been presented. A method for computing its characteristic parameters has been presented too. Selected scenarios of avoiding the aggregated group of moving obstacles have been simulated and results obtained illustrates problems considered.
3
Content available The Machine Learning Method of PIDVCA
EN
Building a dynamic collision knowledge base of self-learning is one of the core contents of implementing "personified intelligence" in Personifying Intelligent Decision-making for Vessel Collision Avoidance (short for PIDVCA). In the paper, the machine learning method of PIDVCA combined with offline artificial learning and online machine learning is proposed. The static collision avoidance knowledge is acquired through offline artificial learning, and the isomeric knowledge representation integration method with process knowledge as the carrier is established, and the Dynamic collision avoidance knowledge is acquired through online machine learning guided by inference engine. A large number of simulation results show that the dynamic collision avoidance knowledge base constructed by machine learning can achieve the effect of anthropomorphic intelligent collision avoidance. It is verified by examples that the machine learning method of PIDVCA can realize target perception, target cognition and finally obtain an effective collision avoidance decision-making.
PL
Do rozwiązania problemu unikania kolizji przez samolot w przestrzeni powietrznej niezbędne jest wykrycie przeszkody, sprawdzenie czy stanowi zagrożenie dla bezpieczeństwa samolotu oraz podjęcie właściwych decyzji o odpowiednim sposobie jej ominięcia. To wszystko są istotne fazy poprzedzające automatyczne ominięcie ruchomej przeszkody. W pracy zaprezentowano algorytm omijania ruchomej przeszkody o niedających się przewidzieć zmianach jej ruchu. Przedstawiono schemat logicznych działań mających na celu nie tylko bezpieczne uniknięcie kolizji z manewrującą przeszkodą, ale także powrót do lotu wzdłuż zaplanowanej przed startem trasy. Zaproponowaną metodę zilustrowano symulacyjnym przykładem automatycznego ominięcia wspomnianej przeszkody dla wybranego scenariusza.
EN
To solve the problem of aircraft avoiding collision, it is necessary to detect an obstacle, check if it poses a threat to the safety of the aircraft and make the right decisions about the appropriate way to bypass it. These are all important phases preceding the automatic bypassing of a moving obstacle. The work presents an algorithm for bypassing a moving obstacle with unpredictable changes in its movement. A diagram of logical actions was presented to not only safely avoid collision with a maneuvering obstacle, but also to return to flight along the route planned before the start. The proposed method is illustrated by a simulation example of automatically bypassing an obstacle for the selected scenario.
EN
The speed ratio is an important factor that must be considered when two vessels will course change to avoid collision. In the process of the research on Personifying Intelligent Decision-making for Vessel Collision Avoidance (short for PIDVCA), it is found that the effect of collision avoidance based on the existing “International Regulations for Prevention Collision at sea” (short for COLREGS) is greatly affected by the high speed ratio (k=Vt/V0≥1.5). Through the analysis on the geometric change law of two vessels’ relative motion in Open waters, the effects of the responsibility for the ship collision avoidance under the COLREGS and special case for high-speed ratio is discussed. According to the collision avoidance measures taken for two vessels encounter situation, some reasonable suggestions are put forward and the simulation experiments that based on ship's intelligent collision avoidance simulation platform are given to support the idea.
EN
In order to give consideration to both comprehensive evaluation and efficient decision-making in collision avoidance decision-making process, a collision avoidance decision-making model based on collision circle is proposed by introducing the concept of collision circle. Firstly, the factors causing ship collision are analyzed. Secondly, the static and dynamic characteristics of collision circles are analyzed and summarized by using collision circle simulation cases. Thirdly, based on the static characteristics, a reasonably distributed collision avoidance decision model of (Possible Point of Collision,PPC) was established. Finally, the spatial data operations core algorithm (Java Topology Suite, JTS) is used for logical operation and visualization, so as to realize the ship collision avoidance evaluation and decision. The decision model was used to verify the accident scenario of "SANCHI", and the results showed that the obtained collision avoidance scheme was reasonable and in line with the "International Regulations for Preventing Collisions at Sea" and safety requirements, thus providing a reference for maritime operators to avoid collisions between ships.
