Showing papers in "Robotics and Computer-integrated Manufacturing in 1997"
TL;DR: In this article, a set of 17 model parametrizations are developed, including simple criteria for deciding which parameter is to be used in modelling a robot, and the model continuity within each parameter's application range is shown by means of differential geometry.
Abstract: New general kinematic models for robot calibration are presented in this paper These models have the distinct advantage of satisfying the model-parameter identification requirements of completeness, minimality and model continuity for all combinations and configurations of revolute and prismatic joints A set of 17 model parametrizations are developed, including simple criteria for deciding which parametrizations are to be used in modelling a robot The parametrizations presented also result in an accurate representation of the physical robot and thus allow realistic integration of elastic deformation models Model continuity within each parametrization's application range is shown by means of differential geometry Also shown is how these models are be extracted from a non-complex “vector-chain” description of a robot
119 citations
TL;DR: In this paper, two independent, broadly applicable formulations for determining the boundary to manipulator workspaces, presented elsewhere, are compared and validated, and insights gained from one method are used to explain behavior exhibited in the other.
Abstract: The accumulation of two independent, broadly applicable formulations for determining the boundary to manipulator workspaces, presented elsewhere, are compared in this paper. Insights gained from one method are used to explain behavior exhibited in the other. Results are also compared and validated. A numerical formulation based on continuation methods is used to map curves that are on the boundary of a manipulator workspace. Analytical criteria based on row rank deficiency criteria of the manipulator's analytical Jacobian are used to map a family of one-dimensional solution curves on the boundary. The other formulation, based on a similar rank-deficiency criteria, yields analytic boundaries parametrized in terms of surface patches on the boundary. Results concerning the applicability of the numerical method to open- and closed-loop systems are compared with those limited to the open-loop for the analytical method. Conclusions regarding the behavior of the manipulator on geometric entities characterized by singular curves, higher-order bifurcation points, and surfaces inside the workspace are drawn. Applicability of both methods and their limitations are also addressed.
65 citations
TL;DR: In this article, an integrated system for the design and production of sheet-metal parts is described, where important features are automatically generated as the design progresses, and these features are used to produce parts on an automatic bending system.
Abstract: This paper describes an integrated system for the design and production of sheet-metal parts. We have identified some important features for the sheet-metal bending process. These features are automatically generated as the design progresses. After the designs are complete, our automatic process planning system uses the features and generates new ones to aid the production of plans with near-minimum manufacturing costs. Finally, these plans are used to produce parts on an automatic bending system. Once a plan is generated, it can be used to manufacture the part, and to provide feedback to design and other factory systems. The application of features and the potential feature interaction problems are discussed. Several key manufacturing problems are also considered and the result of planning is used to resolve these problems. By solving these feature interaction problems and often practical manufacturing issues, we are able to plan and manufacture the majority of the parts we have tested less than one hour after the flat patterns are prepared.
58 citations
TL;DR: The Design for X (DFX) shell as discussed by the authors is a generic framework which can be easily extended or tailored to develop a variety of DFX tools quickly with consistent quality, and a number of formal but pragmatic constructs are provided.
Abstract: The Design for X (DFX) shell is a generic framework which can be easily extended or tailored to develop a variety of DFX tools quickly with consistent quality. A number of formal but pragmatic constructs are provided. Bills of materials are used to describe and analyse the overall product structure and product characteristics. Flow process charts are used to describe and analyse the overall process structure and process characteristics in relation to individual product elements. Standard operation process charts are modified to describe and analyse the overall process structure in relation to the product structure. Appropriate performance measures are used to evaluate the interactions between the elements of products, processes and resources. This paper discusses a systematic DFX development procedure. The DFX development procedure consists of seven steps, and each step focuses on a major building block of the DFX shell.
47 citations
TL;DR: A new representation called sketching abstraction for conceptual design is presented, using the function-form relations in a design to provide a link between pure functional and pure geometric representations.
