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Herein, we report a binder-free, low-cost and high performance cathode for lithium-oxygen batteries based on carbon black BP2000 decorated Ni(OH)2 nanoflakes array on Ni foam. The Ni(OH)2 nanoflakes array is fabricated by hydrothermal treatment of Ni foam in acidic medium without nickel salt. The highly organized structure of Ni(OH)2 nanoflakes array provides a more uniform distribution of catalysts and discharge products, resulting in high capacity with a relatively stable cycling voltage profile. The cathode outputs a discharge capacity as high as 12400 mAh gcarbon −1 at 160 mA gcarbon −1, which is 244% higher than that of BP2000 decorated Ni foam electrode without Ni(OH)2 nanoflakes array. The cathode can sustain 100 cycles under a capacity limitation of 320 mAh gcarbon −1 with high energy efficiency (∼67%). Our work points out the key issues and suggests an effective method for the surface modification technology.

A fundamental functionality of a Programmable Logic Controller (PLC) is to control and execute a set of operations. But a large part of the program code is more involved in supporting the user with concerns like alarm, HMI, communication, safety and manual control. Code related to these supporting concerns is often tangled with operation execution code, the core concerns, which makes it hard to reuse. This paper describes a method to reuse code and functionality when developing PLC programs and code libraries. The method proposes that core concerns are planned with a software tool called Sequence Planner, and the supporting concerns are integrated into the core concerns with a tool based on aspect-oriented programming.

Formal methods for specification and verification are promising in developing programmable logic controller (PLC) programs in manufacturing industry. Particularly this holds for safety PLCs, used to protect humans and equipment from injuries and damages. An important challenge though, is the development of formal specifications, typically a tough task for control engineers. This brief proposes a systematic work procedure that can be used as a first step of developing formal specifications of safety PLC programs in industry. The work procedure intends to facilitate the development of relevant formal properties for safety PLC program components. The formal specifications can be used for automatic formal verification of the components, using model checking techniques. This brief shows how the work procedure has been applied to industrial safety components, resulting in relevant and nontrivial specifications.

The sequential behavior of a manufacturing system results from several constraints introduced during the product, manufacturing, and control logic development. This paper proposes methods and algorithms for automatically representing and visualizing this behavior from various perspectives throughout the development process. A new sequence planning approach is introduced that uses self-contained operations to model the activities and execution constraints. These operations can be represented and visualized from multiple perspectives using a graphical and formal language called Sequences of Operations (SOPs). The operations in a manufacturing system are related to each other in various ways, due to execution constraints expressed by operation pre- and post-conditions. These operation relations include parallel, sequence, arbitrary order, alternative, and hierarchy relations. Based on the SOP language, these relations are identified and visualized in various SOPs and sequences. A software tool, Sequence Planner, has been developed, for organizing the operations into SOPs that visualize only relevant operations and relations.

Hardware-in-the-loop (HIL) is a widely used testing approach for embedded systems, where real components and/or controllers are tested in closed-loop with a simulation model. In this paper, we generalize HIL by combining multiple simulations and real components into a Hybrid Process Simulation (HPS). An HPS is a test setup that contains at least one simulated and one actual component, but may contain many of both. It is implemented such that each simulated component can be swapped out with its real counterpart without making changes to the existing system, and vice versa. In this paper, an ontology which provides a conceptual architecture is developed for an HPS, such that a general interpretation of a manufacturing system's implementation is made possible. A formalized application method is then devised for replacing simulations with real processes and vice versa. A conceptual architecture is put forth that separates the effect of a component from its spatial essence (volume or mass). This separation allows workpieces in a manufacturing process, for example, to go from the physical world into the virtual world (computer simulation) and back again repeatedly. The conceptual architecture is applied to a small manufacturing line in the following scenarios: replacing a real robot with a simulated robot, replacing a manufacturing cell with a simulated manufacturing cell, and adding a new simulated manufacturing cell to the existing system. These applications successfully demonstrate how an HPS can be used to test a manufacturing system setup with multiple regions of real and simulated components.

In order to obtain a unified information flow from early product design to final production, an integrated framework for product, process and automation design is presented. The framework is based on sequences of operations and includes a formal relation between product properties and process operations. This relation includes liaisons (interfaces) and precedence relations, where the precedence relations generate preconditions for the related process operations. From this information a set of sequences of operations (SOPs) is generated. A formal graphical language for hierarchical operations and SOPs is then introduced and defined based on automata extended with variables. Since the operations are self-contained they can be grouped and viewed from different angles, e.g., from a product or a resource perspective. These multiple views increase the interoperability between different engineering disciplines. A case study is performed on a car manufacturing cell, where the suggested modeling framework is shown to give comprehensible SOPs.

