Multiple Robot System Research Articles

Reinforcement learning-based group navigation approach for multiple autonomous robotic systems

In several complex applications, the use of multiple autonomous robotic systems (ARS) becomes necessary to achieve different tasks, such as foraging and transport of heavy and large objects, with less cost and more efficiency. They have to achieve a high level of flexibility, adaptability and efficiency in real environments. In this paper, a reinforcement learning (RL)-based group navigation approach for multiple ARS is suggested. Indeed, the robots must have the ability to form geometric figures and navigate without collisions while maintaining the formation. Thus, each robot must learn how to take its place in the formation, and avoid obstacles and other ARS from its interaction with the environment. This approach must provide ARS with the capability to acquire the group navigation approach among several ARS from elementary behaviors by learning with trialand-error search. Then, simulation results display the ability of the suggested approach to provide ARS with capability to navigate in a group formation in dynamic environments. With its cooperative behavior, this approach makes ARS able to work together to successfully fulfill the desired task.

Self Generating Task Assignment Algorithm for Multiple Mobile Robot in Transportation Task

Multiple mobile robot system under decentralized control has become more popular because of advantage of fault tolerance and extensibility. This paper focuses on a planning method for an interactive transportation task by multiple mobile robot system. In this task, task assignment is important to solve interaction among mobile robots. In this paper, we propose the self-generating task assignment algorithm in order to realize efficient sorting task. First, we considered parallelism in transportation task. Second, we defined variable of “Progress” in order to estimate value of tasks which can execute independently and in parallel. Using Progress, robots can select executable parallel task and generate task assignment based on efficiency. We developed multi-robot simulator and multi robot system in order to verify the effectiveness.

2A1-E19 強化学習を用いた自律移動ロボット群における衝突回避行動獲得

This research proposes a collision avoidance system which is essential in a Distributed Multiple Robot System. In a real environment, it is impossible to apply a Distributed Multiple Robot System unless robots realize to avoid not only the static obstacles they recognise but also unknown obstacles and moving objects. To realize avobe, it is necessary for robots to plan pathes on demand. In this research, robots acquire their own policies in trial-and-error using machine learning for multiagent system dealing with uncertainty. In order to verify the effectiveness of the proposed system, simulator experiments are conducted in several distinctive initial settings. It is shown that some good results of the experiment are obtained up to the four robots meeting together.

A Multi-Agent System for Distributed Control of Networked Mobile Robots

The development of the Internet has provided many opportunities for academic and industrial practitioners to reexamine, extend and adapt existing control architectures in novel ways. One of the significant benefits the Internet has provided is the availability of widely accessible, cost-effective and standardised mechanisms for inter-computer communication. Because of this the Internet has allowed the development of globally based distributed computing architectures, allowing in the field of robotics the development of Internet robot systems1 in which remote robot functionality is made available to users anywhere in the world via a standard web-browser. The Internet and development of standardised Internet protocols have not only made global functionality possible, but have also allowed the increased development of smaller scale distributed systems. Internet protocols and networking functionality can be applied to allow reliable, structured, cost-effective communication to be implemented in systems which may previously have relied on bespoke radio-based solutions. During the period in which Internet technologies have developed, increased interest has been shown in robotics to the development and implementation of multiple robot architectures. This is because relative to single robot architectures, multiple robot architectures can allow improved system performance, task enablement, distributed sensing, distributed action at a distance, and fault tolerance2. Internet technologies have also led to increased interest in distributed computing architectures, with recent years seeing in addition to traditional Client/Server, Remote Computation, and Code on Demand Architectures, the development of an additional distributed computing architecture, Mobile Agents. Mobile agents may offer advantages in the structuring of multiple computing and multiple robot architectures. So far, however, little research has been conducted to examine their potential application and potential benefits in this domain. Research we are conducting at the University of Essex is aimed to examine the potential uses and application of mobile agents in the multiple robot domain, specifically within networked multiple robot systems, in which robots can communicate via Internet-based protocols and make use of Internet-based hardware and software. Through this examination we aim to highlight areas in which mobile agents might be effectively applied, and discover the benefits architectural implementations using this distributed computing architecture might provide. This paper is used to describe the current progress of our investigation. The remainder of the paper attempts to highlight areas in which the use of mobile agents in this domain can be beneficial, through a theoretical/practical examination of mobile agents compared to other distributed computing architectures for multiple robot control. The next section introduces a definition for mobile agents, and an execution environment. It also includes a comparison with traditional distributed computing architectures. This is followed by a brief description of a mobile agent/multiple robot development environment. We describe mobile agent based control systems we have developed. Then experimental results are given. Finally we provide some conclusions and a description of future work.

