Modeling of Flexible Beams for Robotic Manipulators

This work treats the problem of modeling robotic manipulators withstructural flexibility. A mathematical model of a planarmanipulator with a single flexible link is developed. This modelis capable of reproducing nonlinear dynamic effects, such as thebeam stiffening due to the centrifugal forces induced by therotation of the joints, giving it the capability to predictreliable dynamic behaviors for a wide range of applications. Onthe other hand, the model complexity is reduced, in order to keepit amenable for analysis and controller design. The models foundin current literature for control design of flexible manipulatorarms present dynamic limitations for the sake of real timeimplementation in a control scheme. These limitations are theresult of premature linearizations in the formulation of thedynamics equations. In this paper, these common linearizations arepresented and their dynamic limitations uncovered. An alternativereliable model is then presented. The model is founded on twobasic assumptions: inextensibility of the neutral fiber, andmoderate rotations of the cross sections in order to account forthe foreshortening of the beam due to bending. Simulation andexperimental results show that the proposed model has the closestdynamic behavior to the real beam.     

Image-Guided Robotic Flexible Needle Steering

This paper presents a robotic system for steering under real-time fluoroscopic guidance a flexible needle in soft tissue. Given a target and possible obstacle locations, the computer calculates the flexible needle-tip trajectory that avoids the obstacle and hits the target. Using an inverse kinematics algorithm, the needle base maneuvers required for a tip to follow this trajectory are calculated, enabling a robot to perform controlled needle insertion. Assuming small displacements, the flexible needle is modeled as a linear beam supported by virtual springs, where the stiffness coefficients of the springs can vary along the needle. Using this simplified model, the forward and inverse kinematics of the needle are solved analytically, enabling both path planning and path correction in real time. The needle shape is detected in real time from fluoroscopic images, and the controller commands the needle base motion that minimizes the needle tip error. This approach was verified experimentally using a robot to maneuver the base of a flexible needle inserted into a muscle tissue. Along the 40-mm trajectory that avoids the obstacle and hits the target, the error stayed below the 0.5-mm level. This study demonstrates the ability to perform closed-loop control and steering of a flexible needle by maneuvering the needle base so that its tip achieves a planned trajectory.     

基于本体的柔性工作流研究

工作流管理系统通常对工作流模型进行严格的定义.然而,现实情况却是工作流实例在运行过程中常常由于信息不足或者需要的资源不可用等诸多原因,而偏离预先的定义.因此,如何解决工作流实例运行过程中的路径选择问题成为当前研究的热点.本文以前人的研究成果为基础,提出了一个基于Ontology的柔性工作流执行框架.     

Adaptive Fuzzy Backstepping Tracking Control for Flexible Robotic Manipulator

In this paper, an adaptive fuzzy state feedback control method is proposed for the single-link robotic manipulator system. The considered system contains unknown nonlinear function and actuator saturation. Fuzzy logic systems (FLSs) and a smooth function are used to approximate the unknown nonlinearities and the actuator saturation, respectively. By combining the command-filter technique with the backstepping design algorithm, a novel adaptive fuzzy tracking backstepping control method is developed. It is proved that the adaptive fuzzy control scheme can guarantee that all the variables in the closed-loop system are bounded, and the system output can track the given reference signal as close as possible. Simulation results are provided to illustrate the effectiveness of the proposed approach.      

柔性制造系统非阻塞监督控制器优化设计

针对一类含有并发执行装配过程的柔性制造系统G-systems,提出一种新的死锁预防策略保证该系统的非阻塞性,即在控制下,受控系统从任意可达状态都可以到达理想状态.首先对Petri网模型中基本信标实施控制,保证了基本信标的最大可控,然后通过线性规划算法求取所有从属信标满足可控性的条件,即获得基本信标的控制深度变量.与现有方法相比,该策略优点在于只需加入少量的控制库所,就可避免不必要的迭代过程;其次是提出控制器输出弧位置优化策略,得到了结构更为简单、许可行为更多的非阻塞Petri网控制器.     

柔性制造单元的一种调度算法

本文提出了一种新的柔性制造单元的调度算法,它在离散周期控制的基础上加上事件中断以适应系统状态的随机干扰,在流控制中,我们不仅决定产品类型的混合比,同时决定每种工件在各加工路径的比。文中给出了一个制造单元的仿真结果,它表明了算法的有效性。     

柔性微服务监控框架

微服务细化了服务的粒度,针对微服务的监控是微服务管理需要面对的核心问题,以可扩展全链路应用服务监控为目标,在已有服务管理层之上设计实现了一种柔性微服务监控框架,用于监控微服务状态和不断变化的服务负载,与已有的分布式监控架构相比,这种监控框架灵活度更高,对服务变化的感知能力更强,使用Raft算法增强了数据一致性,避免了单点故障的情况,经试验分析,代价更小,在实际项目中验证了框架及方法的有效性.     

