- Email: [email protected]
Mobile robot routing with dynamic programming
Journal of Manuf~Lmring $ystems Volun~ l~No.
I
Cumulative Abstract Index
processed to automatically generate inspection programs for a specific inspection machine. This computer-aided inspection system provides a foundation for research in the area of caddirected inspection. Because the system is modular, additional capabilities may be added to increase the efficiency of the process or to support other inspection devices. Keywords: Computer integrated Inspection, Dimensioning and Tolerancing, Inspection Systems, Offiine Programming
machining costs--particularly the nonproductive costs associated with workpiece handling---become increasingly important. This phenomenon results in rapidly increasing costs per unit weight (or costs per unit volume) for smaller components. It is also found that by using a cost model, such as the one developed here, it is possible to provide information for the product designer who wishes to make trade-off decisions regarding the materials and manufacturing methods for proposed components. Keywords:Cost Estimating, MachiningCost, ManufacturingCost
A Simulation-Based Production Planning Support Systemfor Printed Circuit Board Fabrication, E. McDowell, S. Randlmwa, pp. 225-2M A network-based simulation model is described to analyze the circuit board insertion process using surface mount technology. The network simulation model is developed using simulation analysis SIMAN designed for an IBM PC/XT or a compatible S~,stem. Among the results of the model are workstation ufilizauons, size of work-in-process inventories at different locations in the process, throughput .times and rates, and production costs. Sensitivity analyses are performed on some of the major factors that can effect the efficiency of the system. The model provides a methodology for evaluating alternative production strategies and offers management a tool to develop efficient production policies, thus minimizing capital and operating costs. Keywords: Computer Simulation, Network Modeling, Circuit Board Insertion, Surface Mount Technology
A Tandem Expert Support System as Jusgifica6onfor a Flexible Mam#'acmring System, S. Padmanabhan, pp. 195-205 A tandem model for the application of symbolic and numerical techniques in the jnstifieation of flexible manufacturing systems is presented in this paper. A methodology for combining knowledge-based systems and traditional analytical tools for performing deterministic and heuristic activities and aiding in decision making tasks is proposed. The paper emphasizes the automation efforts of capturing the knowledge involved in analyzing the intangible strategic benefits and the cost of investments encountered in eqnipment jnstificution procedures. The issues involved in acquiring and representing equipment evaluation knowledge and the transfer of control to coupled algorithmic procedures is addressed. A prototype software using personal consultant plus (PCPLUS), an expert system shell that offers a sophisticated frame structure for imposing rule-order strategies, is developed to define and implement the system. Keywords: Capital Eqnipmeot/Machine Tool Justification, Expert Systems, Coupled Systems, Flexible Manufacturing Systems
1989~ Vol. 8/No. 4
A CNC Machining System for Educa~on, A. Tseng, S. Kolluri, P. Radhakrishnan, pp. 207-14 A computer numerical control (CNC) machining system has been developed. The system includes a three-axis milling/drilling machine, a microprocessor, system software, and an automatically programmed tools (APT) processor. The objective of developing this machining system is to enable new features to be introduced, especially for the educational environment. A unique feature of the system is the use of a general purpose microprocessor as a controller. The CNC system is designed to mclude fundamental features with simple software format and a small scale construction. These make the system a versatile educational tool. An APTprocessor is developed, which can be used to link a geometric file devised by a commercial computer aided design software package to the CNC machine. The cost trade-ofts of using the newly designed system and a comparison with commercial systems are also included. Keyword.v:Computer Numerical Control, Microprocessor, Machine Tool, AFT Programming
Knowledge Engineeringfor Small Batch Manufacturing Systems, P. Wright, pp. 245-256 The skilled craftsmen and setup engineers who prepare and operate small batch manufacturing systems are experts in planrung, hand/eye manipulation tasks and sensor-besed monitoring skills. During knowledge engineering experiments, craftsmen can be studied during the enactiun of such skills. For example, this case study considers some of the activities of experts who plan and supervise the fabrication of complex three-dimensiunal metal parts on computer controlled mi!!ing machines. The broad motivation of this research is to automate small-batch machining so that a machine tool can run completely unattended in future factory systems. Keywords: Small Batch, Machining, Expert Systems, Sensors, Domain Sketches Mobile Robot Routing With Dynamic Programming, J. Cesarone, K. Eman, pp. 257-266 The rise of automated manufacturing systems, and autonomous systems in general, is creating a need for increased intelligence in mobile robotic devices, also known as autonomous guided vehicles (AGVs). One of the most important tasks these vehicles must perform is routing their own path in a cluttered environment. The path must ensure that obstacles are avoided without any unnecessary distance being covered. This paper discusses an approach to solvingthis routing problem. The method employed digitizes the workspac~into a~.'d ofnedes and treats the grid as a transition network. The priuczples of dynamic programming, with slight modifications, can be used to generate paths through this network that exhibit the desired de.l~ee of collision avoidance and economy. The algorithm is qmck and
CAD.Directed Programming of a Wuion-BasedInspection System, M. Traband, D. Medeiros, pp. 215-23 A major difficulty in developing the link from computer aided design (CAD) to automatic part inspection involves extracting the dimensioning and tolerancing information from a part drawing. This design information must be associated with the corresponding geometric features when controlling an inspection machine. In this paper, a methodology is developed for extracting the necessary design information from a CAD system to control a two-dimensional video inspection system. Information regarding part geometry, datums, and geometric tolerances and dimensions is generated during the design process and written to machine-independent data files. This information is then post-
71
JournaIVolume ~Mqan..lufacturin8.
