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Über dieses Buch

The contents of this book are based on invited papers submittedfor presentation and discussion at the 1990 Material Handling Research Colloquium held in Hebron, Kentucky, June 19-21,1990. The Colloquium was sponsored and organized by the College Industry Councilfor Material Handling Education (CIC-MHE) with addi­ tional co-sponsorship and funding provided by numerous organizations (see ac­ knowledgements). The purpose of the Colloquium was to foster open discussion about the current state of material handling research at universitiesfrom across the United States and Canada. It was an opportunity to share specific research directions and accomplish­ments. But more importantly, it was an opportunity to discuss the implications of the basic constraints to solving industry relevant problems in the field of material handling and closely related activities; the efficacy of the approaches being taken at the present time; and the directions believed to be of most value to the industry and to advancing the knowledge and science base of the material handling engineering discipline. The sponsoring organization, the College Industry Council for Material Handling Education was founded in 1952. The council is composed of college and university educators, material handling equipment manufacturers, distributors, users and con­sultants, representatives of the business press plus professional staff and members of other organizations concerned with material handling education.

Inhaltsverzeichnis

Frontmatter

Perspective on 1990s

Frontmatter

Material Handling Research: Needs and Opportunities

Despite the impact of material handling on industrial competitiveness, it has not attracted the attention of researchers to the extent it should. In this chapter, a brief retrospective assessment of material handling is provided, followed by a consideration of research needs and opportunities. The connections between material handling education and research are explored and the traditional sources of support are examined. Throughout the chapter, both education and research needs are addressed. The chapter does not attempt to provide a comprehensive review of material handling research. Its focus is on future needs and opportunities, not past successes and failures. Finally, it focuses on the prospects for future support of material handling research.

John A. White

The Focus of Material Handling Research in the United States

Material handling research can be categorized as: Category IMaterial handling equipment design.Category IIOperational optimization of material handling equipment. Category III: Design of material handling systems.Category IVDesign of manufacturing and distribution systems which consider material handling a critical component.The emphasis of material handling research has been on Categories II and III. To increase material handling research credibility and relevance, more emphasis is required on Categories I and IV.

James A. Tompkins

The State of Material Handling Research

Litton Industrial Automation Systems has been a strong supporter of material handling research. New product innovations have been the backbone of Litton’s ability to retain market leadership. In addition to totally new ideas, Litton is constantly looking for improvements of existing products and new ways of applying existing products.

Stephen L. Parsley

Research in the 1990s

The Material Handling Research Colloquium convened June 19–21 in Hebron, Kentucky and brought together over 40 researchers from nearly 25 institutions. The objectives of these two and one-half days of intensive meetings were the exchange of viewpoints, the assessment of the state of material handling research, and the identification of key issues confronting the material handling research community. The goal was to anticipate the directions of material handling research in the 1990s through an examination of current activity and the identification of key barriers. The following sections of this chapter provide some insight into the kinds of problems being addressed, as well as the methodologies and approaches being used by researchers.

Robert J. Graves, Mickey R. Wilhelm, Leon F. McGinnis, Richard E. Ward

Facilities Design and Unit Loads

Frontmatter

Batch Production with Unit Load Design and Scheduling Consideration

Despite the fact that most batch jobs are moved through shops in unit loads, very limited work has been reported on how to select the best unit load size and the routing of these unit loads through the machines to minimize the batch completion time. In this chapter, the problem of determining the best unit load size for a job and the routing of these unit loads through the machines in a multistage system with material handling consideration is addressed. The design objective is the minimization of the batch completion time. Both stationary and mobile based material handling systems are considered. Results indicate that the unit load and routing requirements for mobile and stationary systems are different.

Pius J. Egbelu

A Group Technology Approach for Container Size Selection

The problem considered in this chapter is the selection of carton sizes for shipping items produced in a small batch manufacturing environment. Rather than selecting an optimum container design for each item, the problem is that of selecting a single container or a limited number of containers for the variety of items and range of order sizes that are characteristic of the particular small batch manufacturer. The focus is on two issues: cost considerations and the carton size selection method. The relevant cost factors are identified and used as the criteria for evaluating the selected carton sizes. A grouping technique is used to assist in the determination of carton sizes, and the results of the application of the methodology for a set of historical data are evaluated.

