A design constraint for a double-acting telescopic hydraulic cylinder in a hydraulic erecting system

Hydraulic erecting systems are widely used in missile and rocket launchers because of their high power density.The double-acting telescopic hydraulic cylinder(DATHC)plays a decisive role in the safe and proper operation of such systems.In particular,improper design of effective areas of a DATHC could potentially lead to an overspeed descent with severe damage for the erecting system.Unfortunately,there is no design constraint for DATHC to prevent this.Therefore,in this paper,a simplified and practical design constraint is proposed.Based on a developed mathematical model of a typical erecting system,we simulated and analyzed not only six cases meeting and not meeting the design constraint,but also the effectiveness of the design constraint under different loads.Experiments were then carried out under four cases.Simulation and experimental results validate the simplified design constraint,a constraint inequation guiding the design of diameters of effective areas for a DATHC.

AUTOMATIC APPROACH TO PRODUCT CONCEPTUAL DESIGN BASED ON CONSTRAINT NETWORK

Product design is considered as the constraint satisfaction problem (CSP),and a new design approach basedon constraint network is proposed and applied to make designautomatic partially. By means of constraint extraction, constraint network construction andoperation, constraint chains are acquired, and then the conceptual design scheme can be got bydecoding the information stored in the design constraint chains, which provides a novelty method formechanical product design automation. Shearing mechanism of shearing machine has been designed bythis way.

Constraints Based Decision Support for Site-Specific Preliminary Design of Wind Turbines

This study presents a decision-support tool for preliminary design of a horizontal wind turbine system. The function of this tool is to assist the various actors in making decisions about choices inherent to their activities in the field of wind energy. Wind turbine cost and site characteristics are taken into account in the used models which are mainly based on the engineering knowledge. The present tool uses a constraint-modelling technique in combination with a CSP solver (numerical CSPs which are based on an arithmetic interval). In this way, it generates solutions and automatically performs the concept selection and costing of a given wind turbine. The data generated by the tool and required for decision making are: the quality index of solution (wind turbine), the amount of energy produced, the total cost of the wind turbine and the design variables which define the architecture of the wind turbine system. When applied to redesign a standard wind turbine in adequacy with a given site, the present tool proved both its ability to implement constraint modelling and its usefulness in conducting an appraisal.

Explicit Correlation Model of Multi-source Constraints for Re-design Parts with Complex Curved Surface

In precision machining of complex curved surface parts with high performance, geometry accuracy is not the only constraint, but the performance should also be met. Performance of this kind of parts is closely related to the geometrical and physical parameters, so the final actual size and shape are affected by multiple source constraints, such as geometry, physics, and performance. These parts are rather difficult to be manufactured and new manufacturing method according to performance requirement is urgently needed. Based on performance and manufacturing requirements for complex curved surface parts, a new classification method is proposed, which divided the complex curved surface parts into two categories： surface re-design complex curved surface parts with multi-source constraints（PRCS） and surface unique complex curved surface parts with pure geometric constraints（PUCS）. A correlation model is constructed between the performance and multi-source constraints for PRCS, which reveals the correlation between the performance and multi-source constraints. A re-design method is also developed. Through solving the correlation model of the typical paws performance-associated surface, the mapping relation between the performance-associated surface and the related removal amount is obtained. The explicit correlation model and the method for the corresponding related removal amount of the performance-associated surface are built based on the classification of surface re-design complex curved surface parts with multi-source constraints. Research results have been used in the actual processing of the typical parts such as radome, common bottom components, nozzle, et al., which shows improved efficiency and accuracy of the precision machining for the surface re-design parts with complex curved surface.

An Approach to Collaborative Design Based on Distributed Constraint-Net

We focuse on design process in concurrent engineering and propose an, approach to collaborative design based on distributed constraint-net. The approach adopts agent technology to express kinds of distributed constraints. And through the cooperation among agents, the consistency of constraint is maintained and the constraint conflict is detected and eliminated. The constraints are satisfied concurrently and distributively. Based on the proposed approach, the collaborative design process in concurrent engineering can be well supported.

Judgement of Design Scheme Based on Flexible Constraint in ICAD

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An Intelligent Approach in Design Optimzation Based on Determining Constraints Compatibility

Based on monotonicity analysis and computer symbolic manipulating technique,a procedure for determining constraints compatibility in design optimization hasbeen proposed in this paper. By using the proposed method relationshipsbetween constrains can be determined and the optimization is greatly simplifid.The method is code with intelligent production systems.