Systems
Cumulative Abstract Index
simple enough to be executed by an on-board microprocessor,and it can be updated whenever the environment changes..The I~eneral principles are discussed, both of dynamic prosramnu~g m lenera] and of its modifications to fit the AGV routing problem. Two examples are then presented. Keywords: Collision Avoidance, Navigation, AGV, Dynamic
Programmin8,Optimization, C]M
results for a simple cantilever beam system and for a desk top articular-arm robot are presented. '~Twords: Manipulator Positioning, Vibration Control, Robotic ystems, Velocity Specification
Holography.Akled Testing of Industrial Robots, A. Kurtogiu, pp. 297-305 In this paper, the flexibility of the mechanical construction of a robot is Investigated for the following two purposes: to qLuan,fify the load-Induced flexibility of the component parts and to include the load-Induced flexibility of the componant parts in the robot variables, so that better modeling is possible. Holographic interferometry was used for measurement because of its ability to simultaneously measure the deformation of every viewable point on the total robot manipulator with great accuracy. A multitude of holograms were made recording the displacement that occurred as forces were applied to different configurations of the robot. Its true behavior was thereby revealed and could be studied analytically. The displacement patterns of individual elements were recorded in detail. Especially observable were deformations occurring on the foot, body, and lower arm of the robot. An endeavor was made using FBbl (finite elements method) to stooy the effects of geometrical modifications to the lower arm, and ~ e maximum stresses were obtained. Models that gave better resutts were achieved. Keywords: Manufacturing Systems, Accuracy, Industrial Robots, Holographic lnterferometry
Economy of Scalefor Manufacturing Systems, P.Ostwald, pp. 267-273 This paper presents a new method for determi.nin."]geconomy of scale for discrete manufacturing systems, a technique that formerly could not be quantified. While economies for operating single pieces of equipment or continuous process production are readily determined, this is not the case with whole manufacturin."8. systems for discrete and durable goods. The proposea memoo breaks bottlenecks in production with the addition of equipment and labor, thus allowing for the determination of optimum capacity charts. These charts are then transformed with standard statistical treatment to give the economy-of-scalemeasure. Technological scaling, ~,hen separated from financial effects, shows the relative importance o f capitalization ana operating costs. Using engineering analysis--rather than accounting dat.~ ".voids obscuring of the scaling index. Specific techniques are demonstrated for sheet metal production systems having low volume and high mix products. Likewise, statistical validation of the economyof-scale measure is provided for advanced sheet metal FMSs. Keyword~: Economy of Scale, Bottleneck, Cost Estimating, Equipment Index, Equipment Capital Cost, Six-tenths Factor
Optimizationof Feedrate in Planar Transla6onalMotions of Robot Manipulators,D. Wu, pp. 306-16 Optimal trajectory planning is concerned with the derivation of optimum parameters for the execution of a given task under constraints imposed by both the design of the robot and characteristics of the task. The problem of optimal trajectory planning for applicadons -such as sheet metal contouring--which is characterized by planar, translational motion of end effector at constant speed, is studied in this paper. Under the described conditions, it is theoretically established that the joint velocities are dir~..tly proportional to the square of the feedrate at any position along me contour. Based on this information, a simple, efficient algon'thm is devel0..~d to determine the optimal feedrate that would maximally utilize the capacities o f the robot. As an example, the method is applied to a six-link articulate type robot using computer simulation. Keywords: Optimal Planning, Feedrate, Robot Contouring
Economic Models of Offshore Assembly in a Printed Circuit Board Assembly System, J. Funk, pp. 274-287
Although nonequipment overhead costs typically represent greater than 80% of manufacturing costs, few models of these costs have been developed and therefore, such expenditures are usually not explicitly considered when choosing a manufacturing system. This paper develops and uses models of retrieval and kitting labor costs along with component and board inventory costs---which together represent a large percentage of manufacturing overhead expenses--to compare U.S. And offshore assembly systems. Due to its higher inventory, other overhead, and shipping costs, offshore assembly is found to be less economically advantageous than previously believed. Keywords:Assembly,Econcmics,Offshore,Kitting,Inventory,PCBs
Applying Velocity 5pec~cation Techniques to Control Robotic
PositioningSystems,W. Atherton,P. FIanagan,A. Messuri,pp.
