Network-based reconfiguration routes for a self-reconfigurable robot

This paper presents a network-based analysis approach for the reconfiguration problem of a self-reconfigurable robot. The self-reconfigurable modular robot named ＂AMOEBA-I＂ has nine kinds of non-isomorphic configurations that consist of a configuration network. Each configuration of the robot is defined to be a node in the weighted and directed configuration network. The transformation from one configuration to another is represented by a directed path with nonnegative weight. Graph theory is applied in the reconfiguration analysis, where reconfiguration route, reconfigurable matrix and route matrix are defined according to the topological information of these configurations. Algorithms in graph theory have been used in enumerating the available reconfiguration routes and deciding the best reconfiguration route. Numerical analysis and experimental simulation results prove the validity of the approach proposed in this paper. And it is potentially suitable for other self-reconfigurable robots＇ configuration control and reconfiguration planning.     

Graph-based optimal reconfiguration planning for self-reconfigurable robots

The goal of optimal reconfiguration planning (ORP) is to find a shortest reconfiguration sequence to transform a modular and reconfigurable robot from an arbitrary configuration into another. This paper investigates this challenging problem for chain-type robots based on graph representations and presents a series of theoretical results: (1) a formal proof that this is an NP-complete problem, (2) a reconfiguration planning algorithm called MDCOP which generates the optimal graph-based reconfiguration plan, and (3) another algorithm called GreedyCM which can find a near-optimal solution in polynomial time. Experimental and statistical results demonstrate that the solutions found by GreedyCM are indeed near-optimal and the approach is computationally feasible for large-scale robots.     

Configuration representation and reconfiguration optimization for the reconfigurable robots with independent manipulation

Single module of the reconfigurable robots with independent manipulation can perform the actions of locomotion and manipulation. In conformity with the request for achieving autonomous operation in the unstructurized environment instead of fixed operation in the structurized environment, these robots are applied in the complicated and dangerous environment. The existing researches on the configuration theory focus on the reconfigurable robots with limited locomotion and the ones with independent locomotion, not being applicable to the reconfigurable robots with independent manipulation. The vector configuration is put forward, the research content of which contains the topology and locomotion direction of configuration, the posture and orientation and connection relation between modules. Module state vector and configuration state matrix are proposed for representation methodology for the swarm configuration of these reconfigurable robots, which supports transformation operation to represent and trigger behavior motion of the module and reconfiguration between configurations. Optimization algorithm of assembly reconfiguration applying workload as the optimization target is presented, as well as optimization algorithm of transformation reconfiguration applying the integration of posture orientation workload and connection workload. The result of optimization is the relation of state transformation between the initial configuration and the object one as the basic of reconfiguration plan and control. Supported by the National High-Tech Research and Development Program of China (Grant No. 2006AA04Z254) and the Scientific Research Fund for Doctor of Liaoning Provice (Grant No. 20071007)     

工业机器人的分布式控制系统设计

介绍了通用型工业机器人分布式控制系统的设计方案，总结了工业机器人控制系统设计所必须考虑的问题。分析说明：工业机器人分布式控制系统是一种比较理想的快速实时控制系统。     

ModRED: Hardware design and reconfiguration planning for a high dexterity modular self-reconfigurable robot for extra-terrestrial exploration

This paper presents a homogeneous modular robot system design based on four per-module degrees of freedom (DOF), including a prismatic DOF to increase the versatility of its reconfiguration and locomotion capabilities. The ModRED (Modular Robot for Exploration and Discovery) modules are developed with rotary-plate genderless single sided docking mechanisms (RoGenSiD) that allow chain-type configurations and lead towards hybrid-type configurations. Various locomotion gaits are simulated through the Webots robot simulator and implemented in the real ModRED system. This work also addresses the problem of dynamic reconfiguration in a modular self-reconfigurable robot (MSR). The self-reconfiguration problem is modeled as an instance of the graph-based coalition formation problem. We formulate the problem as a linear program that finds the “best” partition or coalition structure among a set of ModRED modules. The technique is verified experimentally for a variety of settings on an accurately simulated model of the ModRED robot within the Webots robot simulator. Our experimental results show that our technique can find the best partition with a reasonably low computational overhead.     

