Wyniki wyszukiwania - BazTech

1

Occlusion-aware collision avoidance trajectory planning with potential collision risk assessment for autonomous vehicle

Qian Yubin, Deng Chengzhi, Xu Jiejie, Qu Xianguo, Song Zhenyu

Bulletin of the Polish Academy of Sciences. Technical Sciences

|

2024

|

Vol. 72, nr 4

art. no. e149819

EN

Motion planning for autonomous vehicles relies heavily on perception and prediction results to find a safe, collision-free local trajectory that adheres to traffic rules. However, vehicle perception is frequently limited by occlusion, and the generation of safe local trajectories with restricted perception poses a significant challenge in the field of motion planning. This paper introduces a collision avoidance trajectory planning algorithm that considers potential collision risks, within a hierarchical framework of sampling and optimization. The primary objective of this work is to generate trajectories that are safer and align better with human driver behavior while considering potential collision risks in occluded regions. Specifically, in occlusion scenarios, the state space is discretized, and a dynamic programming algorithm is used for a sampling-based search to obtain initial trajectories. Additionally, the concept of a driving risk field is introduced to describe potential collision risk elements within the human-vehicle-road environment. By drawing inspiration from graph search algorithms, potential collision risk areas are accurately described, and a cost function is proposed for evaluating potential risks in occluded regions. Drivers typically exhibit conservative and cautious driving behavior when navigating through occluded regions. The proposed algorithm not only prioritizes driving safety but also considers driving efficiency, thereby reducing the vehicle’s conservativeness when passing through occlusions. The research results demonstrate that the ego vehicle can actively avoid blind spots and tends to move away from occluded regions, aligning more closely with human driver behavior.

2

New Approach to Planning the Complex Movements of 6-DOF Industrial Robot Subjected to Acceleration Constraints

Pająk Grzegorz

Advances in Science and Technology. Research Journal

|

2024

|

Vol. 18, no 3

314--332

EN

A method of trajectory planning with regards to joint velocity and acceleration constraints for industrial 6 DOF manipulator is presented. The task of the robot is to move to specified location in the workspace passing through intermediate waypoints. The proposed algorithm can be used to plan the task of the robot by autonomous systems in smart factories eliminating human participation in the robot programing process. Opposite to similar approaches it does not assume the type of function describing the motion of the robot. The trajectories generated using the proposed approach are smooth and provide smooth velocities and continuous joint accelerations. The motion is planned in such a way to fulfill joint velocity and acceleration constraints. Fulfillment of velocity limitations is accomplished by perturbing the manipulator motion close to velocity limits. To satisfy acceleration constraints a trajectory scaling approach carried out in limited periods of time is used. The results of the research are illustrated by simulations and experiments, in which an analysis of the method of performing robot tasks carried out using built-in algorithms and presented methods are performed.

3

Trajectory Planning for Mobile Manipulators with Control Constraints

Pająk Grzegorz, Pająk Iwona

Pomiary Automatyka Robotyka

|

2023

|

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.

4

Trajectory planning for tractor turning using the trigonometric transition curve

Boryga Marek

Agricultural Engineering

|

2023

|

Vol. 27, No. 1

203--212

EN

This paper presents a method of utilizing a transition curve in planning the movement trajectory of agricultural machinery during the headland turns. The approach involves using the transition curve, whose curvature and tangent angle are described by the trigonometric function. For the designed course, the kinematic quantities, wheel turning angles, and their rates of change were determined for two models of agricultural tractors. The algorithm proposed in this study ensures continuity and smooth changes in the kinematic quantities and can be applied to the trajectory planning of agricultural implements and machines, autonomous vehicles, mobile robots, manipulators, and CNC machines.

PL

W pracy przedstawiono sposób wykorzystania krzywej przejściowej w planowaniu trajektorii ruchu maszyn rolniczych podczas jazdy na uwrociu. Zaplanowano zastosowanie krzywej przejściowej, której krzywizna i kąt stycznej do krzywej opisane są funkcją trygonometryczną. Dla zaplanowanego toru jazdy wyznaczono przebiegi wielkości kinematycznych oraz kąty skręcenia kół i prędkości ich zmian dla dwóch modeli ciągnika rolniczego. Zaproponowany w pracy algorytm, zapewnia ciągłość oraz łagodne zmiany wielkości kinematycznych i może być stosowany do planowania trajektorii ruchu agregatów i maszyn rolniczych, pojazdów autonomicznych, robotów mobilnych, manipulatorów i maszyn CNC.