Abstract: A large number of design decisions are made during the conceptual design of a part. However, there are few representation and reasoning tools for decision support during conceptual design. The conceptual design stage is characterized by a lack of complete geometric information. Existing geometric modelers require complete geometric information, while a functional reasoning methodology using a verb, noun > representation is typically too terse. In this paper, we present a new representation called sketching abstraction for conceptual design, using the function-form relations in a design. The functionally critical part of the geometry is presented using a set of functional features, while the rest of the geometry is abstracted as a set of linkages. Part functionality is correlated with the sketching abstraction using data structures called function-form matrices. The sketching abstraction is annotated using a set of primitives, and a set of grammar rules are used to extract canonical relationships between the functional features. The sketching abstraction can be used for extracting designs that are geometrically dissimilar but functionally similar, thus providing the designer with ideas for design alternatives. The sketching abstraction can also be used to carry out domain-dependent manufacturability evaluation checks. A further use of sketching abstractions is to initiate the development of a process plan for manufacturing. Sketching abstractions are related to the solid model of a part. Thus, this representation provides a link between pure functional and pure geometric representations. The domain of application is stamped metal parts. We present the part functionality and the features used in this domain. We also illustrate the use of sketching abstractions for conceptual design, manufacturability evaluation and preliminary process planning.
33 citations
TL;DR: In this paper, an on-line calibration methodology for robot relative positioning inaccuracy was developed, which eliminates the need for time-consuming off-line calibrations relying on accurate models and expensive devices.
Abstract: Relative position and orientation inaccuracy always exists between a robot and the equipment with which it operates, especially in batch-type production cells that are subjected to dynamic changes. This inaccuracy causes robot relative positioning errors, and may even result in operation failure if the off-line programmed moving path is implemented without adjustment. To make use of off-line programming and simulation tools, an on-line calibration methodology for robot relative positioning inaccuracy was developed in this study. This methodology eliminates the need for time-consuming off-line calibrations relying on accurate models and expensive devices. An industrial robot system was enabled to detect and compensate automatically for relative positioning errors by incorporating a vision system, a 3-D force/torque sensor, and control strategies involving neural networks. The experimental results showed that this methodology is valid and robust in calibrating the relative position and orientation errors automatically without the need for mathematical models and complex off-line calibration procedures for model parameters. Consequently, batch-type production cells would be more flexible, adaptable and intelligent in accommodating dynamic workcell changes with less human effort.
30 citations
TL;DR: In this paper, a vision-aided reverse engineering approach (VAREA) was developed to reconstruct least-square free-form surface models from physical models, with a coordinate measurement machine (CMM) equipped with a touch-triggered probe and a computer vision system.
Abstract: A vision-aided reverse engineering approach (VAREA) has been developed to reconstruct least-square free-form surface models from physical models, with a coordinate measurement machine (CMM) equipped with a touch-triggered probe and a computer vision system. The VAREA integrates computer vision, surface data digitization and surface modelling into a single process. Two main steps are applied in this innovative approach. The initial vision-driven surface triangulation process (IVSTP) generates a triangular patch by using stereo image detection and a constrained Delaunay triangulation method. The adaptive model-based digitizing process is then used to refine the surface reconstruction and to control accuracy to within user-specified tolerances. As a result, a least-squares bicubic B-spline surface model with the controlled accuracy of digitization can be obtained for further application in product design and manufacturing processes. More than 85% reduction has been achieved in the time required to construct free-form surfaces using this approach, as compared with traditional manual methods with CMM. Therefore, product design lead time can be significantly reduced.
29 citations
TL;DR: Experimental results presented show significant promise for the tethered mobile robot system designed and implemented through the utilization of recently developed servo control technology.
Abstract: The use of a self-propelled mobile robot working in close proximity to a support vehicle for purposes of power, materials, etc. would be extremely valuable for highway maintenance and construction operations. This paper discusses the development of such a uniqe mobile robot system and emphasizes the robot's control system. The wheeled mobile robot is differentially steered and tethered to a support vehicle via a mechanical linkage which has position tracking capability. This mobile robot system has been termed the tethered mobile robot (TMR), and such an approach has the potential for use in a wide variety of highway maintenance operations. An optimal control system applicable to many highway maintenance operations is designed and implemented through the utilization of recently developed servo control technology. Experimental results presented show significant promise for the TMR system.
