Multiple Robot System Research Articles

Co-localization of Non-cooperative Targets Based on Multiple Space Robot System

According to the characteristics of relative measurement elements in the on-orbit servicing system with multiple space robots,a non-cooperative target co-localization strategy based on distributed filters is proposed.Firstly,the mission of non-cooperative target co-localization based on multiple space robots is defined,and a co-measurement model is also established.After that,a general expression of relative dynamics of multiple space robots is derived,and a centralized co-localization filter is designed.In order to reduce the computation load of iteration process in filtering,a co-localization method based on distributed filters is proposed.The stabilities of both filters are evaluated with linear system observability theory.Finally,a real-time semi-physical simulation system is established,and the co-location strategy based on distributed filters is simulated.The high stability and accuracy of the co-localization strategy are demonstrated by simulations.

Performance Optimisation of Mobile Robots for Search-and-Rescue

This paper presents a team performance optimisation system for multiple mobile robots in search-and-rescue operations, in which refugees are first discovered and subsequently robots are dispatched to transport themto shelters. Coordination of mobile robots involves two fundamental issues, namely task allocation and motion planning. While task allocation assigns jobs to robots, motion planning generates routes for robots to execute the assigned jobs. Task allocation and motion planning together play a pivotal role in optimisation of the robot team performance. These two issues become more challenging in dynamic search-and-rescue environments, where the refugees are unpredictably discovered at different locations and the traffic conditions of rescue zones keep changing. Weaddress these two issues by proposing an auction-based closed-loop module for task allocation and a bio-inspired intelligent module for motion planning. The task allocation module is characterised with a closed-loop bid adjustment mechanism to improve the bid accuracy even in light of stochastic rescue requests. The motion planning module is bio-inspired intelligent in that it features detection of imminent neighbours and responsiveness of virtual force navigation in dynamic traffic conditions. Simulations show that the proposed system is a practical tool to optimise the dynamic operations of search-and-rescue by a team of mobilerobots.

Research on Cooperation Localization and Mapping for Hoisting Multi-Robot System

According to the practical operation of the hoisting multi-mobile robots system (HMRS), the cooperation localization and mapping is studied. Firstly, an improved algorithm of cooperation localization solution of multiple robot system is proposed based on map gridding algorithm. In addition, by virtue of sensor technology, the grid method is designed, which has the ability of accurate, reliable localization and rapid local mapping of the HMRS. Finally, simulation results demonstrate that the localization and mapping system is feasible and efficient.

A proposal of experimental education system of mechatronics

Recently, many studies on educational system are being conducted. In this manuscript, a unique education system is proposed for mechanical engineers to be able to efficiently learn basic mechatronics techniques. The system is composed of three subsystems. The first subsystem is used to learn input/output port operations, periodically LED lights ON/OFF and a stepping motor control. The second subsystem is effective to learn AD transformation for several sensor information, DA transformation for DC motor control and a PID control method. Further, the third subsystem is multiple mobile robots system to learn the subsumption architecture for schooling behavior. The effectiveness of the proposed systems was confirmed through experimental instructions in Tokyo University of Science, Yamaguchi.

Position synchronised control of multiple robotic manipulators based on integral sliding mode

In this study, a new position synchronised control algorithm is developed for multiple robotic manipulator systems. In the merit of system synchronisation and integral sliding mode control, the proposed approach can stabilise position tracking of each robotic manipulator while coordinating its motion with the other manipulators. With the integral sliding mode, the proposed approach has insensitiveness against the lumped system uncertainty within the entire process of operation. Further, a perturbation estimator is proposed to reduce chattering effect. The corresponding stability analysis is presented to lay a foundation for theoretical understanding to the underlying issues as well as safely operating real systems. An illustrative example is bench tested to validate the effectiveness of the proposed approach.