Jessica O. Matson, Girish N. Naik

Computer-Aided Facility Design Revisited: A Prototype Design Workstation for AGV Systems

In the mid-sixties, there was great hope that computers would revolutionize facility design. Research focused on facility layout and resulted in a number of computer programs for the block layout problem. Sadly, in the intervening twenty years, while computers have become prominent in facility design, facility design research has failed to produce a significant impact on the practice of facility design. Perhaps the reason is that the research has focused on the wrong issues. This chapter describes a strategy for computer-aided facility design, and describes the current state of a prototype design workstation developed from that strategy.

Leon F. McGinnis

A Modelling Framework for Integrating Layout Design and flow Network Design

This chapter introduces a comprehensive modelling framework for integrating layout design and material flow network design toward the direct generation of net layouts including the design of the physical aisle system. Eight models are developed, each being specialized to deal with various facets of this integrated design. The framework offers an alternative conceptual platform to the Quadratic Assignment Problem for layout design researchers.

Benoit Montreuil

Backtracking of Jobs and Machine Location Problems

In flexible manufacturing systems, production lines are often laid out along a linear track. In these lines, facilities engineers attempt to simplify the workflow of jobs by avoiding a job shop structure in favor of a generalized flow line (GFL) by assigning machines to appropriate locations in the layout. The upstream flow of materials in a production line is called backtracking. Determining an optimum assignment of M unique machines to exactly M locations along a track to minimize the total backtracking of jobs is computationally intractable. Therefore, an efficient heuristic is developed in this chapter to overcome these difficulties.An ideal (GFL) incurs no backtracking. In many cases, achieving a GFL is not feasible because of the routing required by jobs. The relative amount of backtracking which does occur in such a configuration is an indication of the degree to which the ideal (and most productive) case is achieved. A measure of backtracking is developed in this chapter to assess the degree which a configuration achieves a (GFL). A simulation model is used to assess the effect of reducing backtracking on overall system performance in day-to-day dynamic operations.

Bhaba R. Sarker, Wilbert E. Wilhelm, Gary L. Hogg, Min-Hong Han

Computer Aided Design of Unit Loads: A Design and Selection Procedure

A computer aided approach for unit load design and selection based on product characteristics, pallet/container dimensions, and facility and operational constraints is discussed in detail. The unit load design and selection problem is formulated as a nonlinear integer programming problem and solved by a heuristic approach and by an intelligent enumeration procedure.

Jaime Trevino, Juan J. Daboub

A Three Dimensional Dynamic Palletizing Heuristic

This chapter extends earlier work on three dimensional palletization completed by the authors. Earlier work focused on the development of a mixed 0-1 integer programming model. While effective, the model proved to be computationally too complicated to permit its use in real time palletizing applications. This chapter describes the development of a three dimensional dynamic programming heuristic. The heuristic’s computational requirements lend themselves more readily to real time palletizing applications.

Russell D. Tsai, Eric M. Malstrom, Way Kuo

Storage Systems and Logistics

Frontmatter

A Generalized Design and Performance Analysis Model for End-of-Aisle Order Picking Systems

In earlier work we presented a design algorithm to determine the nearminimum number of pickers required in an end-of-aisle order picking operation (which is assumed to be based on a miniload automated storage/retrieval system). In this chapter we present an analytical model to determine the approximate values of the expected picker utilization and storage/retrieval machine utilization for general system configurations where two or more pick positions per aisle are allowed and/or two or more aisles are assigned to each picker. Using the estimated picker utilization, we extend the design algorithm presented in the previous work to general system configurations. We also investigate the possibility of improving the picker utilization by sequencing container retrievals within each order.