7
Content available Neuroevolutionary approach to COLREGs ship maneuvers
EN
The paper describes the usage of neuroevolutionary method in collision avoidance of two power-driven vessels approaching each other regarding COLREGs rules. This may be also be seen as the ship handling system that simulates a learning process of a group of artificial helmsmen - autonomous control units, created with artificial neural networks. The helmsman observes an environment by its input signals and according to assigned CORLEGs rule, he calculates the values of required parameters of maneuvers (propellers rpm and rudder deflection) in a collision avoidance situation. In neuroevolution such units are treated as individuals in population of artificial neural networks, which through environmental sensing and evolutionary algorithms learn to perform given task safely and efficiently. The main task of this project is to evolve a population of helmsmen which is able to effectively implement chosen rule: crossing or overtaking.
EN
This research article formulates a mathematical model of the matrix game of the safe ship control process containing: state variables and control, collision risk definition and the form of a collision risk matrix. Multicriteria optimization of the matrix game was introduced, leading to non-cooperative and cooperative game control algorithms and non-game control. Simulation safe trajectories of own ship for various types of control were compared to the example of the real situation at sea.
EN
Collision risk measurement is an essential topic for ship collision prevention. Many risk measures, i.e. DCPA/TCPA, etc., decouple the ship traffic into several pairs of ships and then evaluate the risk in each pair. This kind of measurement loses some information of the entire traffic and might include some biases in risk measurement, especially in multiple-ship scenarios. In this article, Imminent Collision Risk Assessment (ICRA) is extended, which formulates collision risk as a ratio of reachable maneuvers leading to a collision and all reachable maneuvers (velocities). Two groups of scenarios have been simulated to show the ICRA is suitable for assessing the collision risk in multiple-ship scenarios. Moreover, two improvements have been introduced: (1) a generalized velocity obstacle algorithm is introduced to collect the maneuvers leading to collisions, which considers ship dynamics; (2) the constraints of forces are considered in the formulation of reachable maneuvers. As a result, the proposed measurement helps one ship assess the risk of approaching obstacles which are difficult to avoid the collision in terms of own-ship’s dynamics and kinetic constraints.
EN
Maritime Autonomous Surface Ships (MASS) is currently on the agenda in several countries and also in the IMO. In Norway a 120 TEU container feeder is being build and will start sailing autonomously in 2022. The challenge is huge. One question is whether or not the present, quantitative, collision regulations needs to be updated to rules where expressions as “early” and “substantial” are quantified? Or if ships can sail autonomously under the present rules? Another question is if MASS should be marked to signal that the ship is in autonomous mode? Or if it is enough that she follows COLREGS? This discussion paper will take a closer look at these questions and advocate automation transparency, meaning that the behavior of an autonomous vessel has to make sense and be understandable to human operators on other manned ships and crafts.
EN
The maritime shipping industry has been making significant contributions to the development of the regional and global economy. However, maritime accidents and their severe consequences have been posing an incrementing risk to the individuals and societies. It is therefore important to conduct risk analysis on such accidents to support maritime safety management. In this paper, a modified ship collision candidate detection method is proposed as a tool for collision risk analysis in ports and waterways. Time-Discrete Velocity Obstacle algorithm (TD-NLVO) is utilized to detect collision candidates based on the encounter process extracted from AIS data. Ship domain model was further integrated into the algorithm as the criteria for determination. A case study is conducted to illustrate the efficacy of the improved model, and a comparison between the existing method and actual ship trajectories are also performed. The results indicate that with the integration of ship domain, the new method can effectively detect the encounters with significant collision avoidance behaviours. The choice of criteria can have a significant influence on the results of collision candidate detection.
EN
Distributed Stochastic Search Algorithm (DSSA) is one of state-of-the-art distributed algorithms for the ship collision avoidance problem. In DSSA, whenever a ship encounters with any number of other ships (neighboring ships), she will select her course with a minimum cost after coordinating their decisions with her neighboring ships. The original DSSA assumes that ships can change only their courses while keeping their speed considering kinematic properties of ships in general. However, considering future possibilities to address more complex situations that may cause ship collision or to deal with collision of other vehicles (such as mobile robots or drones), the options of speed changes are necessary for DSSA to make itself more flexible and extensive. In this paper, we present DSSA+, as a generalization of DSSA, in which speed change are naturally incorporated as decision variables in the original DSSA. Experimental evaluations are provided to show how powerful this generalization is.
