<p>The effectiveness of a material handling system is essential to a competitive manufacturing environment. Automatic Guided Vehicles (AGVs) are an irnportant technology within today's modern manufacturing facility. Academic programs in manufacturing and industrial engineering must find ways to include this technology in their instructional and research programs to provide the students with sufficient knowledge to address material handling systems design. This project was a first step in the development of such a facility at Virginia Polytechnic Institute and State University.</p> <p> This project accomplished two main objectives. The first one was to create a functional AGV system with the "Orbitor" Automatic Guided Vehicle that incorporates advanced hardware features. This system included a taped guide path with bar codes on the floor, and the communication linkage via wire and radio frequency between the Orbitor on-board computer and a remote computer. The second objective was to establish a software system for the overall control of the Orbitor AGV system. This objective involved creating software for the on-board computer and the remote computer. Software communication protocols were implemented and tested between the remote computer and the Automatic Dispatching Unit, and between the Intersection and Communications Unit and the on-board computer. The user of this system was able to interactively define tasks for the AGV from the remote computer. The AGV provided feedback to the remote computer on the status of the vehicle and it sent appropriate messages when the tasks were complete.</p> / Master of Engineering

No description available.

The problem of evaluating new manufacturing technologies, in particular, flexible manufacturing systems (FMS) is a complex one, as its interdisciplinary nature involves multiple variables. These variables are qualitative as well as quantitative, strategic, as well as technological, intangible as well as tangible. This dissertation deals with the problem of the overall evaluation process, in particular, the evaluation of material handling systems within FMS. In particular, automated guided vehicle systems (MVS) are studied from a technical viewpoint, as they are related to strategic and economic considerations. Two main evaluation frameworks are developed. One integrates multiattribute decision models, namely, the analytic hierarchy process or AHP and the displaced ideal model (DIM), and the other integrates analytical techniques with simulation modeling. As a by product, flexibility indices are also developed for MVS and linked to the fundamental aspects of the evaluation of new technologies. This research also shows how analytical techniques can be combined with simulation modeling to form a more extensive evaluation process that includes opportunity costs as well as the usual tangible costs. Finally, a technical analysis of FMS/MVS is done on some typical cell configurations using the flexibility indices developed in this research. / Ph. D.

A methodology for the design of operational control aspects of an Automatic Guided Vehicle (AGV) based material handling system is presented. The methodology, which is composed of an integrated model of an AGV based system, was implemented using simulation techniques. The model views a manufacturing function as consisting of machining, queueing, and moving of parts in a shop and that these components of manufacturing must be integrated and coordinated if the production objectives of an enterprise are to be realized. A machining center is modeled as a physical region of a plant and it consists of machines for part processing and capacitated queues in which inbound and outbound parts reside, queueing for machining or handling resources. Automatic guided vehicles provide the transport mechanism required to interface the machining centers. A network approach is employed to represent the layout of the facility, including the location of departments, input and output queues in each department, and the layout of the guidance system on which the AGVs operate. The network approach, along with the coordinate system are employed for modeling the actual translation of vehicles and parts through the shop. The travel time of vehicles and parts between points depends on vehicle speed and the prevailing traffic condition along the path of travel. Several shop control strategies in the application of AGVs have been modeled, implemented, and their effects on shop performance demonstrated. Among these factors are vehicle dispatching, vehicle routing, unit load size selection, job sequencing, shop loading, queue constraints, and capacity constraints due to vehicles and machines. A job in the shop is considered to consist of one or more parts grouped in portable unit load sizes. Therefore, it is unit loads rather than jobs that make the flow transitions. The results of the simulation experiments conducted indicated vital control elements in the design of AGV systems. Through a series of output statistics on system performance, the model provides an easy to use tool to analyze, evaluate, and design of AGV based manufacturing system. / Ph. D.