Batching Policy in Kanban Systems, U. Karmarkar, S. Kekre,
288-296 Residual vibration limits the terminal positioning precision of robotic manipulators. The residual vibratton exhibited by robotic manipulators can be due to low frequency structural modes, selfexcited by the manipulator during operations. In these cases, redesigning the structure to modify the resonant frequency 0ES) causing residual vibration can be impractical or too costly. In this paper, an intelligent controller scheme is developed to measure and control residual vibration caused by the principal structural resonance. The controller tests the robot structure for critical resonant modes, calculates a drive profile using motion specification techniques to control the residual vibration, and then evaluates its effectiveness. A frequency domain interpretation is used to select the preferred input driver waveform. A breadboard controller is also developed for a single-degree-of-freedomdrive system and it is used to validate the proposed strategy. Test
pp. 317-28 Kanban systems differ from traditional inventory- oriented pull systems in that the~Ypermit consideration of the interaction between production lend time and inventory levels. In this paper, the effect of batch sizing policy on production lead time---and hence on inventory levels and cell performance is studied. Both single and dual-curd kanban cells and two-stage kenban systems are modeled as Markovian processes, and the effect of batch sizing_ on expected inventory and back order costs is studied. It is further shown that batching policy has a significant impact on costs. The effect of varying the card count in the cell is also examined. The parameters provide substantial control over the performance of kanban systems. Keywords: Kanban System, Batching, Lead Times, WIP Control, Pull System
72
I
Cumulative Abstract Index
processed to automatically generate inspection programs for a specific inspection machine. This computer-aided inspection system provides a foundation for research in the area of caddirected inspection. Because the system is modular, additional capabilities may be added to increase the efficiency of the process or to support other inspection devices. Keywords: Computer integrated Inspection, Dimensioning and Tolerancing, Inspection Systems, Offiine Programming
machining costs--particularly the nonproductive costs associated with workpiece handling---become increasingly important. This phenomenon results in rapidly increasing costs per unit weight (or costs per unit volume) for smaller components. It is also found that by using a cost model, such as the one developed here, it is possible to provide information for the product designer who wishes to make trade-off decisions regarding the materials and manufacturing methods for proposed components. Keywords:Cost Estimating, MachiningCost, ManufacturingCost
A Simulation-Based Production Planning Support Systemfor Printed Circuit Board Fabrication, E. McDowell, S. Randlmwa, pp. 225-2M A network-based simulation model is described to analyze the circuit board insertion process using surface mount technology. The network simulation model is developed using simulation analysis SIMAN designed for an IBM PC/XT or a compatible S~,stem. Among the results of the model are workstation ufilizauons, size of work-in-process inventories at different locations in the process, throughput .times and rates, and production costs. Sensitivity analyses are performed on some of the major factors that can effect the efficiency of the system. The model provides a methodology for evaluating alternative production strategies and offers management a tool to develop efficient production policies, thus minimizing capital and operating costs. Keywords: Computer Simulation, Network Modeling, Circuit Board Insertion, Surface Mount Technology
