可重构制造系统可重构逻辑控制器设计与实现

针对可重构制造系统的逻辑控制问题,提出一种可重构逻辑控制器的解决方案．该逻辑控制器具有递阶分布式的控制体系结构,并根据模块化的设计思想设计成多个分离的功能模块．然后给出基于CORBA组件模型(CCM)的可重构逻辑控制器软件的开发过程．由递阶分布式体系、模块化设计和软件组件开发技术实现的可重构逻辑控制器具有快速动态重构的能力,能满足可重构制造系统逻辑控制的要求．     

Dynamic Analysis and Distributed Control of the Tetrobot Modular Reconfigurable Robotic System

Reconfigurable robotic systems can be adapted to different tasks or environments by reorganizing their mechanical configurations. Such systems have many redundant degrees of freedom in order to meet the combined demands of strength, rigidity, workspace kinematics, reconfigurability, and fault tolerance. In order to implement these new generations of robotic system, new approaches must be considered for design, analysis, and control. This paper presents an efficient distributed computational scheme which computes the kinematics, dynamics, redundancy resolution, and control inputs for real-time application to the control of the Tetrobot modular reconfigurable robots. The entire system is decomposed into subsystems based on a modular approach and Newton's equations of motion are derived and implemented using a recursive propagation algorithm. Two different dynamic resolution of redundancy schemes, the centralized Jacobian method and the distributed virtual force method, are proposed to optimize the actuating forces. Finally, distributed dynamic control algorithms provide an efficient modular implementation of the control architecture for a large family of configurations.     

Modular machine tools: Design and barriers to industrial implementation

The Reconfigurable Manufacturing System (RMS) paradigm has been developed to address challenges in the design of manufacturing systems and equipment that will meet the demands of modern manufacturing. This research involved the development of Modular Reconfigurable Machines (MRMs); as an emerging technology in reconfigurable manufacturing. MRMs are mechanically modular machines. The modularity permits the kinematic architecture and processing functions of the machine to be reconfigured to meet changing production requirements. This paper will focus on aspects of the mechanical design and the development of a control system that supported the modularity and reconfigurability of the mechanical platform. A modular electronic system is presented that is characterized by a plug and play approach to control scalability. This is complemented by a software architecture that has been developed with a focus on hardware abstraction for the management of an augmented mechanical and electronic architecture. The implications of MRMs for RMSs are discussed and key inhibitors to industrial implementation are identified.     

控制面故障下的飞机运动建模与重构控制能力分析及设计

对控制面故障影响飞机运动的机理进行了推导,系统地阐述了控制面故障下的飞机运动建模方法。在建模的基础上,对故障系统的可重构性进行研究。分别从线性系统运动和物理运动两个方面,给出了可重构能力的评定方案。推导了误差反向传播的前向神经网络用于控制系统设计时满足Lyapunov稳定性的学习算法,提出了一种新型的采用反向传播神经网络补偿常规控制器的重构飞行控制设计方案。采用非线性飞机运动模型对控制器进行了仿真,验证了重构飞行控制器的性能。     

An approach to regulating machine sharing in reconfigurable back-end semiconductor manufacturing

By complying with the operational philosophy of virtual production lines, a back-end semiconductor manufacturing system can be controlled and managed with better reconfigurability. However, due to the absence of a fully-integrated information system and the gaining popularity of distributed computing, machine reconfiguration decisions are made by machine controllers on the shop floor where heterarchical control architecture is typically used. This research investigates how non-cooperative game theory could be applied for facilitating the decision process reconfiguration decision-making at the machine controller level as machines are competed by multiple jobs streams. This paper presents how material flow traffic can be better regulated in a reconfigurable manufacturing environment. A study using an industrial pilot system is discussed to demonstrate the applicability of the proposed approach, in which heuristics are used to determine the game specification.     

Configuration selection for reconfigurable control of piecewise affine systems

In this paper, the problem of configuration selection, i.e. sensor/actuator placement for piecewise affine (PWA) systems subject to both sensor and actuator faults is considered. A method is proposed that provides a tool for the design phase to decide about the optimal placement of sensor/actuators where the reconfigurability of the system subject to sensor and actuator faults is also taken into account. Using a lattice of possible configurations (sensor/actuator placements), the reconfigurability of the system subject to faults for each configuration is evaluated and based on that one can draw conclusions about the reconfigurability of the system and the optimal configuration in the architecture design phase. A reconfigurable control must ensure stability of the reconfigured system and, if possible, a graceful degradation in the performance. Therefore, in the proposed reconfigurability analysis, we consider both stabilisability and performance of the system. The efficiency of the proposed method is demonstrated in several numerical examples.     

