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1

Trajectory Planning for Mobile Manipulators with Control Constraints

Pająk Grzegorz, Pająk Iwona

Pomiary Automatyka Robotyka

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2023

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R. 27, nr 2

21--30

EN

This paper presents the method of trajectory planning for mobile manipulators considering limitations resulting from capabilities of robotic system actuators. The fulfillment of control constraints is achieved by introducing virtual control scaling of the robot trajectory in the limited periods of time. Such an approach allows researchers to obtain the trajectories fulfilling control constraints without significantly increasing the time of task execution. The proposed method generates sub-optimal trajectories maximizing the manipulability measure of the robot arm, preserves mechanical and collision avoidance limitations and can be used in real-time trajectory planning. The effectiveness of the presented solution is confirmed by computer simulations involving a mobile manipulator with parameters corresponding to KUKA youBot.

PL

W pracy przedstawiono metodę planowania trajektorii dla manipulatorów mobilnych uwzględniającą ograniczenia wynikające z możliwości układów napędowych robota. Spełnienie ograniczeń na sterowana zostało osiągnięte poprzez wprowadzenie wirtualnego sterowania skalującego trajektorię robota w ograniczonych przedziałach czasu. Takie podejście pozwoliło na uzyskanie trajektorii spełniających ograniczenia na sterowania bez znaczącego wydłużenia czasu realizacji zadania. Zaproponowana metoda generuje sub-optymalne trajektorie maksymalizując miarę manipulowalności ramienia robota, zachowuje ograniczenia mechaniczne oraz warunki unikania kolizji i może być zastosowana do planowania trajektorii w czasie rzeczywistym. Skuteczność zaproponowanego rozwiązania została potwierdzona symulacjami komputerowymi wykonanymi z użyciem mobilnego manipulatora o parametrach odpowiadających robotowi KUKA youBot.

2

Obstacle avoidance method of autonomous vehicle based on fusion improved A*APF algorithm

Qian Yubin, Sun Hongtao, Feng Song

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2023

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Vol. 71, nr 2

art. no. e144624

EN

This paper proposes an autonomous obstacle avoidance method combining improved A-star (A*) and improved artificial potential field (APF) to solve the planning and tracking problems of autonomous vehicles in a road environment. The A*APF algorithm to perform path planning tasks, and based on the longitudinal braking distance model, a dynamically changing obstacle influence range is designed. When there is no obstacle affecting the controlled vehicle, the improved A* algorithm with angle constraint combined with steering cost can quickly generate the optimal route and reduce turning points. If the controlled vehicle enters the influence domain of obstacle, the improved artificial potential field algorithm will generate lane changing paths and optimize the local optimal locations based on simulated annealing. Pondering the influence of surrounding participants, the four-mode obstacle avoidance process is established, and the corresponding safe distance condition is analyzed. A particular index is introduced to comprehensively evaluate speed, risk warning, and safe distance factors, so the proposed method is designed based on the fuzzy control theory. In the tracking task, a model predictive controller in the light of the kinematics model is devised to make the longitudinal and lateral process of lane changing meet comfort requirements, generating a feasible autonomous lane-change path. Finally, the simulation was performed in the Matlab/Simulink and Carsim combined environment. The proposed fusion path generation algorithm can overcome the shortcomings of the traditional single method and better adapt to the dynamic environment. The feasibility of the obstacle avoidance algorithm is verified in the three-lane simulation scenario to meet safety and comfort requirements.

3

Automated UAV to Survey and Monitor Ionising Radiation Levels in a Closed Environment

Anand R., Harshith Kumar M. B., Raghavan Anirudh, Maddara Roopak, Anand Prajna

Power Electronics and Drives

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2022

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Vol. 7 (42)

134--145

EN

Since tragedies caused by nuclear disasters are always a concern, it is essential that nuclear power plants be monitored on a regular basis for any irregularities in ionising radiation levels. Irrespective of leakage proof measures being deployed in the plant, ensuring the safety of these measures is necessary. Given this scenario, the present study proposes the usage of unmanned aerial vehicles (UAVs) to ensure that radiation levels in nuclear plants remain within safe limits. The UAV deployed will map the entire environment following a unique path planning algorithm and monitor the environment with an onboard radiation sensor. If any irregularities are detected, the positional coordinates are flagged, and the A* algorithm is implemented to generate the shortest path between the starting point, and the flagged coordinates, which are considered as the destination coordinates. The UAV is made to traverse the shortest path together with maintaining stability of the system while traversing.

