A Windows bitmap-based numerically controlled sculpture method and its application

Bitmap （BMP） is a widely used format in image processing. With the combination of the digital image processing and computer numerically controlled （NC） techniques, we developed a bitmap-based NC single-step and multi-dot method. An example was provided to illustrate the application and principle of this bitmap-based method in our newly innovated sandblasting glass NC sculpture system.

Java Language for Numerical Control Simulation System Research

Java language is widely used in a variety of development platforms to develop all kinds of application software for its simple and efficient.The programming language owning platform independent is adopted to solve the image flicker,sound loading and other issues by the threading technology,multimedia technology,graphics and point by point comparison techniques.Dynamic real⁃time process simulation is implemented and a two⁃dimensional network of CNC machining simulation system is developed while Java applet application is as a carrier.The simulation results show that the system has a friendly interface and fast calculation speed,and platform portability has a certain practicality and application value.

Kinematics simulation and application for machine tool based on multi-body system theory

Based on the multi-body kinematics principle, the topological structure and restriction relation among parts of machine tool and 3D multi-body model are constructed, the kinematics simulation system of machine tool is developed. The designer can observe the movement and machining course of the whole machine tool and understand accurately the kinematics parameters of components such as position, velocity and acceleration. Also the designer can estimate the pose of components in the virtual circumstance and forecast accurately and correct problems which may appear during the design before the prototype is manufactured to assure the feasibility of design scheme, shorten period of product design and reduce product cost. The simulation system is used during the design of CK1416 high speed and precision numerical control lathe. The curves of ball screw angular velocity and carriage displacement agree well with the results of theoretical calculation and the constructed model is correct.

INTERNET-BASED MACHINING PARAMETER OPTIMIZATION AND MANAGEMENT SYSTEM FOR HIGH-SPEED MACHINING

The theory and its method of machining parameter optimization for high-speed machining are studied. The machining data collected from workshops, labs and references are analyzed. An optimization method based on the genetic algorithm (GA) is investigated. Its calculation speed is faster than that of traditional optimization methods, and it is suitable for the machining parameter optimization in the automatic manufacturing system. Based on the theoretical studies, a system of machining parameter management and optimization is developed. The system can improve productivity of the high-speed machining centers.

CNC SYSTEM OF FLEXIBLE FIXTURE IN AIRCRAFT COMPONENT MANUFACTURING AND ASSEMBLY

The computer numerical control（CNC） system is suited to control varied types of flexible fixtures in aircraft component manufacturing and assembly. The mechanisms and control requirements of flexible fixtures are presented and analyzed. The hardware and software architecture and implementation of CNC system are pro- posed. The flexible fixture mechanism is described using configuration parameters. According to the parameters, the CNC system automatically generates the control feature and the human machine interface （HMI） operation function. The CNC system is implemented in a flexible fixture for skin-strlnger assembly, and results show the effectiveness of the system.

Effects of servo system on limited cutting width in CNC heavy cutting

A mathematical model of the computer numerical control (CNC) heavy cuttingservo system including chatter in cutting courses was constructed for the chatter in CNC heavycutting. The theoretical analysis, computer simulation and orthogonal tests on this model show thatincreasing the gain of position K_(pp) can improve the rapid tracking performance of machine tools,and decreasing the delay time of speed loop τ_s can quickly eliminate the static error in thesystem, but the limited cutting width b_(lim) will descend correspondingly; excessively large orexcessively small gain of speed loop K_(ps) can result in decreasing b_(lim); optimizing K_(pp),τ_s and K_(ps) can improve the dynamic and static performance of the system and increase b_(lim).It is easy and feasible to optimize the servo parameters by the orthogonal test. This method caneffectively improve the system's stability and limited cutting width and it is suitable for the CNCheavy cutting of heavy-duty machine tools.

Development of PLC-based Tension Control System

Fiber winding tension is an important factor in the molding techniques of composite material which influences the quality of winding product directly, and the tension control is a key technique in fiber winding techniques. This paper introduces a closed-loop tension control system with the programmable logic controller （PLC） with function modules as its control kernel, the alternating current （AC） servo motor as execute element and the radius-following device to accomplish the real-time radius compensation. The mechanism of the tension control system is analyzed and the numerical model is set up. The compensation technique of the radius of the scroll is analyzed. Experimental results show that the system is well qualified with high control precision and high reaction speed.

