Tool Path in Terms of NURBS Curves for Five-axis Sculptured Surface Machining Using Flat-end Tools

The method is adopted and developed to keep constant scallop-height in five-axis machining of NURBS surface using flat-end tools to get the CNC tool path. Then, based on the arithmetic of NURBS interpolation, the standard of NURBS during CAM is achieved. As a result, the CC points' quantity is greatly decreased and the problem that the CC path discontinuities of is overcome. Illustrative examples show the substantial improvements achieved over line-interpolation method for decreasing the amount of data on the condition of the same precision.     

The Geometric precision and Performance Analysis for machining Surface based on Fractals

A new analysis method for machining surface profile error is presented in this paper.The linear regression and nonlinear regression are first applied respectively,and then the Weierstrass Mandebrot fractal function is used to obtain the fractal parameters of machining profiles.A minimal parameter set which depicts the machining surface geometric precision is set up,and the surface profile can be reconstructed using these parameters,and an analysis method for part performance and its tolerance structure is proposed.Examples are provided to illustrate the method is feasible and effective.     

Affine invariant shape recognition with particle swarmoptimization algorithm

Focusing on the problem that affine transformation will exist among the contour images due to variation of the viewpoints, a new approach to extract affine invariant features and matching strategy is proposed for shape recognition. First, the centroid distance and azimuth angle of each boundary point are computed. Then, with a prior defined angle interval, all the points in the neighbor region of the sample point are considered to calculate the average distance for eliminating noise. After that, the centroid distance ratios(CDRs) of any two contour points with angle difference of 180° are achieved as the representation of the shape, which would be invariant to affine transformation. Since the angles of contour points changed non linearly among affine related images, the CDRs should be resampled to build corresponding relationship. It could be regarded as an optimization problem of path planning. In our method, a PSO based path planning model is presented to address this problem. The experimental results demonstrate the efficiency of the proposed method in shape recognition with translation, scaling, rotation, distortion and noise interference.     

Algorithm of Cutter Machining Position during Numerical Controlled Last Carving

Numerical control last making machine is a machine that is used to process shoe last. A new principle of numerical control machining shoe last is put forward aiming at the deficiency of current carving last system. On the basis of the principle, the algorithm of cutter machining position during numerical controlled carving last is analyzed in detail. The complex problem of the calculation of cutter machining positiion is resolved by applying spherical milling cutter that is often used in machining free_curve surface today and taking account of practical situation of the shoe last_making machine. At the same time, the calculation of cutter machining position is realized by program using Visual C++6.0. As a result, the calculation time of cutter machining position is reduced greatly and the efficiency of design is improved. Moreover, the process of carving last is agile and precision of carving last is ensured.     

Application of Error Compensation Methods in High Precision Machining of Globoid Worm

鲜食葡萄始终占主导地位是我国葡萄产业发展的一个突出特点.长期以来,我国鲜食葡萄贮运保鲜业一直比较滞后,基本是季产季销,地产地销.因此,我国鲜食葡萄集中产区经常出现采后"运不出、贮不进、销不掉"的被动局面,阻碍了鲜食葡萄产业在适宜栽植区的快速发展.一些非适宜产区为了填补当地鲜食葡萄市场空白,也在积极发展鲜食葡萄生产,其结果必然导致生产成本提高,不利于我国鲜食葡萄的区域化种植和商品化生产基地的建设.     

随机区间置换的安全算术编码及应用

基于压缩编码的加密方式能够同时完成加密和压缩的功能,通过压缩减少了信息的冗余,同时引入加密使对试图推测出明文信息和找到密钥的攻击具有非常好的鲁棒性。提出了一种基于随机区间置换的安全算术编码,在编码过程中通过随机密钥保证图像压缩编码的安全性,且不影响编码的效率,使其方便在网络中安全传输。实验结果和安全性分析表明该安全算术编码有较好的安全性和加密效率。     

Concurrent Optimal Design for the Mechanical Product Accuracy and its Mathematical Model

A new method,the concurrent optimal design for the mechanical product accuracy is addressed presented, this method is very suitable to a concurrent engineering context. Differing from the convensional tolerance design method, this method establishes a direct link between product working accuracy and machining precision of the parts. Therefore, in the product design phase,the optimal machining tolerances which satisfy the product working accuracy can be determined. Using this method, the design and manufacturing time and cost can be enormously reduced and product quality can be guaranteed.     

Corner detection based on evolution difference of plannar curves in B spline scale space

In order to improve image corner detection precision and efficiency, a novel corner detection algorithm based on B spline scale space evolution difference is proposed. The norm of DoB is defined as corner response function to evaluate the multi scale evolution difference. The DoB corner detector confluents the image boundary features with different scales, which can not only strengthen the response of the feature points, but also depress the influence of noise. Among all corner detection algorithms based on B Spline, the proposed algorithm is relatively lower for computation complexity and faster. The comparative experiments demonstrate that the proposed algorithm works well for localization, robustness against noise, as well as invariance to rotation and scalability.     

Adaptive neighborhood method & GA for solving the vacancy route optimization of machining

The mathematical model of vacancy course path optimization of laser machining is built and changed to the travelling salesman problem (TSP). The Nearest Neighbor (NN) is modified to Adaptive Neighborhood Method (ANM). In ANM one mimics the traveller whose rule of thumb is not always to go next to the nearest as yet unvisited location. The next city is randomly selected from the unvisited cities in adaptive neighborhood. While solving the TSP, ANM is used to create the initial population at first, then iterations are done through selection, cross and mutation operation. In selection, the proposed algorithm only keep 90% samples from the previous generation, the remained agents are supplied by the new sample created by ANM. The results show that the algorithm shortens vacancy course in laser machining and the manufacturing efficiency is improved.     

