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Survey of adaptive control in electro discharge machining
Journalvolum© ~21~..1
Systems
Cumulative Abstract Index
Keywords: Directed Graphs, Production Systems, Simulation,
form of the b-spfine curve with the defining polygon adequately. fulfills most essential requirements. Fourth-order curves seemea to be best suited for most cases, as they provide a compromise between smoothness and 'localness,' yet curve orders of varying degrees still have some merit in certain circumstances. The most attractive feature realized with this method is the simplicity of design and the determination of the main input elements. Surface interpolation curves are shown and the production of a mold for a plastic handle indicated. Ke3nvords: Computer-Aided Manufacture, Computer-Aided Design, B-Splines, Free-Form Surfaces, Cross-Sectional Design
Analysis
A Computer Simulation Study of Manual Flow Lines, D. Him, P. Pandey, pp. 117-25 A flow fine production system having finite intermediate buffers and random processing times has been simulated to determine the system efficiency and the average work in-process. From the simulation results, simple and reliable empirical equalions for determining the efficiency of the fine have been developed. Analysis of the buffer utilization results show that in a balanced system, work in-process remains high in the first few stages of the fine, and low towards the end of the fine. It has also been observed that the balanced fine (.ecjualbuffers) is generally the most productive, and that a small nnbalance, due to larger buffers in the center of the fine, has little effect on its performance. Keywords: InterstageBuffers, Processing Times, Balanced, Buffer Level, Buffer Utilization, Unbalancing, Line Efficiency, Production Rate
CAMfor Developi.n.¢Nation.v, B. Brunak, pp. 79-85 Application of high technology in developing countries with the objective of accelerated industrial growth and diversification is the subject of this paper. The use of numerical control and of flexible CAM systems is envisioned to produce a growing variety of new products in small batches and thereby overcome the bottleneck problem of small markets plaguing developing countries. Products from industrialized countries could be duplicated instantaneously at any plant around the globe by the use of computerized data transmission. With such an innovative system, countless new jobs would be generated in developing countries and local demand for affordable new products could be satisfied. For licensors (manufacturers of products) as well as builders of computerized manufacturing and commun.i.'cationsystems, along with related services and products in inclustriafizeo countries, this system would create sizable new markets. Key~ord$: Manufacuning System, Technology Transfer, Developing Countries, Third World, Job Creation
CAIMGenerative Process Planning with TIPPS, T. Chang, R. Wysk, pp. 127-35 Two apI?reaches to computer-aided process planning are defined--variant and generative. The variant approach retrieves existing plans for a similar part while the generative approach synthesizes plans from built-in knowledge. The generative approach to process plannin$ is normally considered more complex and the more automated of the two approaches. This paper discusses a generative process planning system called totally integrated process planmng system (TIPPS). T1PPS uses a computer-aided design (CAD) model as direct input, eliminating part coding or description from the planning process. Currently, TIPPS is capable of planning prismatic parts with one access direction. Relevant issues encountered in constructing a generafive process planning system as well as the TIPPS design philosophy are discussed. Process planning using TIPPS is illustrated. This paper also discusses future research directions in automated process planning. Keyword$: CAD, CAM, Process Planning, Automation, Integrated CAD/CAM
1983~ Vol. 2/No. 2 Machine Diagnostics in Automated Production, M. Weck, pp. 101-06 An increase in productivity can be achieved by scheduling additional shifts of the production facilities and by reducing the number of operating personnel. A further increase in productivity is closely linked to the downtime of the production facilities with respect to technical failure and to the rate of scrap parts and refinishing. This increase can only be achieved if the production facilities ate extended by appropnate monitoring systems. ~nese systems take charge of the diverse supervisory .tasks performed by. the operating personnel and offer functions to locate me type ano reasons for failure. Time and frequency of diagnostics are suitable features for characterization of such monitoring systems. Machine Diagnostics, Monitoring Systems, Process
Cellular Manufacturing Control, T. Greene, R. Sadowski, pp. 137-45 This paper presents a discussion of the variables affecting the control ofagroup technology, cellular manufacturing system. The control function is partitioned into cell loading and cell scheduling. The variables affecting the control of a cellular manufacturing system include the characteristics that describe the physical cellular system, and the characteristics that describe the jobs. In addition, the paper reviews many of the advanta.~es and disadvantages of cellular manufacturing, and the imphed assumptions. Finally, a brief discussion of the problems associated with the techniques for the successful loading and scheduling of the cellular manufacturing system is presentea. Keywords: Group Technology, Cellular Manufacturing, Loading, Scheduling
tion, Productivity Production System Design: A Directed Graph Approach, E. Passler, G. Hutchinson, K. Rudolph, W. Stanek, pp. 107-16 The problems of designing advanced production systems considered from the viewpoints of two quite different social systems and found to be similar. The problems are characterized as being large, complex, and dynamic. Simulation is found to be a good general methodological approach, and directed graphs a particularly useful means of specifying production problem relationships for both analysis and simulation. The appendices contain discussions of the computer systems, both based on directed graphs, in use in these countries.
