Relay Robots Research Articles

Swarm Crawler Robots Using Lévy Flight for Targets Exploration in Large Environments

This study tackles the task of swarm robotics, where robots explore the environment to detect targets. When a robot detects a target, the robot must be connected with a base station via intermediate relay robots for wireless communication. Our previous results confirmed that Lévy flight outperformed the usual random walk for exploration strategy in an indoor environment. This paper investigated the search performance of swarm crawler robots with Lévy flight on target detection problems in large environments through a series of real robots’ experiments. The results suggest that the swarm crawler robots with Lévy flight succeeded in the target’s discovery in the indoor environment with a 100% success rate, and were able to find several targets in a given time in the outdoor environment. Thus, we confirmed that target exploration in a large environment would be possible by crawler robots with Lévy flight and significant variances in the detection rate among the positions to detect the outdoor environment’s target.

Multirobot Data Gathering Under Buffer Constraints and Intermittent Communication

We consider a team of heterogeneous robots, which are deployed within a common workspace to gather different types of data. The robots have different roles due to different capabilities: some gather data from the workspace (source robots) and others receive data from source robots and upload them to a data center (relay robots). The data-gathering tasks are specified locally to each source robot as high-level linear temporal logic formulas, which capture the different types of data that need to be gathered at different regions of interest. All robots have a limited buffer to store the data. Thus, the data gathered by source robots should be transferred to relay robots before their buffers overflow, respecting at the same time a limited communication range for all robots. The main contribution of this work is a distributed motion coordination and intermittent communication scheme that guarantees the satisfaction of all local tasks, while obeying the above constraints. The robot motion and interrobot communication are closely coupled and coordinated during runtime by scheduling intermittent meeting events to facilitate the local plan execution. We present both numerical simulations and experimental studies to demonstrate the advantages of the proposed method over existing approaches that predominantly require all-time network connectivity.

Autonomous Wi-Fi Relay Placement With Mobile Robots

Stable communication plays an important role in many autonomous robotic applications, particularly in challenging environments that lack communication infrastructures. At present, there exists a high demand for wireless communication networks that can be quickly established to operate devices or agents, such as tasked mobile robots. Eliminating the bottlenecks in data transmission and optimizing the communication ability of base stations, mobile robots, and clients are necessary to ensure stable wireless communication. To solve the problem, an efficient approach is proposed by equipping Wi-Fi routers on mobile robots to enable and enhance dynamic communication ability. First, two specific Wi-Fi models are proposed to detect the distribution of Wi-Fi signals over operating environments and assist in the navigation of relay robots. A visual-laser simultaneous localization and mapping is proposed to establish an environmental map and further localize relay robots. A rapidly exploring random trees-based motion planning method is utilized to identify the target relay locations with optimal communication ability based on the built Wi-Fi signal distribution. Mobile relay robots are controlled automatically to the corresponding target locations, and an ad-hoc wireless network with good quality is established. The experimental results are presented to demonstrate the effectiveness of the proposed approach.

Swarm robotic network using Lévy flight in target detection problem

One approach in swarm robotics is homogeneous system which is embedded with sensing, computing, mobile and communication components. In this study, a target detection problem, which is one of navigation problems, was employed. Once a robot detects a target, robots immediately communicate with a base station via intermediate relay robots due to the multi-hop transmission of wireless communication. Therefore, this control task is completed with connectivity of the network. In a target detection problem, we must improve the performance of exploration as well as connectivity of the network. This study investigates the performances of the two types of random walk algorithm in navigation while loosely ensuring connectivity of the robotic network based on our previous study.

Finding the optimal location and allocation of relay robots for building a rapid end-to-end wireless communication

This paper addresses the fundamental problem of finding an optimal location and allocation of relay robots to establish an immediate end-to-end wireless communication in an inaccessible or dangerous area. We first formulate an end-to-end communication problem in a general optimization form with constraints for the operation of robots and antenna performance. Specifically, the constraints on the propagation of radio signals and infeasible locations of robots within physical obstacles are considered in case of a dense space. In order to solve the formulated problem, we present two optimization techniques such as Genetic Algorithm (GA) and Particle Swarm Optimization (PSO). Finally, the feasibility and effectiveness of the proposed methods are demonstrated by conducting several simulations, proof-of-concept study, and field experiments. We expect that our novel approach can be applied in a variety of rescue, disaster, and emergency scenarios where quick and long-distance communications are needed.

