基于归约的几何约束求解策略

针对几何约束系统归约分解中高阶顶点的求解问题,提出高阶低代的低维数值迭代求解算法.通过去除部分约束,使得高阶顶点分解为含有欠约束顶点的低阶求解序列,对求解序列中的欠约束顶点添加虚拟参数变量,以虚拟参数变量的部分迭代求解,替代系统的整体数值求解,提高求解效率和稳定性,算法具有很强的通用性,并在实际应用中得到验证.     

Robust expected violation criterion for constrained robust design problems and its application in automotive lightweight design

Metamodeling techniques are commonly used to replace expensive computer simulations in robust design problems. Due to the discrepancy between the simulation model and metamodel, a robust solution in the infeasible region can be found according to the prediction error in constraint responses. In deterministic optimizations, balancing the predicted constraint and metamodeling uncertainty, expected violation (EV) criterion can be used to explore the design space and add samples to adaptively improve the fitting accuracy of the constraint boundary. However in robust design problems, the predicted error of a robust design constraint cannot be represented by the metamodel prediction uncertainty directly. The conventional EV-based sequential sampling method cannot be used in robust design problems. In this paper, by investigating the effect of metamodeling uncertainty on the robust design responses, an extended robust expected violation (REV) function is proposed to improve the prediction accuracy of the robust design constraints. To validate the benefits of the proposed method, a crashworthiness-based lightweight design example, i.e. a highly nonlinear constrained robust design problem, is given. Results show that the proposed method can mitigate the prediction error in robust constraints and ensure the feasibility of the robust solution.     

对有序组合树法的改进

为了提高有序组合树法的运算效率，必须充分利用约束条件中的有关信息．通过深入分析，提出了极差、必选变量、不可选变量等概念，将多个约束条件联系成为一个整体．提出了用检验约束条件的相容性，并以相容性为判据进行截枝的新办法．证明了如果必选变量全部取值为1是可行解，则必是最优解。给出了改进后的有序组合树法的计算步骤流程．     

Multi-Objective Optimization of Torsion Springs for Solar Array Deployment

For solar array deployment, most existing studies mainly focus on modeling method of deployment dynamics, characteristics of hinges, and synchronization mechanisms. However, torsion springs, which work as the drive mechanisms, have hardly attracted people’s attention. In this study, the influence of the parameters of torsion springs on the deployment behavior of a solar array system with clearance joint is investigated by simulation experiments. The experimental results indicate that the deployment performances are very sensitive to the parameter values of the torsion spring. Suitable torsion springs are highly needed to improve the deployment dynamics of solar array system. Therefore, a multi-objective optimization method for the design of torsion springs is proposed. The objective of the optimization is to make the contact-impact force in revolute joint and the mass of the torsion spring minimum under the constraints of deployment time and structure strength. Finally, the effectiveness of the multi-objective optimization method is verified by an optimization example of solar array system.     

工程建设中的道路选线方法综述

在道路选线模型中,新建道路方案的空间线形自动化几何设计是一个难点,如何更好地实现完全满足道路设计规范限制要求的线形,是未来道路选线研究中的一个重要方向。另外,新建道路往往涉及众多因素的影响,准确考虑并量化这些因素也是道路选线的研究方向。     

A new plan and coordination strategy for robot system based on state space

This paper proposes a general plan and coordination strategy for robot system. The state space for robot system is constructed according to the task requirement and system characteristic. Reachable state of the system is figured out by the system’s internal and external constraints. Task plan and coordination are then transformed as trajectory solving problem in the state space, by which the realizable conditions for the given task are discussed. If the task is realizable, the optimal strategy for task execution could be investigated and obtained in state space. Otherwise, it could be transformed to be realizable via adjusting the system configuration and/or task constraint, and the transformation condition could also be determined. This contributes to design, plan, and coordination of the robotic tasks. Experiments of the manipulator path planning and multi-robot formation movement are conducted to show the validity and generalization of the proposed method. Foundation item: the National Natural Science Foundation of China (No. 60675041) and the Program for New Century Excellent Talents in University (No. NCET-06-0398)     

An Intelligent Response Surface Methodology for Modeling of Domain Level Constraints

An effective modeling method of domain level constraints in the constraint network for concurrent engineering （CE） was developed. The domain level constraints were analyzed and the framework of modeling of domain level constraints based on simulation and approximate technology was given. An intelligent response surface methodology （IRSM） was proposed, in which artificial intelligence technologies are introduced into the optimization process. The design of crank and connecting rod in the V6 engine as example was given to show the validity of the modeling method.     

