准最佳二进阵列偶

本文在最佳二进阵列、准最佳二进阵列和最佳二进阵列偶的基础上,定义了一种新的最佳信号,即准最佳二进阵列偶.讨论了准最佳二进阵列偶的体积、变换性质,并对其进行了Fourier频谱分析,得到了部分有益的结果.还用计算机穷举搜索出了体积从2~24的准最佳二进阵列偶.     

Genetic AlgorithmBased Optimization Used in Rolling Schedule

A genetic algorithmbased optimization was used for 1 370 mm tandem cold rolling schedule, in which the press rates were coded and operated. The superiority individual is reserved in every generation. Analysis and comparison of optimized schedule with the existing schedule were offered. It is seen that the performance of the optimal rolling schedule is satisfactory and promising.     

无缝钢管热轧后控冷工艺的组织性能数值模拟

 为了实现无缝钢管生产工艺流程中定(减)径之后矫直之前的控制冷却,采用数值模拟方法研究了20号钢管轧后冷却过程的组织力学性能变化规律。首先采用试验方法测定钢探头在不同冷却介质条件下的温度变化曲线,根据反传热法基本原理计算得出钢探头冷却过程中表面换热系数与工件温度的关系。然后,采用有限差分法建立了钢管冷却过程中的温度场、组织相变及力能性能预测系统,分析了不同冷却工艺条件下钢管的组织状态与力学性能。最后,进行钢管空冷过程的试验分析,测定了不同时刻的温度数据和冷态钢管的力学性能,其计算结果与实测数据吻合良好。该研究结果可为实现无缝钢管控制冷却提供基础性数据。     

Genetic Algorithm-Based Optimization Used in Rolling Schedule

A genetic algorithm-based optimization was used for 1 370 mm tandem cold rolling schedule,in which the press rates were coded and operated.The superiority individual is reserved in every generation.Analysis and comparison of optimized schedule with the existing schedule were offered.It is seen that the performance of the optimal rolling schedule is satisfactory and promising.     

PERFECT PUNCTURED BINARY SEQUENCE PAIRS

This paper presents the definition of perfect punctured binary sequence pair and the combinatorial admissible conditions for searching the perfect punctured binary sequence pairs and proves that all of the pseudo-random binary sequences satisfy these conditions. Computer calculation verifies that the pseudo-random binary sequences with length up to N=127 can be easily turned into perfect punctured binary sequence pairs.     

一种改进滑模观测器的PMSM矢量控制研究

针对永磁同步电机的传统滑模观测器控制中存在估算误差和高频纹波等问题,提出了采用扩展卡尔曼滤波和滑模观测器相结合的方式代替传统滑模观测器的方法。首先,根据永磁同步电机的滑模观测器的数学模型计算定子电流估计值与实际值的误差和反电动势。然后,根据电机EKF状态方程计算输出量,实现参数在线调整,减少参数估算误差,来提高系统的稳态效果和动态性能。最后,搭建了仿真和硬件实验平台进行验证。实验结果表明,改进的滑模观测器控制减少了系统抖动,当调压器改变电压参数时,系统扰动干扰降低了70%,使得永磁同步电机具有更好的可靠性和跟踪性能。     

Stiffness Analysis of Spherical Parallel Mechanism UP+R with 2-DOF

As one of the typical less-mobility parallel mechanisms, the spherical parallel mechanism Up.s with two degrees of freedom （2-DOF） possess high order overconstraints, and the calculation of its stiffness is partly different with general parallel mechanisms owing to the bars in each branch are assumed to be arc-shaped. By means of small deformation superposition principle, the relationship between the angle displacement and line displacement of moving platform and the forces acted on the branches were derived out. Based on the results of static analysis, the relationship between the applied force, the line displacement and the angle displacement of the mechanism was set up. And then the stiffness matrix was obtained. The six principal stiffness of the mechanism and the corresponding directions were achieved by the orthogonal transformation. The numerical calculation was performed and the results showed that the principal stiffness and directions are varied with the pose-position of the mechanism, and the principal stiffness is gradually enlarged when it is far away from the anigin. In addition, the torsion stiffness is much greater and the line deformation stiffness is smaller, the difference between the two parts is huge. The research content of this paper supplies the theoretical foundation for the further engineering design and application of the spherical parallel mechanism.     

构建电子信息类创新实验教学平台的探讨

针对目前高等院校实验教学的现状,根据实验教学改革的设计思路,就如何通过实验教学内容及方法的改革,全面提高学生的素质,培养出具有创新意识、实践能力强的复合型人才,进行了认真地研究和探讨。本文初步讨论了在专业实验教学中怎样通过实验教学改革来开设创新性实验、增强学生的创新意识和实践能力等问题。对培养高素质的创新型硬件人才有一定参考价值。