No description available.

No description available.

No description available.

This research explores a hardware-based parallel simulation mechanism that can dramatically improve the speed of simulating flexible manufacturing systems (FMS) by applying appropriate enabling hardware technologies. The hardware-based parallel simulation refers to running a simulation on a multi-microprocessor integrated circuit board, called the simulator, which is specifically designed for the purpose of simulating a specific FMS. The board is composed of a collection of micro-emulators capable of mimicking the operation of equipment in FMS such as machining centers, transporters, and load/unload stations. To design possible architectures for the board, a mapping technology is applied by making use of the physical layout information of an FMS. Under such a mapping method, the simulation model is decomposed into a cluster of micro emulator on the board where each workstation is represented by one micro emulator. Three potential architectures for the proposed simulator, namely, the bus-based architecture, the shared-memory based architecture, and the parallel I/O port based architecture, are studied. To provide a suitable parallel computing platform, a prototype simulator based on the combination of the shared-memory and the parallel I/O port architecture is physically built. Besides the development of the hardware simulator, a time scaling simulation method is also developed for execution on the proposed simulator. The method uses the on-board digital clock to synchronize the parallel simulation being performed on different microprocessors. The advantage of the time scaling technology is that the sequence of simulation events is sorted naturally in consistent with the real events. In this way, no entangled waiting is needed as in the conservative parallel simulation methods so as to reduce the synchronization overhead and the danger of having deadlock. Experiments on the prototype simulator show that the time scaling simulation method, combined with the unique hardware features of the FMS specific simulator, achieves a large speedup compared to conventional software-based simulation methods. / Ph. D.

Thesis (MEng)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: The South African manufacturing industry plays a pivotal role in the growth of its local economy. Modern manufacturing requirements include the ability to respond quickly to product variability, fluctuations in product demand and new process technologies. The reconfigurable manufacturing paradigm has been proposed to meet the demands of the new manufacturing requirements. In order to assess the feasibility of incorporating automated, reconfigurable manufacturing technologies into the production process of thermoplastic fibre-reinforced composite parts, a system, based on the thermoforming process, that implements these technologies was developed and evaluated. The assessment uses a seat pan for commercial aircraft as case study. Aspects that were addressed include the architecture, configuration and control of the system. The architecture and configuration addressed the sheet cutting, fixturing, reinforcing, heating, forming, quality assurance and transportation. The control, implemented using agents and based on the ADACOR holonic reference architecture, addresses the cell control requirements of the thermoforming process. An evaluation of the system’s reconfigurability and throughput is performed using KUKA Sim Pro. The evaluation of the system’s throughput is compared to the predicted throughput of the conventional technique for manufacturing thermoplastic fibre reinforced composite parts in a thermoforming process. The evaluation of the system’s performance show that the system designed in this thesis for the manufacture of a thermoplastic fibre-reinforced composite seat pan sports a significant advantage in terms of throughput rate, which demonstrates its technical feasibility. The evaluation of the system’s reconfigurability show that, through its ability to handle new hardware and product changes, it exhibits the reconfigurability characteristics of modularity, convertibility, integrability and scalability. / AFRIKAANSE OPSOMMING: Die Suid-Afrikaanse vervaardigingsbedryf speel 'n sentrale rol in die groei van die plaaslike ekonomie. Moderne vervaardiging vereistes sluit in die vermoë om vinnig te reageer op die produk veranderlikheid, skommelinge in die produk aanvraag en nuwe proses tegnologieë. Die herkonfigureerbare vervaardiging paradigma is voorgestel om te voldoen aan die nuwe produksie vereistes. Ten einde die uitvoerbaarheid van die integrasie van outomatiese, herkonfigureerbare vervaardiging-tegnologieë in die produksieproses van veselversterkte saamgestelde onderdele te evalueer, is 'n stelsel, gebaseer op die termo-vormingsproses, wat sulke tegnologieë implementeer, ontwikkel. Die assessering gebruik 'n sitplek pan vir kommersiële vliegtuie as gevallestudie. Aspekte wat aangespreek is sluit in die argitektuur, konfigurasie en beheer van die vervaardigingstelsel. Die argitektuur en konfigurasie spreek aan die sny, setmate, versterking, verwarming, vorm, gehalteversekering en vervoer van n veselversterkte saamgestelde sitplek pan in 'n termo-vormingsproses. Die beheer, geïmplementeer deur die gebruik van agente en gebaseer op die ADACOR holoniese verwysing argitektuur, spreek die selbeheervereistes van die termo-vormingsproses aan. 'n Evaluering van die stelsel se herkonfigureerbaarheid en deurvoer word gedoen met die behulp van KUKA Sim Pro. Die evaluering van die stelsel se deurvoer word vergelyk met die deurvoer van die konvensionele vervaardigingsproses vir termoplastiese vessel-versterkte saamgestelde onderdele in 'n termo-vormingsproses. Die evaluering van die stelsel se prestasie toon dat die stelsel wat in hierdie tesis ontwerp is vir die vervaardiging van 'n termoplastiese vessel-versterkte saamgestelde sitplek pan, hou 'n beduidende voordeel, in terme van deurvloeikoers, in wat die stelsel se tegniese haalbaarheid toon. Die evaluering van die stelsel se herkonfigureerbaarheid wys dat, deur middel van sy vermoë om nuwe hardeware en produk veranderinge te hanteer, die stelsel herkonfigureerbare einskappe van modulariteit, inwisselbaarheid, integreerbaarheid en skaalbaarheid vertoon.