一种柔性Web展现框架模型

在Web2．0时代,越来越多的网站采用了动态脚本的方式和用户进行交互,大量客户端脚本的应用,造成了代码的可适应性、可维护性、可扩展性较差,无法兼容各种主流浏览器,页面之间的跳转仍然较多,资源的加载没有规则等问题,影响了应用性能和用户体验．提出了一种柔性Web展现框架模型FWF,构造了符合AJAX＋MVC模式的框架模型,定义了组件模型并通过策略适配器的驱动及事件机制,较好解决了软件适应性问题;对UI组件进行面向对象的封装,实现模型（Model）、视图（Ⅵew）和控制（Controller）的合理分层,并通过内置的资源加载规则,缩短资源加载时间,从而提升用户应用体验,通过OSGI框架的模块扩展机制实现了Web组件的可扩展．此外,通过原型实例实验证明了框架的柔性和性能．     

Moore Automata for the Supervisory Control of Robotic Manufacturing Workcells

The potential of flexible-manufacturing workcells (FMCs) to produce a family of parts in many possible orders of operations and choices of different machines is advantageous. Despite intensive research on the theoretical control of discrete-event systems (DESs), however, current techniques can still only be used for the supervisory control of simple cells. In this paper, a novel modeling and control synthesis technique is presented for FMCs that allow part-routing flexibility. Our proposed methodology combines Extended Moore Automata (EMA) and Controlled-Automata theories to synthesize supervisors for such FMCs.     

A digital-twin visualized architecture for Flexible Manufacturing System

The new generation of industrial 4.0 intelligent manufacturing system consists of Human-Cyber-Physical System (HCPS), integrating human with cyber and physical systems. In manufacturing, a digital-twin visualization architecture is to solve the human-machine interaction problem that concerns digital-twin modeling on the Cyber-Physical (C-P) side and on the Human-Cyber side. Although there are many related research and applications, there lacks attention in terms of full life cycle functional services and lightweight architecture. This paper presents a general architecture of digital-twin visualization for flexible manufacturing systems (FMS). How the digital-twin C-P modeling of multi-source heterogeneous information can be described is investigated and how the 3D visualized human-machine interaction with digital-twin scenario information is explored in the proposed architecture. Besides, the visualization method of high-value information, relating to the life cycle planning, design, debugging and service stages, is studied and discussed thoroughly. Also, a digital-twin modeling concept of "Geometric information (G)-Historical samples (H)-Object attribute (O)-Snapshot collection (S)-Topology constraint (T)" (GHOST) is proposed, and methods for developing virtual digital-twin scenes architecture are presented. Based on the proposed modeling concept of GHOST for digital-twin, prototypes have been developed for the general platform of digital-twin RESTful services and the cross-platform general visual mock-up software. Experimental results show that this method is effective in the FMS lifecycle in various aspects.     

柔性机器人的动力学建模及其控制*

本文首先综述了近年来在柔性机器人动力学建模方面所取得的进展，着重介绍了目前较常见的几种建模方法和模型，同时对柔性机器人的控制问题进行了评述，指出了今后研究的方向。     

面向IC制造的硅片机器人传输系统综述

介绍了面向集成电路制造业的硅片机器人传输系统,综述了其主要组成部分——硅片机器人和预对准装置——的工作原理及国内外研究成果．就直接驱动技术、磁性流体密封技术、磁力传动技术、硅片机器人轨迹规划与控制技术、校准技术以及夹持技术,对硅片机器人传输系统的关键技术进行了探讨．     

一种新的FMS混合调度算法

在综合一种新的Petri网模型以及另一种新的混合优化策略的基础上,提出了一种具有全局优化特征的PMS调度算法,最后,仿真结果验证了该算法的有效性以及良好的研究与应用前景。     

水泵叶轮焊接柔性生产单元的开发

焊接柔性生产单元由直角坐标机器人、垛机和机器视觉系统集成,直角坐标机器人执行零件上下料、焊枪抓取、焊接;垛机是加工零件的存储站;机器视觉系统负责叶轮焊接部位检测、焊点质量检测和焊枪钨针烧蚀状态检测。该柔性生产单元适用于各种型号叶轮的自动焊接。     