Adaptive Binary Arithmetic Coding on DSP

As a kind of data compression technique of high efficiency, arithmetic coding is widely used in image compressing. This paper introduces the adaptive binary arithmetic coding used in the new international standard of still image compression named jpeg2000. The implementation of arithmetic coding depends on high power digital signal processor.Fast adaptive binary arithmetic coding and optimized assembly program design are discussed, and its practicability and efficiency are proved.It also can be used in other fields that need compressing data.     

Study of Tooth Contact and Kinematic Precision on Cone-Generated Double Enveloping Worm Gearing

The tooth contact and kinematic precision of cone-generated double-enveloping worm gearing with machining and assembling errors have been investigated. The influence of different errors on driving quality has been discussed. The assembling method to reduce or eliminate the influences of machining errors on tooth contact and kinematic precision has been proposed.     

Analysis on Three -Dimensional Numerical Controlled Last Machining Algorithm

On the basis of applying three dimensional discrete formative technology to describing last surface, working principle of numerical controlled last carving machine is briefly introduced. Then the algorithm of ascertaining milling cutter machining position during the machining process is analyzed in detail. We establish a three dimensional reference frame with spatial analytic geometry and obtain the spatial equation of milling cutter rotary surface. According to last machining character, we put forward a machining algorithm named Minimal Distance Method and is used to calculate the milling cutter machining position. Finally, the glabrous degree of last made by us has reached the conventional demand.     

Improvement of TSP and Application to Oriented Path Optimization for PCB NC Machining

The fast developments of electrical information industry bring electrical manufacture technology the rigorous challenges and the drastic market competitions. This text aiming at the problem, which is instantly solved in the PCB hole sit machining, proposes an oriented path optimized technology for PCB hole sit machining. And the technology uses Greedy algorithm and Ant System Algorithm to solve the problems that more holes and empty runs make machining time longer. The actual applied effect is better and machining efficiency increases 23.9%. Obtain good economic performance.     

Deformable B-spline Curves and Surfaces Model and Its Finite Element Solution

Deformable models are of great importance for contour extraction and surface reconstruction, which cause the deformable models deform to the object contours due to simulated external force.Deformable B spline models can share the merit of the popular used B splie. From the Lagrangian mechanics, the dynamics equation of deformable B spline curve and surface is derived. Its finite element solution is studied including the finite element generation and element matrix calculation. A example is given to verify its validity.     

Nonlinear Forecast System for River Water Pollution Based on GIS

Based on the analysis of the water pollution spatial distribution characters of Yangtze River in Chongqing,a new method based on the integration of BP neural network and genetic arithmetic(GA) is proposed.For some shortcomings existed in the standard BP neural network,this method has ultimately overcome these shortcomings by combining the GA with BP artificial neural network through altering stimulating function,adding momentum factor to power value for BP algorithm and introducing genetic arithmetic to searching for the knots of the hidden layer,momentum factor and learning level.Using this method can easily overcome the difficulty of measuring the water prediction model's parameters.GIS is used as a tool for data management and spatial analysis,and the prediction result of the model for the water pollution spatial distribution characters of Yangtze River in Chongqing is visualized and explored with the precision of more than 78%.     

Sky luminance distribution model by ant colony systems

The sky luminance distribution model is developed by information analysis methods with ant colony system. A new arithmetic is given to solve complex optimization heuristic algorithm. The coefficient values of sky luminance distribution function are obtained by optimization analysis with ant colony system and on which a set of practical software is developed. It can provide an intuitive and easy calculation. The model has higher precision, which can provide valuable results on high precision and standard daylighting design.     

Water Quality Forecasting Method Based on Compensative Fuzzy Neural Network

The forecasting of water quality variation is very important in the process of sewage treatment, which helps the control system work reliably and steadily. In this paper, the compensative fuzzy neural network (CFNN) based on compensative fuzzy logic and neural network and its study arithmetic are introduced. Considering its features as fast speed, steady studying course, global dynamic optimization, CFNN is applied to establish water quality forecasting model. The practical example indicates that the model is not sensitive to initial parameters and has better forecasting precision and faster convergence.     

Application of RBF Algorithm Based on Generalized Genetic Optimization in Prediction Model for Molten Iron Desulfuration

Desulfuration process is a very sophisticate reaction which is not only diverse but also non-line. A RBF algorithm based on generalized genetic optimization is proposed after studying the standard genetic and RBF algorithm. The authors also introduce its application in prediction Model for molten Iron Desulfuration. The algorithm perfectly resolve the problem of random selection of RBF cluster center number. Furthermore, it also reduces the time which GA uses. Comparison between the simulation results of RBF and RBF algorithm Based on GGA optimization further proves the efficiency and precision of its application in Prediction Model for Molten Iron Desulfuration. Finally the result of the test shows that after adopting the algorithm, the end-point hitting ratio can reach eighty-five percent. This indicate the algorithm has the engineering practicability.     

Research on Error Automatic Revised Method of LSI Wafer Honing Process

A new automatic revised method of wafer profile error which uses CCD measuring error,sets up machining data base and carries out a wedge structure for stepless compensating error in honing process is described.Using this technology,a high precision LSI wafers can be obtained.