唐潮小哥英文文献.doc

Product Appearance Designs Based on Reverse EngineeringReverse engineering and its applicationsIn the industrial field, often encountered the demand to build its three-dimensional digital model under the model or in kind. This use of reverse engineering, which refers to a means of measuring the physical model or measurement that digital sampling, and then under the three-dimensional geometric measurement data through the physical reconstruction of Modeling The CAD digital model to achieve product design and manufacturing process. The practical application for Reverse engineering in the industrial manufacturing area includes the following: a) the design of new parts, mainly for imitation or modified product design; b) have been copying and imitation parts, and reproduce the original product design, complex products such as imitation; c) damaged or worn parts of the reduction, in order to repair or re-used; d) product testing, testing of products such as the deformation, welding quality testing, so as to the urgency of processed products with 3-D digital model of the error for analysis. In manufacturing, reverse engineering has become the digestion and absorption of new technologies and secondary development of one of the important building Drive. Improved design as an important tool, which effectively accelerated the response to market new products faster. At the same time, reverse engineering for the rapid prototyping provided a good technical support. The manufacturing sector to become an important and simple transmission of information received from one of the ways. In addition, Reverse engineering has better applications in arts and culture, the medical field, including the wooden model or clay sculpture art aesthetic design, digital artifacts and digital museums, such as virtual surgery. The structural system of Reverse engineeringReverse engineering system mainly consists of three parts: product physical geometry of the figures, CAD model reconstruction, products or die manufacturing. Reverse engineering technology is the key According to the collection, data processing and model of reconstruction. (1) Data Collection Data Acquisition is the first step in reverse engineering, its direct impact on the proper method of whether or not to be accurate, rapid and complete physical access to the two-dimensional, three-dimensional geometry data, affect the reconstruction of CAD solid model of quality, and ultimately affect the product Quality. (2) Data processing For access to a series of data points in the CAD model pre-redevelopment, the need for format conversion, noise filtering, smoothing, alignment, merging, the probe radius compensation and interpolation, and so on-point processing. (3) Model reconstruction Keep the dealt measurement data into CAD system, based on the front curve, surface to build the prototype of the CAD model. Reverse Engineering Research and ApplicationBasic research status quo In reverse engineering of basic research, at home and abroad have done a lot of work, mainly concentrated in the areas of the CAGD surface reconstruction and entities reconstruction algorithm. The international market has a lot of business in the reverse engineering software systems. Domestic basic research of reverse engineering is to start many units, such as Zhejiang University, Huazhong University of Science & Technology, Xian Traffic University, Northwestern University, etc, and has made some achievements.Because of the complexity of the surface reconstruction, reverse engineering fields there are many issues to be studied, including the reconstruction and surface-visual technology, surface modeling methods, feature detection. Application research status quo As an important component of the advanced manufacturing technology, the application research of reverse engineering has become a hot one attention at home and abroad. Reverse engineering is widely used in products imitation or modified design. Siemens electrical panel through the reverse engineering of the turbine blades reverse design, and optimize the design, in less than 12 days time to develop working for other aspects of the new turbine, the system has begun to offer reverse engineering Apps. The use of optical scanners to pump impeller for data collection, designed by reverse the pump impeller three-dimensional modeling. In addition, modified the design of the car Chery and GM are, without exception, the application of the reverse engineering. In the rehabilitation of dilapidated parts of the design, in 2000, the Boeing Company of reverse engineering of the Boeing 747s tail was designed to recover, and in one working day has manufactured parts for older aircraft maintenance and replacement parts provide a fast way. Reverse engineering has also a better application in product testing and error analysis. In the early 1990s, NASA launched a major research on the application of reverse engineering, which was to study X-38 aircraft with the CAD design model match between the precision and error, to analysis and verification CFD (computational fluid dynamics) the accuracy of the simulation. Recently, with the non-contact optical scanners and CAI technology AMT Company improves the speed of inspection parts. CAI scan data input software and CAD design model for comparison and analysis of errors and automatically generate the inspection reports. Before, AMT need to test parts of a half-day set-up and run a few hours now just a half-hour set, the actual testing can be as long as a few minutes. In the field of medical applications, the use of CT tomography technology for obtaining two-dimensional images, through a dedicated software for image processing and model reconstruction. The digital model of human femur, customized for the artificial joint-replacement. Some people at home and abroad to reverse engineering for the design of corrective braces, teeth through the