Robust Parameter Coordination for Multidisciplinary Design

Introduction The essence of multidisciplinary design pro-cess is how to coordinate all the constraints dis-tributed in various disciplines to maintain the con-sistency between product specifications and designvariables. The functions of coordination are to findpotential conflicts, and to provide valid solutions.Young et al[1,2]studied constraint network formodeling and developed several applicable con-straint systems[3-5]. Kannapan et al[6]introduced adesign diagram to represent parametric des…     

高速列车多区间节能操纵优化研究

区间运行时间和操纵方法是实现高速列车节能运行的两个重要方面.本文构建了可调整区间运行冗余时间的高速列车多区间节能操纵模型.考虑到高铁枢纽车站和非枢纽站对列车到达时刻准点性的要求程度不同,模型中增加了枢纽车站的列车到达时刻与列车运行图定到达时刻一致性约束,以及非枢纽车站的列车到达时刻在一定时间范围内的约束.为了避免解空间中不满足定时约束的不可行解的数量影响算法效率,设计了一种三层编码的遗传算法来求解模型.通过1条包含3个枢纽车站、3个非枢纽车站的高速铁路线路验证,结果表明,本文所提出的高速列车多区间节能操纵方法能够保证枢纽车站列车到达时刻不变,非枢纽车站列车到达时刻在一定时间范围内变换时,求得多个区间的列车最优节能操纵速度轨迹.与基于牵引-惰行控制方法和单区间节能操纵方法在图定运行时分下的计算结果相比,本文所提出的方法节能率分别超过16%和4%.     

约束下考虑坐标分量误差相关性的直线拟合

直线拟合在曲线拟合研究及工程实践中受到广泛关注,常用的普通最小二乘和正交最小二乘忽略了坐标分量误差相关性的存在. 基于此,首先论证了在铁路线路整正中全站仪测量坐标点的纵横坐标间存在误差相关性,同时线路中直线的拟合受到相邻线元的约束;然后,基于极大似然估计及拉格朗日条件极值原理,推导出了顾及约束和坐标分量误差相关性的直线拟合通用模型,并给出了高斯-牛顿迭代算法搜索最优解;最后,采用了实测的数据进行了验证及测试. 试验结果表明:该方法能在任何误差分布情况下考虑约束估计直线参数及其精度;考虑坐标相关误差时,参数估计精度在约束及无约束下分别提高了9.2%和2.7%;高斯-牛顿算法在约束及无约束情况下分别仅6次及3次迭代就搜索出最优直线.      

铁水运输调度双层多目标约束优化模型

为实现铁水运输作业排程与资源分配的协同优化，基于约束程序累积调度和字典序多目标优化理论，研究了铁水运输调度双层多目标约束优化方法.首先，基于铁水罐周转率最高和作业效率最高2个字典序优化目标，考虑作业时序、作业实施逻辑、铁水温降时限、铁水罐作业次数限制、资源容量限制和铁水罐资源池等约束条件，建立了上层的铁水运输作业排程约束优化模型；其次，以资源利用均衡度最高为目标，将作业实施唯一性和资源容量限制作为约束条件，建立了下层的铁水运输资源分配约束优化模型；最后，通过约束传播与多点构建性搜索的混合算法迭代求解整个模型.通过实例验证表明：设计的混合算法求得的铁水罐周转率目标和运输作业效率目标，比基本深度优先回溯算法分别提高了14.29%和60.53%；字典序多目标模型比加权和单目标模型求解效率和求解质量分别提高了20.3%和11.11%.     

A Novel Method for Character Segmentation in Natural Scenes

Introduction Nowadays the applications of scene text recog-nition are rapidly expanding with the developmentof portable digital imaging devices[1]. However,character extraction from scene images has alwaysbeen a challenging problem due to complex back-ground, uneven illumination, shadows and noise ofimages[2]. Besides, languages also impose anotherlevel of variation in text. Characters in such lan-guages as Chinese, Japanese and Korean are usual-ly composed of several strokes, which do not n…     

有黏结预应力梁中预应力筋的几何非线性分析

以常规的非线性平面梁元平衡方程为基础,将预应力束视为两端通过刚臂与混凝土梁元节点连接的平面杆元,在局部坐标系(随转坐标系)中计入预应力,根据刚臂在受力后只有刚体运动而本身不变形的特点,采用微分方法导出其在结构坐标系中的切线刚度矩阵,从而获得混凝土梁元与预应力束杆元在结构坐标系中的组合单元切线刚度矩阵;编制了程序,对预应力钢筋混凝土悬臂梁进行几何非线性分析;与ANSYS计算结果比较表明,提出的方法在非线性程度很高时仍能获得高精度数值解,具有对单元数量不敏感,预应力作为非保守荷载的特点容易被计入的优点。     

基于几何约束及迭代的NLOS环境定位算法

针对在非视距 （non-line-of-sight,NLOS）环境中传统最优化定位算法抗NLOS误差能力较弱、且需要一个较准确的初始估计位置以确保算法收敛这一问题,提出一种应用在双基站场景下的基于几何约束及迭代的定位算法. 通过引入最大散射半径作为几何约束条件,以线性迭代方式进行一维全局搜索,并采用最小二乘算法获得移动台（mobile station,MS）初始估计位置,然后利用设定的阈值门限对各初始位置点进行筛选,最后通过加权平均获得MS的最终估计位置. 仿真结果表明:当散射半径为200 m时,本文算法的定位误差在200 m以下的概率能达到100%;在相同环境下,本文算法计算时间开销仅是网格搜索法的0.4%.      