Performance analysis model for real-time Ethernet-based computer numerical control system

In order to optimize the embedded system implementation for Ethernet-based computer numerical control （CNC） system, it is very necessary to establish the performance analysis model and further adopt the codesign method from the control, communication and computing perspectives. On the basis of analyzing real-time Ethemet, system architecture, time characteristic parameters of control-loop ere, a performance analysis model for real-time Ethemet-based CNC system was proposed, which is able to include the timing effects caused by the implementation platform in the simulation. The key for establishing the model is accomplished by designing the error analysis module and the controller nodes. Under the restraint of CPU resource and communication bandwidth, the experiment with a case study was conducted, and the results show that if the deadline miss ratio of data packets is 0.2%, then the percentage error is 1.105%. The proposed model can be used at several stages of CNC system development.

Integrated Systemfor Tube Bending Digital Manufacturing

An integrated CAD/CAPP/CAM system of tube manufacturing based on integration frame is presented. In this system, two kinds of data conventions describing tube shape are presented in tube CAD subsystem, the object-oriented concept and the goal-driven inference mechanism have been applied in the development of the knowledge-based CAPP subsystem and simulation of tube processing under tube bending simulation subsystem is performed based on the tube model＇s piecewise representation. A tube product case is considered to give the application of the integrated system, and the advantages of the system in the use of tube bending are revealed.

Key technologies for the novel distributed numerical control integrated system

A novel distributed numerical control (DNC) integrated system based on plug-in software technology is proposed. It connects new or old numerical control (NC) machine tools which have inhomogeneous numerical control systems with CAD/CAM system by CANbus network. A DNC computer is able to control 15 sets of NC machine tools reliably at the same time. The novel DNC system increases the efficiency of machine tools and improve the production management level by realizing non-paper production, agile manufacturing, networked manufacturing and so on in the near future. Key technologies to construct the novel DNC integrated system include the integration of inhomogeneous numerical control systems, NC program restart, and algorithm for communication competition. Such system has demonstrated successful applications in some corporations that have acquired good economic benefits and social effects.

A high-precision control system for robotic welding positioner

Aiming at the robotic welding positioner with characteristic of parameter change, load change, nonlinearity, and an intelligent control system was researched and developed. This control system used a two-mode controller that based on Fuzzy and PID control method. The results of simulation show that the dynamic and steady performances of the intelligent controller are better than that of single PID or Fuzzy controller. This paper has made a detail theoretical analysis of the constitution design and real-time controlled software and brought up the design and fulfillment method of multi-task real-time control software of high precisely and numerically controlled welding positioner, which has a good result in practice.

OPEN ARCHITECTURE CNC SYSTEM HITCNC AND KEY TECHNOLOGY

Aiming at the characteristics of modularity and reconfigurable in open architecture computer numerical control （CNC） system, the open architecture CNC system, Harbin Institute of Tech- nology computer numerical control （HITCNC）, is researched and manufactured based on the interface standards. The system＇s external interfaces are coincident with the corresponding international standards, and the internal interfaces follow the open modular architecture controller （OMAC） agreement. In the research and manufacturing process, object-oriented technology is used to ensure the openness of the HITCNC, and static programming is applied in the CNC system according to the idea of modularization disassembly. The HITCNC also actualizes real-time and unreal-time modules adopting real-time dynamical linked library （RTDLL） and component object model （COM）. Finite state ma- chine （FSM） is adopted to do dynamically modeling of HITCNC. The complete separation between the software and the hardware is achieved in the HITCNC by applying the SoftSERCANS technique. The application of the above key techniques decreases the programming workload greatly, and uses software programs replacing hardware functions, which offers plenty technique ensures for the openness of HITCNC. Finally, based on the HITCNC, a three-dimensional milling system is established. On the system, series experiments are done to validate the expandability and interchangeability of HITCNC. The results of the experiments show that the established open architecture CNC system HITCNC is correct and feasible, and has good openness.

Web-services-based Integration Design of PDM and DNC Systems

In a networked manufacturing environment, product data integration is the foundation of collaborative manufacturing among manufacturing enterprises. It is very important to build an effective integration mechanism for product data sharing of manufacturing enterprises in geographically dispersed, heterogeneous system platform. In order to integrate enterprise level product data management (PDM) system and shop floor level distributed numerical control (DNC) system, based on the description of Web services technology, a Web-services-based integration approach is presented for facilitating seamless sharing of product data between PDM and DNC systems in a networked manufacturing environment. In order to verify the validity of the proposed approach, an example-based integration development has been implemented with Java 2 Software Development Kit and Java Web Services Developer Pack in Windows 2000 Professional environment.

The Innovation of CNC Machine Interface Based on DNC System

This paper describes the innovation schemes of the interface of a CNC machine which cannot communicate with a computer by a Direct Numerical Control(DNC)interface and the functions of a DNC interface system.One architecture of hardware and software of a practi- cal single-chip computer based on DNC interface system developed by the authors is given. Without any change of the original hardware and software,this DNC interface system has been used to innovate the CNC machine's interface to implement the direct communication between a computer and a CNC machine and to achieve no tape transmission of a part program and ma- chine parameters.It has been demonstrated that this DNC interface system has certain practical values in improving the reliability,efficiency and production management of CNC/NC machine.

