Report covers June 1, 1976-July 31, 1978. / Each v. has also a distinctive title. / National Science Foundation. Grant NSF/RANN APR76-12036 National Science Foundation. Grant DAR78-17826

Stanley B. Gershwin, Ramakrishna Akella, and Yong Choong. / Bibliography: p. 36. / "February, 1984." / Contract DAAK11-82-K-0018.

A flexible workcell controller has been developed using a three level control hierarchy (workcell, workstation, equipment). The cell controller is automatically generated from a model input by the user. The model consists of three sets of graphs. One set of graphs describes the process plans of the parts produced by the manufacturing system, one set describes movements into, out of and within workstations, and the third set describes movements of parts/transporters between workstations. The controller uses an event driven Petri net to maintain state information and to communicate with lower level controllers. The control logic is contained in an artificial neural network. The Petri net state information is used as the input to the neural net and messages that are Petri net events are output from the neural net. A genetic algorithm was used to search over alternative operation choices to find a "good" solution. The system was fully implemented and several test cases are described.

We compare the use of stochastic dynamic programming (SDP), Neural Networks and a simple approximation rule for calculating the real option value of a flexible production system. While SDP yields the best solution to the problem, it is computationally prohibitive for larger settings. We test two approximations of the value function and show that the results are comparable to those obtained via SDP. These methods have the advantage of a high computational performance and of no restrictions on the type of process used. Our approach is not only useful for supporting large investment decisions, but it can also be applied in the case of routine decisions like the determination of the production program when stochastic profit margins occur. (author's abstract) / Series: Working Papers SFB "Adaptive Information Systems and Modelling in Economics and Management Science"

D. Tech. Mechanical Engineering. / Describes reconfigurable manufacturing (RM) is a paradigm that promises to meet the turbulent demands in current global manufacturing. The major findings of this thesis are as follows; 1. The functional description of the machine tool provides a handy mechanism of aiding COTS machine builders come up with vary configurations of machine tools and their classification from a predefined set of COTS modules. 2. The process of linking the respective part demands to the relevant COTS RMT is a rigorous and tiresome process that demands computational power provided for by the KBS. 3. The subjective linguistic manner of linking the parts and the machine configuration can be managed by including an objective constraint for the fuzzy model. 4. Coupling the decision making using a mathematical model with the use of a KBS brings about the optimum route to arriving to the desired configuration.

British manufacturing Abstraot Companies have been slower to automate their facilities, and computerise their information systems, than many of their overseas competitors in Europe, North America and Japan. Initially, this research studied advanced manufacturing technology, (AMT), systems theory, the UK economy and investigated the underlying reasons for and against company' s decisions to automate. Automating procedures were studied for a sample of 20 Engineering companies with particular attention paid to their; systemic approach to implementing AMT, inter-business activity communications, individual company strategies, operational tactics, and implications from previous installations. This information was supported by questionnaires targeted at UK design engineers' and equipment suppliers. Interviews with Trade Unions, financial institutions, professional institutions and Government, were also arranged. The research found that correctly implemented AMT, with the optimum balance of flexibility and complexity, improved businesses' competitiveness, although many operational efficiencies could be attained merely by rationalising existing systems. When a company implements AMT it is critical that they synchronise the equipment with additional complementary systems and manufacturing resources. However, every company has their own unique solutions due to the historical evolution of factory facilities, product ranges and employee skills. The restrictive practices adopted the financial accountants and many of the Trade Union were found to restrain the rate of implementation for AMT and the move towards total integrated businesses. The research analysis yielded a ten point model for the strategic and tactical management of advanced manufacturing systems. Finally, the work concludes by identifying "accounting systems", and procedures for "designing for manufacture", as areas which deserve further investigation.

A flexible workcell controller has been developed using a three level control hierarchy (workcell, workstation, equipment). The cell controller is automatically generated from a model input by the user. The model consists of three sets of graphs. One set of graphs describes the process plans of the parts produced by the manufacturing system, one set describes movements into, out of and within workstations, and the third set describes movements of parts/transporters between workstations. The controller uses an event driven Petri net to maintain state information and to communicate with lower level controllers. The control logic is contained in an artificial neural network. The Petri net state information is used as the input to the neural net and messages that are Petri net events are output from the neural net. A genetic algorithm was used to search over alternative operation choices to find a "good" solution. The system was fully implemented and several test cases are described.

Mass producing custom products requires an innovative type of manufacturing environment. Manufacturing environments at present do not possess the flexibility to generate mass produced custom products. Manufacturers’ rapid response in producing these custom products in relation to demand, yields several beneficial results from both a customer and financial perspective. Current reconfigurable manufacturing environments are yet neither financially feasible nor viable to implement. To provide a solution to the production of mass customised products, research can facilitate the development of a distinctive hybrid manufacturing cell, composed of characteristics inherent in existing manufacturing paradigms. Distinctive hybrid manufacturing cell research and development forms an environment where Computer Integrated Manufacturing (CIM) cells operate in a Reconfigurable Manufacturing environment. The development of this Hybrid Reconfigurable Computer Integrated Manufacturing (HRCIM) cell resulted in functionalities that enabled the production of mass customised products. Manufacturing characteristics of the HRCIM cell were composed of key Reconfigurable Manufacturing System (RMS) features and CIM capabilities. This project required hardware to be used in developing an integrated HRCIM cell. The cell consisted of storage systems, material handling equipment and processing stations. Specific material handling equipment was enhanced in its functionality by incorporating RMS characteristics to its existing structure. The hardware behaviour was coordinated from software. This facilitated the autonomous HRCIM cell behaviour which was derived from the mechatronic approach. The software composed of HRCIM events that were defined by its unique programming language. Highlighted software functionalities included prioritisation scheduling that resulted from customer order input. Performance data, extracted from each type of equipment, were used to parameterise a simulated HRCIM cell. During operation, the cell was frequently introduced to an irregular flow of different product geometries, which required different processing requirements. This irregularity represented mass customisation. The simulated HRCIM cell provided detailed manufacturing results. Significant results consisted of storage times, queueing times and cycle times. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2011.

No description available.

To improve product quality and reduce cost, batch production is often implemented in many exible manufacturing systems. However, the current literature does not provide any method to analyze the quality performance in a flexible manufacturing system with batch production. In this research, we present an analytical method with closed-form formula to evaluate the quality performance in such systems. Based on the model, we discover and investigate monotonic and non-monotonic properties in quality to provide practical guidance for operation management. To improve product quality, we introduce the notions of quality improvability with respect to product sequencing. In addition, we develop the indicators for quality improvability based on the data available on the factory floor rather than complicated calculations. We define the bottleneck sequence and bottleneck transition as the ones that impede quality in the strongest manner, investigate the sensitivity of quality performance with respect to sequences and transitions, and propose quality bottleneck sequence and transition indicators based on the measured data. Finally, we provide a case study at an automotive paint shop to show how this method is applied to improve paint quality. Moreover, we explore a potential application to reduce energy consumption and atmospheric emissions at automotive paint shops. By selecting appropriate batch and sequence policies, the paint quality can be improved and repaints can be reduced so that less material and energy will be consumed, and less atmospheric emissions will be generated. It is shown that such scheduling and control method can lead to significant energy savings and emission reduction with no extra investment nor changes to existing painting processes. The successful development of such method would open up a new area in manufacturing systems research and contribute to establish a solid foundation for an integrated study on productivity, quality and exibility. In addition, it will provide production engineers and operation managers a quantitative tool for continuous improvement on product quality in flexible manufacturing environment