Component-based programming frameworks for industrial control logic development promise to shorten development and modification times, and to reduce programming errors. To get these benefits, it is, however, important that the components are specified and verified to work properly. This work introduces Reusable Automation Components (RACs), which contain not only the implementation details but also a formal specification defining the correct use and behaviour of the component. This formal specification uses temporal logic to describe time-related properties and has a special structure developed to meet industrial control needs. The RAC can be formally verified, to determine whether the implementation fulfils the specification or not. A RAC prototype development tool has been developed to demonstrate this capability. The main difference between the RAC and other frameworks for formal verification of control logic is the specification modeling. In RAC, not only the implementation but also the specification is based on the structure and languages of conventional control logic, aiming at being easy to comprehend for control logic engineers. Several industrial examples are discussed in this paper, showing the benefits and potential of the framework.

The languages defined by the standard IEC 6-1131 for Programm\-able Logic Controllers (PLCs), have both benefits and drawbacks compared to object-oriented programming languages. For example, the current programming approach is good for maintaining the system, since it is easy to program and comprehend for a plant floor personal with limited programming experience. The main drawbacks are reusability, code dependability and flexibility. This paper proposes an aspect-oriented programming (AOP) approach as an alternative solution, which can keep the benefits and eliminate the drawbacks. AOP is an emerging programming methodology in computer science, which helps the programmer by separating different crosscutting concerns in the program. These crosscutting concerns and tangled behavior are especially important issues in PLC programming, which makes AOP a suitable approach. The paper describes how to adapt the AOP methodology into PLC program development and how it can benefit the control design process.

Observations with the Hubble Space Telescope reveal an irregular network of dust spiral arms in the nuclear region of the interacting disk galaxy NGC 2207. The spirals extend from ~50 pc to ~300 pc in galactocentric radius, with a projected width of ~20 pc. Radiative transfer calculations determine the gas properties of the spirals and the inner disk, and imply a factor of ~4 local gas compression in the spirals. The gas is not strongly self-gravitating, nor is there a nuclear bar, so the spirals could not have formed by the usual mechanisms applied to main galaxy disks. Instead, they may result from acoustic instabilities that amplify at small galactic radii. Such instabilities may promote gas accretion into the nucleus., Comment: 4 pages, two figures, accepted by Astrophysical J. Letters, Vol 503, August 20, 1998

The sequential behavior of a manufacturing system results from a number of constraints introduced both in product, manufacturing and control logic development. Sequence planning is therefore an important activity throughout the complete development process. This paper proposes a sequence planning approach using self-contained manufacturing operations that model actions and relevant execution conditions. These operations can have temporal relations with each other, due to execution constraints expressed by operation pre- post- and reset conditions. The operation relations can for example be parallel, sequence, arbitrary order, alternative or hierarchy. Based on a formal operation model, the relations among operations are identified and visualized with a graphical language called Sequences of Operations, SOP.

Formal verification, using model checking tools, is promising in developing (IEC 61131) industrial control logic. Formal verification requires a formal specification of the properties to be verified. Specifications in model checking tools are typically expressed using temporal logic. However, the standard temporal logic dialects are not well suited for control engineers who do rarely have a background within computer science. In this paper a new dialect of linear temporal logic, ST-LTL, is introduced that intends to be easier to use for control engineers than the existing dialects. The relation of ST-LTL compared to existing temporal logic dialects is analyzed.

Reduction of energy consumption is important for reaching a sustainable future. This paper presents a novel method for optimizing the energy consumption of robotic manufacturing systems. The method embeds detailed evaluations of robots' energy consumptions into a scheduling model of the overall system. The energy consumption for each operation is modelled and parameterized as function of the operation execution time, and the energy-optimal schedule is derived by solving a mixed-integer nonlinear programming problem. The objective function for the optimization problem is then the total energy consumption for the overall system. A case study of a sample robotic manufacturing system is presented. It shows that there exists a possibility for a significant reduction of the energy consumption, in comparison to state-of-the-art scheduling approaches.

In order to develop a manufacturing automation system, it is necessary to understand the manufacturing operations and their relationship, the sequence of operations, which is the basis for control logic design. The operations have preconditions that define when they are allowed to start executing, which also defines the sequence relations among them. Requirements and demands throughout the development will add and change these conditions, which also changes the sequence of operations. This paper studies how an operation-oriented development approach better can handle the operations and manufacturing sequences from early product design to detailed control engineering. An operation is defined by an extended finite automaton, with an initial, execute and finished location. The start event is enabled by a precondition, the stop event is enabled by a postcondition and the reset event is enabled by a reset condition. This representation together with a resource and product description enables the possibility to integrate control logic in the complete development process.

