Group Of Autonomous Mobile Robots Research Articles

Area Coverage Optimization using Networked Mobile Robots with State Estimation

In this paper, we present a solution to the area coverage problem using a team of mobile robots with state estimation. A group of autonomous mobile robots is deployed in a two-dimensional area of interest, for example, where communication among robots is limited or noisy as expected in a real life scenario. Each robot estimates its own state (position and orientation) using noisy range and bearing information received from other robots in its operating range. The area of interest is then divided into multiple sub-area using a voronoi tessellation. Using the classical Lloyd's algorithm, each robot employs distributed action command to move towards the centroid of the voronoi cell that it belongs yielding the maximum coverage of the area. Here we emphasize that the network of autonomous robots deployed in the environment is unknown a priori. A set of computer experiments is conducted to validate the fact that the area coverage is still possible under noisy communication among robots deployed in a two-dimensional area.

METHOD OF COORDINATION OF MOTION OF SWARM ROBOTIC SYSTEMS

Maintaining a specific geometric pattern is essential in various applications where groups of autonomous robots must follow a given path. Proper organization of the geometric pattern can lead to several benefits such as cost reduction, increased system reliability, and efficiency while providing a reconfigurable and flexible structure of the system. Military missions and traffic systems are examples where maintaining certain geometric patterns are widely used. However, little is known about how to develop an effective algorithm that guarantees collision avoidance and obstacle avoidance while maintaining the geometric pattern. This paper presents an algorithm for movement with a certain geometric structure of a group of autonomous mobile robots that maintains the required geometric pattern and ensures the avoidance of collisions and obstacles. The proposed algorithm is behavior-based and utilizes a set of rules that allow the robots to navigate around obstacles and avoid collisions. The algorithm's performance is demonstrated through simulations in a variety of scenarios with different numbers of robots and geometric patterns. The algorithm proposed in this paper provides an effective solution for controlling a group of autonomous mobile robots to maintain a certain geometric pattern. The proposed algorithm has the potential to be utilized in numerous applications where multiple robots must work together to achieve a common goal while maintaining a specific formation. The use of behavior-based approach and obstacle avoidance rules ensures that the robots avoid collisions and obstacles while maintaining the required pattern

Analysis of existing approaches to group control of autonomous unmanned aerial vehicle

To ensure coordination and effective interaction between groups of autonomous mobile robots, there are several approaches that can be used to achieve common goals and solve problems in autonomous systems and robotics. These approaches include the Known Field and Leader-Known method, the behavioral approach, and the consensus-based strategy. Each of these methods has its own characteristics and advantages, and they can be used depending on specific conditions and tasks in the context of autonomous systems and mobile robots. The main field and leader-aware approach is based on simulating the motion of particles in a potential field, where one of the works can act as a "leader" and the others follow it. This method provides movement towards a given target and avoids obstacles on the way to passing distances and directions. The behavioral approach involves the use of a set of rules and algorithms that initiate the behavior of everyone in the group. Each robot has its own "behavioral" rules that are used to respond to specific conditions and conditions. This approach provides flexibility and adaptability in different scenarios and efficiency for teams working in a variety of settings. The consensus-based approach is based on the idea of achieving suitability and synchronizing work with each other in a group. Robots exchange information and interact with each other, in order to achieve overall consistency in their movement and activities. This method allows for collaborative coordination and execution of tasks that require interaction between robots. The choice of a specific approach depends on the purpose and requirements of the tasks, and also takes into account specific conditions. In many cases, a combination of these methods can be an effective solution for solving complex problems and achieving the most effective interaction between robots. All this contributes to the further development of autonomous systems and ensures their ability to work as a unified group in various fields, including transport, logistics and other important industries.

