1, CAD technology trends
CAD technology as a mature spread of technology has been widely used in the enterprise, and has become the company's actual productivity. Innovation around the design capabilities and popularity of network computing environment, CAD technology, the main focus on development trends in standardization, open, integrated, intelligent four.
1. In addition to supporting standard CAD software, the progressive realization of ISO standards and industry standards, for the application of standard components (Parts Library), standardized methods have become essential elements in the CAD system, and toward the rationalization of the application of engineering design direction.
Traditional forms of hand-painted drawings already have a mature international standard, mutually understood. And stored on disk, CD-ROM on all kinds of CAD binary digital recording, in order to standardize the complex and much more difficult. From the mid-80s, ISO International Organization for Standardization started brewing the formulation of such standards, called ISO10303 "Product data representation and exchange standard", referred to as STEP. It is designed to cover all the artificial products, the definition of uniform methods of digital. As the STEP standard are involved in a very broad, difficult to reach, standards-making process is very slow, there are many problems. In China, CAD applications with more rigorous implementation of the project organization and leadership system, and actually engaged in the development of CAD application software unit is relatively concentrated, started later than abroad, there is no development with the past to keep the old system compatibility. If you take the initiative to implement the STEP our positive thinking approach, not to dwell on the technical details too cumbersome for our present needs and future technology development, early harmonization of the data model developed software that will help boost domestic CAD industry academic research culture, promote the level of CAD software development greatly improved. This proactive strategy than simply wait for the draft standard version of STEP updated version of a much more favorable. Looking back on history, CAD and computer graphics are always lagging behind the international standard-setting industry standards in the market. CAD product updates frequently. Whose products, technology thought leader, best performance, most users, dominate the market, who is the de facto industry standard. CAD technology is not a purely academic behavior, it is inherent in the high-tech products in the fierce market competition continue to move forward, forever.
CAD software should generally be integrated in a heterogeneous work platform, to support cross-platform heterogeneous environment requires that it should be an open system, and is made by standards-based technology to solve this problem.
Currently, there are two standards: one common standard, mainly from national or international standard-setting unit; the other is the market standard, or industry standards, is a private nature. The former focuses on open standards and the use of advanced technology, which market-oriented, focusing on effectiveness and economic interests into account. Which easily lead to monopoly and unnecessary standard war. By summing up the standardization in this area the experience of several decades, many experts have recognized that standardization of the problems, it has become an obstacle to further development of standards. Therefore raised the question of the standardization work of traditional innovation. Experts suggest that the standard goal of innovation is the common standards should become the industry standard, meaning that after the reform should focus on public standards-based, but from the industry standard in the absorption of its focus on the economy and efficiency advantages. In addition, it was suggested many units are now standard, but the standard-setting process has no standard, which is the standard innovation process should be taken into account. These views on the development of CAD standards in China may be an inspiration.
2. Open CAD systems are widely established in the open operating system, Windows 95/98/NT and UNIX platform, the Java LINUX platform also has CAD products, in addition to CAD systems for the secondary development environment for end users, and even this type of environment can the development of its core source code, so users can customize their own CAD system.
3. Integrated CAD technology integration is reflected in three levels: first, general CAD features CAD / CAE / CAPP / CAM / CAQ / PDM / ERP integration through a variety of forms of an enterprise integration solutions, and promote the process of enterprise information . Ability of innovation and design (CAD) and modern enterprise management (ERP, PDM) integration, has become the focus of enterprise information; Second, is the algorithm used CAD technology, and even functional module or system, made of special chips to improve the efficiency of CAD systems; The third is CAD Web-based computing environment to achieve off-site, heterogeneous systems integration among enterprises. Came into being in the virtual design, virtual manufacturing, virtual enterprise is the level of application integration.
CAD system development of international merchandise Another trend is the worldwide most successful function of component selection, integration. Geometric shape has the most mature platform has two: Parasolid and ACIS; geometric constraint solving component has a, its main products are 2D and 3D DCM. China's development has been part of the mechanical CAD applications using ACIS and Parasolid platform, which is reasonable. However, recently there a kind of international trend to require the liberalization of software development, so as not to be subject to one or two companies the shackles of monopoly products. This is the Linux operating system and its use based on the development of various shareware and open source. China has also developed brewing Internet, operating systems, and various office-made system. At this time, since the development of common platforms and a variety of geometric modeling component will also feature on the agenda, we must be prepared as soon as possible.