Mobile agent approach to networked robots

Mobile agents provide the functionality of all other distributed computing paradigms in a unified environment and enables a natural design philosophy for distributed computing systems. These properties can provide multiple-robot system developers with a wide range of options for initial development and future extension of their systems, and an intuitive and robust design environment. In this paper, we present two examples to show how, by taking advantage of these properties, the adaptability and fault-tolerance of a multiple-robot architecture (the ALLIANCE architecture) can be extended in multiple networked robots.

Analysis of internal loading at multiple robotic systems

When multiple robotics systems with several sub-chains grasp a common object, the inherent force redundancy provides a chance of utilizing internal loading. Analysis of grasping space based internal loading is proposed in this work since this method facilitates understanding the physical meaning of internal loadings in some applications, as compared to usual operational space based approach. Investigation of the internal loading for a triple manipulator has been few as compared to a dual manipulator. In this paper, types of the internal loading for dual and triple manipulator systems are investigated by using the reduced row echelon method to analyze the null space of those systems. No internal loading condition is derived and several load distribution schemes are compared through simulation. Furthermore, it is shown that the proposed scheme based on grasping space is applicable to analysis of special cases such as three-fingered and three-legged robots having a point contact with the grasped object or ground.

A three-level net formalism for the modeling of multiple mobile robot systems

This paper explores qualitative modelling of multiple mobile robot systems. The approach held is Petri net (PN)-based: A definition of a three-level net system in which the tokens may be PNs, called 3LNS, is presented. The formalism allows the definition of net modules at three levels; the interaction among modules is described through transition synchronization. Furthermore a modelling methodology using 3LNS is proposed; the upper level describes the robots, environment, the next level models the general behaviour of the mobile robots, and the third level represents specific features of each robot namely mission, tasks, and roadmaps; at this level resources and robot interaction protocols are also described. The use of 3LNS is illustrated through a case study regarding a mobile robot community evolving into a structured environment.

1P2-S-027 知識ベース拡張進化型群知能ロボットシステムの研究 : 知識の共有による知能の均一化の研究(複数ロボットの協調制御,生活を支援するロボメカ技術のメガインテグレーション)

1P2-S-027 知識ベース拡張進化型群知能ロボットシステムの研究 : 知識の共有による知能の均一化の研究(複数ロボットの協調制御,生活を支援するロボメカ技術のメガインテグレーション)

1P2-S-029 階層型群構造をもったロボットシステムによる協調作業(複数ロボットの協調制御,生活を支援するロボメカ技術のメガインテグレーション)

1P2-S-029 階層型群構造をもったロボットシステムによる協調作業(複数ロボットの協調制御,生活を支援するロボメカ技術のメガインテグレーション)

공동 작업하는 다중 로봇 시스템의 동적 조작도

공동 작업하는 다중 로봇 시스템의 동적 조작도

Real-time cooperative collision avoidance method of multiple mobile robots

In a previous study, the authors have proposed the Cooperative Collision Avoidance (CCA) method. The method extended the Velocity Obstacle to multiple mobile robot systems by introducing the concept of the Common Velocity Obstacle, and achieved cooperative collision avoidance among multiple mobile robot systems without supervisor or communication. The problem of the method was the enormous computation caused by the high dimensional search, and two improved CCA method are introduced in this paper. The first method transforms the search structure from a massive monolithic search into two separate light searches and this leads to significant reduction of the computation from O(a4) to O(a2), where a is the resolution of the search. The second method solves the search analytically by applying an assumption that every robot has a direction oriented objective. The effectiveness of the two methods are confirmed by the computer simulations.

On robot-borne extended object tracking using the em algorithm

High precision tracking of all surrounding objects is a prerequisite to the autononious/senii-autononious management of multiple mobile robot systems. This task comprises not only tracking of moving objects, but also detection of obstacles or other stationary objects. We demonstrate that Expectation-Maximization applied to multiple object tracking is a promising method being flexible enough to handle the problems typical of robot-borne tracking, such as extended objects, dense object environment, mutual occlusions. Observations and preliminary conclusions based on simulated and real sensor data are discussed.