25 citations
TL;DR: This system utilizes case-based techniques for process selection and sequencing to combine the advantages of the variant and generative approaches to process planning to become more effective and efficient.
Abstract: This research focuses on the development of a process-planning system. This system utilizes case-based techniques for process selection and sequencing to combine the advantages of the variant and generative approaches to process planning. The case-based process planner utilizes an object-oriented model representation to operate on general three-dimensional prismatic parts, which are represented by a collection of features (e.g. slots, pockets, holes, etc.). Each feature subplan is developed by the case-based planner. Then the feature subplans are combined into the global process plan for the part via a hierarchical plan-merging mechanism. Abstracted feature subplans correspond to cases, which are used in subsequent planning operations to solve new problems. The abstracting and storing of feature subplans as cases is the primary mechanism by which the planner learns from its previous experiences to become more effective and efficient.
21 citations
TL;DR: The results of this research will facilitate the rationalization and automation ofNet shape product and process development and thus improve the efficiency and quality, and reduce the cost of net shape product development.
Abstract: This paper presents a systematic approach to developing a collaborative environment for computer-aided concurrent net shape product and process development. This approach includes the steps of (1) conventional development process analysis, (2) development process re-engineering, (3) computer-based system functional requirements analysis, (4) system framework design, and (5) system modeling, integration and implementation. This environment can support concurrent net shape product and process development by providing and integrating functions of product data management, process management and development advisory tools. The results of this research will facilitate the rationalization and automation of net shape product and process development and thus improve the efficiency and quality, and reduce the cost of net shape product development. IDEF structural analysis methodology was employed to capture the characteristics of net shape product and process development process. The concept of concurrent engineering was used to re-engineer the development process. The technology of system engineering was used to design the computer-aided system framework. Object-oriented analysis, modeling and design methodology, knowledge engineering and data engineering techniques were employed for system modeling and implementation.
20 citations
TL;DR: In this article, a modified Stewart platform was used for a material transport system for the automated supply of packaging machines with the necessary paper and foil material, using on-board visual sensors for the location of the bobbins with packaging material that are to be transported.
Abstract: A new lightweight parallel kinematic serves as the basis for a material transport system designated for the automated supply of packaging machines with the necessary paper and foil material. The manipulator, a modified Stewart platform, resembles an overhead tripod and is equipped with an air compressor and a PC-based control with a multitasking real-time operating system. It travels on a gantry railway, using on-board visual sensors for the location of the bobbins with packaging material that are to be transported. The intelligent sensors enable the manipulator to locate the proper bobbin in the quasi-disordered arrangement, depalletize it and transfer it to the requesting machine.
TL;DR: In this paper, the response of a previously proposed teleoperator system, which was not based on the traditional notion of telepresence but on an original form of kinesthetic feedback, is tested under modeling errors of up to 50%.
Abstract: The response of a previously proposed teleoperator system, which was not based on the traditional notion of telepresence but on an original form of kinesthetic feedback, is tested under modeling errors of up to 50%. The original system is enhanced by replacing the previous controller of each robot with a sliding mode robust one. A two-stage approach is employed: a desired trajectory is first generated and then tracked by the controller. The difficulties incurred for the man/machine cooperation are discussed. This extension of the original teleoperator architecture is tested through simulations and compared with a twin system based on neural controllers, presented elsewhere.
TL;DR: In this article, a study of robot-based computer-integrated manufacturing (CIM) automation is presented, where the authors investigated issues regarding robotic workspace utilization, accuracy, repeatability and statistical considerations of fixture design that are relevant to the CIM system integration.
