In this paper the basic principles and influenced factors of Direct Methanol Fuel cells(DMFC) are analyzed.To active DMFC as the research object, the DMFC control system is designed based on MSP430 microcontroller. By controlling the... more
In this paper the basic principles and influenced factors of Direct Methanol Fuel cells(DMFC) are analyzed.To active DMFC as the research object, the DMFC control system is designed based on MSP430 microcontroller. By controlling the concentration of methanol,the temperature of DMFC stack operating and the speed of anode and cathode feeding into the system, high performance and high fuel efficiency
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ABSTRACT Conventionally, improving production efficiency, flexibility and responsiveness has been the primary research focus of production management, while energy consumption has received relatively little attention. Energy consumption... more
ABSTRACT Conventionally, improving production efficiency, flexibility and responsiveness has been the primary research focus of production management, while energy consumption has received relatively little attention. Energy consumption plays a more and more important role in manufacturing environment. This is mainly driven by energy cost and environmental concerns. When the energy system becomes complicated and coupled with ongoing production, it is very difficult to hunt the “hidden treasure” which affects the overall benefit of a manufacturing system. This paper provides a systematic method for energy management in a production system. We start from dynamic production transient analysis and provide quantitative analysis for energy saving opportunity in a system. Furthermore, energy saving is integrated into production system which includes downtime and throughput to provide integrated energy management framework for a production system. A case study is conducted to demonstrate its potential on energy savings in a multi-stage manufacturing system.
Abstract Reduction of energy consumption is important for reaching a sustainable future. This paper presents a novel method for optimizing the energy consumption of robotic man-ufacturing systems. The method embeds detailed evaluations... more
Abstract Reduction of energy consumption is important for reaching a sustainable future. This paper presents a novel method for optimizing the energy consumption of robotic man-ufacturing systems. The method embeds detailed evaluations of robots' energy consumptions into a ...
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In the automotive industry an integrated set of manufacturing engineering activities lie on the critical path of the Vehicle Development Process (VDP). After the product integration design is finalized, the Production Tool Design and... more
In the automotive industry an integrated set of manufacturing engineering activities lie on the critical path of the Vehicle Development Process (VDP). After the product integration design is finalized, the Production Tool Design and Build (PTDB) processes becomes the VDP critical path. It is in the PTDB where virtual launch and validation activities are performed. To increase throughput of the
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ABSTRACT 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... more
ABSTRACT 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, executes 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.
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ABSTRACT Effective control of production operations usually leads to improved energy efficiency in manufacturing systems. In this paper, we investigate energy consumption reduction in production systems by scheduling of machine startup... more
ABSTRACT Effective control of production operations usually leads to improved energy efficiency in manufacturing systems. In this paper, we investigate energy consumption reduction in production systems by scheduling of machine startup and shutdown. Specifically, we consider serial production lines with finite buffers and machines having Bernoulli reliability model. This machine reliability model is applicable in production situations, where the downtime is relatively short and comparable to machine cycle time (e.g., automotive paint shops and general assembly). Using transient analysis of the systems at hand, an analytical performance evaluation technique is developed for Bernoulli serial lines with time-dependent machine efficiencies. In addition, trade-off between productivity and energy-efficiency in production systems is discussed and the energy-efficient production problem is formulated as a constrained optimization problem. The effects and practical implications of operations schedule are demonstrated using a numerical study on automotive paint shop operations.
ABSTRACT This paper discusses data synthesis of production and facility knowledge for sustainability analysis by applying the ISA–95 “Activity Models of Manufacturing Operations Management” (MOM) model. Presently, production and facility... more
ABSTRACT This paper discusses data synthesis of production and facility knowledge for sustainability analysis by applying the ISA–95 “Activity Models of Manufacturing Operations Management” (MOM) model. Presently, production and facility management basically function independently of each other. This paper presents the addition of facility activities to the MOM model, in accordance with the needs for attaining a holistic view of sustainability analysis. Historically, production and facility data are represented in various forms, e.g., data bases, CAD, and spread-sheets, without a common unifying representation. Based on this combination of incompatible modeling tools, the use of Core Manufacturing Simulation Data (CMSD) is proposed as a standard framework for integrating the broad range of technology. A case study of the data synthesis for a precision sand casting production facility is explored.