Monotonic self-stabilization and its application to robust and adaptive pattern formation

We introduce, as an enhancement of self-stabilization, the concept of monotonic self-stabilization for distributed systems that ensures that a certain measure of quality of state monotonically improves when the system in an illegitimate state progresses toward a legitimate state. In the concept, the quality is measured by a real-valued function that can be chosen from a certain class of functions. The concept is applied to a multi-robot pattern formation problem in which a group of autonomous mobile robots move from their respective initial positions to the goal positions like a marching band. We solve the problem by presenting two monotonic self-stabilizing pattern formation algorithms, one of which is for FSYNC model and the other is for SSYNC model. The considered real-valued functions to measure the quality take into account both the distance to the goal location and the accuracy of the formation. We present a formal proof of the algorithms' correctness and monotonic self-stability.

Emergency broadcasting strategies for distributed robotic groups under limited communication

Execution of large-scale search and survey operations by groups of autonomous mobile robots requires the ability to respond to unforeseen events of different nature in a quick and efficient manner. In order to achieve this requirement, the available information about recent changes should be spread among all active group members as soon as possible. Informing a non-stationary group of mobile robots distributed across different regions of the operational area is a nontrivial task for large groups with limited communication capabilities. The paper addresses the problem of agent-based information distribution throughout a network in a new original formulation. In essence, the problem is to define an effective order of transferring data between single robots in order to achieve the fastest way of sharing it among the whole group. A number of heuristic strategies are proposed for building initial solutions alongside with the local search scheme for their further optimization. The comparison between the suggested approaches is made regarding both the solution quality and the speed of algorithm operation. Some issues related to the test instances generation are also considered.

Method of Formation of Quantitative Indicators of Complexity of the Environment by a Group of Autonomous Mobile Robots

This article presents the methods that allow forming quantitative estimations of functional characteristics of a group of autonomous mobile robots (AMRs) and local areas of the environment surrounding it. The evaluation of the environment is based on the analysis of scattering of the cloud of obstacle points and made using the information formed by the computer vision system (CVS), which every robot in the group has. The core element of CSV is 3D lidar. Quantitative data about the complexity of the environment can be used for determining the optimal methods of solving the planning tasks and forming the patterns of group formation. Such data about the complexity of local areas of the environment can also be used for determining them as insurmountable for a single robot or a group of robots. The reason for such a decision can be the violation of safety rules and breaking of the group formation. The assessment of robots’ functional characteristics is performed based on the fuzzy model that consists of separate fuzzy classifiers; each of them allows obtaining a quantitative estimation of one of the parameters. The hierarchic structure of the used fuzzy model makes it significantly easier to synthesize and analyze it.

The study of the survey algorithm of the heterogeneous group of autonomous mobile robots

The study of the survey algorithm of the heterogeneous group of autonomous mobile robots

Method of Dynamic Selection of Satellite Navigation System in the Autonomous Mode of Positioning

Today, the list of applications that require accurate operational positioning is constantly growing. These tasks include: tasks of managing groups of Autonomous mobile robots, geodetic tasks of high-precision positioning, navigation and monitoring tasks in intelligent transport systems. Satellite navigation systems are a data source for operational positioning in such tasks. Today, global and local satellite navigation systems are actively used: GPS, GLONASS, BeiDou, Galileo. They are characterized by different completeness of satellite constellation deployment, which determines the accuracy of operational positioning in a particular geographical point, which depends on number of satellites available for observation, as well as the characteristics of the receiver, landscape features, weather conditions and the possibility of using differential corrections. The widespread use of differential corrections at the moment is not possible due to the fact that number of stable operating reference stations is limited - the Earth is covered by them unevenly; reliable data networks necessary for the transmission of differential corrections are also not deployed everywhere; budget versions of single-channel receivers of the navigation signal are widely used, which do not allow the use of differential corrections. In this case, there is a problem of operational choice of the system or a combination of satellite positioning systems, providing the most accurate navigation data. This paper presents a comparison of static and dynamic methods for selecting a system or a combination of satellite positioning systems that provide the most accurate definition of the object's own coordinates when using a single-channel receiver of navigation signals in offline mode. The choice is made on the basis of statistical analysis of data obtained from satellite positioning systems. During the analysis, the results of post-processing of data obtained from satellite navigation systems and refined with the use of differential corrections of navigation data were compared.