Yavuz A. Bozer, John A. White

Order Sequencing in Automated Storage/Retrieval Systems with Due Dates

In this chapter we investigate the multiple address AS/R (Automated Storage/Retrieval) interleaving systems with due date constraints. Orders for retrieval arrive to the AS/RS according to a static arrival pattern. Algorithms are developed to batch and sequence orders to tours such that the total travel time and the total lateness of retrievals per group of orders are minimized.

E. A. Elsayed

Computer Aided Design of Industrial Logistics Systems

The efficient design of complex and effective industrial logistics systems will require the synergy between design engineer(s) and computers. The design engineers must be provided with a powerful, flexible, and intuitive modeling environment for all phases and aspects of the design. If such design environments are to be used successfully in practice, they must address and integrate the data base design and management, user interface, algorithmic, and technology transfer functions.This chapter reports on the development of an interdisciplinary methodology for building engineering workstations for the integrated design of industrial logistics systems. System requirements and design principles are derived, and implementation aspects are illustrated based on two prototype implementations for the modeling of manufacturing transportation and distribution systems.

Marc Goetschalckx

Transportation with Common Carrier and Private Fleets: System Assignment and Shipment Frequency Optimization

In this chapter, a shipment can either be served by a private carrier or a common carrier. The cost of using the private carrier declines as the space between stops decreases. Therefore, if more stops are assigned to private carriage, the cost of adding another stop will decline. The methodology presented in this chapter for assigning stops to private and common carriage accounts for this cost interaction through use of a square-root route length approximation. Techniques are presented for systems with (1) fixed shipping cycle for all stops with a variable fleet size, (2) fixed shipping cycle for all stops with a fixed fleet size, and (3) variable shipping cycles with a variable fleet size. In the last case, the optimal time between shipments accounts for both transportation and inventory costs.

Randolph W. Hall, Michael Racer

Optimal Container Location in Miniload AS/R Systems

A procedure for determining optimal storage locations for containers in a miniload automated storage and retrieval system is presented. Dominance conditions are developed to restrict the search space. An example demonstrates that turnover based assignment is not optimal for miniloads implementing dual cycles.

D. J. Medeiros, Bahram Emamizadeh

Small Parts Order Picking: Analysis Framework and Selected Results

This chapter presents a general analysis framework and the major issues for designing and operating order pick systems for less-than-case retrieval. The interplay among stock keeping unit data analysis, order data analysis, overall system structure, equipment types for subsystems, and operating strategies, is emphasized. Selected results are presented for parametric analysis, batching and zoning using ride-and-pick, proximity batching of small orders with no order splitting, and correlated storage assignment. Future research opportunities are outlined.

Gunter P. Sharp, Kyung Il-Choe, Chang S. Yoon

Economics and Automation

Frontmatter

Justification of Manufacturing Systems

Possibility distributions are recommended for explicit representation of uncertainty in models used for justification of manufacturing systems. A procedure is presented that is capable of obtaining and combining the possibility distributions of strategic and economic aspects of an investment situation. A numerical example is presented, and a method of ranking alternatives is discussed.

F. Choobineh

Economic Justification: Research Concerns

Economic justification of automated material handling and manufacturing systems is a frequently encountered barrier to the implementation of these systems. The purpose of this chapter is to describe the economic justification problem and to outline where current practices are inadequate. A discussion of some of the efforts being made to develop improved justification practices is presented. Individual efforts are described in terms of the issues they address and the progress they are making.

Thomas P. Cullinane

Comments on the Automation of Material Handling

This chapter is a collection of fundamental ideas from several years involvement with the Material Handling Research Center. It results from the interactions of a controls oriented mechanical engineer with many materials handling professionals both in academia and industry. Most, but not all, of these professionals have industrial engineering backgrounds. As a consequence, the material handling community has a strong orientation toward operations issues and rather less concern with the technology of machinery used in material handling. This chapter discusses some very basic issues relative to automation of material handling with emphasis on some perceived misconceptions.

