基于MSRE的机械产品质量特性稳健优化设计方法

为了解决产品质量特性优化设计过程中设计参数发生变差时,最优解变为违反约束条件的不可行解的问题,对产品质量特性的稳健性和稳健性度量进行了分析,建立了基于最小灵敏域估计的产品质量特性稳健优化数学模型,提出了多目标产品质量特性稳健优化设计流程。根据该模型,采用广义差分多目标进化算法求得多目标质量特性稳健优化问题的Pareto稳健优化解集,并使用基于模糊集合理论的方法选择出最优解。在满足产品质量特性设计要求的前提下,优化产品质量特性,提高产品质量特性性能对设计参数变差的稳健性。最后,应用该方法对高速工业平缝机挑线机构进行质量特性稳健优化设计,证明了该方法在工程应用中的正确性与高效性。     

基于区间分析的多边形坯料形状非概率稳健优化

板料实际成形过程中摩擦润滑状态、压边力、拉延筋几何尺寸、材料特性等都具有一定的波动,都存在不确定性。传统的确定性优化设计忽略了不确定因素的影响,导致板料成形性能波动较大,产品质量水平和合格率降低。面向具有很强实用价值的多边形坯料形状优化设计问题,进一步考虑实际生产过程中的不确定因素影响。针对掌握的不确定性数据信息较少的情况,利用非线性区间数规划、函数的区间扩张、响应面代理模型技术及多目标遗传算法,构造基于区间分析的非概率稳健优化方法,并通过实际算例验证该方法的正确性和有效性。该方法大大降低了稳健优化对原始数据的要求,并降低了模具设计对设计人员经验的依赖性,提高了产品质量的稳定性,减少了废品率及生产成本。     

基于冲压成形困难区域的拉延筋阻力稳健设计

汽车覆盖件冲压过程中,工艺参数和材料参数存在不确定性,这种不确定性导致工艺优化设计的难度增加。以冲压件成形困难的局部区域为质量评价区域,通过冲压因素敏感分析筛选出噪声因素和设计变量,将实验设计与响应面法相结合,构建评价指标与设计变量和噪声因素的响应面模型。在此基础上,将响应面模型、蒙特卡洛模拟技术与遗传算法相结合,建立了基于产品质量工程的稳健优化设计方法。实例分析结果表明,经稳健优化后,冲压件成形质量和工艺稳健性获得了显著提高。     

产品质量的模糊稳健性研究及模糊稳健优化设计方法

为解决具有模糊信息时的稳健设计问题，对产品设计质量的模糊特性进行分析，提出了产品质量的模糊目标概念。基于可控因素和噪声因素对模糊目标稳健性影响分析，提出了产品质量模糊稳健性的概念，并给出了模糊稳健设计准则。对模糊稳健设计准则的数学特性和工程意义进行了探讨，进而提出了产品质量模糊稳健优化设计建模方法。设计实例和理论分析表明，产品质量的模糊稳健设计原理，比传统稳健设计方法更接近于工程实际，具有广阔的应用前景。     

基于双响应面法的行星齿轮机构稳健设计研究

双响应面法是通过试验设计分别构造响应面均值和方差的近似模型,并通过该模型进行优化的一种稳健设计方法.文中对双响应面法中的实验设计、响应面模型的建立等内容进行了分析研究,并将此方法应用于行星齿轮机构设计中,建立了基于中心组合试验的行星齿轮机构稳健设计模型.与传统优化方法相比,该方法提高了设计的稳健性.     

基于集成设计平台车辆电磁制动器电磁体的优化及稳健设计

在总结前人研究成果的基础上,通过对电磁制动器电磁体的工作机理及受力情况进行分析,建立基于集成设计平台的电磁体优化设计算法流程,保证所设计的电磁体具有较好的抗倾覆特性及摩擦表面的均匀磨损特性,实现新型非对称结构电磁体的计算机辅助设计。在分析电磁体试验数据的基础上,通过把影响电磁体输出特性的因素划分为可控因素和噪声因素,将基于响应面模型的稳健设计方法应用于电磁体的设计。通过运用回归算法建立电磁体电磁力及其信噪比的二阶响应面模型。将传统的稳健设计方法与现代优化方法相结合,利用Matlab的Fmincon优化函数,获得了电磁体的稳健点以及电磁体所应具有的输出特性,在集成设计平台中实现电磁体的稳健设计。     

基于双响应面模型的6σ稳健设计

双响应面法是通过试验设计分别构造响应均值和方差的近似模型，并通过该模型进行优化的一种稳健设计方法。文中对实验设计方法、响应曲面模型建立以及优化策略等进行分析。为实现质量管理与产品设计的协调，将质量工程中的6σ理念与双响应面法相结合，提出基于双响应面模型的6σ稳健优化设计方法。与传统优化方法相比，该方法不仅提高了优化效率，而且提高了设计的可靠性和稳健性。将其应用于结构优化设计和金属板料的拉深成形优化设计，均获得良好的结果。     

