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Item type:Publication, Access status: with files , Flocking and formation as mission control strategies for multi-agent systems : comparative evaluation and development of a cooperative approachIn this work novel mission control strategies are proposed for multiagent systems, that can be applied to scenarios such as source seeking and level curve tracking. A gradient-based method for source seeking and subsequent level curve tracking is presented, where the agents reach discrete consensus on whether they should switch from Task 1 to Task 2. Moreover, a gradient-free flocking-based approach to the source seeking problem is developed that is based on glowworm swarm optimization. The multiple-source-seeking problem for time-varying communication topologies is solved using a combination of bio-inspired attraction with estimated gradient and formation control, where task-switching is performed under a linear temporal logic rule. Finally an approach that combines flocking and formation control techniques is presented, where low-level agents attain a specified formation, while the formation leaders at the upper level flock to locate an unknown extremum. Convergence analysis for all methods is provided, together with simulation results and experimental validation.Publicationtype: Doctoral Thesis316 595 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Gradient free source-seeking using flocking behavior(2019-07); ; In this paper we propose a novel scheme that allows a group of mobile agents equipped with sensing capabilities to locate the unknown maximum of a scalar field. The scheme avoids the restrictions associated with gradient estimation, imposing predetermined formations on the agents or global localization. Instead the flocking approach is combined with a technique inspired by glowworm swarm optimization. Under reasonable assumptions we prove stability and boundedness of trajectories. 3-D simulation as well as 2-D experimental results illustrate that the proposed method outperform an existing technique in terms of smoothness of the trajectories.Publicationtype: Conference Paper142 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Multiple Source Seeking using Glowworm Swarm Optimization and Distributed Gradient Estimation(2018-08-09); In this paper we propose a novel mission control strategy for a group of agents to locate unknown multiple extrema of a time-invariant scalar field. The goal is to provide a complete solution for realistic scenarios such as malfunction of agents or time-varying topology. Here we present MESA - Multiple Extrema Seeking Algorithm, where a group of autonomous agents are able, from any arbitrary initial location (in a bounded area), to locate multiple, unknown extrema. The proposed algorithm includes a combination of bio-inspired attraction with estimated gradient and formation control, where the task switching methodology is performed under the specification of Linear Temporal Logic formula. At first, agents find neighbors and construct groups for completing the search procedure. Once an extremum is 'located', a virtual repulsive force is produced by the pioneer group which as a result cause others to search for other unexplored extrema. We propose a new measure-source density - evaluating the algorithm efficiency which is tested under different simulations for a unicycle agent's model.Publicationtype: Conference Paper140 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Sensor data fusion of a redundant dual-platform robot for elevation mapping(2018-02-01); ; This paper presents a novel methodology for localization and terrain mapping along a defined course such as narrow tunnels and pipes, using a redundant unmanned ground vehicle kinematic design. The vehicle is designed to work in unknown environments without the use of external sensors. The design consists of two platforms, connected by a passive, semi-rigid three-bar mechanism. Each platform includes separate sets of local sensors and a controller. In addition, a central controller logs the data and synchronizes the plat-forms’ motion. According to the dynamic patterns of the redundant information, a fusion algorithm, based on a centralized Kalman filter, receives data from the different sets of inputs (mapping techniques), and produces an elevation map along the traversed route in the x-z sagittal plane. The method is tested in various scenarios using simulated and real-world setups. The experimental results show high degree of accuracy on different terrains. The proposed system is suitable for mapping terrains in confined spaces such as underground tunnels and wrecks where standard mapping devices such as GPS, laser scanners and cameras are not applicable.Publicationtype: Journal Article99 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Mission control - combined solutions for source seeking and level curve tracking in a time-varying fieldIn this paper we propose a novel mission control strategy for a group of agents to locate an unknown source, represented as maximum of a scalar field, and to track a specified level curve. We propose a distributed control scheme based on hierarchy formation and reduced topology. Without prior knowledge of the field, the agents, equipped with local sensors, navigate in ℝp using an estimated gradient method and their neighbors' shared measurements. The contributions of this paper are twofold. First, we propose a finite iteration process for reaching a discrete consensus between all agents for switching from one task to the next. Each group of agents determines their current task according to the status of the other groups in the network. Second, a 4-tasks algorithm is proposed for exploring a time-varying, noisy field. Simulations for a group of 32 agents are shown, illustrating the algorithm robustness to a time-varying field with noise corrupted measurements.Publicationtype: Conference Paper89