Nonlinear optimization strategy based on multivariate prediction capability ratios: Analytical schemes and model validation for duplex stainless steel end milling

Given the complex nature of their phenomena and interactions, industrial processes often have multiple variables of interest, usually grouped into critical-to-quality and critical-to-performance characteristics. These variables often have significant correlations, which make engineering problems multivariate. For this reason, Response Surface Methodology, coupled with multivariate techniques, has been widely used as a logical roadmap for modeling and optimization of the characteristics of interest. However, the variability and prediction capability of the numerical solutions obtained are almost always neglected, reducing the likelihood that numerical results are indeed compatible with observable process improvements. To fill this gap, this paper proposes a nonlinear multiobjective optimization strategy based on multivariate prediction capability ratios. For this, rotated Factor Analysis is used as the multivariate technique for grouping process characteristics and composing capability ratios, so that the prediction variance is taken as the natural variability of the process modeled and the expected value distances to the nadir solutions of the latent variables are taken as the allowed variability. Normal Boundary Intersection method, combined with Generalized Reduced Gradient algorithm, is used as the numerical scheme to maximize the prediction capability of Pareto optimal solutions. To illustrate the feasibility of the proposed strategy, we present a case study of end milling without cutting fluids of duplex stainless steel UNS S32205. Rotatable Central Composite Design, with three cutting parameters, was employed for data collection. Traditional multivariate and proposed approaches were compared. The results demonstrate that the proposed optimization strategy is able to provide solutions with satisfactory prediction capability for all variables analyzed, regardless of their convexities, optimization directions, and correlation structure. In addition, while critical-to-quality characteristics are more difficult to control, they have been favored by the proposed optimization regarding prediction capability, which was a desirable result.     

国际环境不确定下海外采矿权评估研究

在实物期权理论框架下,基于Black-Schole采矿权评估模型,提出了计量国际环境不确定性的方法以及将其纳入评估模型的途径,以此优化完善海外采矿权评估; 通过一实例验证了本文所述方法的可行性,并依据评估结果进一步分析了投资策略,最后对所提方法的可靠性进行了检验。研究结果显示: ① 采矿权价值来自于矿业权人对矿产资源的开采加工及具有灵活经营的权利,国际环境的不确定变化影响采矿权价值及投资策略。② 矿产品价格升高、价格波动率增加、驻在国矿业行业环境和国家环境变异程度的增加、矿山服务年限的增加,均提高了海外采矿权价值; 但矿产品价格下降、矿山服务年限减少将降低采矿权价值。③ 当矿产品价格持续处于低位时,项目应尽早建设或放弃; 而当价格处于增长或高位时,项目可适当推迟建设。④ 老挝矿业行业环境的变异程度大于该国国家环境的变异程度,前往老挝投资的矿企应重点关注该国涉及矿业投资的法律法规及政策,重点防范行业风险。⑤ 本文所提海外采矿权评估方法是可行、可靠的,具有一定实践意义。     

微型离心泵泵叶三层式滑块机构三板模具设计

针对微型离心泵泵叶塑件成型模具设计困难的问题，设计了一种改进型三板点浇口模以用于该泵叶塑件的成型。塑件的浇注成型应用3个点浇口来进行平衡注塑，以控制塑件成型变形。模腔布局为1模1腔。针对塑件叶槽区域脱模困难问题，设计了一种3层3次复合抽芯脱模用于难脱模叶槽部位特征的脱模，机构中，将叶槽部位特征的成型块分割成2层成型件后，机构的第一次抽芯动作由弹簧驱动上层滑块实施上层成型块的抽芯；机构的第二次抽芯由斜导柱驱动实施下层成型块的抽芯；最后，由弯销驱动基座滑块带动2个侧抽芯滑块向外抽芯，以让出塑件完全顶出脱模的运动空间。第二次抽芯、第三次抽芯的驱动动力分别由模架模板的第三次开模、第四次开模打开来进行驱动。塑件的最终脱模由油缸驱动顶针板及顶杆顶出而实现塑件的完全脱模。基于塑件、流道脱模及抽芯机构的动作需要，将典型三板点浇口模架改进为四板4次开模点浇口，从而能使塑件、流道废料及驱动滑块机构分次按序来实施抽芯脱模。模具脱模机构动作设置合理，机构结构设计巧妙，模具整体工作可靠，有较好的设计参考价值。     

Recovery planning of industrial robots based on semantic information of failures and time-dependent utility

Industrial robots are required to recover from temporary errors and continue operations under a changing environment. In this paper, we propose a recovery planning system that considers the semantic information behind errors during robotic actions. In order to establish general repair strategies for feasible recovery plans under uncertainties, the proposed system uses a conceptual graph based on case grammar and a Bayesian network that is dynamically constructed according to the semantic information. In addition, we tackle the problem that the wealth of the recovery plan depends on the uncertainty of execution costs against the deadline at the production site. The proposed system controls the decision model by using a time-dependent utility. We demonstrate the effectiveness of the proposed system through simulations of assembly tasks by multiple robots.     