Research on engineering-oriented constraints conflict detection in collaborative design of wire harness technology

Engineering-oriented constraint of harness technology has much information and project information presents progressive changes along with the design. Therefore, how to handle conflict resolution quickly is a problem to be solved. Process model of con- flict detection is put forward according to characteristics of harness technology design engineering-oriented constraint, and then two problems of how to conduct conflict positioning and judgment of constraint rules are introduced in this paper. Afterwards in this pa- per, constraint information directed acyclic graph is established by classified project constraint information to solve the conflict posi- tioning problem; solution of constraint satisfaction problem is applied to realize judgment problem of constraint rules. Finally, exam- ple is used to analyze the method in this paper to further verify the correctness and effectiveness of this method.

Conflict detection in collaborative architectural pipe routing design based on constraint network

This paper analyzes conflict features in architecture pipe routing,and builds a pipe routing design conflict model by taking into account of discrete nominal internal diameter selection of pipes,material costs,and conflict solution sequence.Considering pipe routing as an assembling process,a conflict detection approach for pipe routing in collaborative architectural design is proposed based on an aforementioned model.Constraint network is used to describe the relationship among pipe routing design parameters and constraints;design conflicts are detected by matching designers' input and constraint network;and detected design conflicts are reordered according to the number of pipe parameters in conflicts.In order to support the collaborative requirement of pipe routing design,a prototype system using browser/server architecture is developed.An illustrative example of water pipe routing in a room is used to show the effectiveness and efficiency of the approach.

四自由度串联嫁接机器人架构约束模块识别可视化方法

为实现育苗嫁接的智能化与高效化,一类四自由度串联嫁接机器人的新结构被提出;针对其机械结构、时序控制、联动运行等复杂性,发展该类机器人架构约束下的模块识别可视化方法及设计流程。首先,构建考虑特定架构约束下机器人的设计结构矩阵(DSM),并采用大型社区快速展开算法(LOUVAIN算法)实现对机器人架构模块的预划分;其次,采用改进遗传算法(AGA)对DSM进行聚类,获得多组高模块度的划分结果,由此形成成组可能性矩阵(GLM),并将其对角化得到对角GLM(DGLM);最后,提出针对DGLM的可视化策略并完成着色处理,实现对最优模块划分方案的辨识。结果显示:四自由度串联嫁接机器人可分解为较独立的7大模块,模块度可达0.782。

环境约束视角下集合住宅邻里交往空间在垂直维度的重构与进化

目前国内大规模建设的集合住宅与传统住宅比较,普遍存在邻里关系活跃度较低及邻里交往空间有效性不足的问题。因为环境约束条件的变化,传统邻里交往行为的多样性、有机性、心理自由等积极特征在集合住宅中遭到极大的削弱。通过重新建构集合住宅的环境约束条件,在垂直维度上实现多线程交通、开放边界、增加空间冗余度与节点自由度,可以提升邻里交往空间设计的自由度,形成邻里交往空间的自然进化,实现恢复住区内良好邻里关系的目标。

基于Innovus混合放置的布局规划方法优化

随着集成电路后端设计中宏单元数量增多,传统布局规划方法效率低且耗时,而自动布局规划的混合放置(MP)技术存在物理规则违例数量多、电压降大和功耗高等问题。针对传统方式和MP方式的不足,提出了一种优化的MP布局规划方法,通过控制宏单元通道空间和标准单元密度大小、固定边界宏单元位置及脚本修复TSMC芯片集成检查(TCIC)违例的方法解决MP技术存在的问题。研究结果表明,优化的MP方式保留了MP技术的性能、功耗和面积(PPA)优势,且相比于传统方式布线长度优化了28%,时序违例优化了65%,功耗优化了609%。该方案可为多宏单元大规模设计的布局规划提供参考。

基于专利性设计约束的产品可专利性设计方法

可专利性设计是实施专利布局的基础,在设计期间引入专利性设计约束的事前研究领域较为欠缺。文中确定了专利知识表征方式并建立了概念-关系-实体(Concept-Relationship-Entity,CRE)可专利性方案构成模型;基于专利知识和专利三性(实用性、新颖性及创造性)的专利性设计约束进行了构建过程及设计决策路径研究,并构建了可专利性设计过程模型。以沼气制备装置为例,验证了可专利性设计方法的可行性。试验结果表明:在设计过程中引入专利性设计约束避免了事后评估所造成的时间和经济损失,为产品可专利性设计提供了新路径。

多学科设计优化方法在水下无人航行器中应用

为了提高水下无人航行器工作的可靠性和稳健性,本文采用多学科设计优化方法开展航行器的总体设计优化。首先开展水下航行器在总体设计阶段的学科设计,分析了各学科内部的模型和计算方法,明确了各学科输入、输出和耦合关系;开展了学科内参数建模,确立了总体设计的设计变量、系统参数和约束条件。然后以航行器质量最轻和机动性能最强为优化目标,获得设计变量计算最优解和优化设计主要输出结果值。设计变量优化计算值有效提高设计方案满足约束的能力,优化设计主要输出结果为水下无人航行器设计方案的选择提供了定量依据。

DYNAMIC RESPONSE OPTIMIZATION DESIGN FOR ENGINEERING STRUCTURES BASED ON RELIABILITY

In many practical structures, physical parameters of material and applied loads have random property.To optimize this kind of structures,an optimum mathematical model was built.This model has reliability constraints on dynamic stress and displacement and upper & lower limits of the design variables. The numerical characteristic of dynamic response and sensitivity of dynamic response based on probability of structure were deduced respectively. By equivalent disposing, the reliability constraints were changed into conventional forms. The SUMT method was used in the optimization process.Two examples illustrate the correctness and practicability of the optimum model and solving approach.

