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This paper discusses the distributed connected coverage problem for a group of mobile agents in 3-dimensional space and with limited-range interactions. A self-deployment algorithm is proposed, which spreads out the agent group while preserving some special core structures of the time-variant communication topologies. It should be pointed out that the core structure keeps the connectivity of the communication...
In this paper we discuss the estimation of a moving target by cooperative agents equipped with sensors. To locate a moving target, a distributed algorithm is given for the networked agents based on a time-based shift. A nonlinear filter with fusing collected sensor information is proposed to estimate the trajectory of the target with unknown dynamics. The convergence of the estimation in the sensor...
In this paper, we develop decentralized control to drive a swarm of mobile agents into a moving target region while avoiding collisions among themselves. This is achieved with the help of target potential functions and collision avoidance potential functions in Lyapunov synthesis. A basic control framework is designed on a kinematic model. There are neither requirements for pre-specified desired trajectories...
This paper presents a decentralized method to the problem of multiple unmanned aerial vehicles (UAVs) cooperative search of an unknown area. Firstly, based on search map model, the multiple UAVs cooperative search problem is posed as a receding horizon (RH) optimization decision problem, and a RH based UAV search decision process is proposed. Then, this centralized online optimization problem is partitioned...
In this paper, we consider finite-time tracking problems of a moving target by multiple mobile agents. The mobile agents with global sensing areas and limited actuation region are designed to track down a target with estimation error with the help of formation and coverage. In order to capture the target, its location and velocity are first estimated. With observer-based estimation and formation control,...
The experimental implementation and validation of a localization system based on a heterogeneous sensor network is described. The sensor network consists of ultrasound ranging sensors and Web cameras. They are used to localize a mobile robot under sensor communication constraints. Applying a recently proposed sensor fusion algorithm that explicitly takes communication delay and cost into account,...
The primary focus of this work is to design and implement a robust automatic flight control system for a smallscale unmanned helicopter. A comprehensive nonlinear model for the unmanned system, which is constructed by our research team at the National University of Singapore, is first derived and presented. Based on its linearized model, a robust automatic flight control system is then designed by...
This paper presents a fault detection and diagnosis (FDD) method for unmanned ground vehicles (UGVs) operating in multi agent systems. The hierarchical FDD method consisting of three layered software agents is proposed: Decentralized FDD (DFDD), centralized FDD (CFDD), and supervisory FDD (SFDD). Whereas the DFDD is based on modular characteristics of sensors, actuators, and controllers connected...
This paper presents a design of simultaneous localization and mapping (SLAM) for an omni-directional mobile robot using an omni-directional camera. A method is proposed to realize visual SLAM of the omni-directional mobile robot based on extended Kalman filter (EKF). Taking advantage of the 360deg view of omni-directional images, visual reference scan approach is adopted in the SLAM design. Features...
With an accurate estimate of the robot pose, robots will be capable of navigating in the environment autonomously and efficiently. In this paper, an infrastructure comprises of simultaneous camera calibration and robot localization is presented. The presented approach utilizes particle filter that integrates odometry data from robot and images captured from overhead cameras in the environment to localize...
In this paper, we develop a method to realize an autonomous periodic motion of a small blimp system in a horizontal plane. The idea behind the method is to make the dynamics of a small blimp system approach asymptotically to that of the van der Pol equation that has a limit cycle. The method consists of the following two steps: First, we introduce two constraints. One has a role to connect the motion...
Image motion due to self motion is an important cue biological systems use for gathering information about the environment. The motion energy model is commonly used to model the responses of motion selective neurons in the mammalian primary visual cortex. Here, we investigate the hypothesis that these low level responses are directly useful for navigation. This avoids the need for estimating a model...
Most existing flocking algorithms assume one single virtual leader and rely on information about both relative positions and relative velocities among neighboring agents. In this paper, we investigate the problem of controlling a flock of mobile autonomous agents to follow multiple virtual leaders using only position information in the sense that agents with the same virtual leader asymptotically...
In this paper, we propose a behavior selection scheme between a reactive motion control combined with a global path planning algorithm and combined with a trajectory tracking algorithm. We design two navigation behaviors. One is a plan-based reactive navigation behavior, the AutoMovereactive, which exploits the conventional Dynamic Window Approach (DWA) as the reactive motion controller. The other...
This paper presents a novel approach on the implementation of the concept of ldquovirtual pheromonesrdquo for use in controlling autonomous mobile robots. Rather than being deployed in the environment, the virtual pheromones are stored in a map of the environment maintained and updated by a ldquopheromone serverrdquo. This map acts like a shared memory for all the agents, by means of a radio communication...
This paper describes an experiment aimed to demonstrate that a distributed system of embedded microcontrollers, wherein a number of control modules are located on the mobile robot, while others are deployed in an “intelligent environment” can significantly reduce the cost of developing a robotic assistant for the elderly and disabled. The structure of the experimental setup is described in detail,...
This paper addresses a closed-loop control for a mobile robot in navigation. The sonar-based obstacle avoidance algorithm utilizes a region partition strategy by analyzing three forward sensory regions and finds out a navigable region candidate. A probabilistic motion model and the Monte Carlo method are used to estimate the robot pose. The supervisor inside the controller makes a decision to allow...
Complete coverage path planning is a key problem for autonomous mobile robot, which concerns both efficiency and completeness of coverage. This paper proposed a novel strategy of combined coverage path planning method, which combines the template-based and the heuristic coverage path planning. The template-based mode allows the robot to run under some predefined motion templates which can realize...
Even though many researchers have studied spherical mobile robots, a robot with an elastic external frame can hardly be in the literature. Therefore in this study the pendulum-driven spherical mobile robot is introduced. The external frame of the robot is designed as glass fiber sticks which show good elastic characteristics. All control modules, such as a Zigbee wireless communication module and...
In this paper, least squares support vector machine (LS-SVM) based motion control and obstacle avoidance of a mobile robot are proposed under measured data with uncertainty. The proposed scheme can control the mobile robot by using a potential field function, where the potential field function is based on Lyapunov function candidate. The Lyapunov function candidate includes a flat plane, the flat...
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