Stephen L. Dickerson

Industrial Lift Truck Reliability

Material handling systems are designed to be repairable. There may be improvement in reliability early in equipment life and/or deterioration as the system is operated. Reliability is also a function of explanatory variables, such as operating environment or maintenance procedures. This chapter presents modeling approaches for reliability of repairable equipment including improvement or deterioration trends and/or explanatory variables. A case study is discussed for industrial lift trucks including modeling of reliability as stochastic processes. Time-to-first-failure for the lift trucks is shown to be distributed exponential with operational environment being an explanatory variable forming proportional hazards.

Thomas L. Landers, Waseem Mohammed Qureshi

Intelligent Robots for Flexible Packaging

Problems, such as automated palletizing, bin-picking, automated storage and retrieval, automated kitting of parts for assembly, and automated warehousing are currently being considered for expert solutions. The use of expert robots or automated systems often consist of specialized computer programs, manipulators and integrated sensors has been demonstrated with a variety of applications. Games such as robot checkers, peg games, etc. have been developed as test demonstrations. Actual solutions for automated palletizing, pit-carb basket loading, etc. have also been developed for industrial applications at our Center. The generic concepts for flexible packaging will be described in this chapter, some unsolved problems discussed, and some applications briefly described. The significance of this work lies in the broad application of flexible packaging to a variety of generic industrial problems. Solutions can improve product quality, reduce waste, and eliminate the potential for human injuries.

G. D. Slutzky, E. L. Hall, R. L. Shell

Strategic Investment Evaluation of Integrated Manufacturing Systems

The decision to invest in capital equipment is one of the most critical decisions an executive can make. A prudent capital investment in machinery and advanced technologies will increase production, reduce costs, and provide a competitive advantage. The future health of the company is closely tied to the investment decision.

William G. Sullivan, James A. Brimson

Performance Modeling for a Single Material Handling Device with Random Service Requests — Pure Blocking

In this chapter, a manufacturing cell in which a single device provides movement between a number of distinct locations is studied. We propose an approach for analyzing the performance of the material handling device based on finite networks of queues. In this chapter, the case in which a full input buffer at a delivery location blocks the sending location is considered. Numerical results obtained from the proposed approach are compared with simulation results for the specific case of a robot tending several machines. A companion paper, [10], addresses the situation in which an alternative temporary storage area is provided for input buffer overflows.

Zulma R. Toro Ramos, Leon F. McGinnis

Performance Modeling for a Single Material Handling Device with Random Service Requests — Blocking with Recourse

In this chapter, a manufacturing cell is studied in which a single device provides movement between a number of distinct locations and temporary storage is provided between work centers. For the cell under consideration, a bootstrapping strategy is proposed for analyzing the performance of the material handling device. The bootstrapping strategy is based on a finite network of queues model. The proposed strategy is evaluated by means of a computational study. Results from the proposed strategy are compared to results obtained from a high-fidelity discrete event simulation for a microload automated storage/retrieval (AS/R) system.

Zulma R. Toros Ramos, Leon F. McGinnis

Flow Control and AGVS

Frontmatter

Determining the Number of Kanban in Multi-Item Just-in-Time Systems

Kanbans (cards) are one means of controlling just-in-time production systems. The Kanbans serve as production authorization orders and essentially become the information system. The presence of a production ordering Kanban for a specific part type constitutes an instruction to the workcenter to produce a “container” of that part. In this chapter we assume workcenters produce multiple part types and address the issue of the number of Kanbans needed for each part type. Our objective is to minimize the sum of inventory holding and backorder cost. A stochastic model is formulated. Steady-state results are derived for several operating environments and results and validated by simulation.