并联机构敏感性分析和多目标优化设计方法

为了解决并联机构全局性能指标高计算成本引起的敏感性分析和多目标优化设计困难,提出了一种结合多项式响应面模型、基于方差的敏感性分析方法和智能优化算法的高效计算方法。首先,确定并联机构的目标函数和设计参数,增加节点密度以提高目标函数的计算精度,基于拉丁超立方体抽样方法和最小二乘多项式拟合技术建立全局目标函数与设计参数之间的响应面解析映射模型,并结合基于方差的Sobol’敏感性分析方法得到对目标函数有重要影响的设计参数。然后,结合敏感性分析结果简化设计参数并建立并联机构的多目标优化设计模型,包括目标函数、约束函数和设计参数,结合响应面模型与智能优化算法开展并联机构多目标优化设计。最后,考虑规则工作空间体积、运动学性能和动力学性能指标为目标函数,以DELTA并联机构为例实现了本文提出的方法。优化前后的结果对比证明了算法的有效性。     

基于梯度法的多目标稳健设计研究

针对多目标稳健设计问题,提出了基于梯度信息的稳健性设计方法。首先构建了多目标稳健性数学模型,在模型中把目标之一的均值作为约束,而把目标之二的稳健性作为优化目标。进一步地,针对复杂系统的多目标稳健设计中梯度难以计算的问题,提出了利用基于近似梯度的方法来进行稳健设计,并引用一个活塞的实例来验证所研究方法的有效性,与其他的稳健设计方法进行了对比。研究结果表明这种近似梯度能够很好地解决复杂系统的多目标稳健设计问题,实现多个目标之间的权衡。     

基于梯度法的多目标稳健设计研究

针对多目标稳健设计问题,提出了基于梯度信息的稳健性设计方法。首先构建了多目标稳健性数学模型,在模型中把目标之一的均值作为约束,而把目标之二的稳健性作为优化目标。进一步地,针对复杂系统的多目标稳健设计中梯度难以计算的问题,提出了利用基于近似梯度的方法来进行稳健设计,并引用一个活塞的实例来验证所研究方法的有效性,与其他的稳健设计方法进行了对比。研究结果表明这种近似梯度能够很好地解决复杂系统的多目标稳健设计问题,实现多个目标之间的权衡。     

Non-probabilistic Robust Optimal Design Method

For the purpose of dealing with uncertainty factors in engineering optimization problems, this paper presents a new non-probabilistic robust optimal design method based on maximum variation estimation. The method analyzes the effect of uncertain factors to objective and constraints functions, and then the maximal variations to a solution are calculated. In order to guarantee robust feasibility the maximal variations of constraints are added to original constraints as penalty term; the maximal variation of objective function is taken as a robust index to a solution; linear physical programming is used to adjust the values of quality characteristic and quality variation, and then a bi-level mathematical robust optimal model is coustructed. The method does not require presumed probability distribution of uncertain factors or continuous and differentiable of objective and constraints functions. To demonstrate the proposed method, the design of the two-bar structure acted by concentrated load is presented. In the example the robustness of the normal stress, feasibility of the total volume and the buckling stress are studied. The robust optimal design results show that in the condition of maintaining feasibility robustness, the proposed approach can obtain a robust solution which the designer is satisfied with the value of objective function and its variation.     

基于Kriging插值和回归响应面法的冲压成形参数的优化及对比分析

首先采用拉丁方试验设计方法进行样本数据设计,同时,为了提高计算效率,将基于Kriging插值和响应面近似模型引入板料成形优化设计的复杂系统中,并基于初始化变量进行优化,采用Kriging插值和响应面近似方法对样本点和优化过程中形成的优化点重新进行响应面构造,以确定优化范围内新的初始值并将约束减小到一定范围;随后采用遗传优化算法对更新的设计变量初始值和约束范围进行优化。如此循环,直至得到最优解。计算结果表明,在汽车覆盖件行李箱盖的压边力、拉延筋阻力最优设置以及避免出现拉裂、起皱现象方面,Kriging插值近似建模技术优于多项式回归响应曲面近似建模技术,其预测精度高,自由度高,建模效率高。     

基于物理规划的起重机主梁稳健优化设计

在机械优化设计中考虑载荷等不确定性因素的影响,用凸集模型描述设计中存在的不确定性,采用物理规划的方法构造不确定性参数的不满意度函数,通过极小化不满意度函数最差值的方法来实现目标函数的稳健性,通过最坏情况分析方法来实现约束函数的稳健性,使目标函数和约束函数都能实现稳健性。建立基于物理规划的稳健可靠性优化模型,这种模型是一种嵌套的优化模型,采用分层方法对其求解。以起重机主梁优化设计为例说明这种模型的合理性。     