集装箱堆场空间动态配置模型

为了优化集装箱堆场空间资源,减少集卡行驶距离,运用数学规划方法,从平衡箱区倍位箱量和最小化集卡行驶距离入手,在滚动计划的基础上,建立了集装箱堆场空间资源动态配置模型。与集装箱随机配置模型相比,发现集装箱在动态模型配置下,可使集卡行驶距离减少20%左右,提高了集卡使用效率,降低了集装箱作业成本。     

Geometric calibration algorithm of polarization camera using planar patterns

Polarization pattern provides additional information besides spectral signatures. It can be used in many applications, such as navigation, defect detection and object identification. A novel polarization camera composed of four synchronized cameras is proposed, and it can realize real-time polarization measurement. This study particularly concentrates on the geometric calibration of the system. The projection model is analyzed and the multi-camera calibration algorithm is proposed. Firstly, each camera is calibrated separately using planar patterns, and then the geometric calibration algorithms are performed. Due to the geometrical constraint, a global optimization method results in smaller estimation uncertainties. A mean rotation error of 0.025° and a mean translation error of 0.26mm are achieved after geometric calibration. The images are rectified to establish a correspondence among cameras and are combined to acquire the polarization measurement. The polarization pattern of the skylight is measured by the system and the results are consistent with the previous studies.     

确定性空域容量约束下的区域流量管理优化模型

为解决区域内空中交通拥挤问题,以最小化总权重延误和最小化区域外权重延误为优化目标,通过决策偏好参数关联两个优化目标,在确定性扇区容量约束的基础上,增加了流量尾随间隔限制约束和扇区最大允许延误时间约束,构建了满足区域性流量管理实际运行约束条件的基于时间计量的流量管理整数规划模型.选取中南区域的实际空域和航班计划数据,采用CPLEX优化软件求解模型.结果表明:目标函数中的决策偏好参数能调节两个优化目标;新增的约束条件能满足实际运行需求和保证策略的可实施性,即在实施生成的策略时不产生额外的管制员工作负荷.     

沿应变路径准静态加载时混凝土的极限状态现象

为了研究混凝土的力学行为，利用电液伺服系统实验机对立方体试块沿着应变空间中的偏平面压缩路径进行了三轴加载试验．试验结果表明：混凝土材料在应力空间中存在有一个极限状态曲面，当沿着应变路径进行加载时，应力状态点的运动轨迹最后总是汇集到该曲面上，极限状态曲面与应力空间中的破坏面重合．在平均应力p与广义剪应力q构成的直角坐标系中，P轴上存在两个临界值，把p轴划分成低压区、中压区和高压区．当应变路径起点对应的p在同一区内时，p-q曲线彼此相似，在不同区时曲线有一定差异．极限状态现象可能引导研究者建立起一种混凝土特有的新的本构关系理论框架．     

机车车辆车体结构动应力计算方法

为了提高机车车辆的疲劳寿命,优化其结构设计,提出了基于多系统仿真模型和有限元方法的动应力混合计算方法,计算了机车车辆车体结构的动应力。建立以车体为核心的机车多体系统仿真模型,并进行动力学分析,获得关键位置的载荷时间历程。通过有限元准静态应力法,计算了车体结构的准静态应力影响因子。通过载荷时间历程和对应单位载荷作用下的应力影响因子的相互相乘叠加求和计算,获得车体结构在随机动载作用下的应力历程,对实际线路车体结构动应力测试结果和刚性车体与柔性车体的仿真结果进行了对比。对比结果表明:其误差分别是2.462%和7.258%,说明此计算方法计算精度高。     

Research on the Optimization Approach for Cargo Oil Tank Design Based on the Improved Particle Swarm Optimization Algorithm

Based on the improved particle swarm optimization(PSO) algorithm,an optimization approach for the cargo oil tank design(COTD) is presented in this paper.The purpose is to design an optimal overall dimension of the cargo oil tank(COT) under various kinds of constraints in the preliminary design stage.A non-linear programming model is built to simulate the optimization design,in which the requirements and rules for COTD are used as the constraints.Considering the distance between the inner shell and hull,a fuzzy constraint is used to express the feasibility degree of the double-hull configuration.In terms of the characteristic of COTD,the PSO algorithm is improved to solve this problem.A bivariate extremum strategy is presented to deal with the fuzzy constraint,by which the maximum and minimum cargo capacities are obtained simultaneously.Finally,the simulation demonstrates the feasibility and effectiveness of the proposed approach.