2A1-K06 レヴィフライトを用いたスワームロボットネットワークのターゲット探索

One approach in swarm robotics is homogeneous system which is embedded with sensing, computing, mobile and communication components. In this study, a target detection problem, which is one of navigation problems, was employed. Once a robot detects a target, robots immediately communicate with a base station via intermediate relay robots due to the multi-hop transmission of wireless communication. Therefore, it is important to take connectivity of the network into account. This study investigates the performances of the two kinds of random walk algorithm in navigation while loosely ensuring connectivity of the robotic network based on our previous study.

Real-time exploration of a multi-robot rescue system in disaster areas

A system procedure is proposed for a multi-robot rescue system that performs real-time exploration over disaster areas. Real-time exploration means that every robot exploring the area always has a communication path to human operators standing by at a base station and that the communication path is configured by ad hoc wireless networking. Real-time exploration is essential in multi-robot systems for USAR (urban search and rescue) because operators must communicate with every robot to support the victim detection process and ad hoc networking is suitable to configure a communication path among obstacles. The proposed system procedure consists of the autonomous classification of robots into search and relay types and behavior algorithms for each class of robot. Search robots explore the areas and relay robots act as relay terminals between search robots and the base station. The rule of the classification and the behavior algorithm refer to the forwarding table of each robot constructed for ad hoc networking. The table construction is based on DSDV (destination-sequenced distance vector) routing that informs each robot of its topological position in the network and other essentials. Computer simulations are executed with a specific exploration strategy of search robots. The results show that a multi-robot rescue system can perform real-time exploration with the proposed system procedure and reduce exploration time in comparison with the case where the proposed scheme is not adopted.

Deployment control of wireless multihop‐relay mobile robots based on voronoi partition

SummaryThis paper describes a new method for the deployment of wireless relay nodes. When using rescue robots in a building or underground city, radio signals are attenuated significantly, and therefore, multihop extension involving wireless communication relays is required. The goal of this research is to deploy wireless relay nodes to maintain connectivity between the base station and the leader robot that explores around the front line. To move the relay robot autonomously, a distributed algorithm is required.The proposed method is suitable when it is applied for wireless relay purposes. In this method, a virtual force drives a node to the centroid of Voronoi neighbors so that the connectivity of wireless communication is maintained. The proposed method is evaluated by conducting numerical simulations and experiments. In the simulation, one or two leader robots are assumed. In the experiment, a mobile robot equipped with omni‐wheels is used. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 184(4): 42–51, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22413

2P1-L03 無線ネットワーク中継のための自律移動ロボット群の配置制御(複数ロボットの協調制御)

This paper describes a new method for the deployment of wireless relay nodes. When using rescue robots in a building and a disaster, the radio signal is attenuated significantly, and therefore, multi-hop extension involving wireless communication relays is required. The goal of this research is to deploy wireless relay nodes to maintain connectivity between the base station and the leader robot that explores around the front line. To move the relay robots autonomously, a distributed algorithm is required. The proposed method is suitable when it is applied for wireless relay purposes. In the method, a elasticity used as a virtual force drives a node, and it will maintain the connection of wireless communication. The proposed method is evaluated by simulations and experiments. In the simulation analysis, the following motion to the leader robots is testified. The experiment using, mobile robots with omni-wheels verified the validity of the proposed method.

Deployment Control of Wireless Multi-Hop-Relay Mobile Robots Based on Voronoi Partition

This paper describes a new method for the deployment of wireless relay nodes. When using rescue robots in a building or underground city, the wireless radio signal is attenuated significantly, and therefore, multi-hop extension involving wireless communication relays is required. The goal of this research is to deploy wireless relay nodes to maintain connectivity between the base station and the leader robot that explores around the front line. To move the relay robot autonomously, a distributed algorithm is required.The proposed method is suitable when it is applied for wireless relay purposes. In the method, a virtual force drives a node to the centroid of Voronoi neighbors, and it maintains the connectivity of wireless communication. The proposed method is evaluated by conducting numerical simulations and experiments. In the simulation, one or two leader robots are assumed. In the experiment, a mobile robot equipped with omni-wheels is used.