Call number: LD2668 .T4 1984 S47 / Master of Science

published_or_final_version / Industrial Engineering / Master / Master of Science in Engineering

M.Ing. / Potential variation in tasks and relative location of manufacturing equipment (machine tools, robot, automated guided vehicles etc.) resulting from the need to restructure the production environment, require efficient and effective communication for optimal performance. The work presented makes use of information and data flow within a system to achieve an integrated and dynamic environment. Models are presented to describe the integration of processing and auxiliary equipment and to select auxiliary equipment for a specific environment. An analytical approach is included for the integration. Specific examples are included. The work presented attempts to contribute to the flexibility of modern manufacturing environments by integrating all facilities in the environment.

Although much effort has been placed into the reduction of risks associated with manual materials handling, risk of musculoskeletal disorder development remains high. This may be due to the additional muscle activity necessary for the maintenance of postural equilibrium during work tasks. This research proposes that postural control and subsequent additional muscle activity is influenced by the magnitude of the external load and the degree of body movement. The objective of this research was to identify whether performing tasks with increased external load and with a greater degree of trunk motion places additional strain on the musculoskeletal system in excess of that imposed by task demands. Twenty-four male and twenty-four female subjects performed four load manipulation tasks under three loading conditions (0.8kg, 1.6kg, and 4kg). Each task comprised of a static and dynamic condition. For the static condition, subjects maintained a stipulated posture for ten seconds. The dynamic condition required subjects to move and replace a box once every three seconds, such that a complete lift and lower cycle was performed in six seconds. Throughout task completion, muscle activity of six pairs of trunk muscles were analysed using surface electromyography. This was accompanied by data regarding ground reaction forces obtained through the use of a force platform. After the completion of each condition subjects were required to identify and rate body discomfort. Differential analysis was used to isolate the muscle activity and ground reaction forces attributed to increased external load and increased trunk movement. It was found that the heaviest loading conditions (4kg) resulted in significantly greater (p<0.05) muscle activation in the majority of muscles during all tasks investigated. The trend of muscle activity attributed to load was similar in all significantly altered muscles and activation was greatest in the heaviest loading condition. A degree of movement efficiency occurred in some muscles when manipulating loads of 0.8kg and 1.6kg. At greater loads, this did not occur suggesting that heavier loading conditions result in additional strain on the body in excess of that imposed by task demands. In manipulated data, trend of vertical ground reaction forces increased with increased load in all tasks. Sagittal movement of the centre of pressure attributed to load was significantly affected in manipulated data in the second movement phase of the “hip shoulder” task and the second movement phase of the “hip twist” task. The “hip reach” task was most affected by increased load magnitude as muscle activity attributed to load was significantly different (p<0.05) under increased loading conditions in both movement phases in all muscles. Further, a significant interactional effect (p<0.05) between condition and data point was found in all muscles with the exception of the right and left lumbar erector spinae during the second movement phase of the “hip reach” task. Muscle activity associated with increased trunk motion resulted in additional strain on the trunk muscles in the “hip shoulder” and “hip reach” tasks as muscle activity associated with the static component of each of the above tasks was greater than that of the dynamic tasks. Trend of ground reaction forces attributed to increased trunk motion generally increased under increased loading conditions. Additionally, a significant interactional effect (p<0.05) between load and muscle activity pattern was found in all muscles during all tasks, with the exception of the right rectus abdominis in the first movement phase of the “hip shoulder’ task, the left rectus abdominis in the second movement phase of the “hip knee” task and the right latissimus dorsi during the first movement phase of the “hip twist” task. This was accompanied by a significant interactional effect (p<0.05) between load and sagittal centre of pressure movement attributed to load, in both movement phases of all tasks investigated. From this research it can be proposed that guidelines may underestimate risk and subsequently under predict the strain in tasks performed with greater external loads as well as tasks which require a greater degree of trunk motion. Therefore, this study illustrates the importance of the consideration of the muscle activity necessary to maintain postural equilibrium in overall load analyses.

Thesis (M.S.)--Texas State University-San Marcos, 2008. / Vita. Includes bibliographical references (leaves 43-46). Also available on microfilm.

Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 396-419). Also available on the Internet.