Intensive global competition forces automotive manufacturers to develop and produce vehicles at lower cost with shorter life cycles and better quality. Faster Vehicle Development Process (VDP) improve profitability by reducing the time and cost related to designing, engineering and launching a new vehicle model. More importantly, it enables automotive makers to react quickly to trend shift in market, e.g., recent shift from SUV (Sports Utility Vehicle) to small fuel efficient vehicle. However, the current manufacturing system design (especially control logic design), key part of VDP, is labor intensive and time consuming, and design quality and performance are highly dependent on the designer’s knowledge and experience. This paper discusses the issues and challenges identified in the current logic development process. A new method to automatically generate control logic using formal method is proposed. In this approach, the required information is collected and modeled as Automata. Possible control logic sequences are then calculated and the optimal one is identified from a set of alternative solutions. This paper also discusses how to implement and integrate the proposed method into the automotive manufacturing engineering process. The method is applied to automotive industry examples, and results are presented. Based on these case studies, this math-based approach can improve the quality of controls logic codes, and reduce ramp-up time and engineering cost significantly.Copyright © 2008 by General Motors

Intensive global competition requires the automotive manufacturers to launch new vehicle models with a shorter launch time, better quality, lower cost and more customization. One of the key enablers for achieving these objectives is to have an efficient & error-free manufacturing automation system which is typically controlled by Programmable Logic Controllers (PLC). The current PLC logic code testing process in automotive industry is usually performed manually by individual engineer, and the overall testing quality highly depends on the engineer’s expertise and experience. The PLC logic code testing normally consists of two parts, testing requirements (specification) and testing methods. One of the major hurdles for applying rigorous testing methods on PLC logic verification in industry is the lack of formal testing specifications. The current PLC testing specifications and requirements are documented in various formats, such as sequence of operation document, process instrument diagram, wiring diagrams, and time motion diagrams, etc. These varied documents cannot be directly used for control logic testing and require a better alternative. Formal methods, the latest technology widely used in software testing, is an approach selected for generating comprehensive test cases to ensure the correctness and consistency of PLC programs. This paper presents a novel approach for specifying the expected behavior of the already implemented industrial PLC code. The generated formal specification models can work with math-based logic verification tool to facilitate the usage of formal verification in manufacturing automation control. The specification modeling methodology contains all the required information from different logic design and testing phases, such as process sequence, wiring information, logic pattern, code comments, and domain knowledge, etc. And the statecharts is used as model formalism, because of its capability to model states hierarchically and provide a better visual representation.Copyright © 2008 by General Motors

In the past simulation and prototyping coexisted as disjointed iterative steps with limited benefits. As technology has advanced and processes have become more complex, the traditional isolated simulation and prototyping approaches can't satisfy dynamic, global competition requirements. Because of this there is a need for a mixture of simulation and physical implementation, called hardware-in-the-loop (HIL). This paper will explore the most active fields and research achievements within HIL including component compatibility testing, controller verification, and software. This assessment is used to highlight regions within HIL research that would benefit manufacturing automation control.

In these days, manufacturing organizations are facing global competition and short technological cycles. The flexibility of an enterprise and its ability to respond to miscellaneous customer requests decide the competitiveness in the global market. It also requires that the manufacturing plant must reorganize efficiently to produce various products at low cost and short time. This flexibility in the manufacturing process must be able to accommodate various tasks to share resources under safe and efficient control. In the current development processes of manufacturing systems, information handling usually is an undeveloped area. Domains such as design, validation, and deployment will be separated and isolated. One reason for the redundant non-value-added implementation of the component model is that existing system development largely consists of isolated sub-processes that generate proprietary information such as control logic, simulation models, etc. This paper focuses on introducing an innovative software environment, EMBench, which integrates mechanical design, control configuration, simulation and deployment services seamlessly for manufacturing automation systems. Its auto-generated user-friendly GUI (Graphical User Interface) supports direct commanding to the controller at different layers, and internal data (control/mechanical) and model (simulation/physical) mapping eliminates redundant and error-prone manual data entry and model replication at different stages. This tool provides a means of layered and encapsulated services so that complex systems can be designed, configured, simulated and deployed hierarchically with various levels of details. IEC61499 is an emerging industrial standard for distributed industrial process measurement & control systems. Using IEC61499 function blocks and service layer architecture, control services ranging from basic joint servo, to kinematics of a mechanism, to trajectory interpolation, to language parsing and HMI processing, to complex multiple resources/processes coordination can be configured for an application. With the adaptation of IEC61499, EMBench serves as a modular, component-based design, simulation and prototyping tool for shop floor control. Several case studies are presented in details and various potential usages in different fields are discussed. EMBench uses IEC61499 as a means for modularization and reuse of control services.Copyright © 2006 by ASME