A process-driven computing model for reconfigurable semiconductor manufacturing

Reconfigurability is essential for semiconductor manufacturing systems to remain competitive. Reconfigurable systems avoid costly modifications required to change and adapt to changes in product, production and services. A fully automated, collaborative, and integrated while reconfigurable manufacturing system proves cost-effective in the long term and is a promising strategy for the semiconductor manufacturing industry. However, there is a lack of computing models to facilitate the design and development of control and management systems in a truly reconfigurable manner. This paper presents an innovative computing model for reconfigurable systems and controlled manufacturing processes while allowing for the integration of modern technologies to facilitate reconfiguration, such as radio frequency identification (RFID) and reconfigurable field programmable gate array (FPGA). Shop floor manufacturing activities are modeled as processes from a business perspective. A process-driven formal method that builds on prior research on virtual production lines is proposed for the formation of a reconfigurable cross-facility manufacturing system. The trajectory of the controlled manufacturing systems is optimized for on-demand production services. Reconfigurable process controllers are introduced in support of the essential system reconfigurability of future semiconductor manufacturing systems. Implementation of this approach is also presented.     

DPP: An agent-based approach for distributed process planning

A changing shop floor environment characterized by larger variety of products in smaller batch sizes requires creating an intelligent and dynamic process planning system that is responsive and adaptive to the rapid adjustment of production capacity and functionality. In response to the requirement, this research proposes a new methodology of distributed process planning (DPP). The primary focus of this paper is on the architecture of the new process planning approach, using multi-agent negotiation and cooperation. The secondary focus is on the other supporting technologies such as machining feature-based planning and function block-based control. Different from traditional methods, the proposed approach uses two-level decision-making—supervisory planning and operation planning. The former focuses on product data analysis, machine selection, and machining sequence planning, while the latter considers the detailed working steps of the machining operations inside of each process plan and is accomplished by intelligent NC controllers. By the nature of decentralization, the DPP shows promise of improving system performance within the continually changing shop floor environment.     

An integrated approach for remote manipulation of a high-performance reconfigurable parallel kinematic machine

Flexible and effective manipulation is important and meaningful for the further development and applications of parallel manipulators in the industrial fields, especially for high-performance manufacturing. Web-based manufacturing has emerged as an alternative manufacturing technology in a distributed environment. In this paper, an integrated approach is proposed for remote manipulation of the reconfigurable parallel kinematic machine (RPKM) based on sensor-driven Wise-ShopFloor framework. The concept of Wise-ShopFloor integrates the modules of detailed architecture design, module interactions, sensor data utilization and model predictive control. In order to demonstrate the efficiency of this novel methodology, an example of a five degrees-of-freedom (DOF) RPKM is developed for surface finishing. The reconfigurability, the necessary kinematic analysis, and the performance mapping of the 5-DOF RPKM are conducted so as to implement the proposed approach.     

考虑时间特性影响的控制系统可重构性定量评价方法研究

故障诊断时间和控制重构延时严重影响了控制系统的实际重构性能,然而目前缺乏相关研究.基于该现状,本文针对执行器快变偏差故障,重点考虑时间特性影响,结合能量与输入约束,对控制系统可重构性的定量评价问题展开了研究.首先,以基于观测器的故障诊断算法和控制重构方案为例,建立了重构系统模型;然后,以该模型为对象,通过对重构过程中关键时刻的分析,深入研究了系统故障后的动态特性,并综合考虑故障引起的状态偏差、资源浪费以及诊断误差,设计了用于描述故障系统性能下降程度的二次型性能指标;其次,利用Lyapunov稳定性理论,定量求解了性能指标关于时间的一般表达式,进而求得该指标在整个时域中的最优解;最后,基于最优性能指标,引入了可重构度的概念,实现了对控制系统可重构性的理论判定以及定量描述,并通过数值仿真验证了所提可重构性分析方法的有效性.     