4

The obstacle vector field (OVF) method for collision-free trajectory planning of free-floating space manipulator

Rybus Tomasz

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2022

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Vol. 70, nr 2

art. no. e140691

EN

Manipulators mounted on small satellites will be used to perform on-orbit servicing, removal of space debris, and assembly of large orbital structures. During such operations, the manipulator must avoid collisions with the target object or the elements of the assembled structure. Planning of the manipulator trajectory is one of the major challenges for the proposed missions because the motion of the manipulator influences the position and orientation of the satellite. Thus, the dynamic equations of motion must be used during trajectory planning. Methods developed for fixed-base manipulators working on Earth cannot be directly applied. In this paper, we propose a new obstacle vector field (OVF) method for collision-free trajectory planning of a manipulator mounted on a free-floating satellite. The OVF method is based on a vector field that surrounds the obstacles and generates virtual forces that drive the manipulator around the obstacles. The OVF method is compared with the classical artificial potential field (APF) method and the rapidly exploring random trees (RRT) method. In the presented examples the trajectory planning problem is solved for a planar case in which the satellite is equipped with a 2 DoF manipulator. It is shown that the OVF method is more efficient than the APF method, i.e., it allows us to solve the trajectory planning problem in some of the cases, in which the APF method is unsuccessful. The time required to find the solution with the use of the OVF method is shorter than the time needed by the APF and the RRT method.

5

Koncepcja algorytmu antykolizyjnego bezzałogowych statków powietrznych

Tatko Sebastian, Konatowski Stanisław

Biuletyn Wojskowej Akademii Technicznej

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2022

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Vol. 71, nr 3

113--128

PL

Podstawą nowatorskiego algorytmu antykolizyjnego jest implementacja programowa umożliwiająca unikanie kolizji przez BSP z przeszkodami otoczenia, a także z innymi obiektami latającymi. W artykule wykorzystano uproszczone równania opisujące dynamikę czterowirnikowca ułatwiające modelowanie struktury symulacyjnej. Programowa realizacja modelu czterowirnikowca wraz z kontrolerem jest podstawą działania algorytmu antykolizyjnego. W układzie sterowania modelem zastosowano trójstopniowy kontroler proporcjonalno-całkująco-różniczkujący. Inspiracją powstałego programu jest oddziaływanie magnetyczne. Algorytm omijania przeszkód bazuje na pomiarze wartości kątowych i doborze proporcjonalnej siły wirtualnej. Siła odpychająca czterowirnikowiec od przeszkody jest parametrem zależnym od jego składowych prędkości liniowych, namiaru na przeszkodę oraz odległości od niej. Uzyskane mapy ciepła odzwierciedlają skalowanie wartości oraz kierunku oddziaływania siły odpychającej. Po zdefiniowaniu punktu docelowego oraz położenia przeszkody na pokładzie czterowirnikowca dokonuje się pomiaru niezbędnych parametrów oraz doboru współrzędnych korygujących kurs kolizyjny. Analizie poddano parametry lotu czterowirnikowca oraz współczynniki kontroli algorytmu antykolizyjnego. Poprawność działania programu została sprawdzona w sposób symulacyjny z wykorzystaniem licznych charakterystyk.