One reason that the development of distributed control system is hard is that the communication primitives are at a low abstraction level. To put less burden on the developer it would be an advantage to have support for high-level communication primitives. One such primitive is the full synchronous composition (FSC) operator. This operator can be used to model the interaction between an arbitrary number of concurrently executing applications. This paper shows how to implement the FSC operator using an open communication standard for distributed control systems, IEC 61499. The operator is used in the supervisory control theory, a framework for automatic generation of provable correct supervisors. In manufacturing systems, for example, the supervisor might have to interact with a physically distributed plant. This paper concludes therefore by showing how to use the proposed implementation of the FSC operator to execute a supervisor against a physically distributed plant.

At the enterprise level, manufacturing organizations are faced with accelerating technological cycles, global competition and an increasingly mobile work force. The flexibility of the enterprise and its ability to respond to various customer demands governs the competitiveness of the enterprise to the changes in its market and in the society in which it operates. It has been recognized for many years that flexibility on the enterprise floor can always be achieved if the resulting cost of product and process changeovers and its operations are not considered. However, with the increasing competitive pressures on today’s manufacturing enterprise, a flexible-manufacturing environment must be achieved at relatively low cost and high work-force productivity while maintaining a competitive advantage. To accomplish this goal, the manufacturing enterprise must be able to be reconfigured and verified with an increased level of automation that is scalable and flexible to meet diverse product demands quickly and economically. In this paper, we will introduce the recent research work on developing an integrated rapid prototyping environment, EMBench [22, 23], which can provide design, control configuration, simulation and deployment services for flexible manufacturing systems. This rapid prototyping environment has its own user-friendly GUI (Graphical User Interface) that allows user to issue various commands to the controller at different layers, from the simple joint servo to the complex manufacturing cell. In this paper, we also propose the implementation diagram for the controller of manufacturing cells that consists of scheduler, dispatcher, real-time database and structural control policy. All these internal components are responsible for storing system configuration, optimizing processing plan, releasing appropriate command, etc. We also present the idea of cell model and explore its characteristics and behaviors as well as the resource and workstation models. All above modules and architecture are developed using IEC-61499 function blocks that support scalable expansion and modular design. To demonstrate our theoretical achievements, we have developed various IEC-61499 function blocks to integrate various resources on the enterprise shop floor and achieve flexibility at a low cost. This software environment facilitates a modular, component-based mechanical and control design, simulating and prototyping tool for shop floor control.

At the enterprise level, manufacturing organizations are faced with accelerating technological cycles, global competition and an increasingly mobile work force. The flexibility of an enterprise and its ability to respond to new customer demands governs the competitiveness of the enterprise to changes in its market and in the society in which it operates. The flexibility in production processes must be able to accommodate differing product mixes with the changing availability of a skilled work force. It has been recognized for many years that flexibility on the enterprise shop floor can always be achieved if the resulting cost of product, process and system changeovers are not considered. However, with the increasing competitive pressures on today’s manufacturing enterprise; a highly flexible and reconfigurable manufacturing environment must be achieved at relatively low cost and high work-force productivity while maintaining a competitive advantage. To accomplish this goal the manufacturing enterprise must be able to be reconfigured with an increased level of automation that is scalable and flexible to meet diverse product demands. In this paper, we will introduce EMBench as the design and simulation environment for reconfigurable manufacturing systems. This environment provides a universal GUI (Graphical User Interface) that allows user to design, configure and simulate various resources on the shop floor level. In this paper, we present the resource model, workstation model and cell model and explore their characteristics and behaviors. We also propose the general interface for different models using IEC-61499 function blocks that allow scalable expansion and modular design. We use IEC-61499 function blocks and a service layer architecture to integrate various resources on the enterprise shop floor and achieve flexibility at a low cost. This environment facilitates a modular, component-based design of services for enterprise shop floor control.Copyright © 2003 by ASME

In this paper we describe an environment for performing both mechanical and control design for flexible automation systems. The environment provides a means of layering and encapsulating services so that complex multi-axis numerical control systems can be configured, detailed electromechanical simulations performed and then deployed. The system uses IEC-61499 as a means for modularization and reuse of implemented control services. Using IEC-61499 function blocks and a service-layer architecture, control services ranging for basic servoing of a joint, to kinematic co-ordination of joints of a mechanism, to trajectory interpolation, to language parsing and HMI processing, can be configured for an application. The environment facilitates a modular, component-based design of services for numerical control systems.Copyright © 2002 by ASME