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Modelling flexible manufacturing systems using mean-value analysis
Journal ofManufacturing Systems Volume 12/No. 1
Cumulative Abstract Index
mances. Existing adaptive controllers for EDM are surveyed. Economic benefits as well as practical results which could be achieved with adaptive control systems are discussed. Keywords: Nontraditional Machining, Electro Discharge Machining, Automatic Control, Adaptive Control
ing cells, which are being developed as major components of new manufacturing facilities. The functional specifications are motivated by recent experiences with the creation of a prototype cell for an open die forging process. Keywords: CAM, Control Equipment, Robots, CNC, Industrial Robots, Robot Controller Design, Manufacturing Cell Communication
Variable Gain Adaptive Control Systemfor Turning, O. Masory, Y. Koren, pp. 165-73 Adaptive control as applied to machine tool systems refers to control of the operating parameters based on measurement of the process characteristics. Even the simplest adaptive control system with feedrate control based on cutting force measurements, is quite complex. The adaptive control loop is of a sampled-data nature with a nonlinear variable gain which depends on the operating parameters themselves. Experiments have shown that an operating computer numerical control/adaptive control system can become unstable due to changes in depth-of-cut or spindle speed. The purpose of this paper is to demonstrate a new design method for machine tool adaptive control systems. The proposed method is based on simultaneous estimation of process parameters and control of the cutting process. The parameter estimation is based on available measurements of the cutting force. The estimator is used to modify the adaptive control controller gain in real-time to achieve an effective and stable system. Keyworda: Adaptive Control, Variable Gain Controllers, Numerical Control, Machine Tools, Computerized Systems
A Sensor-Based Techniquefor Automated Robot Programming, N. Duffle, J. Bollinger, L. Aken, R. Piper, J. Zik, C. Hou, K. Lan, pp. 13-26 This paper presents the concept of integrating a tactile sensor based, automated part measuring technique and a CAD programming scheme to perform off-line programming for a welding robot. Keywords: Automated Welding, Robot Programming, Coordinate Measurement, Tactile Sensors, Seam Tracking Modelling FlexibleManufacturing Systems UsingMean.Value Analysis, R. Suri, R. Hildebrant, pp. 27-38 Flexible manufacturing systems (FMSs) represent an important new development in automated manufacturing of parts with mid-volume demand. In the design and operation of these complex systems, it is useful to have tools that predict their performance under various conditions. This paper describes one such tool called MVAQ, a computer program based on mean-value analysis of queues. Part production rates, machine utilization and average work-in-process sizes are easily obtained using MVAQ. The reader is advised on when MVAQ should be used for modelling FMSs and how the program can be used. A simple design example is given to illustrate the use of MVAQ. A brief tutorial on the theory behind MVAQ is included. Keyworda: Design Evaluation, Scheduling, Production Control, Queuing Models, Machine Utilization, Production Rate
Decision Based on ProductivityAnalysis--An toa thec MAPIMethod, Rternative • p l e m e L.nLeung, t J. Tanchoco, pp. 175-87 An alternative replacement approach to Terborgh's MAPI procedure is presented. Described in the format of a case study, this illustrative example incorporates considerations on different machine types, factors of production, expansion of output, finite planning horizon, and the 1983 accelerated cost recovery system (ACRS) depreciation schedule along with other factors traditionally considered. A solution procedure is also provided to determine the optimal replacement policy; the criterion is the maximization of the production process' future worth at the end of the planning horizon. A general literature review is included. Keywords: Equipment Replacement, MAPI, Replacement Policy, Capacity Expansion
The Design of a FlexibleMachining Cellfor Small Batch cell for a small batch manufacturer. The cellproduces small parts with dimensional tolerances of plus or minus 0.005 inch (0.13Mm) using a minimum of machining equipment. The proposed cell can run unattended for a moderate period of time (e.g., overnight). The cell design emphasizes near-term technology and uses offthe-shelf items where possible. The design philosophy is to partition the cell components and control programs into modules according to their function. The resulting cell is easily integrated into a larger system and is readily modified or expanded as more sophisticated equipment and techniques become available. Keywords: Robot Machining Cell, Computer Control, Flexible Manufacturing Systems
Effect of Part Symmetry on ManualAssembly Times, Z. Yoosufani, M. Ruddy, G. Boothroyd, pp. 189-95 The effect of symmetry of parts on the time taken to handle parts during manual assembly is studied. It is experimentally shown that part symmetry can be classified into four categories; in each category, the parts require significantly different orientation times. This information can be used by product designers when considering design for ease of assembly. Keyworda: Symmetry, Handling, Assembly, Orientation, Assembly Time, Work Measurement
Decision Support Requirements in FlexibleManufacturing, R. Suri, C. Whimey, pp. 61-69 Flexible manufacturing systems are being installed by many organizations to improve productivity. Because efficient operation of these systems is such a complex task, their capacity is often underutilized. The concept of computer-hased decision support systems promises to remedy the situation. This p.aper defines the components of a decision support system that wall enable the user to get the maximum benefit from a flexible manufacturing system. The structure of this decision support system parallels the organizational activities involved in running the flexible manufacturing system. This structure should be implemented using appropriate hardware and software components.
