A Multi-Robot Control Architecture for Fault-Tolerant Sensor-Based Coverage (original) (raw)

Fault Tolerant Deployment, Search, and Task Cooperative Control of Robot/Sensor Networks

2005

This thesis focuses on developing of a distributed, efficient and fault tolerant multiresolutional architecture for sensor networks. For demonstrative purpose, a powerful simulation environment using 3D environment model has been developed. The robot network is composed of autonomous robots capable of working cooperatively equipped with single typed simple sensor. The developed layered control architecture is hybrid including both subsumption and motor schema control strategies. In this proposed control method, behaviors in different or in same layer are coordinated with an evaluator unit that overcomes the difficulties of subsumption based architectures in terms of behavioral coordination. The final coordination between these layers is achieved cooperatively. We performed many simulation experiments to test robot deployment, search and task execution. It is shown that some important parameters such as target reaching time, energy consumption, and v communication range can be optimized if an approximate prior information about the environment is known. Robots executes task based on a task allocation algorithm. Market based auction method is used as a task allocation algorithm with completely different robot fitness evaluation method allowing a distributive problem solving. Six non-linear fitness functions are developed to increase the fairness, and fault tolerance of task allocation. These functions have been tested to represent the successes and failures of robots in a compact form. Performance analyses test results have shown that fairness increases two times more in task allocation when these fitness functions are used, compared to the results existing fitness evaluation methods used in the market based auction algorithms. Moreover, fault tolerance is increased by using fitness functions devoted to failure conditions.

A Multi-robot Coverage Approach Based on Stigmergic Communication

Multiagent System Technologies, 2012

Recent years have witnessed a rapidly growing interest in using teams of mobile robots for autonomously covering environments. In this paper a novel approach for multi-robot coverage is described which is based on the principle of pheromone-based communication. According to this approach, called StiCo (for "Stigmergic Coverage"), the robots communicate indirectly via depositing/detecting markers in the environment to be covered. Although the movement policies of each robot are very simple, complex and efficient coverage behavior is achieved at the team level. StiCo shows several desirable features such as robustness, scalability and functional extensibility. Two extensions are described, including A-StiCo for dealing with dynamic environments and ID-StiCo for handling intruder detection. These features make StiCo an interesting alternative to graph-based multi-robot coverage approaches which currently are dominant in the field. Moreover, because of these features StiCo has a broad application potential. Simulation results are shown which clearly demonstrate the strong coverage abilities of StiCo in different environmental settings.

An Adaptive Stigmergic Coverage Approach for Robot Team

In this paper, an adaptive multi-robot coverage approach called A-StiCo (for "Adaptive Stigmergic Coverage") is described. According to A-StiCo multiple robots partition the environment into different regions in an adaptive way and each robot takes responsibility for covering one of these regions. Moreover, the robots communicate indirectly via depositing/detecting pheromones in the environment. Characteristic of A-StiCo is that the movement policy for the individual robots is intentionally kept very simple, so that it can be implemented on any unicycle vehicle with minimum computation capability. Crucial for the practical value of any coverage approach is its robustness. Simulation studies are presented which show that A-StiCo allows robot teams to fulfill coverage missions in a very efficient and robust way. In particular, the results demonstrate that this approach achieves very robust coverage behavior at the team level under different challenging circumstances (including robot failures and non-convex environments).

Limited communication, multi-robot team based coverage

IEEE International Conference on Robotics and Automation, 2004. Proceedings. ICRA '04. 2004, 2004

This paper presents an algorithm for the complete coverage of free space by a team of mobile robots. Our approach is based on a single robot coverage algorithm, which divides the target two-dimensional space into regions called cells, each of which can be covered with simple back-and-forth motions; the decomposition of free space in a collection of such cells is known as the Boustrophedon decomposition. Single robot coverage is achieved by ensuring that the robot visits every cell. The new multi-robot coverage algorithm uses the same planar cell-based decomposition as the single robot approach, but provides extensions to handle how teams of robots cover a single cell and how teams are allocated among cells. This method allows planning to occur in a two-dimensional configuration space for a team of N robots. The robots operate under the restriction that communication between two robots is available only when they are within line of sight of each other.

Fault-tolerant multi-robot area coverage with limited visibility

2010

Abstract—We address the problem of multi-robot area coverage and present a new approach in the case where the map of the area and its static obstacles are known and the robots have a limited visibility range. The proposed method starts by locating a set of static guards on the map of the target area and then builds a graph called Reduced-CDT, a new environment representation method based on the Constrained Delaunay Triangulation (CDT).

A fault-tolerant modular control approach to multi-robot perimeter patrol

2009

The use of large scale multi-robot systems is motivated by a number of desirable features, such as scalability, fault tolerance, robustness and lower cost with respect to more complex and specialized agents. This work is focused on a a behavior-based approach to the problem of the multi-robot border patrolling, in the framework of the Null-Space-based Behavioral control (NSB); it is based on two previous works of the same authors, where the feasibility of the approach is demonstrated. Namely, a few aspects of the approach, not yet tackled in previous works, are investigated: its robustness to faults of individual agents, its capability of managing large numbers of robots, the possibility of adding new tasks in the framework of the multi-robot patrolling problem. Along these directions, our approach has been validated in simulation with a large number of robots and sudden faults as well as experimentally on a team composed by three Pioneers 2-DX robots.

Coverage, Exploration and Deployment by a Mobile Robot and Communication Network

Telecommunication Systems, 2000

We consider the problem of coverage and exploration of an unknown dynamic environment using a mobile robot. The environment is assumed to be large enough such that constant motion by the robot is needed to cover the environment. We present an efficient minimalist algorithm which assumes that global information is not available (neither a map, nor GPS). Our algorithm deploys a network of radio beacons which assists the robot in coverage. The network is also used by the robot for navigation. The deployed network can also be used for applications other than coverage (such as multi-robot task allocation). Simulation experiments are presented which show the collaboration between the deployed network and mobile robot for the tasks of coverage/exploration, network deployment and maintenance (repair), and mobile robot recovery (homing behavior). We discuss a theoretical basis for our algorithm on graphs and show the results of the simulated scenario experiments.

Enhancing fault tolerance of autonomous mobile robots

Robotics and Autonomous Systems, 2015

Experience demonstrates that autonomous mobile robots running in the field in a dynamic environment often breakdown. Generally, mobile robots are not designed to efficiently manage faulty or unforeseen situations. Even if some research studies exist, there is a lack of a global approach that really integrates dependability and particularly fault tolerance into the mobile robot design. This paper presents an approach that aims to integrate fault tolerance principles into the design of a robot real-time control architecture. A failure mode analysis is firstly conducted to identify and characterize the most relevant faults. Then the fault detection and diagnosis mechanisms are explained. Fault detection is based on dedicated software components scanning faulty behaviors. Diagnosis is based on the residual principle and signature analysis to identify faulty software or hardware components and faulty behaviors. Finally, the recovery mechanism, based on the modality principle, proposes to adapt the robot's control loop according to the context and current operational functions of the robot. This approach has been applied and implemented in the control architecture of a Pioneer-P3DX mobile robot.