5

Fast and smooth trajectory planning for a class of linear systems based on parameter and constraint reduction

Liu Guangyu, Wu Shangliang, Zhu Ling, Wang Jiajun, Lv Qiang

International Journal of Applied Mathematics and Computer Science

|

2022

|

Vol. 32, no. 1

11--21

EN

Fast and smooth trajectory planning is crucial for modern control systems, e.g., missiles, aircraft, robots and AGVs. However, classical spline based trajectory planning tools introduce redundant constraints and parameters, leading to high costs of computation and complicating fast and smooth execution of trajectory planning tasks. A new tool is proposed that employs truncated power functions to annihilate some constraints and reduce the number of parameters in the optimal model. It enables solving a simplified optimal problem in a shorter time while keeping the trajectory sufficiently smooth. With an engineering background, our case studies show that the proposed method has advantages over other solutions. It is promising in regard to the demanding tasks of trajectory planning.

6

Algorithms and calculation scheme for planning the way of movement of trajectory point during maneuvering for anchoring

Surinov I.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

|

2021

|

Vol. 15 No. 3

629--638

EN

The analysis of the historical aspect of the development of the maneuvering during anchoring shows that during the movement there is no time to control the position by technical means, due to the speed of the process of changing the parameters of movement. The main purpose of this research is to modify the methodological basis for the preparation of flight planning during anchoring with increased accuracy to determine the coordinates along which the ship will move. The methodology of this work is based on the calculation of trajectory points of the path in combination with the method of segments on the map using the characteristics of the maneuverability of the vessel. The method is based on determining the coordinate matrices of rectilinear and curvilinear sections through which the vessel passes during maneuvering for anchoring. The calculation program is developed in Excel, and allows without the help of a micro calculator that takes into account the maneuverability of the vessel in the automatic system. Thus, the control of the center of gravity of the vessel relative to a given path line is performed. A high-precision system for automatic determination of planned coordinates by trajectory points on track and traffic control during anchoring has been developed, which is based on recently developed algorithms, calculation schemes and methods at the Maritime University, which are based on the latest meaningful models of high-precision planning movement on them. This approach automates the process of controlling safe traffic, including the use of decision support systems, including stranding prevention and collisions with other vessels. The results of the research can be used on a ship for automated planning of coordinates on waypoints and control of traffic on them for safe maneuvering, as well as for training navigators on specialized simulators to perform trajectory planning, including limited conditions.

7

Trajectory planning for narrow environments that require changes of driving directions

Roth Jörg

Journal of Automation Mobile Robotics and Intelligent Systems

|

2021

|

Vol. 15, No. 4

18--29

EN

In the area of mobile robotics, trajectory planning is the task to find a sequence of primitive trajectories that connect two configurations, whereas non-holonomic constraints, obstacles and driving costs have to be considered. In this paper, we present an approach that is able to handle situations that require changes of driving directions. In such situations, optimal trajectory sequences contain costly turning maneuvers – sometimes not even on the direct path between start and target. These situations are difficult for most optimization approaches as the robot partly has to drive paths with higher cost values that seem to be disadvantageous. We discuss the problem in depth and provide a solution that is based on maneuvers, partial backdriving and free-place discovery. We applied the approach on top of our Viterbi-based trajectory planner.

8

Continuous-curvature trajectory planning

Roth Jörg

Journal of Automation Mobile Robotics and Intelligent Systems

|

2021

|

Vol. 15, No. 1

9--23

EN

Continuous-curvature paths play an important role in the area of driving robots: as vehicles usually cannot change the steering angle in zero-time, real trajectories must not have discontinuities in the curvature profile. Typical continuous-curvature paths are thus built of straight lines, arcs and clothoids. Due to the geometric nature of clothoids, some questions in the area of trajectory planning are difficult the answer – usually we need approximations here. In this paper we describe a full approach for continuous-curvature trajectory planning for mobile robots – it covers a maneuver-based planning with Viterbi optimization and geometric approximations required to construct the respective clothoid trajectories.