Cooperative Control Algorithm for Object Transportation by Multiple Robot System with a Pushing Leader

Cooperative Control Algorithm for Object Transportation by Multiple Robot System with a Pushing Leader

A geometric approach to single and multiple robot control

This paper describes the control of single and multiple robot teams in the framework of Hilbert spaces. For single robots the control problem is defined in terms of the convergence between the set of feasible velocities, defined by the robot kinematics, and the set of goal velocities, defined by the mission specifications and environment data acquired along the mission. The convergence between these velocity sets is obtained by chosing a set of controls leading to a decrease in the distance between them. This distance is measured through the use of a monotonic and non-expansive projection map.Team control is approached through the definition of neighboring relationships among the teammates, to be preserved along the mission. Each robot monitors these relationships for relevant changes and adapts its motion to the rest of the team according to a negotiation procedure supervised by a finite state automaton. Simulation results on single and multiple cart robot systems are presented.

Solving function distribution and behavior design problem for cooperative object handling by multiple mobile robots

This paper addresses the function distribution and behavior design problem for a multirobot system which incorporates a behavior-based dynamic cooperation strategy for object handling. The proposed multiple robot system is composed of a managing robot and homogeneous behavior-based robots. The cooperation strategy in this system is realized in two steps: designing the distributed robot's cooperative behavioral attributes according to the robot's abilities, and organizing these behavioral attributes so that team cooperation is realized. For indicating an incremental style of local behavior construction, an advanced design of cooperative behavior for coping with unknown disturbance is addressed. Additionally, two extended cooperation strategies designed for a path tracking task are described. These three strategies are based on the same concept on performing manipulation in coordination. Therefore, by considering the function distribution among the managing robot and worker robots, and considering behavior design of each worker robot, the proposed system is able to achieve the object handling task with different performances according to the task requirement, such as with or without path tracking and with or without contact with the environment. Experimental results demonstrate the applicability of the proposed system.

LOGUE: an architecture for task and behavior object transmission among multiple autonomous robots

This paper proposes a new communication and control architecture which improves the capability and the flexibility of multiple autonomous robot systems in performing a complicated task and coping with unpredictable situations. This system treats robot’s information as a Behavior Element Object (BEO) and a Task Object (TO) in terms of Object Oriented paradigm. Both BEO and TO can be serialized, so they can be communicated among the robots and behavior server system in the network. The action manager module, device module, and some checking mechanisms are also designed for executing new TO or BEO sent from other robots or a server system. A simulation and basic experiments are presented for a situation of robots’ relief for an emergency purpose.

Multiple manipulator control from a human motor-control perspective

The human motor-control system has a hierarchical and decentralized structure, and building such a control system for a multiple robot system would require a decomposed model. The difficulty in decomposing complex robotic systems is due to interactions between robots, and the paper proposes a control architecture that controls the manipulator joints and interactions separately. A decomposable model for an N - n degrees-of-freedom multimanipulator/object system handling an object is derived. This model is then used to design a Lyapunov-based fuzzy logic controller for the system by solving linear matrix equalities. It is shown that this controller is closed-loop stable and a stable suboptimal controller for the system may be designed using bounds.

Practical stability of multiple robot manipulators in contact tasks

Practical stability of multiple robots for compliant manipulation on dynamic enviroments is addressed in this paper. The complete dynamic model of multiple robots holding a dynamic object is presented. The control task is specified as a task of practical stability of multiple robots around the nominal robot trajectories. An adaptive control law composed of an identification part (parameter update law), and a control law part is synthesized. It has the inverse dynamics controller structure. The test condition for the practical stability of the multiple robots system with the proposed adaptive control law is derived.

2A1-3F-C5 群ロボットシステムにおける群体の保持と移動に関する研究

2A1-3F-C5 群ロボットシステムにおける群体の保持と移動に関する研究

MACROSCOPIC QUANTITATIVE OBSERVATION OF MULTI-ROBOT BEHAVIOR

In observing behavior of multiple autonomous robots, a microscopic observation expressed by dynamic equations is usually used. However, it is very difficult to estimate behavior of robots or mutual interactions among them in real time. Furthermore, it is hard to realize the observed system by taking consideration in all the factors of the system. On the other hand, a macroscopic observation defined by state equations is efficient for recognizing behavior of multiple robots. In this study, a quantitative observation approach is proposed on behavior of multiple robots. This approach introduces macroscopic state quantities in thermodynamics into expression of the multiple robots system. The advantage of this approach is that observation on the behavior of autonomous robots in real world can be mapped to characteristic quantities in another conceptual state space. At first, the state quantities of multiple robots system are defined and their physical meaning is discussed regarding it as quantitative observation of multiple robots. The macroscopic state quantities in thermodynamics, such as temperature, pressure and entropy, are introduced into mobile robots system. Each mobile robot is regarded as a particle in term of thermodynamic systems. Experiments show that the states of robots system can be classified from a viewpoint of the macroscopic state quantities in thermodynamics. This verifies that the macroscopic quantitative observation is efficient and applicable to controlling multiple robots system.