Abstract: In this paper, a study of robot-based computer-integrated manufacturing (CIM) automation is presented. In the study, we investigated issues regarding robotic workspace utilization, accuracy, repeatability and statistical considerations of fixture design that are relevant to the CIM system integration. Taguchi Methods are used to conduct parameter design to improve the accuracy of the Cartesian positions of the end-effector within the robot workspace, subject to spatial considerations of the manufacturing process and required boundary conditions. A SCARA robot with known tolerances of link length and joint angles is used to illustrate the methodology. We find the region within the workspace of the robot which gives rise to better accuracy using the S/N ratios of the Taguchi Methods. The results are compared with theoretical development and show very good agreement. In addition, the design of fixture is investigated with both analytical and statistical approaches. Reliability is defined to facilitate the fixture design. The robot-based CIM system encompasses equipment including a SCARA robot, a spatial robot, a CNC milling machine, a conveyor belt and programmable logic controllers (PLC). The system follows a typical factory floor set-up to demonstrate the ability of robotic applications in manufacturing automation. The CIM system utilizes a graphics user interface (GUI) within a message-based, object-oriented programming environment and is also packaged with interactive multimedia to facilitate the dissemination of research results.
TL;DR: A novel walking principle and control architecture for a walking robot that responds to light, sound and touch in different ways, based on prevailing environmental conditions is presented.
Abstract: This paper presents the design and development of a four-legged mobile robot with intelligent sensing and decision-making capabilities. Multiple sensors with embedded knowledge bases and learning capabilities are used in a novel approach towards environmental perception and reaction. These sensors continuously monitor the environment as well as their own operating parameters. Priority is given to any one or a group of sensors based on prevailing environmental conditions. Intelligent sensing is shown to be the key towards a high degree of autonomy for a mobile robot. Nicknamed Flimar, this robot has the ability to function at varying degrees of intelligence made possible by an object-oriented architecture with embedded intelligence at various levels. This architecture is shown to be conducive towards incremental learning. Each of the four legs has three degrees of freedom, i.e. Flimar has a total of 12 motors on its four legs. Flimar can walk and turn without dragging or skidding, and also turns about its center of gravity with a zero radius. Flimar responds to light, sound and touch in different ways, based on prevailing environmental conditions. The overall goal of the paper is to present a novel walking principle and control architecture for a walking robot.
TL;DR: This research presents a robust “figureiground” framework for visually detecting objects of interest and develops actual servoing systems in order to test the framework's feasibility and demonstrate its usefulness for visually controlling a robot manipulator.
Abstract: Robot manipulators require knowledge about their environment in order to perform their desired actions. In several robotic tasks, vision sensors play a critical role by providing the necessary quantity and quality of information regarding the robot's environment. For example, “visual servoing” algorithms may control a robot manipulator in order to track moving objects that are being imaged by a camera. Current visual servoing systems often lack the ability to detect automatically objects that appear within the camera's field of view. In this research, we present a robust “figureiground” framework for visually detecting objects of interest. An important contribution of this research is a collection of optimization schemes that allow the detection framework to operate within the real-time limits of visual servoing systems. The most significant of these schemes involves the use of “spontaneous” and “continuous” domains. The number and location of continuous domains are. allowed to change over time, adjusting to the dynamic conditions of the detection process. We have developed actual servoing systems in order to test the framework's feasibility and to demonstrate its usefulness for visually controlling a robot manipulator.
TL;DR: A new Bayesian probability map construction method is proposed, which considers estimation of the position error of a mobile robot, and introduced cell ordering uncertainty caused by the position uncertainty of a robot in cell-based map updating.
Abstract: This paper suggests a new sonar mapping method considering the position uncertainty of a mobile robot. Sonar mapping is used for recognizing the unknown environment for a mobile robot during navigation. Usually accumulated position error of a mobile robot causes considerable deterioration of the quality of a constructed map. In this paper, therefore, a new Bayesian probability map construction method is proposed, which considers estimation of the position error of a mobile robot. In this method, we applied approximation transformation theory to estimate the position uncertainty of a real mobile robot, and introduced cell ordering uncertainty caused by the position uncertainty of a robot in cell-based map updating. Through simulation we showed the effect of a robot's position uncertainty on the quality of a reconstructed map. Also, the developed methods were implemented on a real mobile robot, AMROYS-II, which was built in our laboratory and shown to be useful enough in a real environment.