ABSTRACT Research efforts for energy consumption reduction in manufacturing systems have been centered at technology and process innovation. These projects, however, often involve major capital investment of new equipment and material. In... more
ABSTRACT Research efforts for energy consumption reduction in manufacturing systems have been centered at technology and process innovation. These projects, however, often involve major capital investment of new equipment and material. In this paper, we explore energy saving opportunities through improvement in factory floor operations. Specifically, in the framework of Bernoulli serial lines, we consider production systems with stripping operations. In such systems, the in-process buffers have to be depleted at the end of each shift to avoid quality deterioration during off-shift periods. Transient analysis of the systems are carried out and formulas to calculate the performance measures are derived. In addition, we investigate the effect of machine startup schedule on the system performances and develop optimal startup schedule which, as shown in the paper, can lead to significant improvement in energy utilization efficiency.
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There are many types of Energy Management Systems (EMS) that may be found in the industrial, commercial, and residential sectors. These systems range from the largest and most complex ones found in power generation and industrial plants... more
There are many types of Energy Management Systems (EMS) that may be found in the industrial, commercial, and residential sectors. These systems range from the largest and most complex ones found in power generation and industrial plants down to the smallest and simple systems utilized by the residential consumer of energy. Independent of the magnitude and sophisication of the application,
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ABSTRACT Real-time control of production systems has significant practical and theoretical implications, especially in rapid response and decision making under critical conditions. However, analytical methods for analysis and control of... more
ABSTRACT Real-time control of production systems has significant practical and theoretical implications, especially in rapid response and decision making under critical conditions. However, analytical methods for analysis and control of production system in real-time remain largely unexplored. In the framework of serial production lines with Bernoulli machines and finite buffers, this paper develops a mathematical model for real-time performance analysis and derives closed-form expressions for evaluating the production rate, consumption rate, work-in-process, and probabilities of machine starvation and blockage, in real-time. In addition, a computation-efficient procedure based on recursive aggregation is developed to approximate the real-time performance measures with high accuracy.
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Effective control of production operations is con- sidered as one of the most economical methods to improve energy efficiency in manufacturing systems. This paper in- vestigates energy consumption reduction in Bernoulli serial lines with... more
Effective control of production operations is con- sidered as one of the most economical methods to improve energy efficiency in manufacturing systems. This paper in- vestigates energy consumption reduction in Bernoulli serial lines with buffer stripping, i.e., with the buffers that must be depleted at the end of each shift. This buffer depletion activity is widely used in automotive paint shops and other production systems with perishable products to avoid quality deterioration. Clearly, to reduce energy consumption in such systems, the startup schedule of the machines downstream of the depleted buffers should be controlled properly at the beginning of each shift. In this paper, using transient analysis of the systems at hand, performance evaluation formulas are derived and system-theoretic properties are analyzed. In addition, effective controllers for machine startup schedule are proposed. The efficacy and practical implications of these controllers are demonstrated using numerical investigation. Finally, insights for obtaining the optimal controllers are provided.
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ABSTRACT
Closed production lines have been analyzed in the literature under the assumption that the machines obey either the Bernoulli or exponential reliability models. Empirical evidence indicates, however, that manufacturing equipment on the... more
Closed production lines have been analyzed in the literature under the assumption that the machines obey either the Bernoulli or exponential reliability models. Empirical evidence indicates, however, that manufacturing equipment on the factory floor often has the coefficients of variation of up- and downtime less than 1; therefore, the statistics of machine reliability may be neither Bernoulli nor exponential. This paper analyzes the performance, system-theoretic, and improvability properties of closed production lines with machines having up- and downtime distributed according to any unimodal distribution, provided that the coefficients of variation are less than or equal to 1.