EN
The automatic collision avoidance system introduced in this paper is a system constantly calculating optimal manoeuvring method from the risk and economic preference in the ship manoeuvring space where the course change and the deceleration are performed. The authors also propose a system that quantitatively evaluates the collision avoidance manoeuvring results. Based on the evaluation results of this system, the authors are setting parameters so that ship manoeuvring that does not give anxiety to target ships to be avoided is also realized in automatic collision avoidance manoeuvring. In addition, comparison between the manoeuvring results of the automatic collision avoidance system and the veteran captain's manoeuvring results was quantitatively compared by the proposed evaluation system. Verification experiments were successfully conducted to verify the effectiveness of the proposed automatic collision avoidance system on the actual ship navigating in congested waters.
EN
The issue of controlling a swarm of autonomous unmanned surface vehicles (USVs) in a practical maritime environment is studied in this paper. A hierarchical control framework associated with control algorithms for the USV swarm is proposed. In order to implement the distributed control of the autonomous swarm, the control framework is divided into three task layers. The first layer is the tele-operated task layer, which delivers the human operator’s command to the remote USV swarm. The second layer deals with autonomous tasks (i.e. swarm dispersion, or avoidance of obstacles and/or inner-USV collisions), which are defined by specific mathematical functions. The third layer is the control allocation layer, in which the control inputs are designed by applying the sliding mode control method. The motion controller is proved asymptotically stable by using the Lyapunov method. Numerical simulation of USV swarm motion is used to verify the effectiveness of the control framework.
15
Content available Trajectory planning of the humanoid manipulator
EN
The paper presents a method of planning a collision-free trajectory for a humanoid manipulator mounted on a rail system. The task of the robot is to move its end-effectors from the current position to the given final location in the workspace. The method is based on a redundancy resolution at the velocity level. In addition to this primary task, secondary objectives are also taken into account. The motion of the robot is planned in order to maximize a manipulability measure in purpose of avoiding manipulator singularities. State inequality constraints resulting from collision avoidance conditions are also considered. A computer example involving a humanoid manipulator operating in a three dimensional task space is also presented.
EN
Port approaches are high-traffic areas with limited manoeuvring space. Navigation in such areas requires the analysis of large amounts of information, which can impede decision processes. One solution may be the development of decision support systems dedicated to these areas. This paper presents an attempt to build a navigation decision support system operable in the approach area leading to the port of Świnoujście (Poland), with ship domain implemented as a safety criterion. Assumptions for a decision support system to be used by sea-going vessels in port approach areas are formulated and discussed. Specific features of these areas, such as traffic density, bathymetry, available manoeuvring space and legal limitations are taken into account. The source and scope of information available to the ship have been analysed. The scope of decision support has been defined. A ship domain has been proposed as a safety criterion. Approach areas leading to the port of Świnoujście have been investigated on the basis of real Automatic Identification System (AIS) data. Vessel movement processes in the chosen area were analysed. Ship domains in various parts of the area were determined. The first results concerning criteria for navigational safety assessment are presented. The conducted studies showed significant differences in the size of domains. A case study was performed on a decision support system operable in the approach area leading to Świnoujście.
17
Content available The Entrants’ View on Collision Avoidance
EN
Collisions are a serious threat to ship’s safety and despite the existence of codified rules and obligatory COLREG course for the seafarers, the number of maritime accidents is still great. Noticing this we have decided to use group model building to extract the knowledge about the process of collision avoidance from our group of experts. As a result, we obtained 18 factors which we have divided into 4 categories in order of importance. After reviewing the results we have noticed that the experts focused on superficial and theoretical aspects of collision avoidance. Therefore we have concluded that their knowledge despite our initial assumptions was insufficient to thoroughly revise this topic. However, we have also recognized some patterns that would suggest that the current rules could be improved. Our goal is to cause a discussion that will, hopefully, result in changes in education, laws, or both.
PL
Zderzenia są poważnym zagrożeniem dla bezpieczeństwa statku i pomimo istnienia skodyfikowanych przepisów oraz obowiązkowej dla marynarzy znajomości Między­narodowych Przepisów Zapobiegania Zderzeniom na Morzu, liczba wypadków morskich wciąż jest ogromna. Zauważając to, podjęto decyzję o wykorzystaniu modelowania grupowego w celu wydobycia wiedzy o przebiegu procesu mijania się statków z wybranej grupy ekspertów. W rezultacie uzyskano 18 czynników, które zostały podzielone na cztery kategorie w zależności od ich znaczenia. Po przejrzeniu wyników zauważono, że eksperci skupili się na powierzchownych i teoretycznych aspektach zagadnieniach unikania zderzeń statków. W związku z tym wysunięto wniosek, że ich wiedza, pomimo naszych pier­wotnych założeń, nie była wystarczająca, żeby dogłębnie przyjrzeć się tematowi. Niemniej dostrze­żono także pewne wzorce, które mogą sugerować pole do poprawy aktualnie funkcjo­nujących przepisów. Celem pracy jest spowodowanie dyskusji, która, być może, zaskutkuje zmianami w systemie edukacji marynarzy, prawie lub też w obu tych dziedzinach.