4. Intelligent design is a highly intelligent man with the field of creative activity, the development of intelligent CAD CAD is the inevitable direction. From the model of human knowledge and thinking point of view, the existing artificial intelligence technology to simulate human thinking activities (including image thinking, abstract thinking and creative thinking and other forms) are often helpless. Therefore, intelligent CAD than simply existing intelligence technology combined with CAD technology, but also to in-depth study of the mental model of human design and use of information technology to express and simulate it. This will not only produce efficient CAD system, and for the artificial intelligence will provide new theory and methods. CAD of this development, the development of information science will have a profound impact.
Second, CAD technology research and development focus
1. Computer aided conceptual design on the one hand, according to the statistics show that 70% of product production cost is determined in the product design stage. At the same time, once the concept design has been finalized, product design, 60% -70%, also was determined. Special mention is that even if the detailed design no matter how good, can hardly make up for the conceptual design phase of the defection. There is product innovation and the competitiveness of the conceptual design stage basically been determined under. Therefore, the design process of conceptual design is a very important stage, it has become a commanding height enterprise competition. Therefore, more and more computer-aided conceptual design attention. On the other hand, during the conceptual design, involving all the design requirements and constraints of knowledge, is often imprecise, approximate or unknown, that is highly complex, this gives a great deal of CAD technology difficult.
Conceptual design process is basically the process of evaluation and decision-making, which involves product features, movement and structure and other factors, its product's price performance, reliability, security, etc. play a decisive effect. Because of these factors and objectives are manifold. Therefore, evaluation and decision-making process is a very complicated and difficult process. Computer aided conceptual design of the present can be divided into two categories: the automatic generation of programs and interactive generation program. Of course, the application can mix the two methods.
(1) automatic generation of program currently uses artificial intelligence techniques. In order to effectively support the conceptual design of computer activities, need to address two problems. The modeling and reasoning problems: A. The former is a product of function, movement and structural factors influence the complex relationship between the modeling or expression. Such as boilers of steam valve, the base function is to prevent the boilers exploded, its action is when a certain pressure difference is detected, it will automatically open, and its structure is the actual component used in the layout and connection of the building The results provide reasoning model used; B. The inference problem is actually generated and select the appropriate program.
Modeling problem is modeling notation, has proposed a wide range of representation. Such as language, geometric model, graphics, objects, knowledge model and image method, etc., language representation method is a form of description, it can ensure the effective conduct of computer reasoning, known as machine-oriented representation. The image representation is a high visual representation (ie, as the model of thinking), it is focused on providing an environment conducive to innovation-aided design modeling environment for staff, called for people representation, and above other sectors in order of representation between the two.
Although there are many different modeling notation, but they tend to only support 描述 conceptual design of a particular aspect, the lack of one kind of description of conceptual design Neng Tong Yi Ge Zhong factor representation, this is the next target.
Reasoning point at issue is the conversion process, that is, the user needs to map to achieve the requirements set by some of the actual structure. The difficulty is the generation and selection of suitable mapping methods.
The same reasoning, there are many ways to support conceptual design activities, such as neural networks, case-based reasoning, knowledge-based reasoning technology, optimization, value engineering and qualitative reasoning and so on. But only certain areas of design examples, from the full application yet. But in the long run, a lot of work in this area should continue. For example, artificial intelligence, knowledge acquisition is a major problem, in order to solve this problem, you can use data mining technology from the design library has been interested in the field of automatic acquisition of knowledge.
(2) interactive technology, the program generated the concept of design complexity as to automatically generate appropriate program is very difficult. Automatic generation and selection than before the program is not yet ripe, interactive technology is an important means. In the conceptual design phase can take advantage of multimedia technology, such as including effective information search technology to the Internet can be found on the conceptual design of a large number of useful design examples. Another example is the concept of collaborative design technology, so that group members readily participate in the conceptual design and make a positive contribution.