1 9 8 4 TV o l . 3 / N o . 1 A Design of a Controlleras a Component of a Robotic Manufacturing System, P. Fussell, P. Wright, D. Bourne, pp. I-I I This paper specifies the functional design of a robot or machine tool controllersuitablefor inclusion in robotic manufacturing systems. The principle interestis the unmanned manufactur-
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Cumulative Abstract Index
mances. Existing adaptive controllers for EDM are surveyed. Economic benefits as well as practical results which could be achieved with adaptive control systems are discussed. Keywords: Nontraditional Machining, Electro Discharge Machining, Automatic Control, Adaptive Control
ing cells, which are being developed as major components of new manufacturing facilities. The functional specifications are motivated by recent experiences with the creation of a prototype cell for an open die forging process. Keywords: CAM, Control Equipment, Robots, CNC, Industrial Robots, Robot Controller Design, Manufacturing Cell Communication
Variable Gain Adaptive Control Systemfor Turning, O. Masory, Y. Koren, pp. 165-73 Adaptive control as applied to machine tool systems refers to control of the operating parameters based on measurement of the process characteristics. Even the simplest adaptive control system with feedrate control based on cutting force measurements, is quite complex. The adaptive control loop is of a sampled-data nature with a nonlinear variable gain which depends on the operating parameters themselves. Experiments have shown that an operating computer numerical control/adaptive control system can become unstable due to changes in depth-of-cut or spindle speed. The purpose of this paper is to demonstrate a new design method for machine tool adaptive control systems. The proposed method is based on simultaneous estimation of process parameters and control of the cutting process. The parameter estimation is based on available measurements of the cutting force. The estimator is used to modify the adaptive control controller gain in real-time to achieve an effective and stable system. Keyworda: Adaptive Control, Variable Gain Controllers, Numerical Control, Machine Tools, Computerized Systems
A Sensor-Based Techniquefor Automated Robot Programming, N. Duffle, J. Bollinger, L. Aken, R. Piper, J. Zik, C. Hou, K. Lan, pp. 13-26 This paper presents the concept of integrating a tactile sensor based, automated part measuring technique and a CAD programming scheme to perform off-line programming for a welding robot. Keywords: Automated Welding, Robot Programming, Coordinate Measurement, Tactile Sensors, Seam Tracking Modelling FlexibleManufacturing Systems UsingMean.Value Analysis, R. Suri, R. Hildebrant, pp. 27-38 Flexible manufacturing systems (FMSs) represent an important new development in automated manufacturing of parts with mid-volume demand. In the design and operation of these complex systems, it is useful to have tools that predict their performance under various conditions. This paper describes one such tool called MVAQ, a computer program based on mean-value analysis of queues. Part production rates, machine utilization and average work-in-process sizes are easily obtained using MVAQ. The reader is advised on when MVAQ should be used for modelling FMSs and how the program can be used. A simple design example is given to illustrate the use of MVAQ. A brief tutorial on the theory behind MVAQ is included. Keyworda: Design Evaluation, Scheduling, Production Control, Queuing Models, Machine Utilization, Production Rate
Decision Based on ProductivityAnalysis--An toa thec MAPIMethod, Rternative • p l e m e L.nLeung, t J. Tanchoco, pp. 175-87 An alternative replacement approach to Terborgh's MAPI procedure is presented. Described in the format of a case study, this illustrative example incorporates considerations on different machine types, factors of production, expansion of output, finite planning horizon, and the 1983 accelerated cost recovery system (ACRS) depreciation schedule along with other factors traditionally considered. A solution procedure is also provided to determine the optimal replacement policy; the criterion is the maximization of the production process' future worth at the end of the planning horizon. A general literature review is included. Keywords: Equipment Replacement, MAPI, Replacement Policy, Capacity Expansion
The Design of a FlexibleMachining Cellfor Small Batch cell for a small batch manufacturer. The cellproduces small parts with dimensional tolerances of plus or minus 0.005 inch (0.13Mm) using a minimum of machining equipment. The proposed cell can run unattended for a moderate period of time (e.g., overnight). The cell design emphasizes near-term technology and uses offthe-shelf items where possible. The design philosophy is to partition the cell components and control programs into modules according to their function. The resulting cell is easily integrated into a larger system and is readily modified or expanded as more sophisticated equipment and techniques become available. Keywords: Robot Machining Cell, Computer Control, Flexible Manufacturing Systems
Effect of Part Symmetry on ManualAssembly Times, Z. Yoosufani, M. Ruddy, G. Boothroyd, pp. 189-95 The effect of symmetry of parts on the time taken to handle parts during manual assembly is studied. It is experimentally shown that part symmetry can be classified into four categories; in each category, the parts require significantly different orientation times. This information can be used by product designers when considering design for ease of assembly. Keyworda: Symmetry, Handling, Assembly, Orientation, Assembly Time, Work Measurement
Decision Support Requirements in FlexibleManufacturing, R. Suri, C. Whimey, pp. 61-69 Flexible manufacturing systems are being installed by many organizations to improve productivity. Because efficient operation of these systems is such a complex task, their capacity is often underutilized. The concept of computer-hased decision support systems promises to remedy the situation. This p.aper defines the components of a decision support system that wall enable the user to get the maximum benefit from a flexible manufacturing system. The structure of this decision support system parallels the organizational activities involved in running the flexible manufacturing system. This structure should be implemented using appropriate hardware and software components.
1 9 8 4 TV o l . 3 / N o . 1 A Design of a Controlleras a Component of a Robotic Manufacturing System, P. Fussell, P. Wright, D. Bourne, pp. I-I I This paper specifies the functional design of a robot or machine tool controllersuitablefor inclusion in robotic manufacturing systems. The principle interestis the unmanned manufactur-
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