智能数据分区与布局研究

大数据时代,数据规模庞大,由数据进行驱动的应用分析场景日益增多.如何快速、高效地从这些海量数据中提取出用以分析决策的信息,给数据库系统带来重大挑战.同时,现代商业分析决策对分析数据的实时性要求数据库系统能够同时快速处理ACID事务和复杂的分析查询.然而,传统的数据分区粒度太粗,且不能适应动态变化的复杂分析负载;传统的数据布局单一,不能应对现代大量增加的混合事务分析应用场景.为了解决以上问题,“智能数据分区与布局”成为当前的研究热点之一,它通过数据挖掘、机器学习等技术抽取工作负载的有效特征,设计最佳的分区策略来避免扫描大量不相关的数据,指导布局结构设计以适应不同类型的工作负载.首先介绍了智能数据分区与布局的相关背景知识,然后对智能数据分区与布局技术的研究动机、发展趋势、关键技术进行详细的阐述.最后,对智能数据分区与布局技术的研究前景做出总结与展望.     

基于动态策略的移动警务终端安全管控系统的设计与实现

对移动警务安全接入平台中的终端设备的安全防护问题进行了研究,提出并研制了一种基于动态策略的移动警务终端安全管控系统,整个系统由客户端、前置服务端和内网服务端组成,前置服务端和内网服务端分别部署在前置区和公安内网,客户端部署在移动终端设备上,确保在移动接入区和公安内网区有效进行物理隔离的前提下,将系统制定的各种安全策略规则下发到客户端执行,规范用户对移动终端的本地软硬件资源和网络资源的使用,实现安全威胁检测、防护及预警,对移动终端用户的违规访问、操作行为进行全面监测和上报,实现终端设备安全和行为的统一管理.     

可控中高软压光控制策略分析

可控中高软压光具有纸面整饰作用,可大幅提高纸张平滑度、光泽度。重点介绍可控中高软压光系统组成、工作原理及液压系统组成。研究其控制策略并应用ESC700系统实现其控制过程。     

Research on the hydrogen injection strategy of a direct injection natural gas/hydrogen rotary engine considering apex seal leakage

The purpose of the present paper is to investigate the hydrogen injection strategy on the combustion performance of a natural gas/hydrogen rotary engine. Considering that apex seal leakage (ASL) is an inevitable problem in the actual working process of a rotary engine, the action of ASL cannot be ignored for an in-depth study of its combustion performance. Therefore, in this paper, a 3D dynamic simulation model that put the effect of ASL into consideration was established. Furthermore, based on the established 3D model, the combustion process of a natural gas/hydrogen rotary engine under various hydrogen injection angle (HIA) and hydrogen injection timing (HIT) was investigated. The results indicated that the hydrogen jet flow first impacted on the rotor wall after entering the cylinder, and then diffused under the action of the vortexes in the cylinder. Therefore, the HIA and HIT could change the hydrogen distribution by changing the hydrogen impact location and the intensities of the vortexes in the cylinder. In addition, the ideal hydrogen distribution at the ignition timing which could improve the combustion efficiency was given. That is, under the premise of ensuring minimized hydrogen leakage, the hydrogen should mainly distribute in the middle and the front of the cylinder, and a high hydrogen concentration is maintained near the spark plug.     

Fast filling strategy of type III on-board hydrogen tank based on time-delayed method

In order to study the fast filling problem of the type III on-board hydrogen tank, a 3D computational fluid dynamics (CFD) simulation model is proposed. Several simulation calculations are completed to simulate the fast filling process under different initial conditions. In order to control the temperature rise during the fast filling process, the effects of different mass flow rates are studied. Based on the control of mass flow rate, various time-delayed filling strategies for different conditions are proposed to meet the requirement of shortening the filling time as much as possible without exceeding the maximum temperature limit. It is found that if the delay duration is determined, how the filling time is allocated has little effect on the final temperature rise. The proposed strategy can complete the filling within 155s in a general environment, which saves 62% of the time compared with the filling with constant mass flow rate. This research provides the theoretical basis and technical support for mass flow control strategies of fast filling in the hydrogen refueling stations and has guiding significance for the actual filling process of large-capacity hydrogen tanks.