Numerical Controlled Rolling Process of Thick Metal Plate

Thick metal plate rolling process has become more and more important in building a flat roof of drilling on the bottom at sea. This is because not only the product quality requirement higher and higher but also the marketing competition. To improve the process of thick metal plate rolling and to increase productivity a numerical controlled rolling process is developed, which include the process planning, the mathematical model establishment and the numerical control system development. The process is for the 17 000 kN×3 000 mm movable up roller bending machine. According to the machine configuration non-symmetry rolling process is planed. This makes it possible to integrate all the steps of plate shaping up such as end side bending, several times of semi-shape bending and the last shape finishing. Since the process will perform under the numerical controlled condition whole steps of the process are considered can be worked in the automatic cycle. The mathematic model consists of two sections, the theory model and the experience parameters model. Which takes the original plate parameters such as geometry and mechanics, characters of the machine such as the movement limits, tonnage and so on as input and calculates all the parameters needed in process performing. Meanwhile, the mathematic Model is totally adapted to the control system. The numerical control system development scheme is based on all the works above. Here, a system plan is provided. The functional modules and hardware selection, in detail, are introduced. The system software on top level and the controlling software for controller are developed. And some unit techniques in the system such as timer setting, communication between system and controller, video integration, and the ability of resisting impact force are introduced. The process has been used successfully in production for more than two years. Practice approves that the process is robust.

Design and Implementation of Distributed Numerical Control in Flexible Manufacturing System

To monitor, control and manage the work process of computer numerical control machine tools in a flexible manufacturing system (FMS) effectively, the distributed numerical coutrol (distributed-NC) software should be innovated with the characteristics of modularization and reconfiguration. In this paper, firstly, distributed-NC functions in the FMS environment are described. Then, we present a design and development method of the real time distributed-NC that is on the basis of the re-coufigurable software and hardware platform and with an object-oriented model concept. Finally, to verify the proposed method, the distributed-NC software has been implemented in VC++ 6.0 and has been tested in connection with the different physical flexible manufacturing shops.

Importance Analysis on Subsystem of CNC Lathe Based on TOPSIS

An importance analysis model for computer numerical control（CNC）lathe subsystems was proposed.The model was based on technique for order preference by similarity to an ideal solution（TOPSIS）and considered the structure correlation between subsystems and the complete machine,the fault correlation of each subsystem and so on.The model can obtain a comprehensive sequencing of subsystems based on their importance to the complete machine.It lays a theoretical foundation for reliability allocation.

Adaptive explicit Magnus numerical method for nonlinear dynamical systems

Based on the new explicit Magnus expansion developed for nonlinear equations defined on a matrix Lie group, an efficient numerical method is proposed for nonlinear dynamical systems. To improve computational efficiency, the integration step size can be adaptively controlled. Validity and effectiveness of the method are shown by application to several nonlinear dynamical systems including the Duffing system, the van der Pol system with strong stiffness, and the nonlinear Hamiltonian pendulum system.

NURBS CURVE INTERPOLATOR WITH ADAPTIVE ACCELERATION-DECELERATION CONTROL

The feedrate profile of non-uniform rational B-spline （NURBS） interpolation due to the contour errors is analyzed. A NURBS curve interpolator with adaptive acceleration-deceleration control is presented. In interpo- lation preprocessing, the sensitive zones of feedrate variations are processed with acceleration-deceleration control. By using the proposed algorithm, the machining accuracy is guaranteed and the feedrate is adaptively adjusted to he smoothed. The mechanical shock imposed in the servo system is avoided by the first and the second time derivatives of feedrates. A simulation of NURBS interpolation is given to demonstrate the validity and the effectiveness of the algorithm. The proposed interpolator can also be applied to the trajectory planning of the other parametric curves.

SOME ALGORITHMS FOR NC MACHINING SIMULATION AND VERIFICATION

This paper presents an approximation method to display realistic pictures of numerical control (NC) machining simulation very quickly. T he tool movement envelope is divided into many small regions and the normal to t hese small regions is calculated. The system saves the calculated result in a fi le before starting animation display. When the system starts displaying machinin g animation, it does not need to calculate small triangular facets normal to the workpiece surface. It only needs to find out what part of the cutter cuts the w orkpiece surface and to read the normal from the file. A highly efficient NC cod e verification method is also presented in this paper. The method first detects the error in z direction. If some points are reported to be out of the tolerance , the system divides neighborhood of these points into smaller grids and calcula tes the normal surface at each grid intersection and the error in the normal ve ctor direction.