EN

The basis of the novel anti-collision algorithm is a software implementation that allows the UAV to avoid collisions with environmental obstacles, as well as with other flying objects. The paper uses simplified equations describing the dynamics of the quadcopter to facilitate the modelling of the simulation structure. The software implementation of the quadcopter model together with the controller is the basis for the operation of the anti-collision algorithm. The model control system uses a three-stage proportional-integral-differential controller. The inspiration of the resulting program is magnetic interaction. The obstacle avoidance algorithm is based on the measurement of angular values and the selection of a proportional virtual force. The force repelling a quadcopter from an obstacle is a parameter that depends on its linear velocity, bearing on the obstacle and distance to the obstacle. The heat maps obtained reflect the scaling of the value and direction of the repulsive force. After defining the target point and the position of the obstacle, the necessary parameters are measured and the collision course correcting coordinates are selected onboard the quadcopter. The flight parameters of the quadcopter and the control coefficients of the anti-collision algorithm were analysed. The correctness of the program’s operation was checked by simulation using numerous characteristics.

6

Analysis of methods and control systems of unmanned platforms

Adamski Mirosław, Żyluk Andrzej, Chodnicki Marcin

Journal of KONBiN

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2021

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Vol. 51, iss. 4

143--156

EN

The key aspect affecting the safety of routing and the unmanned platform mission execution is the autonomy of control systems. To achieve the mission goal, control algorithms supported by advanced sensors have to estimate the obstacle location. Moreover, it is needed to identify potential obstacles, as well as algorithms for trajectory planning in two or three dimensions space. The use of these algorithms allows to create an intelligent object that performs tasks in difficult conditions in which communication between the platform and the operator is constricted. The article mainly focuses on unmanned aerial vehicle (UAV) control systems.

PL

Kluczowym aspektem mającym wpływ na bezpieczeństwo trasowania oraz realizacji misji platformy bezzałogowej jest autonomia systemów sterowania. Z tego względu algorytmy sterowania wspierane przez zaawansowane czujniki muszą oszacować lokalizację przeszkody. Poza tym, należy identyfikować potencjalne przeszkody oraz algorytmy dotyczące planowania trajektorii w dwóch lub trzech wymiarach przestrzennych. Zastosowanie wyżej wspomnianych algorytmów umożliwia stworzenie inteligentnego obiektu wykonującego zadania w trudnych warunkach, podczas których komunikacja pomiędzy platformą a operatorem jest ograniczona. Artykuł opisuje głównie systemy sterujące bezzałogowych statków powietrznych (BSP).

7

Motion planning of planar and redundant underwater serial link manipulator based on minimization of energy consumption

Kumar Virendra, Sen Soumen, Roy Shibendu Shekhar

Archive of Mechanical Engineering

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2021

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LXVIII, nr 4

415--434

EN

The article describes motion planning of an underwater redundant manipulator with revolute joints moving in a plane under gravity and in the presence of obstacles. The proposed motion planning algorithm is based on minimization of the total energy in overcoming the hydrodynamic as well as dynamic forces acting on the manipulator while moving underwater and at the same time, avoiding both singularities and obstacle. The obstacle is considered as a point object. A recursive Lagrangian dynamics algorithm is formulated for the planar geometry to evaluate joint torques during the motion of serial link redundant manipulator fully submerged underwater. In turn the energy consumed in following a task trajectory is computed. The presence of redundancy in joint space of the manipulator facilitates selecting the optimal sequence of configurations as well as the required joint motion rates with minimum energy consumed among all possible configurations and rates. The effectiveness of the proposed motion planning algorithm is shown by applying it on a 3 degrees-of-freedom planar redundant manipulator fully submerged underwater and avoiding a point obstacle. The results establish that energy spent against overcoming loading resulted from hydrodynamic interactions majorly decides the optimal trajectory to follow in accomplishing an underwater task.

8

Efficient non-odometry method for environment mapping and localisation of mobile robots

Adamowicz Mateusz, Ambroziak Leszek, Kondratiuk Mirosław

Acta Mechanica et Automatica

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2021

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Vol. 15, no. 1

24--29

EN

The paper presents the simple algorithm of simultaneous localisation and mapping (SLAM) without odometry information. The proposed algorithm is based only on scanning laser range finder. The theoretical foundations of the proposed method are presented. The most important element of the work is the experimental research. The research underlying the paper encompasses several tests, which were carried out to build the environment map to be navigated by the mobile robot in conjunction with the trajectory planning algorithm and obstacle avoidance.