No description available.

M.Sc. / MANTIS, which is the acronym for "Motion Analysis and Tracking Integrated System", was originally conceived as part of the Interactive Visual-Event Scheduling tool (IVIS). MANTIS is used as an interpreter of and to interface between the vision system, which monitors the visual objects on the shop floor, and the physical-environment manager. MANTIS uses object behaviour models in order to validate the motion of each object and to identify exceptions in this regard. The physical-environment manager then further evaluates this information in relation to other data which it collects and passes on to the Dynamic Scheduling System. It also tracks the objects on the shop floor and uses this information to generate a kinematics model for each object which, in turn, is used to track the object, as well as to predict its position in the next frame. The main reasons for the predictions are to provide the vision system with pertinent information which it can use in order to improve its efficiency and accuracy by reducing its search space and providing additional information to be used in weighing close matches of objects up against each other. In order to accomplish all this, MANTIS needs to define the behavior model of an object and the valid margins for each model. These models are then used for the validation, tracking and prediction of each object's motion on the shop floor, thereby providing real-time feedback to the scheduling system, which then uses this data to maintain its Master Production Schedule.

In this paper a review on scheduling of batch processors (SBP) in semiconductor manufacturing (SM) is presented. It classifies SBP in SM into 12 groups. The suggested classification scheme organizes the SBP in SM literature, summarizes the current research results for different problem types. The classification results are presented based on various distributions and various methodologies applied for SBP in SM are briefly highlighted. A comprehensive list of references is presented. It is hoped that, this review will provide a source for other researchers/readers interested in SBP in SM research and help simulate further interest. / Singapore-MIT Alliance (SMA)

The thesis presents an approach to adaptive decision making strategies to reduce bottlenecks in a drilling operation and to extend tool life. It is an attempt to portray the real drilling system in a typical Flexible Manufacturing System (FMS) layout. The system designed serves as back end intelligence to drilling machines (INTELLIDRILL) in a Flexible Manufacturing System for making dynamic and real time decisions. INTELLIDRILL uses mathematical and adaptive tool reliability models to simulate the machining conditions and tool availability for an operation based on history of tool failures. The results are used to compute the machining parameters and the tools required for an operation. INTELLIDRILL can devise strategies for different tool materials to operate on batches of different materials. INTELLIDRILL decisions could lead to significant savings in tooling costs and reduction in flow line bottlenecks.

The thesis presents an approach to adaptive decision making strategies to reduce bottlenecks in a drilling operation and to extend tool life. It is an attempt to portray the real drilling system in a typical Flexible Manufacturing System (FMS) layout. The system designed serves as back end intelligence to drilling machines (INTELLIDRILL) in a Flexible Manufacturing System for making dynamic and real time decisions. INTELLIDRILL uses mathematical and adaptive tool reliability models to simulate the machining conditions and tool availability for an operation based on history of tool failures. The results are used to compute the machining parameters and the tools required for an operation. INTELLIDRILL can devise strategies for different tool materials to operate on batches of different materials. INTELLIDRILL decisions could lead to significant savings in tooling costs and reduction in flow line bottlenecks.