基于灵敏度分析的区间不确定性稳健设计

针对机电产品优化设计中存在的大量不确定性因素，在灵敏度分析的基础上提出了区间不确定性稳健设计方法。首先探讨了灵敏度分析理论，借用Sobol'法筛选出对系统影响较大的因素并将不灵敏项进行固化；然后根据区间不确定性因素的特性，分析了不确定因素在某一区间变化时对系统整体的影响；最后给出了基于灵敏度分析的区间不确定性稳健设计优化模型。工程实例证明了该方法的有效性。     

Using response surface methodology with response transformation in optimizing plasma spraying coatings

The paper aims at proposing a method to develop a robust partially stabilized zirconia (PSZ) performance for the plasma spraying process with applications of surface response methodology and fractional factorial experiment. First, with the application of analysis of variance, significant factors are screened. Appropriately choosing control factors while constructing response functions helps to develop a robust process. Second, a nonlinear response surface function is designed to explore the space of the process. This smooths the progress of developing not only a proper relation between yielded and process variables, but also an optimal parameter setting that produces desirable response values. Experimental results show that a quadratic model with the proposed two-step design make it a simple, effective, and efficient way to a robust process. Model prediction is improved by additional data transformation. Optimization of PSZ performance in the plasma spraying process has been achieved.     

基于方差传递模型的飞机蒙皮拉形工艺稳健设计

在蒙皮拉形工艺中,由于诸多不确定因素的存在,传统最优工艺条件下的成形质量存在较大波动.针对该问题,将有限元分析和稳健设计有效结合,提出基于方差传递模型的飞机蒙皮拉形工艺稳健设计方法.分析蒙皮拉形中的主要质量缺陷及关键设计参数,考虑成形过程中设计参数的波动和噪声因子;基于有限元分析和响应面法给出蒙皮拉形工艺的质量缺陷指标...     

六自由度运动平台的动态响应特性分析及AMESim仿真

为了解决液压伺服系统中存在负载干扰等的不确定因素对系统造成不稳定性的问题,以伺服系统中的六自由度液压运动平台试验样机为研究对象,通过对伺服系统动态响应特性进行分析的基础上,提出了动态压力输出补偿的鲁棒H∞控制策略,并进行了物理模型的AMESim仿真.研究结果表明:该方法可在较大摄动的情况下获得好的鲁棒性,并且可以满足设计要求的响应频宽,从而保证平台运动的响应速度和精度.     

Identification of uncertain nonlinear systems for robust fuzzy control

In this paper, we consider fuzzy identification of uncertain nonlinear systems in Takagi-Sugeno (T-S) form for the purpose of robust fuzzy control design. The uncertain nonlinear system is represented using a fuzzy function having constant matrices and time varying uncertain matrices that describe the nominal model and the uncertainty in the nonlinear system respectively. The suggested method is based on linear programming approach and it comprises the identification of the nominal model and the bounds of the uncertain matrices and then expressing the uncertain matrices into uncertain norm bounded matrices accompanied by constant matrices. It has been observed that our method yields less conservative results than the other existing method proposed by S?krjanc et al. (2005) [11] and [12]. With the obtained fuzzy model, we showed the robust stability condition which provides a basis for different robust fuzzy control design. Finally, different simulation examples are presented for identification and control of uncertain nonlinear systems to illustrate the utility of our proposed identification method for robust fuzzy control.     

A normal boundary intersection approach to multiresponse robust optimization of the surface roughness in end milling process with combined arrays

Robust parameter design (RPD) has recently been applied in modern industries in a large deal of processes. This technique is occasionally employed as a multiobjective optimization approach using weighted sums as a trade-off strategy; in such cases, however, a considerable number of gaps have arisen. In this paper, the use of normal boundary intersection (NBI) method coupled with mean-squared error (MSE) functions is proposed. This approach is capable of generating equispaced Pareto frontiers for a bi-objective robust design model, independent of the relative scales of the objective functions. To verify the adequacy of this proposal, a central composite design (CCD) is developed with combined arrays for the AISI 1045 steel end milling process. In this case study, a CCD with three noise factors and four control factors are used to create the mean and variance equations for MSE of two quality characteristics. The numerical results indicate the NBI-MSE approach is capable of generating a convex and equispaced Pareto frontier to MSE functions of surface roughness, thus nullifying the drawbacks of weighted sums. Moreover, the results show that the achieved optimum lessens the sensitivity of the end milling process to the variability transmitted by the noise factors.     

A novel non-probabilistic approach using interval analysis for robust design optimization

A technique for formulation of the objective and constraint functions with uncertainty plays a crucial role in robust design optimization. This paper presents the first application of interval methods for reformulating the robust optimization problem. Based on interval mathematics, the original real-valued objective and constraint functions are replaced with the interval-valued functions, which directly represent the upper and lower bounds of the new functions under uncertainty. The single objective function is converted into two objective functions for minimizing the mean value and the variation, and the constraint functions are reformulated with the acceptable robustness level, resulting in a bi-level mathematical model. Compared with other methods, this method is efficient and does not require presumed probability distribution of uncertain factors or gradient or continuous information of constraints. Two numerical examples are used to illustrate the validity and feasibility of the presented method.