9

Fuzzy logic controller with fuzzylab python library and the robot operating system for autonomous mobile robot navigation

Avelar Eduardo, Castillo Oscar, Soria José

Journal of Automation Mobile Robotics and Intelligent Systems

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2020

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Vol. 14, No. 1

48--54

EN

The navigation system of a robot requires sensors to perceive its environment to get a representation. Based on this perception and the state of the robot, it needs to take an action to make a desired behavior in the environment. The actions are defined by a system that processes the obtained information. This system can be based on decision rules defined by an expert or obtained by a training or optimization process. Fuzzy logic controllers are based on fuzzy logic on which degrees of truth are used on sy‐ stem variables and has a rule‐base that stores the knowledge about the operation of the system. In this paper a fuzzy logic controller is made with the Python fuzzylab library which is based on the Octave Fuzzy Logic Toolkit, and with the Robot Operating System (ROS) for autonomous navigation of the TurtleBot3 robot on a simulated and a real environment using a LIDAR sensor to get the distance of the objects around the robot.

10

Energy-efficient walking over irregular terrain: a case of hexapod robot

Luneckas Mindaugas, Luneckas Tomas, Udris Dainius, Plonis Darius, Maskeliunas Rytis, Damasevicius Robertas

Metrology and Measurement Systems

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2019

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Vol. 26, nr 4

645--660

EN

Adaptive locomotion over difficult or irregular terrain is considered as a superiority feature of walking robots over wheeled or tracked machines. However, safe foot positioning, body posture and stability, correct leg trajectory, and efficient path planning are a necessity for legged robots to overcome a variety of possible terrains and obstacles. Without these properties, any walking machine becomes useless. Energy consumption is one of the major problems for robots with a large number of Degrees of Freedom (DoF). When considering a path plan or movement parameters such as speed, step length or step height, it is important to choose the most suitable variables to sustain long battery life and to reach the objective or complete the task successfully. We change the settings of a hexapod robot leg trajectory for overcoming small terrain irregularities by optimizing consumed energy and leg trajectory during each leg transfer. The trajectory settings are implemented as a part of hexapod robot simulation model and tested through series of experiments with various terrains of differing complexity and obstacles of various sizes. Our results show that the proposed energy-efficient trajectory transformation is an effective method for minimizing energy consumption and improving overall performance of a walking robot.

11

Multiquery motion planning in uncertain spaces: Incremental adaptive randomized roadmaps

Khaksar Weria, Uddin Md Zia, Torresen Jim

International Journal of Applied Mathematics and Computer Science

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2019

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Vol. 29, no. 4

641--654

EN

Sampling-based motion planning is a powerful tool in solving the motion planning problem for a variety of different robotic platforms. As its application domains grow, more complicated planning problems arise that challenge the functionality of these planners. One of the main challenges in the implementation of a sampling-based planner is its weak performance when reacting to uncertainty in robot motion, obstacles motion, and sensing noise. In this paper, a multi-query sampling-based planner is presented based on the optimal probabilistic roadmaps algorithm that employs a hybrid sample classification and graph adjustment strategy to handle diverse types of planning uncertainty such as sensing noise, unknown static and dynamic obstacles and an inaccurate environment map in a discrete-time system. The proposed method starts by storing the collision-free generated samples in a matrix-grid structure. Using the resulting grid structure makes it computationally cheap to search and find samples in a specific region. As soon as the robot senses an obstacle during the execution of the initial plan, the occupied grid cells are detected, relevant samples are selected, and in-collision vertices are removed within the vision range of the robot. Furthermore, a second layer of nodes connected to the current direct neighbors are checked against collision, which gives the planner more time to react to uncertainty before getting too close to an obstacle. The simulation results for problems with various sources of uncertainty show a significant improvement compared with similar algorithms in terms of the failure rate, the processing time and the minimum distance from obstacles. The planner is also successfully implemented and tested on a TurtleBot in four different scenarios with uncertainty.