Distributed motion misbehavior detection in teams of heterogeneous aerial robots

This paper addresses the problem of detecting possible misbehavior in a group of autonomous mobile robots, which coexist in a shared environment and interact with each other and coordinate according to a set of common interaction rules. Such rules specify what actions each robot is allowed to perform in order to interact with the other members of the group. The rules are distributed, i.e., they can be evaluated only starting from the knowledge of the individual robot and the information the robot gathers from neighboring robots. We consider misbehaving those robots which, because of either spontaneous failures or malicious tampering, do not follow the rules and whose behavior thus deviates from the nominal assigned one. The main contribution of the paper is to provide a methodology to detect such misbehavior by observing the congruence of actual behavior with the assigned rules as applied to the actual state of the system. The presented methodology is based on a consensus protocol on the events observed by robots. The methodology is fully distributed in the sense that it can be performed by individual robots based only on the local available information, it has been theoretically proven and validated with experiments involving real aerial heterogeneous robots.

Surrounding Robots – A Discrete Localized Solution for the Intruder Problem –

Decentralized algorithms are often used in the cooperative robotics field, especially by large swarm systems. We present a distributed algorithm for a problem in which a group of autonomous mobile robots must surround a given target. These robots are oblivious, i.e., they have no memory of the past. They use only local sensing and need no dedicated communication among themselves. We introduce, then solve the problem in which the group of autonomous mobile robots must surround a given target – we call it the “discrete multiorbit target surrounding problem” (DMTSP). We evaluate our solution using simulation and prove that our solution invariably ensures that robots enclose the target in finite time.

Decentralized Coverage Control for Multi-Agent Systems with Nonlinear Dynamics

In this paper, we study the decentralized coverage control problem for an environment using a group of autonomous mobile robots with nonholonomic kinematic and dynamic constraints. In comparison with standard coverage control procedures, we develop a combined controller for Voronoi-based coverage approach in which kinematic and dynamic constraints of the actual mobile sensing robots are incorporated into the controller design. Furthermore, a collision avoidance component is added in the kinematic controller in order to guarantee a collision free coverage of the area. The convergence of the network to the optimal sensing configuration is proven with a Lyapunov-type analysis. Numerical simulations are provided approving the effectiveness of the proposed method through several experimental scenarios.

Local control strategy for moving-target-enclosing under dynamically changing network topology

This paper studies the moving-target-enclosing problem for a group of autonomous mobile robots, which can be seen as the requirement of achieving a formation surrounding a moving target whose movement is not known a priori. A local information control law is proposed to solve the problem utilizing only the relative position information from the target and its neighbors. The derivation of the controller is based on the idea of decoupling the task of target tracking and the task of inter-robot coordination. It is shown that the group of autonomous mobile robots collaboratively estimates the moving velocity of the target and asymptotically reaches a regular polygon formation to keep the moving target as its centroid. The neighbor topology may dynamically change as the system evolves. Hence, a non-smooth version of LaSalle’s invariance principle is used to show the convergence.

Towards group transport by swarms of robots

We examine the ability of a swarm robotic system to transport cooperatively objects of different shapes and sizes. We simulate a group of autonomous mobile robots that can physically connect to each other and to the transported object. Controllers – artificial neural networks – are synthesised by an evolutionary algorithm. They are trained to let the robots self-assemble, that is, organise into collective physical structures and transport the object towards a target location. We quantify the performance and the behaviour of the group. We show that the group can cope fairly well with objects of different geometries as well as with sudden changes in the target location. Moreover, we show that larger groups, which are made of up to 16 robots, make possible the transport of heavier objects. Finally, we discuss the limitations of the system in terms of task complexity, scalability and fault tolerance and point out potential directions for future research.