A Tandem Expert Support System as Jusgifica6onfor a Flexible Mam#'acmring System, S. Padmanabhan, pp. 195-205 A tandem model for the application of symbolic and numerical techniques in the jnstifieation of flexible manufacturing systems is presented in this paper. A methodology for combining knowledge-based systems and traditional analytical tools for performing deterministic and heuristic activities and aiding in decision making tasks is proposed. The paper emphasizes the automation efforts of capturing the knowledge involved in analyzing the intangible strategic benefits and the cost of investments encountered in eqnipment jnstificution procedures. The issues involved in acquiring and representing equipment evaluation knowledge and the transfer of control to coupled algorithmic procedures is addressed. A prototype software using personal consultant plus (PCPLUS), an expert system shell that offers a sophisticated frame structure for imposing rule-order strategies, is developed to define and implement the system. Keywords: Capital Eqnipmeot/Machine Tool Justification, Expert Systems, Coupled Systems, Flexible Manufacturing Systems
1989~ Vol. 8/No. 4
A CNC Machining System for Educa~on, A. Tseng, S. Kolluri, P. Radhakrishnan, pp. 207-14 A computer numerical control (CNC) machining system has been developed. The system includes a three-axis milling/drilling machine, a microprocessor, system software, and an automatically programmed tools (APT) processor. The objective of developing this machining system is to enable new features to be introduced, especially for the educational environment. A unique feature of the system is the use of a general purpose microprocessor as a controller. The CNC system is designed to mclude fundamental features with simple software format and a small scale construction. These make the system a versatile educational tool. An APTprocessor is developed, which can be used to link a geometric file devised by a commercial computer aided design software package to the CNC machine. The cost trade-ofts of using the newly designed system and a comparison with commercial systems are also included. Keyword.v:Computer Numerical Control, Microprocessor, Machine Tool, AFT Programming
Knowledge Engineeringfor Small Batch Manufacturing Systems, P. Wright, pp. 245-256 The skilled craftsmen and setup engineers who prepare and operate small batch manufacturing systems are experts in planrung, hand/eye manipulation tasks and sensor-besed monitoring skills. During knowledge engineering experiments, craftsmen can be studied during the enactiun of such skills. For example, this case study considers some of the activities of experts who plan and supervise the fabrication of complex three-dimensiunal metal parts on computer controlled mi!!ing machines. The broad motivation of this research is to automate small-batch machining so that a machine tool can run completely unattended in future factory systems. Keywords: Small Batch, Machining, Expert Systems, Sensors, Domain Sketches Mobile Robot Routing With Dynamic Programming, J. Cesarone, K. Eman, pp. 257-266 The rise of automated manufacturing systems, and autonomous systems in general, is creating a need for increased intelligence in mobile robotic devices, also known as autonomous guided vehicles (AGVs). One of the most important tasks these vehicles must perform is routing their own path in a cluttered environment. The path must ensure that obstacles are avoided without any unnecessary distance being covered. This paper discusses an approach to solvingthis routing problem. The method employed digitizes the workspac~into a~.'d ofnedes and treats the grid as a transition network. The priuczples of dynamic programming, with slight modifications, can be used to generate paths through this network that exhibit the desired de.l~ee of collision avoidance and economy. The algorithm is qmck and
CAD.Directed Programming of a Wuion-BasedInspection System, M. Traband, D. Medeiros, pp. 215-23 A major difficulty in developing the link from computer aided design (CAD) to automatic part inspection involves extracting the dimensioning and tolerancing information from a part drawing. This design information must be associated with the corresponding geometric features when controlling an inspection machine. In this paper, a methodology is developed for extracting the necessary design information from a CAD system to control a two-dimensional video inspection system. Information regarding part geometry, datums, and geometric tolerances and dimensions is generated during the design process and written to machine-independent data files. This information is then post-
71
JournaIVolume ~Mqan..lufacturin8.