2, computer supported collaborative design is a typical design of group work. Members of both groups, the division of labor, but also cooperation. Therefore, the work group consists of two parts: individual work, group members should complete the task of the respective division; the other is to work together as group work can not be decomposed into mutually independent individual to work with each other between group members related issues. Commonly referred to as interface issues, the interface will inevitably be inconsistencies and conflicts, if not found and coordinate the solution, will result in rework and loss. Traditional CAD systems support only after the division of their specific tasks to be accomplished, as members of the interface issues between the computer can not support, mainly through interviews or a communication tool to discuss and resolve them. But these methods is very difficult to timely and full consultation and to discuss the possibility. Therefore a large design task interface issues inevitably go wrong, that is why the design work will continue to occur repeatedly and constantly modify the main reason for this process.
Computer supported collaborative design of computer supported cooperative work (CSCW) technology in the design of an application. Used to support the design group members to exchange design ideas, discussions about the design, we found that the interface between members of the contradictions and conflicts in a timely manner to coordinate and resolve, reduce and even avoid design iterations, and thus further enhance the efficiency and quality of design work.
People pay more attention collaborative design, there are many prototype systems, some products have been sold in the market. Already work, some are basic, such as modeling, system architecture for CSCW support environment and so on. But the establishment of practical collaborative design system point of view, mainly face the following three questions:
(1) multimedia messaging between members of the group present in the LAN communication method has been more mature, but in the remote network, exchange data, asynchronous transfer, the existing network platform, not a big problem, but more real-time exchange of data. The most important is the selection of transmission media, that is based on the public network (such as the WWW), based on the private network (such as voice transmission can use the phone line, and if leased ISDN bus). Now, most research is focused on public networks on the Internet and Intranet. However, more consideration on product development-only lanes. From the practical effect, the public network less effective, and dedicated lines although the results better, but the price is too high.
(2) co-design of heterogeneous platforms, in the members are scattered in various places, and the variety of equipment conditions. Therefore, the practical co-design system must be able to run in heterogeneous environments, including data transmission, tool integration, there is cross-platform interface, which mainly rely on standardization to address the problem of heterogeneous environment is currently used is a common CORBA, JAVA technology and communications sector standards. But such technology currently on the support of CSCW are inadequate to be enhancements. As for cross-platform interface for development, although a lot of progress, but have yet to see the support of its industry standard.
(3) people - people should be said that interaction between support staff who design groups - people interaction is one of the core issues of collaborative design, in particular, is the automatic discovery of contradictions and conflicts, and automatically coordinated and resolve technology is not mature , so people - particularly important means of human interaction. Currently, the most common is the use of electronic meetings (including whiteboard, voice, video, etc. tools) to support discussion among the members, it is more suitable in design, but use it to discuss the results of very strenuous design, common design modifications result the more impossible. The current design results discussed mainly by the application sharing tool, the tool can reach one person to operate a CAD tool, other members can see in their own end the process and results of operations. This tool can also be integrated and electronic conferencing systems, voice and other tools used in the discussion, application sharing is not the biggest problem is the source of the CAD tool, allowing only one person at a time operation, the other one wants to operate the prior application, approved and In the current operator can operate the rear exit, it is very easy interoperability among its members not directly, it is further resolved.
In short, the status of collaborative design system is a local area network has reached a practical stage, in asynchronous mode, the remote collaborative design is also smaller, but the remote real-time work, and especially on public networks, is still in the experimental stage, of course the whole collaborative design system, there is a certain distance away from the mature stage, many problems to be solved.
3, massive information storage, management and retrieval of CAD system to process information more and more, but also multimedia information. Despite the fast growth of disk capacity, but still can not meet rapidly growing demand for the amount of information. Massive information storage, management and rapid retrieval has become an issue of world attention. In addition to relying on hardware to solve problems, DBMS is an important technology, proven, traditional relational database management system EDBMS hard to have adapted to the requirements and the relationship between object-oriented model of the combination may be a transitional solution.
