Browsing by Author "Ozsoyeller, Deniz"

Now showing 1 - 9 of 9

AID: Assistant-Based Approach for K-Leader Network Formation in Multi-Robot Systems
(Institute of Electrical and Electronics Engineers Inc., 2025) Abuzahra, Hamza; Ozkasap, Oznur; Ozsoyeller, Deniz
Data Collection with a Team of Capacity-Constrained Unmanned Aerial Vehicles Assisted by a Mobile Recharger
(Elsevier, 2025) Ozsoyeller, Deniz; Ok, Ahmet Enes
Wireless Sensor Networks (WSNs) have been utilized in various applications such as environmental monitoring, precision agriculture, disaster response, and military surveillance. A critical challenge that affects the system lifetime is the limited battery capacity of the sensors. In this paper, we study the sensor data collection problem with a team of unmanned aerial vehicles (UAVs) and a single unmanned ground vehicle (UGV). The UAVs work as data collectors while the UGV provides recharging and data-relaying services to the UAVs. We envision partitioned WSN scenarios, where the communication graph on the initial locations of all sensors is not connected. The objective is to minimize the total time required for the UAVs to collect the data of all sensors. We present a multi-stage online data collection algorithm that plans the paths for the UAVs that do not know the locations of the sensors in advance and are subject to both energy and storage capacity constraints. Our algorithm also plans the path of the UGV and determines the recharging sites for UGV-UAV rendezvous considering not only the limited energy capacity of the UAVs but also the total units of sensor data to be collected by each UAV. We analyze its performance theoretically, in extensive simulations, and on well-known benchmark instances.
Citation - WoS: 2
Citation - Scopus: 2
Distributed asynchronous rendezvous planning on the line for multi-agent systems
(ELSEVIER, 2024) Deniz Ozsoyeller; Oznur Ozkasap; Özkasap, Öznur; Ozsoyeller, Deniz
Multi-agent systems have become increasingly significant in various application areas such as search-andrescue exploration surveillance and assembly. In this study we focus on the asynchronous autonomous rendezvous planning in multi-robot (i.e. multi-agent) systems. The objective is that the robots located in linear environments to gather rapidly at a previously unknown rendezvous location. We consider that no robot knows the positions of the other robots and its own global position. Furthermore the robot does not know its initial distance to any other robot. Our focus is on the asynchronous case where it is not required the robots to start executing the algorithm simultaneously. We propose and develop a rendezvous planning algorithm namely MAR that combines distributed coordination and online motion planning. We theoretically analyze the performance of our algorithm and show that it has a constant competitive ratio. Our extensive simulations demonstrate the performance and scalability through the analysis of the key performance metrics of interest including competitive ratio distance traveled total time number of rounds and number of meetings. Additionally we demonstrate the performance and applicability of our algorithm MAR through experimental analysis in a realistic robotic simulator.
Citation - Scopus: 1
Forming Connected Multi-Robot Teams Utilizing Aerial Robots
(IEEE, 2025) Deniz Ozsoyeller; Ozsoyeller, Deniz
In this paper we study the connected multi-robot team formation problem. We consider the settings where multiple aerial and ground robots with limited communication ranges are operating in an unbounded environment. The ground robots do not have a priori knowledge about the initial locations of each other and the aerial robots. Moreover the aerial robots do not know the initial locations of the ground robots in advance. Our goal is to divide the robots into teams as quickly as possible by relocating them. Each team should be of same size and include one aerial robot assigned to it as its leader and the final configurations of the robots in each team should form a fully connected network topology. To solve this problem we present an algorithm that combines distributed coordination and online planning of the robots. We evaluate the performance of the proposed algorithm in simulations.
Citation - WoS: 7
Citation - Scopus: 9
m-RENDEZVOUS: Multi-Agent Asynchronous Rendezvous Search Technique
(Elsevier B.V., 2022) Deniz Özsoyeller; Öznur Özkasap; Moayad Aloqaily; Ozkasap, Oznur; Ozsoyeller, Deniz; Aloqaily, Moayad
We study the problem of asynchronous rendezvous search with multiple mobile agents (robots) in the plane. The goal of the robots is to meet at a location in the environment which is not determined in advance as quickly as possible. They do not know the initial locations of each other or their own initial locations. Moreover the initial distance between any pair of robots is also unknown. Therefore the problem must be solved using an online approach. We study a new variant of the rendezvous search problem which we call m-RP. The objective of m-RP is exactly m
Citation - WoS: 7
Citation - Scopus: 8
Multi-Robot Symmetric Rendezvous Search on the Line
(IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2022) Deniz Ozsoyeller; Pratap Tokekar; Ozsoyeller, Deniz; Tokekar, Pratap
We study the Symmetric Rendezvous Search Problem for a multi-robot system. There are n > 2 robots arbitrarily located on a line. Their goal is to meet somewhere on the line as quickly as possible. The robots do not know the initial location of any of the other robots or their own positions on the line. The symmetric version of the problem requires the robots to execute the same search strategy to achieve rendezvous. Therefore we solve the problem in an online fashion with a randomized strategy. In this letter we present a symmetric rendezvous algorithm which achieves a constant competitive ratio for the total distance traveled by the robots. We validate our theoretical results through simulations.
