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Öğe A target tracking approach for nonholonomic agents based on artificial potentials and sliding mode control(Asme, 2012) Gazi, Veysel; Fidan, Barış; Ordonez, Raul; Koksal, M. İlterIn this paper, we consider the task of tracking a maneuvering target both with a single nonholonomic agent and a swarm of nonholonomic agents. In order to achieve the tracking task, a decentralized continuous-time control scheme, which combines artificial potentials and sliding mode control techniques, is developed via constructive analysis. The effectiveness of the proposed control scheme is established analytically and demonstrated via a set of simulation results. [DOI: 10.1115/1.4006622]Öğe Adaptive formation control and target tracking in a class of multi-agent systems: Formation maneuvers(Ieee, 2013) Gazi, Veysel; Fidan, BarışIn this article we develop a direct adaptive fuzzy control based methodology for formation control and target tracking in a class of multi-agent systems with nonlinear and uncertain dynamics. The agents are assumed to be able to measure only their relative position to the other agents and the target and high gain observers are applied to estimate the derivatives of the combined tracking and formation errors. Various formation maneuvers such as contraction/expansion, rotation, and reconfiguration of the formation are also considered. Bounding and sliding mode control terms are used to guarantee stability and robust performance. Simple numerical simulations are also provided to verify the effectiveness of the algorithm.Öğe Adaptive internal model based formation control of a class of multi-agent systems with switched exosystems(Ieee, 2012) Gül, Esma; Gazi, VeyselIn this article we consider a class of multi-agent dynamic systems with uncertainties and the problem of moving in a predefined formation along a reference trajectory. The reference trajectory is generated by switched exosystems each of which are neutrally stable and have unknown parameters. The problem is formulated as a nonlinear servomechanism problem and an adaptive internal model based controller is used to solve this problem. Various formation maneuvers such as expansion/contraction, rotation, and reconfiguration (change of shape) are also considered. The performance of the system is verified with simple numerical simulations.Öğe Adaptive internal model-based distributed output agreement in a class of multi-agent dynamic systems(Springer International Publishing, 2016) Gül, Esma; Gazi, VeyselIn this study we consider the distributed output agreement problem in a class of multi-agent dynamic systems with uncertainties. The problem is formulated as a nonlinear servomechanism problem and an adaptive internal model-based controller is used to achieve agreement of the agent outputs using local information. Various agent neighborhood topologies are considered and the performance of the system is verified using simple numerical simulations. © Springer International Publishing Switzerland 2016.Öğe Chemical concentration map building using whale optimization algorithm(Ieee, 2017) Merzi, Alp; Gazi, VeyselIn this work, we adapted the Whale Optimization Algorithm (WOA) to a mobile robot system to map the chemical gas concentration in an unknown environment. It is assumed that robots do not know the environment beforehand but can measure it with the existing sensors on them. The chemical gas concentration in the environment is modeled by a multimodal Gaussian function (a function composed of a sum of multiple Gaussian functions). In addition, we assume that the sensor measurements of the robots are corrupted by a normally distributed random noise and investigate the effect of the noise on the performance of the algorithm. While WOA acts as a high-level path planning algorithm for the agents, low-level navigation and collision avoidance of the robots with unicycle dynamics is achived utilizing potential functions. The measurements of the robots are filtered and interpolated to obtain the chemical concentration map of the environment. Successful performance of the algorithm is verified through simulations performed in the MATLAB environment.Öğe Distributed adaptive output agreement in a class of multi-agent systems(Ieee, 2013) Gazi, VeyselIn this article we consider the distributed output agreement problem in a class of heterogeneous multi-agent dynamic systems composed of agents with nonlinear and uncertain dynamics. We develop a distributed direct adaptive fuzzy control methodology which using only local information guarantees achievement of agreement of the agent outputs despite the uncertainties in the agent dynamics. The performance of the proposed strategy is verified for various neighborhood topologies using representative numerical simulations.Öğe Distributed output agreement in a class of uncertain linear heterogeneous multi-agent dynamic systems(Ieee, 2014) Gazi, VeyselIn this article we consider the distributed output agreement problem in a class of heterogeneous multi-agent dynamic systems composed of single input single output linear systems with system uncertainties. Under very mild assumptions local adaptive internal model based controllers augmented with high gain observers are designed to achieve agreement of the agent outputs. The performance of the proposed controllers is verified for various neighborhood topologies using representative numerical simulations.Öğe Experimental studies on chemical concentration map building by a multi-robot system using bio-inspired algorithms(Springer, 2014) Turduev, Mirbek; Cabrita, Goncalo; Kırtay, Murat; Gazi, Veysel; Marques, LinoIn this article we describe implementations of various bio-inspired algorithms for obtaining the chemical gas concentration map of an environment filled with a contaminant. The experiments are performed using Khepera III and miniQ miniature mobile robots equipped with chemical gas sensors in an environment with ethanol gas. We implement and investigate the performance of decentralized and asynchronous particle swarm optimization (DAPSO), bacterial foraging optimization (BFO), and ant colony optimization (ACO) algorithms. Moreover, we implement sweeping (sequential search algorithm) as a base case for comparison with the implemented algorithms. During the experiments at each step the robots send their sensor readings and position data to a remote computer where the data is combined, filtered, and interpolated to form the chemical concentration map of the environment. The robots also exchange this information among each other and cooperate in the DAPSO and ACO algorithms. The performance of the implemented algorithms is compared in terms of the quality of the maps obtained and success of locating the target gas sources.