Fu Hongya

Development of a PC-based Open Architecture Software-CNC System

Abstract As a key technology in the field of advanced manufacturing, an open architecture controller is studied. In order to develop an open architecture software-CNC system on personal computer (PC) according to open modular architecture controllers (OMAC). First, the software and hardware platform is chosen and software realization methodology for the CNC system is determined. Second, static modeling methods of an open architecture controller inclusive of object-oriented (OO) programming technology, dynamic link library (DLL) technology and system modules partition are investigated. Third, the dynamical behavioral modeling and the data flow representation of open architecture controller are discussed, which are both described in hierarchy finite state machine (FSM) model. Fourth, a reusable software module model is established to develop software function module library. Finally, a 3-axis milling machine tool test-bed, named for HIT-CNC, is successfully designed by means of the constructed software function module library and the system configuring method. The experimental results show that, besides increasing the degree of reusability and openness, application of above-mentioned methodology leads to significant decrease of development time as well as maintenance cost.

Development of PLC-based Tension Control System

Abstract 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.

Cutting Path Planning for Ruled Surface Impellers

Abstract At present, most commercial computer-aided manufacturing (CAM) systems are deficient in efficiency and performances on generating tool path during machining impellers. To solve the problem, this article develops a special software to plan cutting path for ruled surface impellers. An approximation algorithm to generate cutting path for machining integral ruled surface impellers is proposed. By fitting sampling data points of an impeller blade into a curve, a model of ruled surface blade of an impeller is built up. Furthermore, by calculating the points where the cutter axis vector intersects the free-form hub surface of an impeller, problems about, for instance, the ambiguity in calculation and machining the wide blade surface with a short flute cutter are solved. Finally, an integral impeller cutting path is planned by way of an integrated cutter location control algorithm. Simulation and machining tests with an impeller are performed on a 5-axis computer numerically controlled (CNC) mill machine, which shows the feasibility of the proposed algorithm.

Abnormal Shape Mould Winding

Abstract A theory of composite material patch winding is proposed to determine the winding trajectory with a meshed data model. Two different conditions are considered in this study. One is Bridge condition on the concave surface and the other is Slip line condition in the process of patch winding. This paper presents the judgment principles and corresponding solutions by applying differential geometry theory and space geometry theory. To verify the feasibility of the patch winding method, the winding control code is programmed. Furthermore, the winding experiments on an airplane inlet and a vane are performed. From the experiments, it shows that the patch winding theory has the advantages of flexibility, easy design and application.

An Intelligent Controller Based on Constant Cutting Force for 5-Axis Milling

In the machining, process parameters need to be monitored and adjusted automatically, which can improve production quality and reduce machining time. At present, it is mainly concentrated on the study of some algorithms about tool wearing and tool breakage, or theory modeling of interrelated models in the processing machining. The monitoring systems independent of CNC are also investigated to realize the status monitoring on external parts, which result in lower integration and difficulty in operation. Consequently, an integrated controller of five axis milling, which is modular and configurable, is established. Its composition and control flow have been introduced in detail. This controller has the ability of keeping constant cutting force, adjusting feed-rate intelligently, which is a part of CNC system. With this system it can realize the real time status monitoring in machining, and improve the work-pieces quality and efficiency in rough milling. At last, the operating principle of the intelligent algorithm in this controller has been described.

A closed-loop and self-learning STEP-NC machining system

STEP-NC standard has the capability to transfer multiple information relates to machining process among CAD, CAPP, CAM and CNC. In this paper, a machining system which has closed-loop information transmission and self-learning feature is proposed. The architecture of the proposed system is structured utilizing IDEF0 functional modeling languages and the system numerical chain adopts ISO 14649 as the data exchange standard. The system includes following functions: part design, offline process planning, online process planning, part machining, condition monitoring, part measurement, information collection and information analysis. Geometrical data and technological data is transmitted from the upstream of the system to the downstream of the system. Meanwhile, process data which is gathered both during and after machining is sent back to the upstream, therefore the data flow is a closed-loop. All of the information is stored in a database for obtaining design and machining know-how so that the system is self-learning.

Research on reusable and configurable intelligent machining system

To improve production rates and the economic benefits, process parameters need to be monitored and adjusted automatically in the machining. At present, it is mainly concentrated on the study of the algorithms about tool wearing and tool breakage, and theory modeling of interrelated models in the processing machining. The monitoring systems independent of CNC are also investigated to realize the status monitoring on external parts, which result in lower integration and difficulty in operation. Consequently, a modular and configurable machining system of three axis milling is established, with the ability of constant cutting force, which is a part of CNC system and can coordinate with traditional CNC to implement the function of integration state monitoring. With this system it can realize the real time status monitoring in machining, and improve the work-pieces quality and efficiency by controlling the constant cutting force between the work-piece and the tool.

An open architecture motion controller for CNC machine tools

In this paper, a motion controller for computerized numerical control (CNC) machining is developed in accordance with open modular architecture controllers (OMAC) agreement and industry standards. The motion controller is a software package running on personal computer. It is developed based on modular structure adopting hierarchic organization mode. After analysis of software and hardware structure of common CNC machine tools, the motion controller is divided into series of module units. Dynamical behaviors of the controller are described using hierarchic finite state machine (FSM). Reconfigurable controller is realized through setting customizable parameters, appointing rules in module units naming, designing communication interfaces between modules and prescribing format of configuration file. The open architecture motion controller developed has characteristics of user-oriented modules and reconfigurable software, compared with the traditional CNC system of close structure. Besides increasing the degree of reusability and openness, application of above-mentioned open architecture motion controller leads to significant decrease of development time and maintenance cost.

Design and Application of Support Vector Regression Algorithm Based on Ant Colony Optimization

A new data fitting algorithm based on ant colony optimization (ACO) and support vector regression (SVR) is proposed. Ant colony algorithm optimizes three parameters of SVR, including penalty parameter C, insensitive loss function ε and kernel function σ. SVR constructs hyperplane in high dimension space and fits the data in non-linear form. Mean square error of fitting result is used as target of ant colony optimization. ACO finds the best parameters which correspond to the least mean square error. Then, build error compensation scale according to the prediction result, store the scale in motion control card and compensate error in real time. At last, compared ACO-SVR fitting algorithm with polynomial fitting and cubic spline fitting, the results showed that peak-peak value after ACO-SVR compensation was improved from 12.1″ to 2.3″, which was superior to polynomial fitting (4.95″) and cubic spline fitting (2.85″). The ACO-SVR compensation algorithm was proved availability and it was used to compensate shafting system of simulator table successfully.