Sherman Y. T. Lang

Reconfigurable manufacturing systems: the state of the art

In this paper, general requirements of next generation manufacturing systems are discussed, and the strategies to meet these requirements are considered. The production paradigms which apply these strategies are also classified. Particular emphasis is put on the paradigm of Reconfigurable Manufacturing System (RMS). Some key issues of the RMS design are discussed, and a critical review is presented concerning the developments of RMSs. Finally, suggestions of the RMS research are made and future research directions are identified.

iShopFloor: an Internet-enabled agent-based intelligent shop floor

Global competition is driving manufacturing companies to change the way they do business. New kinds of shop floor control systems need to be implemented for these companies to respond quickly to changing shop floor environments and customer demands. This paper presents a new concept called iShopFloor-an intelligent shop floor based on the Internet, web, and agent technologies. It focuses on the implementation of distributed intelligence in the manufacturing shop floor. The proposed approach provides the framework for components of a complex control system to work together as a whole rather than as a disjoint set. It encompasses both information architecture and integration methodologies. The paper introduces the basic concept of iShopFloor, a generic system architecture, and system components. It also describes the implementation of eXtensible Markup Language message services in iShopFloor and the application of intelligent agents to distributed manufacturing scheduling. A prototype environment is presented, and some implementation issues are discussed.

Distributed device networks with security constraints

In todays globalized business world, outsourcing, joint ventures, mobile and cross-border collaborations have led to work environments distributed across multiple organizational and geographical boundaries. The new requirements of portability, configurability and interoperability of distributed device networks put forward new challenges and security risks to the systems design and implementation. There are critical demands on highly secured collaborative control environments and security enhancing mechanisms for distributed device control, configuration, monitoring, and interoperation. This paper addresses the collaborative control issues of distributed device networks under open and dynamic environments. The security challenges of authenticity, integrity, confidentiality, and execution safety are considered as primary design constraints. By adopting policy-based network security technologies and XML processing technologies, two new modules of Secure Device Control Gateway and Security Agent are introduced into regular distributed device control networks to provide security and safety enhancing mechanisms. The core architectures, applied mechanisms, and implementation considerations are presented in detail in this paper.

A Java 3d-enabled cyber workspace

Along with the browser paradigm, Java has fundamentally changed the work environment, helping produce compelling applications for collaborating over the Internet.

Integrated Design Toolbox for Tripod-Based Parallel Kinematic Machines

This paper presents a concept and implementation of a toolbox for design and application of tripod-based parallel kinematic machines (PKMs). The toolbox is a suite of design tools to support users from conceptual design to actual application of tripod-based PKMs. These design tools have been individually developed in different languages and development environments, and are integrated seamlessly using a JAVA-based platform. Users can access all the design tools through a friendly graphical user interface (GUI). It is the first computer-aided design system specially developed for tripod-based PKMs. The toolbox includes some innovative methodologies, such as a forward kinematics solver, the concept of joint workspace, on-line monitoring based on forward kinematics, and the concept of motion purity. The paper gives an overview on the toolbox architecture and some key technologies.

Parallel Kinematic Machines: Design, Analysis and Simulation in an Integrated Virtual Environment

Selecting a configuration for a machine tool that will best suit the needs of a forecast set of requirements can be a difficulty and costly exercise. This problem can now be addressed using an integrated virtual validation system. The system includes kinematic/ dynamic analysis, kinetostatic model, CAD module, FEM module, CAM module, optimization module and visual environment for simulation and collision detection of the machining and deburring. It is an integration of the parallel kinematic machines (PKM) design, analysis, optimization and simulation. In this paper, the integrated virtual system is described in detail; a prototype of a 3-dof PKM is modeled, analyzed, optimized and remote controlled with the proposed system. Some results and simulations are also given. Its effectiveness is shown with the results obtained by NRC-IMTI during the design of the 3-dof NRC PKM.

A Web-based collaborative workspace using Java 3D

The paper presents a framework for building Web-based collaborative workspaces using the latest Java technologies-Java 3D, JavaServer Page (JSP), and Java Servlet. This Web-based approach allows designers, engineers and production managers to share a common workspace that can be used for design review, production monitoring, remote control, and troubleshooting, based on a set of interactive Java 3D models that represent the physical world with common interests. Following a brief overview of the related research work, the paper discusses the Java 3D concept from its scene graph structure to behavior control, and explains our approach to building Web-based collaborative workspaces using Java 3D. The proposed framework uses the popular client-server architecture and view-control-model design pattern with a secured session control. Control logic and the interfaces, which interact with the real world, are handled by an application server through servlets. The benefits enabled by the framework include reduced network traffic, increased flexibility of remote monitoring, interactive control, Web-based synchronous collaboration and quick response. It also shows significant potential for various Web-based real-time and distributed applications.

Wise-ShopFloor: a web-based and sensor-driven shop floor environment

Targeting the remote monitoring and control of shop floors, this paper proposes a new framework called Wise-ShopFloor Web-based integrated sensor-driven e-Shop Floor that can be applied to distributed manufacturing environments. It utilizes the latest Java technologies (Java 3D and Java Servlet) as enabling technologies for system implementation. This web-based framework allows users to monitor and control a distant shop floor device using Java 3D models instead of cameras. The behavior of a 3D model is driven by sensor signals of its physical counterpart. The goal of this research work is to eliminate network traffic, while still providing end users with intuitive environments.

Graph theoretic modeling and analysis of multibody planar mechanical systems

A methodology of modeling and analysis of planar mechanical systems is developed based on graph theoretic methods, with improvements in component models. The system model based on cutset and circuit topologies is used to derive a new hybrid cutset-circuit method of formulation of the equations of motion for planar systems. Computer-aided formulation is based on analysis of the substitution procedure mandated by the hybrid cutset-circuit formulation. A new graphical representation of the formulation process is introduced: substitution graphs. No special programming is needed for computer-aided formulation which can be achieved in a symbolic form using the off the shelf Maple symbolic mathematics system. Symbolic formulation requires only inputting the systems equations in an order and form as derived from the analysis of the hybrid formulation. An algorithm for symbolic formulation using Maple is given. A compact set of differential-algebraic equations results, which can be solved numerically. Some simple systems will result in closed-form solutions. A number of examples are given to illustrate the modeling and formulation. Numerical solutions are also given to demonstrate the effectiveness and correctness of the formulation procedure.

Improved control and simulation models of a tricycle collaborative robot

The objective of collaborative manufacturing is to create the synergism from the collaboration of manufacturing resources. Most of the studied collaborations are made among intelligent machines; however, the collaboration can be realized even between machines and human being, and a collaborative robot (Cobot) belongs to the latter. A cobot is a robot designed to assist human beings as a guide or assistor in a constrained motion. Various prototypes have been developed and the potentials of these robots have been demonstrated. The research presented in this paper focuses on the control and simulation models of a tricycle cobot with three steered wheels, with the following two contributions: (i) A concise model for the closed-loop control is developed. Existing closed-loop control has been implemented in an intuitive way, and some control parameters have to be determined by a trial-and-error method. (ii) A simulation model is proposed to validate the control algorithms. No simulation model is available and the control models of other existing systems have to be validated experimentally. The developed control and simulation models have been implemented. Graphic simulation is also developed. Case studies are provided and the simulation results are analyzed.