Guest Editors' Introduction: Intelligent Control in the Manufacturing Supply Chain

In recent years, a major thrust in addressing the requirements of adaptivity and responsiveness for manufacturing control has been the application of tools from distributed artificial intelligence. These tools can be called intelligent control systems. Typically, these tools are adaptable to a changing environment; resilient to disturbance; distributed, in the sense that typically more than one decision-making element exists; and dynamic in decision making. They range from modeling tools such as neural networks, fuzzy logic, and evolutionary programming to new distributed forms of manufacturing control and management systems. Of particular importance are multiagent-based manufacturing control and management systems. Such approaches bring new features of flexibility and easy reconfigurability to industrial-control solutions. These features result from agent-based systems' basic properties such as a high degree of autonomy for decision-making units, the ability to communicate complex messages asynchronously, the capability to negotiate and cooperate, and, mainly, the ability to achieve complex global goals without a central decision element.     

The role of the customer order decoupling point in production and supply chain management

In order to compete successfully, operations in any type of firm need to be strategically aligned to the market requirements. This concerns both manufacturing and supply chain operations. The customer order decoupling point (CODP) is getting increasing attention as an important input to the design of manufacturing operations as well as supply chains. This paper investigates the impact of the position and role of the CODP on issues of concern for production and supply chain management. The focus is on the design and strategic planning aspects of the supply chain, and the design of manufacturing planning and control systems. The paper proposes a dual design approach for production and supply chain planning systems; one type of system for operations upstream the CODP and another type of system for downstream operations in order to fully support the characteristics and objectives of each respective part of the supply chain.     

Digital microfluidics: is a true lab-on-a-chip possible?

The suitability of electrowetting-on-dielectric (EWD) microfluidics for true lab-on-a-chip applications is discussed. The wide diversity in biomedical applications can be parsed into manageable components and assembled into architecture that requires the advantages of being programmable, reconfigurable, and reusable. This capability opens the possibility of handling all of the protocols that a given laboratory application or a class of applications would require. And, it provides a path toward realizing the true lab-on-a-chip. However, this capability can only be realized with a complete set of elemental fluidic components that support all of the required fluidic operations. Architectural choices are described along with the realization of various biomedical fluidic functions implemented in on-chip electrowetting operations. The current status of this EWD toolkit is discussed. However, the question remains: which applications can be performed on a digital microfluidic platform? And, are there other advantages offered by electrowetting technology, such as the programming of different fluidic functions on a common platform (reconfigurability)? To understand the opportunities and limitations of EWD microfluidics, this paper looks at the development of lab-on-chip applications in a hierarchical approach. Diverse applications in biotechnology, for example, will serve as the basis for the requirements for electrowetting devices. These applications drive a set of biomedical fluidic functions required to perform an application, such as cell lysing, molecular separation, or analysis. In turn, each fluidic function encompasses a set of elemental operations, such as transport, mixing, or dispensing. These elemental operations are performed on an elemental set of components, such as electrode arrays, separation columns, or reservoirs. Examples of the incorporation of these principles in complex biomedical applications are described.     

Extending process automation systems with multi-agent techniques

This paper presents a design of a process automation system extended with multi-agent systems (MAS) and experiments with its implementation. According to this design, MAS can be used to extend the functionality of ordinary process automation systems at higher levels of control. Anticipated benefits of this include enhanced reconfigurability, responsiveness and flexibility of the resulting automation system. The design also takes into account particular characteristics of process automation. An agent platform for process automation is presented as a basis for applying MAS. A FIPA-compliant agent platform is extended with process automation specific functionality. The platform utilizes a hierarchical agent organization and a BDI-agent model. Two applications are implemented using the platform. One of these shows how the techniques of distributed planning can be applied in discrete control. The other provides a model for supervisory continuous control using the techniques of distributed search. Experiments performed with a laboratory test environment using the applications are presented. They are able to demonstrate the feasibility of the approach in test scenarios.     

Self-reconfigurable software architecture: Design and implementation

To respond quickly to the rapidly changing manufacturing environment, it is imperative for the system to have such capabilities as flexibility, adaptability, and reusability. The fractal manufacturing system (FrMS) is a new manufacturing paradigm designed to meet these requirements. To facilitate a dynamic reconfiguration of system elements (i.e., fractals), agents as well as software modules should be self-reconfigurable. Embodiment of a self-reconfigurable manufacturing system can be achieved by using self-reconfigurable software architecture. In this paper, therefore, self-reconfigurable software architecture is designed by conducting the following studies: (1) analysis of functional requirements of a fractal and environmental constraints, (2) design of reconfigurable software architecture especially for a reconfigurable agent, (3) selection of proper techniques to implement software modules, and realization of software architecture equipped with self-reconfigurability. To validate this approach, the designed architecture is applied to the FrMS.     