12

An automatic collision avoidance algorithm for multiple marine surface vehicles

Hedjar Ramdane, Bounkhel Messaoud

International Journal of Applied Mathematics and Computer Science

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2019

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Vol. 29, no. 4

759--768

EN

In recent years, unmanned surface vehicles have been widely used in various applications from military to civil domains. Seaports are crowded and ship accidents have increased. Thus, collision accidents occur frequently mainly due to human errors even though international regulations for preventing collisions at seas (COLREGs) have been established. In this paper, we propose a real-time obstacle avoidance algorithm for multiple autonomous surface vehicles based on constrained convex optimization. The proposed method is simple and fast in its implementation, and the solution converges to the optimal decision. The algorithm is combined with the PD-feedback linearization controller to track the generated path and to reach the target safely. Forces and azimuth angles are efficiently distributed using a control allocation technique. To show the effectiveness of the proposed collision-free path-planning algorithm, numerical simulations are performed.

13

Legal and technical aspects of the safety of autonomous vehicles

Wicher J.

Zeszyty Naukowe Instytutu Pojazdów / Politechnika Warszawska

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2018

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z. 3/117

5--18

EN

The article is presented the predicted effects of the dissemination of autonomous vehicles and the consequences of exploiting the opportunities that modern traffic control systems can achieve. Attention has been paid to the need for using high processing power systems in vehicles and several planning strategies for traffic trajectories.

PL

W artykule przedstawiono przewidywane skutki upowszechniania pojazdów autonomicznych oraz konsekwencje wykorzystania możliwości jakie są do osiągnięcia przez nowoczesne systemy sterowania nimi w ruchu drogowym. Zwrócono uwagę na konieczność stosowania w pojazdach systemów o dużej mocy obliczeniowej oraz pokazano kilka strategii planowania trajektorii ruchu.

14

Planowanie trasy bezzałogowego statku powietrznego podczas lotu nad terenem z przeszkodami

Basmadji F. L., Gruszecki J.

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika

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2017

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z. 89 [295], nr 1

5--17

PL

Pomimo znacznych postępów w tematyce zwiększenia autonomiczności bezzałogowych obiektów latającego, pozostaje jeszcze wiele problemów do rozwiązania, jednym z nich to problem autonomicznego planowania trasy. Mimo iż ten problem jest obecnie przedmiotem badań licznych ośrodków badawczych na świecie, nadal jednak nie opracowano uniwersalnego sposobu planowania trasy, gdyż jest to związane nie tylko z właściwościami danego obiektu, ale również z realizowaną misją. W niniejszym artykule omówiono problem planowania trasy dla bezzałogowego statku powietrznego podczas lotu nad terenem z przeszkodami. Opracowany został algorytm do wyznaczania trasy uwzględniający ograniczenia nałożone przez właściwości obiektu latającego, ukształtowanie terenu, strefy zakazane oraz maksymalny dopuszczalny pułap lotu. Ponadto zaproponowano metodę poszukiwania quasi-optymalnej trajektorii w przypadku większej liczby przeszkód. Przeprowadzono szereg badań symulacyjnych weryfikujących poprawność działania opracowanego algorytmu.

EN

Despite significant progress in the field of increasing the autonomy of unmanned aerial vehicles (UAVs), there are still a number of problems which needs to be solved. One of such example is the problem of autonomous path planning. In this paper, the problem of UAV path planning in mountainous terrain with obstacles has been discussed. AUAV path planning algorithm that takes into account limitations imposed by UAVs dynamics, terrain configuration, no-fly zones and the maximum allowable flight altitude has been developed. Furthermore, the method of searching for the quasi-optimal path in the case of multiple obstacles has been proposed. A series of simulation investigations to verify the correctness of developed algorithm have been carried out.

15

An evasive manoeuvre, automatically controlled to avoid the one of a group of many obstacles moving in a vicinity of flying airplane

Graffstein J.