TL;DR: In this paper, a three-stage intelligent controller for non-circular cutting with a lathe (NCL) is developed, where an effective neural network is used to learn the dynamics of the voice coil servomotor system and a modified zero-phase tracking control is designed to obtain an acceptable tracking result.
Abstract: In this paper, a three-stage intelligent controller (TSIC) for non-circular cutting with a lathe (NCL) is developed. In the first stage, an effective neural network is used to learn the dynamics of the voice coil servomotor system. Then a modified zero-phase tracking control (MZPTC) based on the learned model is designed to obtain an acceptable tracking result. Because MZPTC is a type of feedforward control, its performance cannot be ensured as the system is subjected to external load or the aging of system components. In the second stage, an adaptation in control input generated by a fuzzy sliding-mode control is then synthesized with the previous MZPTC to ameliorate control performance. The third stage is to use a forecast compensate control to compensate the cutting error caused by the variant cutting depth (or cutting force). The experimental results of NCL using TSIC, including tracking accuracy (i.e. profile error of finished workpiece) and smoothness of control input (i.e. surface roughness of finished workpiece), are much improved.
TL;DR: In this paper an information system is presented, which fulfils the requirements for an appropriate information management in CIM, an EXPRESS-oriented information system built on top of a commercial relational DBMS.
Abstract: One of the main problems when implementing the computer-integrated manufacturing (CIM) concept concerns information integration. In order to support information integration, an information system provided with suitable data models is required. In this paper an information system is presented, which fulfils the requirements for an appropriate information management in CIM. For this purpose, an EXPRESS-oriented information system has been built on top of a commercial relational DBMS. The conceptual model of the information is built in EXPRESS and then parsed and translated to the corresponding relational constructs. A data access interface has been implemented which allows EXPRESS-oriented data manipulation. The information system was developed inside ESPRIT project No. 2202 CIM-PLATO “CIM System Planning Toolbox” to integrate the information used by the tools developed for flexible manufacturing system planning.
TL;DR: The compliant end-effector coupling (CEEC) as discussed by the authors is a compliant coupling that can be used to assist in precision assembly of a peg insertion and disassembly of a part.
Abstract: Many manipulation tasks require compliance, i.e. the robot's ability to comply with the environment and accomplish force as well as position control. Examples are constrained motion tasks and tasks associated with touch or feel in fine assembly. Few compliance-related tasks have been automated, and usually by active means of active compliance control: the need for passive compliance offered by the manipulator itself has been recognized and has led to the development of compliant end-effectors and/or wrists. In this paper we present a novel passively compliant coupling, the compliant end-effector coupling (CEEC), which aids automated precision assembly. It serves as a mechanical interface between the end of the robot arm and the end-effector. The coupling has 6 degrees of freedom. The design of the coupling is based on a “lock and free” assembly idea. The coupling is locked and behaves like a stiff member during robot motion, and is free (compliant) during constrained motion. It features an air bearing, a variable stiffness air spring and a center-locking mechanism. The end-effector assembly, being centrally unlocked, will float within the designed compliance limits assisted by the air bearing. These frictionless and constraint-free conditions facilitate a fast correction of any initial lateral and angular misalignments. In a peg insertion assembly, such accommodation is possible provided that the tip of the peg is contained within the chamfer of the hole. A variable stiffness air spring was incorporated in the design to allow variable and passive vertical compliance. This vertical compliance allows the accommodation of angular and vertical errors. The center-locking mechanism will return the end-effector assembly to its initial position upon an error correction. In a robot application program, the CEEC can be locked during rapid motion to securely transport a part or be set free during assembly or disassembly processes when the motions are constrained.
TL;DR: The local path-planning algorithm using a human's heuristic and a laser range finder which has an excellent resolution with respect to angular and distance measurements is presented for real-time navigation of a free-ranging mobile robot.