Robust formation control of multiagent systems on the Lie group SE(3)

This paper addresses the robust formation control problem of multiple rigid bodies whose kinematics and dynamics evolve on the Lie group SE(3). First, it is assumed that all followers have access to the state information of a virtual leader. Then, a novel adaptive super‐twisting sliding mode control with an intrinsic proportional‐integral‐derivative sliding surface is proposed for the formation control problem of multiagent system using a virtual structure (VS) approach. The advantages of this control scheme are twofold: elimination of the chattering phenomenon without affecting the control performance and no requirement of prior knowledge about the upper bound of uncertainty/disturbance due to adaptive‐tuning law. Since the VS method is suffering from the disadvantages of centralized control, in the second step, considering a network as an undirected connected graph, we assume that only a few agents have access to the state information of the leader. Afterward, using the gradient of modified error function, a distributed adaptive velocity‐free consensus‐based formation control law is proposed where reduced‐order observers are introduced to remove the requirements of velocity measurements. Furthermore, to relax the requirement that all agents have access to the states of the leader, a distributed finite‐time super‐twisting sliding mode estimator is proposed to obtain an accurate estimation of the leader's states in a finite time for each agent. In both steps, the proposed control schemes are directly developed on the Lie group SE(3) to avoid singularity and ambiguities associated with the attitude representations. Numerical simulation results illustrated the effectiveness of the proposed control schemes.     

Distributed plantwide control based on differential dissipativity

Modern chemical plants are becoming very complex, often consisting of a number of nonlinear process units (subsystems) with strong interactions due to material recycle and energy integration. The operation setpoint may need to be adjusted from time to time based on the market demand. To address the aforementioned challenges, a plantwide distributed nonlinear control scheme based on differential dissipativity is proposed in this paper, which can ensure plantwide incremental exponential stability and achieve bounded incremental L₂ gain performance. As a non‐unique property, the differential dissipativity of individual subsystem is shaped by a setpoint‐independent control structure – differential state feedback control. The dissipativity properties of subsystems and individual controllers are determined simultaneously as a large‐scale feasibility problem to ensure the plantwide stability and performance. It is converted into an LMI condition for plantwide supply rate planning and small‐scale sum‐of‐squares programming problems for individual subsystem dissipativity shaping, by using the alternating direction method of multipliers method. The proposed approach is illustrated using a chemical reactor network with a recycle stream. Copyright © 2016 John Wiley & Sons, Ltd.     

Zeus: A toolkit for building distributed multiagent systems

The multiagent systems approach of knowledge- level cooperation between autonomous agents promises significant benefits to distributed systems engineering, such as enhanced interoperability, scalability, and reconfigurability. However, thus far, because of the innate difficulty of constructing multiagent systems, this promise has been largely unrealized. Hence there is an emerging desire among agent developers to move away from developing point solutions to point problems in favor of developing methodologies and toolkits for building distributed multiagent systems. This philosophy led to the development of the ZEUS Agent Building Toolkit, which facilitates the rapid development of collaborative agent applications through the provision of a library of agent- level components and an environment to support the agent-building process. The ZEUS toolkit is a synthesis of established agent technologies with some novel solutions to provide an integrated collaborative agent-building environment.     

Evolution in architectures and programming methodologies of coarse-grained reconfigurable computing

In order to meet the increased computational demands of, e.g., multimedia applications, such as video processing in HDTV, and communication applications, such as baseband processing in telecommunication systems, the architectures of reconfigurable devices have evolved to coarse-grained compositions of functional units or program controlled processors, which are operated in a coordinated manner to improve performance and energy efficiency.In this survey we explore the field of coarse-grained reconfigurable computing on the basis of the hardware aspects of granularity, reconfigurability, and interconnection networks, and discuss the effects of these on energy related properties and scalability. We also consider the computation models that are being adopted for programming of such machines, models that expose the parallelism inherent in the application in order to achieve better performance. We classify the coarse-grained reconfigurable architectures into four categories and present some of the existing examples of these categories. Finally, we identify the emerging trends of introduction of asynchronous techniques at the architectural level and the use of nano-electronics from technological perspective in the reconfigurable computing discipline.