9

A trajectory planning based controller to regulate an uncertain 3D overhead crane system

Aguilar-Ibanez Carlos, Suarez-Castanon Miguel S.

International Journal of Applied Mathematics and Computer Science

|

2019

|

Vol. 29, no. 4

693--702

EN

We introduce a control strategy to solve the regulation control problem, from the perspective of trajectory planning, for an uncertain 3D overhead crane. The proposed solution was developed based on an adaptive control approach that takes advantage of the passivity properties found in this kind of systems. We use a trajectory planning approach to preserve the accelerations and velocities inside of realistic ranges, to maintaining the payload movements as close as possible to the origin. To this end, we carefully chose a suitable S-curve based on the Bezier spline, which allows us to efficiently handle the load translation problem, considerably reducing the load oscillations. To perform the convergence analysis, we applied the traditional Lyapunov theory, together with Barbalat’s lemma. We assess the effectiveness of our control strategy with convincing numerical simulations.

10

Legal and technical aspects of the safety of autonomous vehicles

Wicher J.

Zeszyty Naukowe Instytutu Pojazdów / Politechnika Warszawska

|

2018

|

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.

11

An offline path planning method for autonomous vehicles

Barsi Á., Nyerges Á., Potó V., Tihanyi V.

Production Engineering Archives

|

2018

|

Vol. 19

37--42

EN

Driving a road vehicle is a very complex task in terms of controlling it, substituting a human driver with a computer is a real challenge also from the technical side. An important step in vehicle controlling is when the vehicle plans its own trajectory. The input of the trajectory planning are the purpose of the passengers and the environment of the vehicle. The trajectory planning process has several parts, for instance, the geometry of the path-curve or the speed during the way. Furthermore, a traffic situation can also determine many other parameters in the planning process. This paper presents a basic approach for trajectory design. To reach the aim a map will be given as a binary 2204 x 1294 size matrix where the roads will be defined by ones, the obstacles will be defined by zeros. The aim is to make an algorithm which can find the shortest and a suitable way for vehicles between the start and the target point. The vehicle speed will be slow enough to ignore the dynamical properties of the vehicle. The research is one of the first steps to realize automated parking features in a self-drive car.

12

The agent, state-space model of the mobile robot

Oprzędkiewicz K., Ciurej M., Garbacz M.

Pomiary Automatyka Robotyka

|

2018

|

R. 22, nr 3

41--50

EN

The paper is devoted to present a new agent model of wheeled mobile robot. The proposed model based on nonlinear state space, discrete model of kinematics and employes Braitenberg algorithm to control the robot during move to target with passing obstacles. As a real robot the Khepera robot with IR proximity sensors was considered. The proposed agent model can be generalized onto another similar classes of devices. Results of experiments show that the proposed model correctly describes the behaviour of real device during realization of different jobs, for example obstacle passing.

PL

W artykule zaprezentowano nowy model agentowy kołowego robota mobilnego. Proponowany model bazuje na nieliniowym równaniu stanu opisującym kinematykę robota i wykorzystuje algorytm Braitenberga z zadanym punktem końcowym w celu omijania przeszkód. Jako przykład rzeczywistego robota rozważono robot Khepera III z czujnikami IR do wykrywania i omijania przeszkód. Zaproponowany model agentowy może być uogólniony na inne klasy podobnych urządzeń. Wyniki symulacji pokazują, że zaproponowany model dobrze opisuje zachowanie się rzeczywistego urządzenia podczas realizacji różnych zadań, np. przy omijaniu przeszkód.

13

Modelling of ship’s trajectory planning in collision situations by hybrid genetic algorithm

Ni S., Liu Z., Cai Y., Wang X.

Polish Maritime Research

|

2018

|

nr 3

14--25

EN

Ship collision-avoidance trajectory planning aims at searching for a theoretical safe-critical trajectory in accordance with COLREGs and good seamanship. In this paper, a novel optimal trajectory planning based on hybrid genetic algorithm is presented for ship collision avoidance in the open sea. The proposed formulation is established based on the theory of the Multiple Genetic Algorithm (MPGA) and Nonlinear Programming, which not only overcomes the inherent deficiency of the Genetic Algorithm (GA) for premature convergence, but also guarantees the practicality and consistency of the optimal trajectory. Meanwhile, the encounter type as well as the obligation of collision avoidance is determined according to COLREGs, which is then considered as the restricted condition for the operation of population initialization. Finally, this trajectory planning model is evaluated with a set of test cases simulating various traffic scenarios to demonstrate the feasibility and superiority of the optimal trajectory.