Citation - Scopus: 3
Online Planning Approaches for Multi-Robot Rendezvous
(Institute of Electrical and Electronics Engineers Inc., 2024) Deniz Özsoyeller; Ozsoyeller, Deniz
In this paper we study the rendezvous of a group of robots in a bounded environment. The robots do not know the locations of each other. Moreover no robot knows the distance between any pair of robots. A rendezvous location is not determined in advance. For this problem we present two algorithms with different online planning approaches: (1) cluster-search and (2) single-search. In the first approach the robots that meet continue searching as a team. Whereas in the second approach the robots that meet split and continue as single searchers. We investigate and compare the performances of our algorithms through simulations. The results show that the algorithm with the single-search approach performs better than the algorithm with the cluster-search approach. © 2024 Elsevier B.V. All rights reserved.
Online Planning for Data Collection in Multi-Robot Systems
(2025) Ozsoyeller, Deniz
Kablosuz sensör ağları, çeşitli sivil ve askeri uygulamalarda veri toplamak için kullanılmıştır. Bir grup hareketli robotun ve bir küme hareketsiz kablosuz sensör düğümünün sınırsız geniş bir alanda aralıklı olarak konuşlandırıldığını düşünüyoruz. Bu gibi senaryolarda, tüm sensör düğümleri bir iletişim ağı ile bağlı olmayabilir. Buna ek olarak, birbirinin iletişim ağı içinde olan herhangi bir sensör düğümü çifti bulunmayabilir. Bu nedenle, ağ bağlantısının sağlanması için birçok aktarma düğümüne ihtiyaç vardır. Fakat, bu yaklaşım, veri iletiminden kaynaklanan enerji tüketiminden dolayı sistemin ömrünü etkiler. Bu makalede, robotlardan faydalanarak konuşlandırılmış olan sensör düğümlerinden veri toplama problemini çalışıyoruz. Robotlar, birbirlerinin ve sensör düğümlerin konumunu bilmezler. Dahası, sensör düğümleri de birbirlerinin ve robotların konumunu bilmezler. Robotların sensör düğümleri bulmak için alanda keşif yaptığı ve düğümlerdeki veriyi topladığı çevrimiçi bir algoritma öneriyoruz. Robotların, robot sayısını önceden bilip bilmediğine bağlı olarak problemin iki durumunu inceliyor ve karşılaştırıyoruz. Simülasyonlarla, algoritmamızın performansını deneysel olarak değerlendiriyor ve robotun, sensör düğümü ve robot sayısını önceden bilmediği durumda performansın alan boyutu, robot sayısı ve iletişim alanının bir fonksiyonu olarak ölçeklendiğini gösteriyoruz.
Citation - WoS: 1
Citation - Scopus: 1
TAP: Distributed team assignment in heterogeneous multi-agent systems
(ELSEVIER, 2026) Deniz Ozsoyeller; Ozsoyeller, Deniz
In this article we introduce and study the problem of autonomous balanced team assignment in a heterogeneous multi-robot (i.e. multi-agent) system. The system includes n robots that are initially located in a large open area. We consider a scenario where there are two types of robots namely worker and service with limited communication ranges and specialized capabilities. The robots should be divided into teams so that each team can be assigned to a different location. The objective is to minimize the maximum distance traveled among the worker robots while ensuring that each constructed team is of equal size and has exactly one service robot to assist the worker robots in the team. Depending on the robot's initial configuration the robot can be either single or a part of a connected communication network of robots. In the former case the robot does not know the location of any other robot whereas in the latter case the robot only knows the locations of the robots in its network but not the ones outside it. For this problem we propose two algorithms TAm and TAnm that combine the distributed coordination and online motion planning methods. For assignment TAm uses a mutual decision making approach whereas TAnm uses a nonmutual decision making approach. We evaluate the performances of our strategies through extensive simulations varying the key parameters of interest including communication range environment size number of worker robots and number of service robots. The results show that TAm outperforms TAnm in sparse configurations but the performances of the algorithms approach to each other as the configuration becomes dense.