Survey of Adaptive Control in Electro Discharge Machining, R. Snoeys, D. Dauw, J. Kruth, pp. 147-64 This~paper deals with control systems for the electro discharge macbimng process. Special attention is paid to techniques of inprocess evaluation of the EDM process. The paper focuses on adaptive control systems used to optimize the process perfor-
54
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-
55
Systems
Cumulative Abstract Index
Keywords: Directed Graphs, Production Systems, Simulation,
form of the b-spfine curve with the defining polygon adequately. fulfills most essential requirements. Fourth-order curves seemea to be best suited for most cases, as they provide a compromise between smoothness and 'localness,' yet curve orders of varying degrees still have some merit in certain circumstances. The most attractive feature realized with this method is the simplicity of design and the determination of the main input elements. Surface interpolation curves are shown and the production of a mold for a plastic handle indicated. Ke3nvords: Computer-Aided Manufacture, Computer-Aided Design, B-Splines, Free-Form Surfaces, Cross-Sectional Design
Analysis
A Computer Simulation Study of Manual Flow Lines, D. Him, P. Pandey, pp. 117-25 A flow fine production system having finite intermediate buffers and random processing times has been simulated to determine the system efficiency and the average work in-process. From the simulation results, simple and reliable empirical equalions for determining the efficiency of the fine have been developed. Analysis of the buffer utilization results show that in a balanced system, work in-process remains high in the first few stages of the fine, and low towards the end of the fine. It has also been observed that the balanced fine (.ecjualbuffers) is generally the most productive, and that a small nnbalance, due to larger buffers in the center of the fine, has little effect on its performance. Keywords: InterstageBuffers, Processing Times, Balanced, Buffer Level, Buffer Utilization, Unbalancing, Line Efficiency, Production Rate
CAMfor Developi.n.¢Nation.v, B. Brunak, pp. 79-85 Application of high technology in developing countries with the objective of accelerated industrial growth and diversification is the subject of this paper. The use of numerical control and of flexible CAM systems is envisioned to produce a growing variety of new products in small batches and thereby overcome the bottleneck problem of small markets plaguing developing countries. Products from industrialized countries could be duplicated instantaneously at any plant around the globe by the use of computerized data transmission. With such an innovative system, countless new jobs would be generated in developing countries and local demand for affordable new products could be satisfied. For licensors (manufacturers of products) as well as builders of computerized manufacturing and commun.i.'cationsystems, along with related services and products in inclustriafizeo countries, this system would create sizable new markets. Key~ord$: Manufacuning System, Technology Transfer, Developing Countries, Third World, Job Creation
CAIMGenerative Process Planning with TIPPS, T. Chang, R. Wysk, pp. 127-35 Two apI?reaches to computer-aided process planning are defined--variant and generative. The variant approach retrieves existing plans for a similar part while the generative approach synthesizes plans from built-in knowledge. The generative approach to process plannin$ is normally considered more complex and the more automated of the two approaches. This paper discusses a generative process planning system called totally integrated process planmng system (TIPPS). T1PPS uses a computer-aided design (CAD) model as direct input, eliminating part coding or description from the planning process. Currently, TIPPS is capable of planning prismatic parts with one access direction. Relevant issues encountered in constructing a generafive process planning system as well as the TIPPS design philosophy are discussed. Process planning using TIPPS is illustrated. This paper also discusses future research directions in automated process planning. Keyword$: CAD, CAM, Process Planning, Automation, Integrated CAD/CAM
1983~ Vol. 2/No. 2 Machine Diagnostics in Automated Production, M. Weck, pp. 101-06 An increase in productivity can be achieved by scheduling additional shifts of the production facilities and by reducing the number of operating personnel. A further increase in productivity is closely linked to the downtime of the production facilities with respect to technical failure and to the rate of scrap parts and refinishing. This increase can only be achieved if the production facilities ate extended by appropnate monitoring systems. ~nese systems take charge of the diverse supervisory .tasks performed by. the operating personnel and offer functions to locate me type ano reasons for failure. Time and frequency of diagnostics are suitable features for characterization of such monitoring systems. Machine Diagnostics, Monitoring Systems, Process
Cellular Manufacturing Control, T. Greene, R. Sadowski, pp. 137-45 This paper presents a discussion of the variables affecting the control ofagroup technology, cellular manufacturing system. The control function is partitioned into cell loading and cell scheduling. The variables affecting the control of a cellular manufacturing system include the characteristics that describe the physical cellular system, and the characteristics that describe the jobs. In addition, the paper reviews many of the advanta.~es and disadvantages of cellular manufacturing, and the imphed assumptions. Finally, a brief discussion of the problems associated with the techniques for the successful loading and scheduling of the cellular manufacturing system is presentea. Keywords: Group Technology, Cellular Manufacturing, Loading, Scheduling
tion, Productivity Production System Design: A Directed Graph Approach, E. Passler, G. Hutchinson, K. Rudolph, W. Stanek, pp. 107-16 The problems of designing advanced production systems considered from the viewpoints of two quite different social systems and found to be similar. The problems are characterized as being large, complex, and dynamic. Simulation is found to be a good general methodological approach, and directed graphs a particularly useful means of specifying production problem relationships for both analysis and simulation. The appendices contain discussions of the computer systems, both based on directed graphs, in use in these countries.
Survey of Adaptive Control in Electro Discharge Machining, R. Snoeys, D. Dauw, J. Kruth, pp. 147-64 This~paper deals with control systems for the electro discharge macbimng process. Special attention is paid to techniques of inprocess evaluation of the EDM process. The paper focuses on adaptive control systems used to optimize the process perfor-
54
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-
55