14

Navigational decision support system during approach manoeuvre in emergency STS transfer operation

Witkowska A., Śmierzchalski R., Wilczyński P.

Journal of Polish Safety and Reliability Association

|

2017

|

Vol. 8, No. 1

175--182

EN

The paper is concerned with the problem of safe trajectory planning for approaching during emergency STS (Ship to Ship) transfer operation with oil spill. The safe trajectory means that the way points does not cross in the area of the environment with the static and dynamic obstacles and at the same time satisfies ship's stopping and speed deceleration performance. The evolutionary path planning algorithm is used to determine trajectory designed as way points and straight line segments between them. The way points - ship positions and velocity can be treated as reference value to support navigator in decision making during Approach Manoeuvre and to mitigate the risk of collision which mostly results from exceed velocity of approaching. The task of trajectory planning is defined as constant optimization process to minimize trajectory length, course alteration and maximize safety in a navigational environment. This paper examines exemplary navigational scenario based on emergency STS accident.

15

Trajectory planning for kinematically redundant robots using jacobi matrix – an industrial implementation

Walther M., Sewohl A., Schlegel H., Neugebauer R.

Journal of Machine Engineering

|

2017

|

Vol. 17, No. 3

24--35

EN

The widespread use of robots in industry contributes significantly to high productivity. Serial 6-axis robots are used in large quantities, e.g. for assembly or welding. A current emerging trend is the use of robots for classic tasks of a machine tool like finishing of milled workpieces. For such applications, standard robots are usually extended by additional axes like linear axes or rotary tilting tables. Therefore, the overall system becomes kinematically redundant. To be able to calculate the axis quantities via inverse kinematics for a given path, additional degrees of freedom must be bound. In order to automatically and optimally consider the additional axis motion a method, using the pseudoinverse of the Jacobian matrix, is discussed. Due to the dependence of the Jacobi matrix on the robot's current joint position, numerical inaccuracies, which in turn reflect a path error, are inherent to this method. By feedback control of the path error, in the form of a classic control loop, the error can be reduced so that a practical implementation on industrial robot controller is possible. In the article possibilities for parameterisation of the algorithm as well as proof of stability of the closed loop are presented. The results obtained are verified by a concrete application.

16

Analiza więzów manipulatora w zadaniu zrobotyzowanej obróbki mechanicznej dyfuzora

Gierlak P.

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika

|

2016

|

z. 88 [293], nr 3

199--212

PL

Artykuł dotyczy analizy więzów geometrycznych narzuconych na końcówkę roboczą robota manipulacyjnego, którego zadaniem jest realizacja obróbki mechanicznej dyfuzora. Z punktu widzenia teorii sterowania, realizacja omawianego zadania jest traktowana jako sterowanie obiektem z ograniczeniami ruchu. Wymaga to określenia zadanej trajektorii układu sterowania robota rozumianej jako trajektoria pozycyjna oraz siłowa. W pracy zaprezentowano geometrię dyfuzora wraz z opisem matematycznym krawędzi, która ma zostać zatępiona. Podano zestaw więzów naturalnych i sztucznych, pozycyjnych i siłowych dla tego zadania oraz dla zadania wiercenia otworów. Podano sposób wyznaczania trajektorii pozycyjnej i siłowej, która będzie stanowić trajektorię zadaną układu sterowania robota. Zaprezentowano wyniki symulacji generowania trajektorii ruchu końcówki roboczej.

EN

This paper presents the analysis of the geometrical constraints of the robotic manipulator end effector, the task of which is the realisation of the diffuser machining. In terms of control theory, the realisation of this task is considered as a control of an object with partial movement restrictions. It requires determination of the desired trajectory of the robot’s control system understood as so-called position and force trajectory. In this paper the geometry of the diffuser and the mathematical description of edges that will be deburred, are presented. The sets of natural and artificial, position and force constraints for this task and for task of hole drilling are given. The procedure of determining position and force trajectory which will be the reference trajectory of robot’s control system is provided. The simulation results of generating robot’s tip trajectory are presented.