Shared Control : Balancing Autonomy and Human Assistance with a Group of Quadrotor UAVs

Robustness and flexibility constitute the main advantages of multiple-robot systems with respect to single-robot ones as per the recent literature. The use of multiple unmanned aerial vehicles (UAVs) combines these benefits with the agility and pervasiveness of aerial platforms [1], [2]. The degree of autonomy of the multi-UAV system should be tuned according to the specificities of the situation under consideration. For regular missions, fully autonomous UAV systems are often appropriate, but, in general, the use of semiautonomous groups of UAVs, supervised or partially controlled by one or more human operators, is the only viable solution to deal with the complexity and unpredictability of real-world scenarios as in, e.g., the case of search and rescue missions or exploration of large/cluttered environments [3]. In addition, the human presence is also mandatory for taking the responsibility of critical decisions in high-risk situations [4].

Closed-Curve Path Tracking for Decentralized Systems of Multiple Mobile Robots

In this paper we address the problem of making a group of mobile robots cooperatively track an assigned path. We consider paths described by completely arbitrarily shaped closed curves. The proposed control strategy is a fully decentralized algorithm and it does not require any global synchronization. The desired behavior is obtained by means of some properly designed artificial potential functions. Analytical proofs are provided to show the asymptotic convergence of the system to the desired behavior. Matlab simulations and experiments on real robots are described as well for validation purposes.

입력 제한을 가진 추종 로봇을 고려한 선도 로봇 제어기

This paper proposes controller of leader robot considering following robot with input constraints based on leader-following approach. In the previous formation control researches, it was assumed that leader and follower is same object. If leader robot drives as maximum speed that the initial position errors still remain even if following robot have same velocity as a leader. In the situation that velocity of following robot is lower than its leader robot, following robot cannot follow leader robot. Furthermore, the following robot will not be able to made formation with leader robot and keep proximity communication or sensing range. Therefore, multiple mobile robot system using leader-following method should be guaranteed range to get information each other. In this paper, Leader robot is driving to goal position using linear controller and following robot is following trajectory to be made from leader robot. We assume that following robot has input constraints to realize different performance between leader robot and following robot. We design controller of leader robot for desired goal position including the errors between formation and following robot. Thus, we propose leader robot controller considering input constraints of following robot. Finally, we were able to confirm the validity of the proposed method based on simulation results.

행동기반 다개체 로봇 시스템을 이용한 환경감시 알고리즘

This paper proposes an environment monitoring algorithm using a behavior-based multiple robot system. This paper handles an escort and a boundary-tracking especially. Unlike previous research works, the proposed environment monitoring system which is based on the behavior-based multiple robot control allows the system to employ the reusable code and general algorithm. Also, the proposed method can be applied to cheaper process with low performances. In the proposed method, escort and boundary-tracking missions are constructed by weighted sum of predefined basic behaviors after redefining the basic behaviors in previous works and introducing the novel basic behavior. Simulation results of the proposed method are included to demonstrate the practical application of the proposed algorithm.

Discrete Event Net Based Modeling and Control System Design for Real-Time Concurrent Control of Multiple Robot Systems

This paper deals with control system design and implementation problems encountered in multiple robot systems. The methodology developed is depicted by a set of coordination mechanisms using hierarchical net structures and their accompanying rules. With the net models, the hierarchical and distributed control system is designed for an assembly task. Synchronization commands allow coordination of the movements of the robots. The net models make concurrency of the movements of the robots transparent to users. The net based machine controller executes robot motion control through the communication with the external robot controller using the command/response concept. Sensory signals indicating the change of state of robots are used to trigger or initiate tasks. Simultaneous movement of the robots is obtained by creating different background threads running in parallel under Windows OS. The multilevel hierarchical control system can be consistently constructed using net models.