Zeszyty Naukowe Akademii Marynarki Wojennej

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2017

|

R. 58 nr 2 (209)

39--49

EN

Detection of a collision threat and an appropriate decision on passing by an obstacle are necessary for solving the problem of collision avoidance in case of aircraft motion within the airspace. In the article a method for detecting a threat of collision with the obstacle is presented for the case of many moving objects appearing within the neighbourhood of the aircraft. The analysis of an algorithm for making a preliminary decision on avoiding a collision with more than one moving obstacle was carried out. The shape of a class of evasive trajectories was proposed, and its reliability was proved. Numerical simulations of flight were completed for the considered type of aircraft in aforementioned conditions. The scope of these simulations covered all phases of obstacle avoiding manoeuvre, including a return to a straight-line part of flight trajectory pre planned before the start.

PL

Do rozwiązania problemu unikania przeszkód przez poruszający się samolot w przestrzeni powietrznej niezbędne jest wykrycie zagrożenia kolizji oraz podjęcie właściwej decyzji o sposobie ominięcia przeszkody. W artykule przedstawiono sposób wykrywania niebezpieczeństwa zderzenia z przeszkodą dla przypadku, gdy w otoczeniu samolotu znajduje się wiele ruchomych obiektów. Przeprowadzono analizę algorytmu podejmowania wstępnych decyzji o sposobie unikania kolizji z więcej niż jedną ruchomą przeszkodą. Zaproponowano kształt klasy trajektorii manewru omijania i potwierdzono jej wykonalność na drodze symulacji numerycznej. Wykonano symulację numeryczną lotu przyjętego typu samolotu we wspomnianych warunkach. Zakres tych symulacji obejmował wszystkie fazy manewru omijania przeszkody, włącznie z powrotem do prostoliniowego odcinka lotu, stanowiącego fragment trasy zaplanowanej przed startem.

16

Mobile Robot Path Planning with Obstacle Avoidance using Particle Swarm Optimization

Chołodowicz E., Figurowski D.

Pomiary Automatyka Robotyka

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2017

|

R. 21, nr 3

59--68

EN

This paper presents a constrained Particle Swarm Optimization (PSO) algorithm for mobile robot path planning with obstacle avoidance. The optimization problem is analyzed in static and dynamic environments. A smooth path based on cubic splines is generated by the interpolation of optimization solution; the fitness function takes into consideration the path length and obstaclegenerated repulsive zones. World data transformation is introduced to reduce the optimization algorithm computational complexity. Different scenarios are used to test the algorithm in simulation and real-world experiments. In the latter case, a virtual robot following concept is exploited as part of the control strategy. The path generated by the algorithm is presented in results along with its execution by the mobile robot.

PL

W artykule przedstawiono algorytm rojowy z ograniczeniami realizujący planowanie bezkolizyjnej ścieżki ruchu robota mobilnego. Problem optymalizacyjny został przeanalizowany dla środowiska statycznego i dynamicznego. Do stworzenia gładkiej ścieżki ruchu wykorzystano interpolację rozwiązania optymalizacji przy użyciu sześciennych funkcji sklejanych. Funkcja kosztu uwzględnia długość ścieżki ruchu oraz penalizację za naruszenie przestrzeni przeszkód. Wprowadzono transformację świata w celu redukcji złożoności obliczeniowej algorytmu optymalizacji. Przeprowadzono zróżnicowane scenariusze badawcze testujące algorytm w eksperymentach symulacyjnych i rzeczywistych. W przypadku tych ostatnich wykorzystano ideę podążania za wirtualnym robotem. Zaprezentowano wyniki obrazujące wygenerowaną ścieżkę ruchu oraz ocenę jej realizacji przez robota mobilnego.

17

Spatial motion of the aircraft manoeuvring to avoid moving obstacle

Graffstein J.