plaster model of scanning and three-dimensional reconstruction, the teeth were three-dimensional digital model. Then, review and correct based on the model, creating a series of corrective braces. At present, the technology has been commercially available in foreign countries. Shanghai Traffic University in China has developed based on the rapid braces reverse engineering design and manufacturing system, and began preliminary application. In general, foreign in reverse engineering research and application of an earlier start: domestic reverse engineering applications mainly concentrated in parts of the complex surface development and mold design. In the automotive, aerospace, toys, and a comprehensive range of industrial applications.Key technologies in Reverse engineeringKind of digital technology That is, scanning the kind of regional planning and ensure accuracy, study the impact of measurement accuracy when scanning the various factors to ensure the accuracy and the method used and measures to check and verify the accuracy of methods in how to scan the region is zoned comprehensive consider scanning accuracy , Scanning efficiency and surface fitting reconstruction of the fitting precision, surface-of-stitching; parts benchmark guarantee the accuracy of measurement problems. The new FlexME of Drake Technology Co., Ltd represents a new generation of reverse engineering (RE) and Computer Aided Inspection (CAI) system has been has begun to enter China. Different from the traditional FlexME system not only has high accuracy, speed, flexibility, and Range, lightweight and easy to move, without the use of special environmental requirements, can be used for the reverse engineering machinery, mold-made computer-aided detection, product processing and assembly-line or off-line detection. Survey data preprocessing That is the cloud data-processing technology: high-density, high-capacity point cloud data processing technologies, including multiple scan point cloud the issue of Mosaic, scanning point cloud data to simplify the problem, cloud-like feature extraction of data and so on. Surface reconstruction Do research on how to choose a suitable method of mathematics, fitting modified algorithms, control parameters and surface reconstruction methods to get high-quality, high-precision surface model. Based on neural network technology in more recent report, Jiang has built such as using a neural network model and the corresponding rapid learning algorithm used in surface reconstruction. The model can be effectively removed approaching surface and enter data points in the bad points. Zhang Wei made based on neural network, such as the triangular grid method can be effective in maintaining the original data points of the topology at the same time achieving the desired characteristics of the scale and precision of the triangular grid post-reverse engineering of key technologies and research. The evaluation and testing of reconstruction surface On the surface of the evaluation index, testing methods and tools that. In SURFACER and CAD software, use NURBS to express surface. It can be very complicated shape that the surface, but the surface, that can not operate very intuitive way, it is difficult to evaluate the surface, testing and modification. Use of graphics center of mass and inertia minimum spindle positioning as a benchmark, measured free surface can be realized with the standard CAD model of the automatic alignment, known CAD model for the realization of the free on-line detection of surface provides a theoretical basis. However, this method of online testing free surface need to overcome a number of factors, such as CMM actual speed measurement system, the actual measurement accuracy of the path of conversion as well as its own part in the work piece at a high field of view outside the region at the center to the location and The impact of measurement accuracy. Related technology research priorities in reverse engineering3D Digital Technology Most of the current measurement system is tailored to specific applications development, data processing often target specific measurement equipment, measurement targets, GM bad. Need to develop reverse engineering for the common measurement system, high-speed, high-precision three-dimensional objects to achieve the surface of digitization, and to follow-up based on geometry and measurement methods and choice of the path, a path to the planning and automatic measurement. Data Preprocessing Research will also focus on hot spots scan point cloud data to simplify the problem of cloud-like feature extraction of data problems. Surface reconstruction Based on neural network technology reconstruction of the surface of the study will have great future, the focus of the study is bound by complex characteristics of the reconstruction and how quickly and accurately identify and restore a point cloud data in the characteristics and constraints, and in ensuring under the premise of effective restraint how to improve the characteristics of the model renewal rate. The evaluation and testing of reconstruction surface This kind of research is also less, I believe that with the reverse engineering in industrial production in the increasing role of online testing and the use of surface reconstruction of the evaluation will cause you enough attention.Reverse engineering: the catalyst behind the next big aerospace leapTen years ago, Boeing Commercial Airplane Groups 777 division created the first airplane that was 100 percent digitally designed and pre-assembled on computer. From that achievement has come two basic facts: using digital processes accelerates design and increases quality, and new technologies need to be adopted to make the next big automation steps.In creating the 777, Boeing used new approaches to designing and building an airplane. The 777 program established design/build teams to develop each element of the