Abstract: The local path-planning algorithm using a human's heuristic and a laser range finder which has an excellent resolution with respect to angular and distance measurements is presented for real-time navigation of a free-ranging mobile robot. The algorithm utilizes the human's heuristic by which the shortest path from the various pathways to the goal can be found, even though the path may not have been taken before. In this paper, the attractive potentials in each candidate pathway are calculated in terms of the angle between the goal and pathway direction, the pathway width, and the angle between pathway and previous heading direction of the mobile robot. Consequently, the mobile robot chooses the optimal path that has the maximum attractive potential among candidate pathways. The heuristic principles are applied to the path decision of the mobile robot such as forward open way, side open way and no way. Also, the effectiveness of the established path-planning algorithm is examined by computer simulation and experiment in a complex environment.
TL;DR: A robust simulation-based method is introduced to solve the trajectory-planning problem heuristically for industrial robot manipulators due to the highly non-linear and non-convex constraints involved.
Abstract: This paper presents a near-optimal trajectory-planning method for industrial robot manipulators. Trajectory planning is discussed considering robot dynamics, singular configurations and collision-free constraints. The problem is formulated as a non-linear mathematical programming model. Owing to the highly non-linear and non-convex constraints involved, a robust simulation-based method is introduced to solve this optimization problem heuristically. This simulation method was tested on a CRS-PLUS robot with a sphere obstacle in three-dimensional work space. Numerical analysis and computational results are presented.
TL;DR: In this paper, a closed loop path precompensation method for a flexible arm robot is proposed to improve the torque profiles and the trajectory fidelity by using partial deformation compensation to track the spatial trajectory.
Abstract: This paper constructed a closed loop path precompensation method for a flexible arm robot. A torque computation method taking care of the elastic arm deformation was first proposed and discussed. A concept of partial deformation compensation was subsequently proposed to improve the torque profiles and the trajectory fidelity. The advantage of this concept was first shown by examples of planar trajectory. After the construction of the closed-loop path precompensation method for a flexible arm, the torque method and partial deformation compensation were incorporated to track the spatial trajectory. Numerical simulations were given to show the usefulness of the proposed concept and method.
TL;DR: In this paper, strategies are presented aimed at improving system efficiency and minimizing tooling costs by considering tool provision as work-oriented, where the tooling is changed to suit the production task, or tool-orientated, where resident tools dictate the work flow, or a combination of the two.
Abstract: The difficulties encountered in managing the tool flow in flexible manufacturing systems for the manufacture of prismatic parts indicate the requirement to handle operational issues such as tool assignment. The choice of operational strategy and its relationship to machine specification, work and tool loading, scheduling and specific mode of tool management may significantly enhance machine utilization and work throughput. In this paper, strategies are presented aimed at improving system efficiency and minimizing tooling costs by considering tool provision as work-orientated, where the tooling is changed to suit the production task, or tool-orientated, where resident tools dictate the work flow, or a combination of the two. This paper draws on evidence from current industrial practice and recent developments.
TL;DR: An assembly sequence planning scheme, giving the time optimal solution for a two-robot cell, is presented, based on dynamic programming, and the time optimum assembly sequence is generated in two stages.
Abstract: An assembly sequence planning scheme, giving the time optimal solution for a two-robot cell, is presented. The scheme is based on dynamic programming, and the time optimum assembly sequence is generated in two stages. In stage one, an initial candidate sequence is derived. The stage-one algorithm is computationally efficient, the complexity being O( log n k ) , where n is the number of elements in k groups. It also gives near-optimal results. Expression for the lower bounds for the total assembly time are derived in order to assess the departure from optimality of the stage-one sequence. In stage two, the initial candidate sequence is optimized using an iterative technique to yield the time optimal sequence. The scheme is extended to account for precedence constraints. It can also be extended for assembly cells with more than two robots. The scheme is tested using computer simulations, and some test results are presented. For the problems solved (typically involving 20 elements), the computational times were less than 5 sec in an Apollo 300 workstation.
TL;DR: In this article, the authors present the results of the research and the development of the universal adaptive compliant device for customary assembly task robot configurations, based on a newly developed SCARA robotic mechanism and combined properties of the SCARA concept and RCC devices.