Sliding-Mode Formation Control for Cooperative Autonomous Mobile Robots

This paper considers the control of a group of autonomous mobile robots. A coordinated control scheme based on a leader-follower approach is developed to achieve formation maneuvers. First and second order sliding-mode controllers are proposed for asymptotically stabilizing the vehicles to a time-varying desired formation. The latter controller, based on the relative motion states, eliminates the need for measurement or estimation of the leader velocity. It enables formation stabilization using a vision system carried by the followers and ensures the collision avoidance from the initial time instance. Experimental investigation has been conducted using a test bench made of three nonholonomic mobile robots in order to demonstrate the effectiveness of the proposed strategy.

Coordinated Collective Motion of Groups of Autonomous Mobile Robots with Directed Interconnected Topology

Coordinated collective motion of groups of autonomous mobile robots is studied. A qualitative analysis for the collective dynamics of multiple autonomous robots with directed interconnected topology using nearest neighbor rules is given. A necessary and sufficient graphical condition is proposed to guarantee that the headings of all robots converge to the same heading. The graph having a globally reachable node plays a crucial role in convergence analysis. Furthermore, we show that the globally reachable node having no neighbors serves as a group leader as a special case

Decentralised coordination of groups of autonomous mobile robots

The paper gives a qualitative analysis of the dynamics of a system consisting of several mobile robots coordinating their motion using simple local nearest neighbour rules. We show that under some assumptions the headings of all robots will be eventually constant. We give an example of a multi-agent system with a cyclic dynamics.

The problem of coordination and consensus achievement in groups of autonomous mobile robots with limited communication

The paper considers a consensus seeking problem for a multirobot system with limited communication. Multirobot systems with limited communication are modelled as hybrid dynamical systems. The proposed model is a modification of some mathematical models introduced in physics and biology. We derive a necessary and sufficient condition for the system to converge to a single value of the coordination variable with probability 1.

Coordinated Collective Motion of Groups of Autonomous Mobile Robots: Analysis of Vicsek's Model

This note gives a qualitative analysis of the dynamics of a system consisting of several mobile robots coordinating their motion using simple local nearest neighbor rules. We show that under some assumptions the headings of all robots will be eventually constant.

Swarm robotic odor localization: Off-line optimization and validation with real robots

This paper presents an investigation of odor localization by groups of autonomous mobile robots using principles of Swarm Intelligence. First, we describe a distributed algorithm by which groups of agents can solve the full odor localization task more efficiently than a single agent. Next, we demonstrate that a group of real robots under fully distributed control can successfully traverse a real odor plume, and that an embodied simulator can faithfully reproduce these real robots experiments. Finally, we use the embodied simulator combined with a reinforcement learning algorithm to optimize performance across group size, showing that it can be useful not only for improving real world odor localization, but also for quantitatively characterizing the influence of group size on task performance.

Stability analysis of M-dimensional asynchronous swarms with a fixed communication topology

Coordinated dynamical swarm behavior occurs when certain types of animals forage for food or try to avoid predators. Analogous behaviors can occur in engineering systems (e.g., in groups of autonomous mobile robots or air vehicles). In this paper, we study a model of an M-dimensional (M/spl ges/2) asynchronous swarm with a fixed communication topology, where each member only communicate with fixed neighbors, to provide conditions under which collision-free convergence can be achieved with finite-size swarm members that have proximity sensors, and neighbor position sensors that only provide delayed position information. Moreover, we give conditions under which an M-dimensional asynchronous mobile swarm with a fixed communication topology following an edge-leader can maintain cohesion during movements even in the presence of sensing delays and asynchronism. In addition, the swarm movement flexibility is analyzed. Such stability analysis is of fundamental importance if one wants to understand the coordination mechanisms for groups of autonomous vehicles or robots, where intermember communication channels are less than perfect and collisions must be avoided.