airplanes airframe or system. Under this approach, all of the different specialists involved in airplane development designers, manufacturing and tooling engineers, finance, suppliers, customers and others worked jointly to create the new airplane. Based at the same location, team members worked concurrently, sharing their knowledge rather than applying their skills sequentially. Communication among the programs 238 design/build teams was enhanced by sophisticated computers linked by the largest mainframe installation of its kind in the world. Using three-dimensional, digital software, designers could see parts as solid images and then simulate the assembly of those parts on the screen, easily correcting misalignments and other fit or interference problems. As a result of these digital processes, the 777 program has exceeded its goal of reducing change, error and rework by 50 percent. Parts and systems fit together better than anticipated and at the highest level of quality. The first 777 was just .023 of an inch about the width of a playing card away from perfect alignment, compared to a half inch for most airplanes. Boeing has been able to achieve these milestones by using standard forms of data representation and computer-aided design (CAD) tools. In recent years, Boeing and other aerospace companies are finding that modern reverse-engineering systems can extend digital technology into areas such as recreating legacy parts and comparing as-built parts to CAD models for quality assurance.Reducing hard-tooling costsOne of the biggest challenges facing the aerospace industry is reducing costs associated with hard tooling. Many airplanes built 30 years ago are still flying, and hard tooling for spare parts is critical for repairs. Tooling is the standard for manufacturing parts because drawings and digital models either do not exist or are not accurate enough. Keeping aging aircraft flying is as critical to aerospace as keeping computers running is to information technology. From an economic point of view, less than 10 percent of the investment in a new airplane can keep 80 percent of aging airplanes flying. Reducing hard tooling costs is a sure way to boost profit margins. Boeing has again taken the lead in addressing the hard-tooling problem. In 2000, Boeing launched a test project to digitally duplicate a 747 wing tip, create a CAD model, and manufacture the part within one working day. The completed part needed to meet tolerances of three-thousands of an inch. The wing tip was mounted on a platform for scanning by Boeings custom-made system, comprising a line-laser scan head and a mechanical motion controller. Several types of reverse engineering software were used to create the CAD model, and the part was manufactured on site with a process that is consistent with Boeings new product design. Boeings goal was that once the CAD model was obtained, the manufacturing process would be the same whether it was for a new airplane or for the spare parts of an aging airplane. If this process was relatively easy and cost effective, there would be a huge potential to reduce the costs of hard-tooling maintenance.Using the reverse engineering process, a database of 3D CAD files for hard tools can be stored in the computer. If an airplane is on ground for repairs, parts can be made on demand.At the time of Boeings wing-tip project, software vendors were offering a fraction of the functionality available today. The Boeing team was using pre-release betas of first-generation reverse-engineering software. Although the old wing was replicated within the tolerance, the process took more than a day. Simply put, the technology was not mature enough for prime time.Today, reverse engineering technology can reproduce a part like this within one working day. But so far, the new generation of software has not been used widely to reduce the costs of hard-tooling maintenance. One of the reasons is that the process has not been tested in a real production environment.Despite the huge cost-saving potential, companies are more reluctant to spend money on spare parts then they are to spend on development of new products. Nevertheless, there is real value in creating digital inventory of hard tooling, especially in an economic climate where profit matters. Digital hard tooling inventory is one area in which return on investment can be measured and both short- and long-term benefits can be realized.Verifying CFD accuracyReverse engineering also shows promise in aerodynamic computational fluid dynamics (CFD) applications.In the early 1990s, NASA conducted a major study to achieve an accurate match between a physical prototype of an X-38 Autonom Crew Return Vehicle and its digital counterpart. This would allow the agency to verify the accuracy of CFD simulations.Images courtesy of Capture3D and NASAA company called Capture3D was contracted by NASA to create CAD models from point cloud data that resulted from scanning a working X-38 prototype. A combination of a white-light scanner and a photogrammetry system were used to capture the data.Measurement, data calculation and data post-processing took just four days. For the CFD analysis, a CAD model was derived in eight hours based on decimated polygonal data. For detailed analysis, a CAD model based on the dense polygon data was built in five days.A color visualization showed very little deviation between the actual model and the CAD data. Only the symmetry of the wings was slightly out of tolerance. In addition, the CFD analysis showed that a simulated hard landing had not caused damage to the model. Based on its findings, NASA was able to make some corrections to the prototype to improve performance.The success of this project has led NASA to adopt reverse engineering as part of its processes, providing the agency with the equipment to digitize an entire full-sized X-38 CRV in house. Removing the inspection clampAs Matt R