分布式系统动态配置技术的研究与实现

动态配置技术用于系统运行时刻改变系统配置,从而满足分布式系统对在线演化的需求。如何保证系统一致性,并尽可能提高动态配置性能,是动态配置研究需要解决的关键问题。本文提出了行为一致性,并将系统一致性总结为行为一致性、构件状态一致性、应用状态一致性和引用一致性。通过扩展静止状态理论,本文提出了采用等待方式和阻塞方式驱动构件进入静止状态的算法,保证了行为一致性。通过分析动态配置意图,本文提出了保证系统一致性的动态配置算法,确定了采用等待方式和阻塞方式的动态配置场景,从而在严格保证行为一致性的前提下,尽可能地提高了动态配置性能。最后,本文基于 CCM 构件平台实现了动态配置平台。性能测试的结果表明,该平台可满足应用对性能的要求。     

Distributed Control for 3D Metamorphosis

In this paper, we define Proteo as a class of three-dimensional (3D) metamorphic robotic system capable of approximating arbitrary 3D shapes by utilizing repeated modules. Each Proteo module contains embedded sensors, actuators and a controller, and each resides in a 3D grid space. A module can move itself to one of its open neighbor sites under certain motion constraints. Distributed control for the self-reconfiguration of such robots is an interesting and challenging problem. We present a class of distributed control algorithms for the reconfiguration of Proteo robots based on the goal-ordering mechanism. Performance results are shown for experiments of these algorithms in a simulation environment, and the properties of these algorithms are analyzed.     

支持动态配置的分布式程序设计模型

分布式系统的动态配置问题近年来引起了各国研究者的广泛关注.该文对面向图结构的分布式程序设计模型GOM(graph-oriented model)进行了扩充和改进,提出了支持动态配置的程序设计模型ExGOM(extended graph-oriented model).ExGOM提供了多种基于图结构的配置操作.用户可在配置文件中描述系统结构的动态变化,也可在程序中利用配置操作进行动态配置.这一特性使得系统可支持不可预计的动态配置.文章还给出了以多Agent机制实现ExGOM的系统结构.     

低复杂度重构在分布式实时数据密集型Web服务架构中的应用

针对下一代分布式实时系统在重构时实时性要求较高的问题,本文提出了一种降低系统图复杂度并在有限时间内重构的方法。首先,利用服务组合确保重构在有限时间内实现;然后,通过路径选择算法和路径发送算法对图进行实时剪裁;最后,引入图构建算法消除具有更多非可调度路径的服务实现来降低图的复杂度。在iLAND服务重构和组合组件内部验证了本文方法,实验结果表明,本文方法能够显著减少解空间,大大减少了重构过程的计算时间。     

Mobile robot navigation by a Distributed Vision System

This paper proposes aDistributed Vision System (DVS), which is an intelligent infrastructure for mobile robots consisting of manyvision agents (VAs) embedded in an environment. The system monitors the environment from various viewing points with the VAs, maintains the dynamic environment models, and provides various information to robots. Based on this concept, we have developed a prototype of the DVS which consists of sixteen vision agents and simultaneously navigates two robots in a model town.     

Hormone-Inspired Self-Organization and Distributed Control of Robotic Swarms

The control of robot swarming in a distributed manner is a difficult problem because global behaviors must emerge as a result of many local actions. This paper uses a bio-inspired control method called the Digital Hormone Model (DHM) to control the tasking and executing of robot swarms based on local communication, signal propagation, and stochastic reactions. The DHM model is probabilistic, dynamic, fault-tolerant, computationally efficient, and can be easily tasked to change global behavior. Different from most existing distributed control and learning mechanisms, DHM considers the topological structure of the organization, supports dynamic reconfiguration and self-organization, and requires no globally unique identifiers for individual robots. The paper describes the DHM and presents the experimental results on simulating biological observations in the forming of feathers, and simulating wireless communicated swarm behavior at a large scale for attacking target, forming sensor networks, self-repairing, and avoiding pitfalls in mission execution.     

Distributed nonlinear control of mobile autonomous multi-agents

This paper studies the distributed nonlinear control of mobile autonomous agents with variable and directed topology. A new distributed nonlinear design scheme is presented for multi-agent systems modeled by double-integrators. With the new design, the outputs of the controlled agents asymptotically converge to each other, as long as a mild connectivity condition is satisfied. Moreover, the velocity (derivative of the output) of each agent can be restricted to be within any specified neighborhood of the origin, which is of practical interest for systems under such physical constraint. The new design is still valid if one of the agents is a leader and the control objective is to achieve leader-following. As an illustration of the generality and effectiveness of the presented methodology, the formation control of a group of unicycle mobile robots with nonholonomic constraints is revisited. Instead of assuming the point-robot model, the unicycle model is transformed into two double-integrators by dynamic feedback linearization, and the proposed distributed nonlinear design method is used to overcome the singularity problem caused by the nonholonomic constraint by properly restricting the velocities. Simulation results are included to illustrate the theoretical results.     

A performance optimization algorithm for controller reconfiguration in fault tolerant distributed model predictive control

This paper presents a performance optimization algorithm for controller reconfiguration in fault tolerant distributed model predictive control for large-scale systems. After the fault has been detected and diagnosed, several controller reconfigurations are proposed as candidate corrective actions for fault compensation. The solution of a set of constrained optimization problems with different actuator and setpoint reconfigurations is derived by means of an original approach, exploiting the information on the active constraints in the non-faulty subsystems. Thus, the global optimization problem is split into two optimization subproblems, which enable the online computational burden to be greatly reduced. Subsequently, the performances of different candidate controller reconfigurations are compared, and the better performing one is selected and then implemented to compensate the fault effects. Efficacy of the proposed approach has been shown by applying it to the benzene alkylation process, which is a benchmark process in distributed model predictive control.     