Öğe Implementation studies of robot swarm navigation using potential functions and panel methods(Ieee-Inst Electrical Electronics Engineers Inc, 2016) Merheb, Abdel-Razzak; Gazi, Veysel; Sezer-Uzol, NilayThis paper presents a practical swarm navigation algorithm based on potential functions and properties of inviscid incompressible flows. Panel methods are used to solve the flow equations around complex shaped obstacles and to generate the flowlines, which provide collision-free paths to the goal position. Safe swarm navigation is achieved by following the generated streamlines. Potential functions are used to achieve and maintain group cohesion or a geometric formation during navigation. The algorithm is implemented and tested through numerical simulations, as well as experimental implementations on real robots in a laboratory environment in two settings, in which the flowlines are calculated either offline or in real time. The algorithm is easy to implement and can serve as an effective tool for cohesive navigation of robotic swarms.Öğe Indirect adaptive formation control with nonlinear dynamics and parametric uncertainty(Ieee, 2013) Güler, Samet; Köksal, Nasrettin; Fidan, Barış; Gazi, VeyselThis paper focuses on coordination of multi-agent systems with agents having holonomic nonlinear dynamics and uncertain system parameters. An indirect adaptive control scheme composed of a parameter estimator and a feedback-linearization based control law is designed based on the certainty equivalence principle. (i) Simple linear and (ii) sliding mode control structures are used in the outer control loop. The controllers successfully satisfy the objectives of formation maintenance and trajectory tracking. Simulation results for a sample two-dimensional formation are presented, demonstrating the performance of the proposed control scheme.Öğe On lagrangian dynamics based modeling of swarm behavior(Elsevier, 2013) Gazi, VeyselIn this article a Lagrangian dynamics based approach for modeling swarm dynamics is presented. The approach is based on energy and is alternative to the commonly used Newtonian dynamics, which is based on forces. For that purpose first the concept of biological potential energy is introduced. Various components of the biological potential energy such as swarming potential energy, environmental potential energy, and predator potential energy are also introduced and example kernel functions discussed. Simple illustrative numerical simulations are also provided. (C) 2013 Elsevier B.V. All rights reserved.Öğe Particle swarm optimization based distributed agreement in multi-agent dynamic systems(Ieee, 2014) Gazi, Veysel; Ordonez, RaulIn this article we approach the problem of distributed agreement in multi-agent systems using asynchronous particle swarm optimization (PSO) with dynamic neighborhood. The agents are considered as PSO particles which are assumed to have time-dependent neighborhoods, operate asynchronously and incur time delays during information exchange. The performance of the PSO based agreement algorithm is verified using representative numerical simulations.Öğe Sensor coverage maximization with potential fields(Institute of Electrical and Electronics Engineers Inc., 2014) Hanay, Y. Sinan; Gazi, VeyselThis paper proposes a novel algorithm to deploy mobile sensors for maximization of sensing area coverage. The algorithm presented is distributed and robust to errors. Our method is dynamic and based on potential fields. Although some methods using potential fields have been proposed previously, the approach we take here is different in constructing the potential field. In particular, we utilize an entropy-based potential function and use the Newton's iteration to determine the sensor positions. Simulations show that our method is more robust to errors, and less likely to be trapped in local minima compared to some previously proposed methods. © 2014 IEEE.Öğe Single-view distance-estimation-based formation control of robotic swarms(Ieee-Inst Electrical Electronics Engineers Inc, 2013) Fidan, Barış; Gazi, Veysel; Zhai, Shaohao; Cen, Na; Karataş, EnginThis paper presents a practical formation motion control scheme for robotic swarms based on single-view distance estimation, which is performed using a single nonsophisticated camera on each robot agent, and the prior information about the heights of the robots and other objects in the environment. Here, a nonsophisticated camera means one that has limited field of view and limited resolution. First, the vision mechanism is analyzed, and a single-view distance estimation scheme is designed. Then, a set of decentralized control laws, to be incorporated with distance estimation scheme, is introduced to move the robotic swarm in formation from an arbitrary initial position to an arbitrary final position without deforming the formation shape. The robots do not have any global positioning sensors, and they do not communicate with each other. The stability and performance of the overall system are analyzed mathematically. Later, practical issues are discussed regarding the proposed scheme, and the effects of delay and quantization in distance estimation are formally analyzed. Finally, we present experimental results demonstrating the performance of the proposed control scheme in real time.Öğe Stable adaptive particle swarm optimization(Ieee, 2013) Djaneye-Boundjou, Ouboti; Ordonez, Raul; Gazi, VeyselUsing discrete-time adaptive control tools found in literature, we develop an adaptive particle swarm optimizer. We show, using Lyapunov's direct method, that our devised error system is ultimately uniformly bounded, ultimately goes to zero by Lasalle-Yoshizawa theorem, and our optimizer is stable.Öğe Stochastic stability analysis of the particle dynamics in the PSO algorithm(Ieee, 2012) Gazi, VeyselIn this article we analyze the stability of the particle dynamics in the Particle Swarm Optimization algorithm using tools from the nonlinear control systems literature including positive realness and stability of stochastic systems.Öğe Öğe Virtual cancelation plume for multiple odor source localization(Ieee, 2013) Cabrita, Goncalo; Marques, Lino; Gazi, VeyselThis article presents a novel algorithm for multiple odor source localization by a multi-robot system based on a virtual cancelation plume approach. The proposed method is based on rendering a previously declared odor source invisible to the robots so that the declared source and the odor plume it generates do not interfere with the effects of other existing plumes, allowing the localization of the remaining sources. Exploration and plume tracking by the robots is achieved using a decentralized asynchronous particle swarm optimization algorithm. The divergence operator is used to declare the odor sources. A set of simulations and real world experiments are performed on two different scenarios on a controlled environment using a swarm of 5 robots to validate the proposed methodology. Results show that the virtual plume cancelation algorithm can be successfully used to find multiple odor sources, even when two plumes overlap. It can also extend the operation of many odor source localization algorithms developed for single source localization.
