三通管液压成形加载路径模糊控制优化

为准确高效地获得优化的管材液压成形加载路径,提出一种结合模糊控制与自适应模拟的实时反馈优化方法,建立缺陷控制规则,通过模糊控制器在有限元模拟过程中实时侦测缺陷的发展趋势并反馈至模拟程序以调整工艺参数,以避免起皱及破裂缺陷的发生,最终获得优化的成形加载路径。通过对典型液压成形件——三通管零件的研究表明：优化加载路径后零件成形质量有了明显改善,模糊控制实现了预期的控制目标。     

基于灰色理论的T形管内高压成形加载路径优化

以最大轴向进给力、支管背压力、内压力为因子,建立正交试验设计方案,进行有限元模拟,获得不同加载路径下的质量目标函数值。利用灰色系统理论,计算各个目标矢量与参考目标值之间的关联系数,将多目标转化为以关联度为目标的单目标。进一步计算各成形工艺参数的平均关联度,获得优化加载路径组合参数,以此进行有限元模拟验证。结果表明,通过该优化方法能获得综合质量较高的内高压成形的T形三通管。     

多目标拟神经优化方法

根据具有最佳逼近和学习功能的神经网络原理 ,建立了多目标拟神经优化方法 ,给出了有关定理及其证明 .     

基于贝叶斯网络的多目标优化算法

针对多目标进化算法中存在的无效进化和计算浪费,本文探讨了基于贝叶斯网络的多目标进化算法,并提出一个新的贝叶斯多目标优化算法。该算法结合个体的强度值和密度值完成非劣择优,利用具有局部结构BD度量机制进行网络度量,采用树形模型构建网络结构。实验结果表明了该算法的有效性。     

ANSYS Workbench的液压油缸多目标优化设计

以液压缸筒为研究对象,利用Ansys Workbench对其进行了数值仿真,并利用其特有的专业优化模块De-sign Xplorer对液压缸筒的质量进行了优化,为液压缸筒的小型化,轻量化提供了有效依据.     

液压支架总体参数多目标优化设计

本文提出了支撑掩护式液压支架总体参数多目标优化设计的一个新的数学模型和算法。编制的BASIC语言程序在IBM-PC/XT微型计算机上通过。对BC480-22/42型液压支架进行计算,验证了程序的正确性和先进性。     

一种自适应混合多目标粒子群优化算法

文章针对多目标粒子群优化算法多样性损失和收敛性不好的问题,提出了一种自适应混合多目标粒子群优化算法。首先,使用Sobol序列映射决策变量初始值,使得初始解集在全决策空间范围有更均匀的分布。使用线性递减权重法调整粒子群算法的权重,增强算法收敛性。提出了使用基于多样性指标SP的自适应变异算子增加种群多样性的同时,还提出了在最优档案集中,使用基于改进的世代距离指标GD的自适应混沌搜索增强算法局部搜索能力。最后,将文中提出的改进算法与MOPSO(基本多目标粒子群优化算法)和NSGA2对比,结果显示出该算法能够在保持优化解收敛性的同时获得更好的多样性。     

板料回弹控制的成形工艺面多目标优化

针对高强度板成形后回弹大的问题,以工件回弹前后对应节点的位移偏差和等效塑性应变裕度最小化为目标,以板料最大增厚率和最小减薄率为约束条件,建立基于车身侧外板回弹控制的工艺面多目标优化模型。采用实验设计（DOE）和径向基函数（RBF）神经网络方法建立优化代理模型,对均匀实验设计方案进行改进以提高优化精度,并与未改进的RBF神经网络和响应面（RSM）代理模型的优化结果进行对比分析。结果表明,建立的多目标优化模型是合理的,改进RBF神经网络代理模型的优化精度较高,在所抽取的满意解中,回弹和等效塑性应变裕度目标函数的相对误差分别为15.9%和2.2%。与实验设计中回弹量最大的样本方案相比,优化后车身侧外板回弹量减少5.149 2 mm。     

三通管内高压成形载荷路径试验优化设计

采用DYNAFORM有限元软件对三通管内高压成形过程进行了数值模拟研究,采用正交试验优化设计方法进行载荷路径参数优化,找出了T型管内高压成形的内压力、轴向进给力、背压力三参数的最优组合,采用该最优组合参数的试验结果与数值模拟结果相吻合。     

Deformation and defects in hydroforming of Y-shaped tubes

Hydroforming process of a Y-shaped stainless steel tube was investigated through numerical simulation and experiments. The forming process and reasons of typical defects were analyzed with three different loading paths. Thickness distribution of formed Y-shaped tube was obtained. It is shown by numerical and experimental results that the transition regions are depressed in the forming condition of low inner pressure and wrinkles occur, while fracture occurs in the forming condition of high inner pressure. After forming, the thickness in left transition fillet region is the largest, that in fight transition fillet region is thinner, and the thinnest thickness is at the top of the protrusion. The original thickness line is below the top of the protrusion. The thinning area occurs above this line, while the thickening area is below this line. The maximum thinning rate is significantly increased as the calibration pressure increases, while the maximum thickening rate remains almost unchanged.     

Multi-objective optimization of process based on resource capability

To improve the practicability, suitability and accuracy of the trade-off among time, cost and quality of a process, a method based on resource capability is introduced. Through analyzing the relationship between an activity and its’ supporting resource, the model trades off the time, cost and quality by changing intensity of labor or changing the types of supporting resource or units of labor of resource in a certain time respectively according to the different types of its’ supporting resources. Through contrasting this method with the model of unit time cost corresponding to different quality levels and inter-related linear programming model of time, cost and quality for process optimizing, it is shown that this model does not only cover the above two models but also can describe some conditions the above two models can not express. The method supports to select different function to optimize a process according to different types of its supporting resource.     

Multi-objective optimization design for leg mechanism of hydraulic-actuated quadruped robot

In order to improve the robot’s abilities of bearing heavy burdens and transporting in complex terrains,the multi-objective optimization design for leg mechanism of the quadruped robot with hydraulic actuated is studied in this paper. The kinematics and dynamics of the robot are analyzed and the two-dimensional linear inverted pendulum model is adopted in planning the trajectories of joints. Then the mathematical model of valve-controlled asymmetric cylinder and control model of single leg are proposed respectively. In the end,NSGA-II algorithm is used to achieve the multi-objective optimization design of parameters concerning single leg mechanism and PD torque control. The results prove that the optimized leg mechanism can significantly reduce the required maximum power of hydraulic system,thus decrease its own weight and lead to the obtaining of good dynamic performance.     

车辆钢板弹簧的多目标可靠性稳健优化设计

为提高车辆钢板弹簧的安全性和稳健性,运用可靠性稳健优化设计理论和多目标思想,为车辆钢板弹簧建立一个可靠性稳健优化设计的高维多目标模型。为提高模型的求解精度,利用层次分析法选取粒子群算法中的全局极值和个体极值,提出了基于层次分析法的多目标粒子群算法。与传统方法相比,利用该算法进行可靠性稳健优化设计高维多目标模型求解,简便易行并能迅速准确地得到车辆钢板弹簧的可靠性稳健优化设计信息。     

花键筒成形有限元模拟及模具优化设计

本文通过分析花键筒的结构特点,分别从塑性成形力、摩擦力等方面进行计算、设计出最优的成形模具参数.通过花键筒成形有限元模拟和实验,验证了设计的最优模具参数,成功成形了合格的花键筒零件.