Papers by Author: Jian Zhao

Abstract: The NURBS curve interpolation algorithm based on parabolic interpolation error and the first-order Taylor expansion interpolation algorithm is proposed to improve part surface quality and chord error of NURBS curve interpolation algorithm. The part surface quality is improved effectively by the parabolic interpolation algorithm in the conduction that the previous point, the current point and the next point which was computed by the first order Taylor expansion interpolation algorithm were known. The effectiveness of this algorithm is proved by the NURBS curve interpolation simulation.

Abstract: The curved surface simple expression which met a given tolerance and fairing can be obtained under the conduction that the surface tolerance and fairing had been predetermined by the fitting optimization of the scattered points of the origin curved surface. The genetic factor and evaluation function are designed for the optimized expression of surface is acquired. The validity of the solution is verified by comparing the computed error between fitting optimization surface and the original surface through the numerical simulation.

Abstract: Dynamic characteristic of a system have to be obtained so as to offer the reliable data for the system dynamic modification and dynamic optimum design. The system modal parameters identification can be changed into the global optimization problem in wavelet plane because the wavelet ridges can carry much information of system characteristic parameters. Firstly, the paper will introduce the so-called PSO (Particle Swarm Optimization) technique into the modal analysis and propose the PSO wavelet ridge extraction algorithm. Furthermore, the formulas identifying modal parameters from a wavelet ridge are derived and computation steps were given. The simulation experiments are implemented in order to evaluate precision of this method and the robustness of noise. Finally, the proposed method applies to the modal parameters identification of a watermelon to explore the effectiveness. The experiment results prove the method is precision and insensitive to noise.

Abstract: With the increase of expanded functions, Open CNC system is getting overstuffed gradually, which leads to the decrease of flexibility and reliability. Also, it is hard for users to define their special functions of CNC system. The paper proposes a strategy of intelligent reconfiguration based on floating hierarchical structure. The stepwise control structure of CNC system is broken and a reticular structure is built. Each function unit is assigned a code-array representing its layer levels. By changing values of the code-arrays, the system adjusts layer levels of the function units to adapt change of external environment. Redundant structure and technology of switch circuit are applied to establish internal structure of function unit. Technology of redevelop based on self-conducted configuration and structured language description is put forward. Strategies of simulation and evaluation are applied to prevent the CNC system from being damaged by improper redevelop.