Journal of Theoretical and Applied Mechanics

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2016

|

Vol. 54 nr 1

99--111

EN

In the paper, mathematical relationships which are used to describe kinematic variables of the aircraft-obstacles configuration and motion of the aircraft are presented. These define the base for the set of conditions enabling determination of the possibility and threat of collision. The second important aim of such a definition is creation of prerequisites for selection of an appropriate anti-collision manoeuvre, computation of reference signals and inequalities used as limitations on these signals in the automatic flight control process. Theoretical analysis is illustrated by an example of computer simulation of the flight of aircraft. Two anti- -collision manoeuvres are studied in this experiment. The first one, performed in a vertical plane, consists in emergency climbing. The second one, performed in the horizontal plane, is shaped by three turns, each one of small radius, to go around the obstacle and then return to the previously realised flight path.

18

Neural Based Autonomous Navigation of Wheeled Mobile Robots

Al-Sagban M., Dhaouadi R.

Journal of Automation Mobile Robotics and Intelligent Systems

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2016

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Vol. 10, No. 2

64--72

EN

This paper presents a novel reactive navigation algorithm for wheeled mobile robots under non-holonomic constraints and in unknown environments. Two techniques are proposed: a geometrical based technique and a neural network based technique. The mobile robot travels to a pre-defined goal position safely and efficiently without any prior map of the environment by modulating its steering angle and turning radius. The dimensions and shape of the robot are incorporated to determine the set of all possible collision-free steering angles. The algorithm then selects the best steering angle candidate. In the geometrical navigation technique, a safe turning radius is computed based on an equation derived from the geometry of the problem. On the other hand, the neural-based technique aims to generate an optimized trajectory by using a user-defined objective function which minimizes the traveled distance to the goal position while avoiding obstacles. The experimental results demonstrate that the algorithms are capable of driving the robot safely across a variety of indoor environments.

19

Analysis of selected variables characterising the manoeuvre for moving obstacle avoidance

Graffstein J.

Zeszyty Naukowe Akademii Marynarki Wojennej

|

2015

|

R. 56 nr 2 (201)

13--21

EN

The article is focused on the results of analysis aimed at selected variables, which are found to be important for the automatic flight control in case of passing by a moving obstacle. Considerations are focused on parameters describing an aircraft — moving obstacle system. Numerical simulation of the selected anti-collision, automatically controlled manoeuvre has been carried out. On the basis of this example, the effect has been analysed that parameters, found to be necessary for the realisation of such a manoeuvre, exert on state variables and variables describing the relations between discussed objects. The results obtained can be treated as the source of information opening the deeper insight into a behaviour of the controlled aircraft in case of known scenario of obstacle’s motion.

PL

W artykule przedstawiono wyniki analizy wybranych zmiennych istotnych z punktu widzenia automatycznego sterowania samolotem podczas omijania ruchomej przeszkody. Rozważania dotyczyły przebiegu parametrów opisujących układ samolot — ruchoma przeszkoda. Przeprowadzono numeryczną symulację wybranego automatycznie sterowanego manewru antykolizyjnego. Na tym przykładzie przeanalizowano wpływ parametrów niezbędnych do jego realizacji na zmienne stanu lotu samolotu i zmienne opisujące wzajemne relacje omawianych obiektów. Uzyskane wyniki stanowią źródło informacji pozwalających na lepsze zrozumienie zachowania sterowanego samolotu dla znanej konfiguracji ruchu przeszkody.

20

Navigation of autonomous mobile robot using different activation functions of wavelet neural network

Panigrahi P. K., Ghosh S., Parhi D. R.

Archives of Control Sciences

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2015

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Vol. 25, no. 1

21--34

EN

An autonomous mobile robot is a robot which can move and act autonomously without the help of human assistance. Navigation problem of mobile robot in unknown environment is an interesting research area. This is a problem of deducing a path for the robot from its initial position to a given goal position without collision with the obstacles. Different methods such as fuzzy logic, neural networks etc. are used to find collision free path for mobile robot. This paper examines behavior of path planning of mobile robot using three activation functions of wavelet neural network i.e. Mexican Hat, Gaussian and Morlet wavelet functions by MATLAB. The simulation result shows that WNN has faster learning speed with respect to traditional artificial neural network.