A Flexible Framework for Fault Tolerance in the Grid

This paper presents a failure detection service (FDS) and a flexible failure handling framework (Grid-WFS) as a fault tolerance mechanism on the Grid. The FDS enables the detection of both task crashes and user-defined exceptions. A major challenge in providing such a generic failure detection service on the Grid is to detect those failures without requiring any modification to both the Grid protocol and the local policy of each Grid node. This paper describes how to overcome the challenge by using a notification mechanism which is based on the interpretation of notification messages being delivered from the underlying Grid resources. The Grid-WFS built on top of FDS allows users to achieve failure recovery in a variety of ways depending on the requirements and constraints of their applications. Central to the framework is flexibility in handling failures. This paper describes how to achieve the flexibility by the use of workflow structure as a high-level recovery policy specification, which enables support for multiple failure recovery techniques, the separation of failure handling strategies from the application code, and user-defined exception handlings. Finally, this paper presents an experimental evaluation of the Grid-WFS using a simulation, demonstrating the value of supporting multiple failure recovery techniques in Grid applications to achieve high performance in the presence of failures.     

一个灵活的操作系统安全框架FMAC

当前,操作系统的安全需求越来越多样、灵活和具体,它们往往只描述系统中一小部分实体之问的约束,但对安全策略的灵活性厦定制的简洁性有较高的要求。传统的安全框架,如FLASK等,难于满足此类“轻量级”的安全需求。本文提出的FMAC框架专门面向此类安全需求,它定义了基于标记迁移系统LTS的安全策略模型,以规范和简化安全策略的定制。FMAC框架由通用的对象管理器模型和安全策略管理器模型组成。讨论了FMAC在Unix类操作系统中的实现,通过层次式的客体组织与基于角色的主体组织,普通用户可以方便快捷地定制出满足要求的轻量级安全策略。     

A Flexible Framework for Communication Evaluation in SoC Design

Multi-core System-on-Chips (SoCs) with on-chip networks are becoming a reality after almost a decade of research. One challenge in developing such SoCs is the need of efficient and accurate simulators for design space exploration. This paper addresses this need by presenting SoCExplore, a framework for fast communication-centric design space exploration of complex SoCs with network-based interconnects. Efficiency is achieved through abstraction of computation as a high-level trace, while accuracy is maintained through cycle-accurate interconnect simulation. The flexibility offered allows for fast partition/mapping and interconnect design space exploration. In a case study, a speed-up of 94% over architectural simulation is obtained for the MPEG application. A critical evaluation of the capabilities of our (or any trace based) framework is also provided.     

A Flexible Integration Framework for Semantic Web 2.0 Applications

The Semantic Web application framework extends Ruby on Rails to enable rapid development of integrated Semantic Web mash-ups. Web applications are mostly database driven. Developers design a database schema and then construct the application logic (which generates Web pages for user interaction) on top of the schema. These applications are centralized and rely on their own relational database, limiting the possibilities for data integration. Mash-ups (often called Web 2.0 applications) are an emerging Web development paradigm that combines functionality from different Web applications.     

A Framework for Automatic Generation of a Contact State Graph for Robotic Assembly

Dynamic manipulation of an active object is introduced as a general model of hopping and juggling tasks. In this setting, juggling and hopping are two extreme cases of this general model. Behavioral resemblance of these two tasks is afterwards extended to a detailed mathematical analogy between them. Then the analogy is exploited to develop a unified and abstract planning framework for juggling and hopping. To this end, dynamic manipulation of an active object is decomposed into three distinct phases and two transitions: Carry I, Free flight and Carry II phases. These phases are analogous to Lift off, Free flight and Touch down in hopping. In the next step, a mathematical model for each phase is developed. It is shown that dynamic grasp (in Carry phases of juggling) and foot stability (in Support phases of hopping) conditions share similar sets of dynamic equations. Accordingly, Lift off/Release and Touch down/Catch conditions in hopping/juggling are derived. It is shown that analogous strategies can be developed for Lift off and Release. The analogy is held for Touch down and Catch conditions as well. It is discussed that in the planning framework the initial and the goal configurations of the three phases are set in a model-based and forward manner. To do so, Touch down/Landing time, Free flight duration and robot/object maneuvers during Free flight are used as free parameters for planning in order to ensure foot stability in hopping and dynamic grasp in juggling along with other constraints.