PL
Do rozwiązania problemu unikania przeszkód przez poruszający się samolot w przestrzeni powietrznej niezbędne jest wykrycie zagrożenia kolizji oraz wykonanie bezpiecznego manewru w celu ominięcia zagrażających przeszkód. W pracy przedstawiono sposób wykrywania niebezpieczeństwa zderzenia z przeszkodą dla przypadku, gdy w otoczeniu samolotu znajduje się wiele ruchomych obiektów. Zaproponowano sposób wyboru optymalnej trajektorii manewru antykolizyjnego, i potwierdzono jej wykonalność. Wybór trajektorii przeprowadzono rozwiązując zagadnienie optymalizacji metodą roju cząstek (PSO). W tym celu zaproponowano postać funkcji celu i przedstawiono wyniki analizy jej przebiegu dla różnych współczynników wagowych. Wykonane symulacje lotu wzdłuż optymalnej trajektorii manewru antykolizyjnego potwierdziły wykonalność takiego manewru.
EN
For solving the airplane to obstacle collision avoidance problem two methods are necessary: one, for detecting a collision threat, and the other one, for synthesizing a safe manoeuvre avoiding threating obstacles. In the article a method for detecting a threat of collision to obstacle was presented for the case of many obstacles moving within the neighbourhood of the airplane. Methods for optimal anti collision trajectory synthesis and for proving the workability of such a result were proposed too. A solution of an optimisation problem, obtained by the Swarm of Particles Optimization was used for trajectory synthesis. A form of quality index was proposed for this task and the analyses of its behaviour for several values of weighting factors were presented. Results of simulations of flight along an optimal, anti collision manoeuvre trajectory proved that such a manoeuvre is workable.
EN
This article presents algorithms for controlling a mobile robot. An algorithms are based on artificial neural network and fuzzy logic. Distance was measured with the use of ultrasonic sensor. The equipment applied as well as signal processing algorithms were characterized. Tests were carried out on a mobile wheeled robot. The analysis of the influence of algorithm while avoiding obstacles was made.
PL
W artykule przedstawiono algorytmy sterowania robotem mobilnym. Wykorzystano algorytm oparty o sztuczną sieć neuronową oraz logikę rozmytą. Odległość od przeszkód mierzono za pomocą czujnika ultradźwiękowego. Scharakteryzowano zastosowane urządzenia oraz algorytmy przetwarzania sygnałów. Testy przeprowadzono na mobilnym robocie kołowym. Przeprowadzono analizę wpływu algorytmów sterowania podczas omijania przeszkód.
EN
This study aims to the development of a Fuzzy Inference System (FIS) that will guide the operator of a Bucket Wheel Excavator (BWE) equipped with geophysical sensors to avoid collision of the excavating buckets with the hard rock formations. The developed FIS uses the probability of occurrence of a hard rock formation (estimated from the measurements of the geophysical sensor) and the operational data of the BWE to estimate the risk for collision and the diggability of the excavated material. The structural and operational characteristics of the used BWEs as well as the applied mining practices were used to modify the structure and the inference rules of the FIS and to maximize the exploitation of the existing factual and experiential knowledge.
PL
W artykule zaprezentowano wyniki badań mających na celu opracowanie Systemu Wnioskowania Rozmytego (FIS), który będzie wspomagał operatora koparki wyposażonej w czujniki geofizyczne, aby uniknąć kolizji koła czerpakowego z twardymi formacjami skalnymi. Opracowany system FIS wykorzystuje prawdopodobieństwo wystąpienia nieurabialnej skały (oszacowanego na podstawie pomiarów czujnika geofizycznego) oraz dane operacyjne koparki w celu oszacowania ryzyka kolizji i urabialności wybieranych utworów. Cechy konstrukcyjne i użytkowe używanych koparek, a także stosowane praktyki górnicze zostały wykorzystane do modyfikacji struktury i zasad wnioskowania FIS oraz maksymalizacji wykorzystania istniejącej wiedzy faktycznej i empirycznej.
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