Abstract: The paper presents the results of the research and the development of the universal adaptive compliant device for customary assembly task robot configurations. The developed system is based on a newly developed SCARA robotic mechanism and combined properties of the SCARA concept and RCC devices. It successfully operates around its true compliance center, obtained under precisely determined conditions.
TL;DR: The evolution of the MARK III FAA cell from research to industrial launch is described, a hybrid cell, combining automatic and manual assembly, which enables a major reduction in the cost of feeders and programming.
Abstract: MARK III is a new concept in flexible automatic assembly (FAA) cells and has technically evolved out of the MARK II concept. The MARK III FAA cell is stepwise upgradeable and enables a major reduction in the cost of feeders and programming. It is a hybrid cell, combining automatic and manual assembly. The cell consists of a railtrack-mounted robot and adopts the sub-batch principle. Developed in order to account for the assembly of a vast range of products and variants, the MARK III allows for near-zero changeover times. By incorporating free-coupled manual assembly stations, the stepwise automation of manual operations is supported. These factors permit the automatic assembly of products with an annual volume normally too low to justify automation. Likewise, MARK III offers excellent opportunities for gradual capacity increase. Furthermore, it can account for unpredictable order schemes. The MARK III FAA cell also adopts a new programming and control system (FACE) which enables a drastic reduction in programming costs. This paper describes the evolution of this FAA cell from research to industrial launch.
Journal Article•
TL;DR: In this article, the authors present new concepts, such as the service task logic route, the logic layout graph of shop floor, the address code of production resource, etc., which can be expressed by retrievable data in a database.
Abstract: For the control of material handling and equipment setup on the shop floor, the sequences of operations such as providing, storing, maintaining, setting up and down production resources, need to be determined according to the layout and production system configuration of the shop floor. In the case of frequent changes of shop floor layout to produce different products in 'one-of-a-kind production' OKP , the sequence of operations will also change frequently. This frequent change of operation sequence creates a conflict between the robustness of the control system structure and the flexibility of the production system configuration in the automatic control of material handling and equipment set-up. To solve this problem, a number of new concepts, such as the service task logic route, the logic layout graph of shop floor, the address code of production resource, etc., are presented. Based on these new concepts, the layout of a shop floor can be expressed by retrievable data in a database. Using this retriev...
TL;DR: The principles for the acquisition of a three-dimensional (3-D) computational model of the treatment area of a burn victim for a vision-servo-guided robot which ablates the victim's burned skin tissue by delivering a high-energy laser light to the burned tissue are discussed.
Abstract: This paper discusses the principles for the acquisition of a three-dimensional (3-D) computational model of the treatment area of a burn victim for a vision-servo-guided robot which ablates the victim's burned skin tissue by delivering a high-energy laser light to the burned tissue. The medical robotics assistant system consists of: a robot whose end effector is equipped with a laser head, whence the laser beam emanates, and a vision system which is used to acquire the 3-D coordinates of some points on the body surface; 3-D surface modeling routines for generating the surface model of the treatment area; and control and interface hardware and software for control and integration of all the system components. Discussion of the vision and surface modeling component of the medical robotics assistant system is the focus of this paper. The robot-assisted treatment process has two phases: an initial survey phase during which a model of the treatment area on the skin is built and used to plan an appropriate trajectory for the robot in the subsequent phase—the treatment phase, during which the laser surgery is performed. During the survey phase, the vision system employs a camera to acquire points on the surface of the patient's body by using the camera to capture the contour traced by a plane of light generated by a low power laser, distinct from the treatment laser. The camera's image is then processed. Selected points on the camera's two-dimensional image frame are used as input to a process that generates 3-D body surface points as the intersection point of the plane of light and the line of sight between the camera's image point and the body surface point. The acquired body surface points are then used to generate a computational model of the treatment area using the non-uniform rational B-splines (NURBS) surface modeling technique. The constructed NURBS surface model is used to generate a treatment plan for the execution of the treatment phase. The robot plan for treatment is discussed in another paper. The prototype of the entire burn treatment system is at an advanced stage of development and tests of the engineering principles on inanimate objects, discussed herein, are being conducted.