Crystalline Robots: Self-Reconfiguration with Compressible Unit Modules

We discuss a robotic system composed of Crystalline modules. Crystalline modules can aggregate together to form distributed robot systems. Crystalline modules can move relative to each other by expanding and contracting. This actuation mechanism permits automated shape metamorphosis. We describe the Crystalline module concept and show the basic motions that enable a Crystalline robot system to self-reconfigure. We present an algorithm for general self-reconfiguration and describe simulation experiments.     

Distributed control of simulated autonomous mobile robot collectives in payload transportation

A behavior-based control paradigm that allows a distributed collection of autonomous mobile robots to control the lifting and lowering processes of payload transportation is proposed and then tested with computer simulations. This control paradigm, which represents an approach to solving the cooperative load-bearing problem inherent in multi-agent payload transportation, is based upon a control structure we term thebehavior pathway controller. The behavior pathway controller emphasizes simple, feasible methodologies over complex, optimal methodologies, although we show that with some global self-organization of the collective, the feasible solutions approach and become optimal solutions. Using this controller in simulated environments, our robots demonstrate an ability to function with inaccurate sensor data, which is an important consideration for real world implementations of an autonomous mobile robot control paradigm. The simulated robots also demonstrate an ability to learn their place, or role, within the collective. They must learn their relative roles because they possess no predetermined knowledge about pallet mass, pallet inertia, collective size, or their positions relative to the pallet's center of gravity.     

面向服务软件的蜕变测试方法

在面向服务软件的测试过程中,由于在服务发现之前不可知的交互对象和同一个服务可能会有不同实现,往往出现程序执行结果不能提前预知的Oracle问题。为了有效地解决面向服务软件测试中的Oracle问题,基于面向服务架构(SOA)的特点,提出将蜕变测试方法用于面向服务软件的单元测试和集成测试过程中,依据面向服务软件每个服务的自身性质构造蜕变关系,设计蜕变测试类执行测试用例并验证蜕变关系是否保持,如果蜕变关系被违反了,则发现和报告缺陷,从而有效地支持面向服务软件的测试。     

A distributed perception infrastructure for robot assisted living

This paper presents an ambient intelligence system designed for assisted living. The system processes the audio and video data acquired from multiple sensors spread in the environment to automatically detect dangerous events and generate automatic warning messages. The paper presents the distributed perception infrastructure that has been implemented by means of an open-source software middleware called NMM. Different processing nodes have been developed which can cooperate to extract high level information about the environment. Examples of implemented nodes running algorithms for people detection or face recognition are presented. Experiments on novel algorithms for people fall detection and sound classification and localization are discussed. Eventually, we present successful experiments in two test bed scenarios.     

Smart monopole antenna with pattern and frequency reconfiguration characteristics based on programmable metasurface

Metasurfaces having ultrathin and planar structure with sub‐wavelength unit cell, have recently gained significant potential for use thanks to their control capabilities over the electromagnetic waves from microwave to the visible range. The structure and the dimensions of the sub‐wavelength elements determine the electromagnetic properties, capabilities, and functionalities of the metasurfaces providing a full control of the reflected and transmitted fields and these metasurfaces are referred to as analog metasurfaces. When adjustability is added to the unit cells, programmable or digital metasurfaces are obtained, allowing us to take multiple unique functionality advantages controlled by external stimuli. In this study, we propose a metasurface structure, also known as 1‐bit coding metasurface, which is controlled depending on the “On/Off” state. The “On/Off” state is controlled by a computer program using genetical algorithm. Depending on the operating state, electromagnetic waves can be manipulated and different functionalities of the metasurfaces can be realized. The contribution and innovation of the study is the demonstration of the beam rotation, resonance frequency shift and radiation pattern reconfiguration properties of a simple monopole antenna by using controllable metasurface composed of T shaped resonator and circular patch with an operating frequency between 4.3 and 5.6 GHz.     

一种面向软件体系结构的动态重配置方法*

通过在整个软件生命周期建立开发模型,研究了当前软件工程与实际需求之间差异。利用基于XML的中间脚本,提出一种事务处理软件开发模型,实现用户功能需求到表单流、事件流和数据流的转换,动态重配置出不同应用的事务处理软件。建立了企事业信息综合事务处理系统开发平台,分析了平台体系结构和中间脚本,表明可以根据业务变化进行整个系统功能重组而不需要编写一句程序,验证了该模型的可行性和有效性。