Systems
Cumulative Abstract Index
simple enough to be executed by an on-board microprocessor,and it can be updated whenever the environment changes..The I~eneral principles are discussed, both of dynamic prosramnu~g m lenera] and of its modifications to fit the AGV routing problem. Two examples are then presented. Keywords: Collision Avoidance, Navigation, AGV, Dynamic
Programmin8,Optimization, C]M
results for a simple cantilever beam system and for a desk top articular-arm robot are presented. '~Twords: Manipulator Positioning, Vibration Control, Robotic ystems, Velocity Specification
Holography.Akled Testing of Industrial Robots, A. Kurtogiu, pp. 297-305 In this paper, the flexibility of the mechanical construction of a robot is Investigated for the following two purposes: to qLuan,fify the load-Induced flexibility of the component parts and to include the load-Induced flexibility of the componant parts in the robot variables, so that better modeling is possible. Holographic interferometry was used for measurement because of its ability to simultaneously measure the deformation of every viewable point on the total robot manipulator with great accuracy. A multitude of holograms were made recording the displacement that occurred as forces were applied to different configurations of the robot. Its true behavior was thereby revealed and could be studied analytically. The displacement patterns of individual elements were recorded in detail. Especially observable were deformations occurring on the foot, body, and lower arm of the robot. An endeavor was made using FBbl (finite elements method) to stooy the effects of geometrical modifications to the lower arm, and ~ e maximum stresses were obtained. Models that gave better resutts were achieved. Keywords: Manufacturing Systems, Accuracy, Industrial Robots, Holographic lnterferometry
Economy of Scalefor Manufacturing Systems, P.Ostwald, pp. 267-273 This paper presents a new method for determi.nin."]geconomy of scale for discrete manufacturing systems, a technique that formerly could not be quantified. While economies for operating single pieces of equipment or continuous process production are readily determined, this is not the case with whole manufacturin."8. systems for discrete and durable goods. The proposea memoo breaks bottlenecks in production with the addition of equipment and labor, thus allowing for the determination of optimum capacity charts. These charts are then transformed with standard statistical treatment to give the economy-of-scalemeasure. Technological scaling, ~,hen separated from financial effects, shows the relative importance o f capitalization ana operating costs. Using engineering analysis--rather than accounting dat.~ ".voids obscuring of the scaling index. Specific techniques are demonstrated for sheet metal production systems having low volume and high mix products. Likewise, statistical validation of the economyof-scale measure is provided for advanced sheet metal FMSs. Keyword~: Economy of Scale, Bottleneck, Cost Estimating, Equipment Index, Equipment Capital Cost, Six-tenths Factor
Optimizationof Feedrate in Planar Transla6onalMotions of Robot Manipulators,D. Wu, pp. 306-16 Optimal trajectory planning is concerned with the derivation of optimum parameters for the execution of a given task under constraints imposed by both the design of the robot and characteristics of the task. The problem of optimal trajectory planning for applicadons -such as sheet metal contouring--which is characterized by planar, translational motion of end effector at constant speed, is studied in this paper. Under the described conditions, it is theoretically established that the joint velocities are dir~..tly proportional to the square of the feedrate at any position along me contour. Based on this information, a simple, efficient algon'thm is devel0..~d to determine the optimal feedrate that would maximally utilize the capacities o f the robot. As an example, the method is applied to a six-link articulate type robot using computer simulation. Keywords: Optimal Planning, Feedrate, Robot Contouring
Economic Models of Offshore Assembly in a Printed Circuit Board Assembly System, J. Funk, pp. 274-287
Although nonequipment overhead costs typically represent greater than 80% of manufacturing costs, few models of these costs have been developed and therefore, such expenditures are usually not explicitly considered when choosing a manufacturing system. This paper develops and uses models of retrieval and kitting labor costs along with component and board inventory costs---which together represent a large percentage of manufacturing overhead expenses--to compare U.S. And offshore assembly systems. Due to its higher inventory, other overhead, and shipping costs, offshore assembly is found to be less economically advantageous than previously believed. Keywords:Assembly,Econcmics,Offshore,Kitting,Inventory,PCBs
Applying Velocity 5pec~cation Techniques to Control Robotic
PositioningSystems,W. Atherton,P. FIanagan,A. Messuri,pp.
Batching Policy in Kanban Systems, U. Karmarkar, S. Kekre,
288-296 Residual vibration limits the terminal positioning precision of robotic manipulators. The residual vibratton exhibited by robotic manipulators can be due to low frequency structural modes, selfexcited by the manipulator during operations. In these cases, redesigning the structure to modify the resonant frequency 0ES) causing residual vibration can be impractical or too costly. In this paper, an intelligent controller scheme is developed to measure and control residual vibration caused by the principal structural resonance. The controller tests the robot structure for critical resonant modes, calculates a drive profile using motion specification techniques to control the residual vibration, and then evaluates its effectiveness. A frequency domain interpretation is used to select the preferred input driver waveform. A breadboard controller is also developed for a single-degree-of-freedomdrive system and it is used to validate the proposed strategy. Test
pp. 317-28 Kanban systems differ from traditional inventory- oriented pull systems in that the~Ypermit consideration of the interaction between production lend time and inventory levels. In this paper, the effect of batch sizing policy on production lead time---and hence on inventory levels and cell performance is studied. Both single and dual-curd kanban cells and two-stage kenban systems are modeled as Markovian processes, and the effect of batch sizing_ on expected inventory and back order costs is studied. It is further shown that batching policy has a significant impact on costs. The effect of varying the card count in the cell is also examined. The parameters provide substantial control over the performance of kanban systems. Keywords: Kanban System, Batching, Lead Times, WIP Control, Pull System
72