Ronald G. Askin, M. George Mitwasi, Jeffrey B. Goldberg

An Advanced AGVS Control System: An Example of Integrated Design and Control

The Automated Guided Vehicle System (AGVS) has attracted increased attention over the past decade from both the material handling user community and from academics, primarily due to its flexibility. From an academic perspective, the key challenges addressed have been 1) measuring or understanding AGVS performance and 2) extending its flexibility. Georgia Tech Material Handling Research Center programs, in this regard, have included: • Development of an integrated path layout, fleet sizing and evaluation, and simulation tool, known as the AGVS Engineering Design Workstation, or AGVS EWS [1,2]. This tool is intended to be used by industrial engineers planning AGVS applications.• Development of new guidance technologies incorporated in a software-guided vehicle which does not follow either a wire or stripe on the floor [3]. The vehicle still follows a prescribed path, but this is specified in software rather than by a continuous marker on the floor.

Ronald A. Bohlander, Wiley D. Holcombe, James W. Larsen

A Virtual Cell Scheduling Algorithm

In this chapter, we begin by defining a new manufacturing concept termed Virtual Cellular Manufacturing System (VCMS). The VCMS is an expansion of the virtual cell concept proposed by McLean and all at the NIST AMRF in the early 1980’s [4].Then, we will show how the virtual cellular concept can be a provider of flexibility for factories of the future. A time-phased linear programming algorithm which has been developed especially for controlling VCMS will be presented. Finally, a simulation comparison between a VCMS and a Group Technology Cell has been performed. Results obtained from the simulations demonstrate the superiority of VCMS over the GT Cell System.

Jocelyn R. Drolet, Colin L. Moodie

A Modular Algorithm for Pre-Simulation Design of Automatic Guided Vehicle Systems

The AGVS design problem is extremely complex. The interrelationships among the many design variables make the development of a single, comprehensive analytical solution model practically impossible. Therefore, this chapter presents a modular modeling framework for breaking the AGVS design problem down into smaller, more tractable, sub-problems. The solutions resulting from each module act as input to the next sub-problem module. This process is iterated until convergence is reached.

Gerald W. Evans, Mickey R. Wilhelm, John S. Usher

Recent Analytical Results on Miniload Performance

We describe a basic model of miniload order picking systems. We also review selected analytical results on miniload performance.

R. D. Foley, E. H. Frazelle

Impacts of Flexible Routing in Control Architectures for Material Flow Systems

The degree to which routing flexibility can influence manufacturing system performance is the focus of this chapter. Of special interest is the performance of material flow control architectures which integrate flexible routing concepts (e.g., the conduct of fabrication/assembly operations in alternate sequences) with flexibility in the determination of product mix or machine level sequencing. The manufacturing context is that of diverse mixed technology circuit boards assembled using a cellular approach. The research methodology is that of simulation using the SIMAN language. Results indicate that the incorporation of flexible routing concepts into material flow architectures can significantly affect system performance, especially when integrated with other operational control mechanisms.

G. Don Taylor, Robert J. Graves

Prototyping the Integration Requirements of a Free-Path AGV System

Automated guided vehicle systems (AGVS) are gaining more attention from both academic and industrial research organizations. However, there exist some basic problems that still remain unsolved which prevent widespread installation of AGV systems. System integration is such an issue.This chapter describes an on-going research on Intelligent Transport Systems (ITS) at Purdue University. It is an AGV-based factory transport system composed of experimental free-path vehicles, a vehicle simulator, a transport system controller and a shop simulator. Discussions include issues related to the integration requirements of a free-path AGV system. The main focus is on the design of the control architecture, division of functions between system components, data communications considerations, etc. The concept of a virtual transport system is also presented.

Chang Wan Kim, J. M. A. Tanchoco

A PC Based Implementation of the Control Zone Model for AGVS Design

A computerized decision support system is introduced for implementation of the zone control model for AGVS design. A hypothetical design problem is introduced and defined in terms compatible with the system database. The application of the computer model is illustrated through a series of six adjustments in the original design profile corresponding to variation in AGVS design variables including guidepath layout, vehicle routing, vehicle dispatching, and load transfer point location. For each variation, the package is used to study the performance of the proposed system including gridlocking risk factors and the minimum vehicle fleet size needed to meet a fixed throughput requirement.

Charles J. Malmborg
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