Modeling and Distributed Implementation of Synchronization and Coordination in Multi-Robot Systems

This paper deals with control system design and implementation problems encountered in multiple robot systems. A systematic method of constructing hierarchical net models is described for their direct implementation such that the net is translated into the detailed net by stepwise refinements from the highest task specification level to the lowest machine control level. Basic Petri nets are extended as a prototyping tool for expressing real-time control of robotic systems based on command response concept. The hierarchical and distributed coordinators are introduced to perform the synchronization and coordination of the robots and other machines in the system. The proposed method allows a direct coding of the inter-task cooperation from the net specification and can be implemented using off–the-shelf real-time executives.

Information Sharing System for Multiple Mobile Robots using IC Tags

This paper discussed an information sharing system for multiple mobile robots using IC tags. In our system, the multiple mobile robots share the environmental information using IC tags. It is necessary for intelligent mobile robot to recognize the environmental information around the robot. The IC tag is very useful device for getting the environmental information around the robot. We developed the mobile robot which is equipped an IC tag reader/writer with an antenna, a laser rangefinder and a PC. We use the laser rangefinder in order to detect the collision-free space around the robot. The mobile robots write and read the information to the IC tag and share the environmental information each other. This mobile robot moves according to the information from the IC tags. The effectiveness of our system is demonstrated by several experimental results.

Consensus Formation Control for a Class of Networked Multiple Mobile Robot Systems

A consensus-based formation control for a class of networked multiple mobile robots is investigated with a virtual leader approach. A novel distributed control algorithm is designed based on the Lyapunov method and linear matrix inequality (LMI) technique for time delay systems. A multiple Lyapunov Krasovskii functional candidate is proposed for investigating the sufficient conditions to linear control gain design for the system with constant time delays. Simulation results as well as experimental studies on Pioneer 3 series mobile robots are shown to verify the effectiveness of the proposed approach.

Research on Multi-Robot Cooperation Capture Based on Virtual Reality Technology

This paper researches on cooperation capture for mobile multi-robots. We use finite state machine principle to do research on cooperation capture for mobile multi-robots. Meanwhile this paper uses virtual reality technology to simulate the multi-robot operation stalking, namely, produces a realistic external environment and multiple mobile robot system by using computer technology, makes multi-robot system cooperation stalking consistent with the actual environment in virtual 3D environment. Researchers and observers can use their own sensory systems or some corresponding control equipment for generating virtual system which were observed and interacted.

Cooperative Path Planning and Constraints Analysis for Master-Slave Industrial Robots

A strategy of cooperative path planning for a master-slave multiple robot system is presented in this paper. The path planning method is based on motion constraints between the end-effectors of cooperative robots. Cooperation motions have been classified into three types by relative motions between end-effectors of master and slave robots, which is concurrent cooperation, coupled synchronous cooperation and combined synchronous cooperation. Based on this classification, position /orientation constraints and joint velocity constraints are explored in-depth here. In order to validate the path planning method and the theoretical developments in motion constraints analysis, representative experiments based on two industrial robots, Motoman VA1400 and HP20, are provided at the end of the paper. The experimental results have proved both the effectiveness of the path planning method and the correctness of the constraints analysis.

Multiple Objective Robot Coalition Formation

Abstract In multiple robot systems, the problem of allocation of complex tasks to heterogeneous teams of robots, also known as the multiple robot coalition formation problem, has begun to receive considerable attention. Efforts to address the problem range from heuristics based approaches that search the subspaces of the coalition structure to evolutionary learning approaches. Conventional approaches typically strive to optimize a single objective function such as the number of tasks executed or the time required to execute all tasks, or a weighted function of such objectives. In real world applications, objectives such as minimizing distance traveled and maximizing the number of tasks completed are often conflicting in nature. The coalition formation problem thus naturally lends itself to a multi-objective optimization approach based on evolutionary learning. In this paper, we formulate the problem of mapping coalitions of robots to a set of tasks as a multi-objective optimization problem and propose a variant of non-dominated sorting genetic algorithm (NSGA-II) to arrive at trade-off solutions. Additionally, we extend the solution to domains where robot resources are non-additive. Simulations demonstrate the efficacy of the proposed approach in generating the set of Pareto-optimal solutions.