17

Planowanie ścieżek pierścienia prowadzącego w docieraniu jednotarczowym

Barylski A., Piotrowski N.

Mechanik

|

2016

|

R. 89, nr 5-6

532--533

PL

Praktyka pokazuje, że przy danych warunkach kinematycznych docierania tarcza docierająca przyjmuje kształt wklęsły, wypukły lub z osiowym biciem powierzchni roboczej. Aby osiągnąć wymaganą płaskość, docierak musi być kondycjonowany. W artykule zaprezentowano niekonwencjonalny układ docierania jednotarczowego, w którym pierścień prowadzący wykonuje ruch uzupełniający. Przeanalizowano szereg ścieżek pierścienia prowadzącego z uwzględnieniem kinematyki obrabiarki i zużycia narzędzia.

EN

The practice shows that in given conditions the lapping plate changes their shape to convex, concave or axial runout. In order to achieve the required flatness, the plate has to be conditioned. This paper shows an unconventional single-sided lapping system in which conditioning ring performs an additional movements. A set of the conditioning ring trajectories with respect to the machine and the tool wear are analysed.

18

Trajectory Planning with Negotiation for Maritime Collision Avoidance

Hornauer S., Hahn A., Blaich M., Reuter J.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

|

2015

|

Vol. 9, no. 3

335--341

EN

The problem of vessel collisions or near-collision situations on sea, often caused by human error due to incomplete or overwhelming information, is becoming more and more important with rising maritime traffic. Approaches to supply navigators and Vessel Traffic Services with expert knowledge and suggest trajectories for all vessels to avoid collisions, are often aimed at situations where a single planner guides all vessels with perfect information. In contrast, we suggest a two-part procedure which plans trajectories using a specialised A* and negotiates trajectories until a solution is found, which is acceptable for all vessels. The solution obeys collision avoidance rules, includes a dynamic model of all vessels and negotiates trajectories to optimise globally without a global planner and extensive information disclosure. The procedure combines all components necessary to solve a multi-vessel encounter and is tested currently in simulation and on several test beds. The first results show a fast converging optimisation process which after a few negotiation rounds already produce feasible, collision free trajectories.

19

Data Acquisition in a Manoeuver Auto-negotiation System

Szlapczynska J.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

|

2015

|

Vol. 9, no. 3

343--348

EN

Typical approach to collision avoidance systems with artificial intelligence support is that such systems assume a central communication and management point (such as e.g. VTS station), usually located on shore. This approach is, however, not applicable in case of an open water encounter. Thus, recently a new approach towards collision avoidance has been proposed, assuming that all ships in the encounter, either restricted or open water, communicate with each other and negotiate their maneuvers, without involving any outer management or communication center. Usually the negotiation process is driven by the collision avoidance software and called auto-negotiation. This paper elaborates on data acquisition problem in case of the maneuver auto-negotiation. It focuses on ships' initialization in the system and data gathering.

20

Model manipulatora o strukturze szeregowej w programach Catia i Matlab

Kocurek Ł., Góra M.

Mechanik

|

2014

|

R. 87, nr 2CD

PL

W pracy opracowano modele manipulatora Fanuc S-420F o strukturze szeregowej z uwzględnieniem jego analizy kinematycznej w środowisku CATIA i Matlab. Otrzymane modele wykorzystano do generowania trajektorii robota we współrzędnych konfiguracyjnych. Wyznaczono zależności współrzędnych kartezjańskich członu roboczego względem podstawy manipulatora od czasu dla zadanego przejścia z położenia A do B. Porównano wyniki uzyskane z modeli utworzonych w środowisku CATIA i Matlab.

EN

Models of Fanuc S-420F serial manipulator for kinematic analysis were formulated in CATIA and Matlab environment. The resulting models were used to generate the manipulator trajectory in joint space. Cartesian coordinates of the robot end-effector were determined in relation to time of passing from pose A to B. The results obtained from the models created in CATIA and Matlab environments were compared.