4, design and related issues of design is a complex and knowledge-intensive group activities, in order to improve the efficiency of the design must follow a correct way, although the design methodology of over half a century, but for CAD for design has only recently, called the formal design process method, which not only let us know what design is a process, but also for the development of CAD tools provide the basis, so understand and identify different aspects of the design process (ie different design activities), is the key to developing a new generation of CAD systems.
Now there have been many design flow method. In the past used the top-down, bottom-up natural possible way, but this method only applies to the detailed design stage. Today, to support the entire design, design research should focus on conceptual design methods and in support of collaborative design on top. For example, the new CAD system can eliminate much as distance and time result in restrictions on the working methods and organization, collaborative designs face of not only people - computer interaction, there are people - human interaction, and thus CAD process more complicated, although People are expected to provide a flexible, mobile, secure and reliable remote collaborative design environment, but if there is no right way to guide, it will be difficult to achieve the desired results.
At present business organization is basically a very strict hierarchy organization, the Democratic organization in this limited, although it can prevent the emergence Tomorrow is the phenomenon and endless debate, but it tied into full play the people with wisdom and intelligence . According to the present situation, using this structure is necessary. But with the change in the way of work methods and organizational structure may change the dynamic composition, as long as the mutual understanding among group members, easy cooperation, perhaps this non-formal organization structure is feasible and can give better play to each person competence.
It should be said so far, design work, or dominated by the designer, but in fact involved in the design of a wide area, including market demand, production feasibility, acceptability and so on price, and therefore co-design, the design group should include all categories of personnel, in addition to the designer, there should be customers, social and human sciences, craft personnel, production personnel, management personnel.
5, support the design of innovative product design innovation is the soul, how to use computers to support innovation, this is a new subject. Currently can only provide a source of inspiration, such as design data into a large number of multimedia and for network designers to easily query, which could lead a fantastic innovative design. Another example is use of CSCW tools, through direct discussion of ways to inspire each other to generate new design ideas, promote innovation and design.
CAD technology can be expected to have a new leap, while a design change would cause.
6, the new technology in the CAD application as described above, CAD is the absorption of new technologies one of the fastest growing areas. Only the following examples:
(1) virtual reality and virtual reality technology for CAD integrated CAD, CAD technology to improve, mainly in two aspects: First, more realistic to see the products being designed and its development process; the other hand, increased interactivity, persons or groups to design and the design products directly interact. VR technology in the CAD application side is also very wide, first of all can have all kinds of immersive visual simulation to verify the correctness and feasibility of the design. For example you can use this simulation technology to design analysis, it is clear that the object deformation and stress distribution, the effect even better than the real test. Second, it can simulate components at the design stage assembly process, to examine the suitability and proper use of parts. As a by-product, it can generate detailed schedule processing, assembling a detailed list of such materials, and directly into the database. In the conceptual design stage, it can be used to program than the election. In particular the use of VR interaction, and support the concept of ergonomic design, test operations are comfortable, convenient, and this motorcycle, automobile, aircraft design is especially useful in collaborative design, the use of VR technology, design groups can directly interact with the designed products should include sharing of design data, discussion and mutual manipulation. VR technology can also be used to develop other people - people interface more realistically perceived and their interaction are members of the group's existence and activities of each other.
Although VR technology in the CAD application prospects great, it's developed very rapidly, but still in the experimental stage at present, widely used from a certain distance. The reason, first of all such equipment is expensive, followed by the performance also needs further improvement. Helmet and data glove not only inconvenient to use them, and use a long time, they will feel uncomfortable. In addition, VR technology applied to CAD itself very much to be done, including the VR data for further processing, the CAD technology in order to better integrate with the VR technology.
(2) Computer security is now the community's work, study and life just can not do without computers, an industry's computer systems were destroyed, it may be affected in this industry and even the whole socio-even Tanhuan. Engineering or product design is separable from the computer, and because ultimately design more and more dependent on computers also growing. At the same time, it not only deal with the large number of design data, and often have some privacy, this is due to fierce market Jing Zheng. So if can not solve the safety and reliability problems, it is difficult to further promote the use of the new CAD system.