Multi-EKF Localization Algorithm for Multi-Robots Formation Navigation

This research presents a dynamic multi-robots formation navigation algorithm named multi-EKF localization algorithm, which derived from single EKF. In this algorithm, all formation members are treated as landmarks with known association. When the formation is running, the traditional EKF is used for individual robot to get its own localization, and the proposed multi-EKF is used to get the position of the whole formation. By calculating the joint probability distribution, the mean and covariance of the formation position are achieved, which is used to guide and constrain the individual robot localization adjustment. With this method, the multiple mobile robots system shows more stable and robust on formation navigation. The simulation and physical experiment results show the feasibility, efficiency and stability of the proposed algorithm.

Laser-based geometrical modeling of large-scale architectural structures using co-operative multiple robots

For the construction of 3-D shape models of large-scale architectural structures using laser range finders, a number of range images are taken from different viewpoints around the targets. Next, the obtained images are normally aligned by post-processing procedures, such as the ICP algorithm. However, to obtain convergent results in the ICP algorithm and align these range images to their proper positions, the initial position of each range image needs to be manually aligned to roughly the correct position. This paper proposes a new measurement and modeling system using a group of multiple robots and an on-board laser range finder. Each measurement position is identified by a highly precise positioning technique called the Co-operative Positioning System (CPS), which utilizes the characteristics of the multiple-robot system. Therefore, the proposed system can construct 3-D shapes of large-scale architectural structures without any post-processing procedure or manual intervention. In addition, it is possible to register range images even if the number of measurements is few and there are only a few range images, for example, due to range images containing insufficient feature shapes or overlapping regions. Measurement experiments in unknown and large indoor/outdoor environments including a large hall, a building, an urban district, and a cultural heritage have been successfully carried out using the newly developed measurement system consisting of three mobile robots named CPS-V. Path generation experiments of the mobile robots based on the partially measured 3-D model are also presented.

A PATH PLANNING METHOD BASED ON CELLULAR AUTOMATA FOR COOPERATIVE ROBOTS

A Cellular Automaton-based technique suitable for solving the path planning problem in a distributed robot team is outlined. Real-time path planning is a challenging task that has many applications in the fields of artificial intelligence, moving robots, virtual reality, and agent behavior simulation. The problem refers to finding a collision-free path for autonomous robots between two specified positions in a configuration area. The complexity of the problem increases in systems of multiple robots. More specifically, some distance should be covered by each robot in an unknown environment, avoiding obstacles found on its route to the destination. On the other hand, all robots must adjust their actions in order to keep their initial team formation immutable. Two different formations were tested in order to study the efficiency and the flexibility of the proposed method. Using different formations, the proposed technique could find applications to image processing tasks, swarm intelligence, etc. Furthermore, the presented Cellular Automaton (CA) method was implemented and tested in a real system using three autonomous mobile minirobots called E-pucks. Experimental results indicate that accurate collision-free paths could be created with low computational cost. Additionally, cooperation tasks could be achieved using minimal hardware resources, even in systems with low-cost robots.

Low-pass-filter-based position synchronization sliding mode control for multiple robotic manipulator systems

In this study, a novel low-pass-filter-based position synchronization sliding mode control (PSSMC) approach is developed for the operation of multiple robotic manipulator systems (MRMSs). In terms of system synchronization theory and the sliding mode control (SMC) principle, the proposed approach can stabilize position tracking of each robotic manipulator while coordinating its motion with other robotic manipulators. By application of a low-pass filter, the chattering of the robotic manipulator system with SMC can be eliminated. A corresponding stability analysis is presented to lay a foundation for theoretical understanding of the underlying issues as well as safely operating real systems. An illustrative example is bench tested to validate the effectiveness of the proposed approach.