收缩、分离和聚合:面向长尾视觉识别的特征平衡方法

数据在现实世界中通常呈现长尾分布,即,少数类别拥有大量样本,而多数类别仅有少量样本.这种数据不均衡的情况会导致在该数据集上训练的模型对于样本数量较少的尾部类别产生过拟合.面对长尾视觉识别这一任务,提出一种面向长尾视觉识别的特征平衡方法,通过对样本在特征空间中的收缩、分离和聚合操作,增强模型对于难样本的识别能力.该方法主要由特征平衡因子和难样本特征约束两个模块组成.特征平衡因子利用类样本数量来调整模型的输出概率分布,使得不同类别之间的特征距离更加均衡,从而提高模型的分类准确率.难样本特征约束通过对样本特征进行聚类分析,增加不同类别之间的边界距离,使得模型能够找到更合理的决策边界.该方法在多个常用的长尾基准数据集上进行实验验证,结果表明不但提高了模型在长尾数据上的整体分类精度,而且显著提升了尾部类别的识别性能.与基准方法BS相比较,该方法在CIFAR100-LT、ImageNet-LT和iNaturalist 2018数据集上的性能分别提升了7.40%、6.60%和2.89%.

不同约束条件下普速铁路平面线形重构效果对比分析

针对普速铁路平面线形重构设计问题,结合相关规范要求系统梳理了平面线形参数限制因素。在此基础上,以整体平面调整量平方和最小为平面线形重构设计目标函数,提出了无约束、原始台账约束和多参数约束条件下的平面线形重构原则,并结合实测数据对比分析了不同约束条件下平面调整量、曲线参数和行车安全性的差异。结果表明:采用多参数约束条件所得平面线形既可达到现场工程量较小,又可满足曲线半径、缓和曲线长度和行车安全性要求,其重构设计结果最优。建议在普速铁路数字化捣固方案设计时,采用多参数约束条件对平面线形进行重构设计,结合现场实际和相关规范要求对曲线半径和缓和曲线长度进行适当调整。

改良粽角榫的参数化设计方法

粽角榫结构复杂,当其零件尺寸变化时,内部榫卯尺寸应相应变化。多变的零件尺寸使结构设计工作效率低下,不适合榫卯数字化加工的发展。基于粽角榫结构间的尺寸关系,用参数化设计的方法提高粽角榫结构的加工效率很有必要。分析传统粽角榫和6种改良粽角榫的结构特点,选择最适合数字化加工的改良粽角榫结构。建立所选改良粽角榫的零件模型,确定榫卯形态、设定榫卯尺寸参数,并建立尺寸参数表。基于装配约束关系,建立粽角榫内部各尺寸参数间的函数关系,并区分驱动尺寸和从动尺寸;基于工艺约束关系,设定部分尺寸参数的合理取值范围和预设值。最后,整合自变量、预设参数、固定参数和因变量建立改良粽角榫尺寸参数系统及函数关系表,完成参数化设计的数据架构。通过改良粽角榫尺寸参数系统及函数关系表,结合数控加工设备的操作系统进行编程,可实现输入榫卯驱动尺寸后系统自动输出其他尺寸参数的作用,为零件尺寸不同的粽角榫结构设计提供了快速便捷的方法。家具榫卯内部有规律的结构关系可表达为榫卯尺寸参数间的函数关系,以此为基础建立的榫卯参数化设计方法为多变的家具结构设计提供了简化增效的途径。

Multilevel Optimal Design of Prestressed Lightweight Concrete-Steel Platform Structures

The concrete-steel platform structure is rather complicated because it involves such materials as concrete, reinforcing bars, steel, and so on. If the traditional dimension optimization method is employed, the optimal design of the platform will meet many handicaps, even it cannot be implemented at all. The multilevel optimal design approach is an efficient tool for the solution of large-scale engineering structures. In this paper, this approach is applied to the optimal design of a concrete-steel platform, which is formulated as a system level optimal design problem and a set of uncoupled substructure level optimal design problems. The process of optimization is a process of iteration between system level and substructure level until the objective function converges. An illustrative example indicates that this method is effective in the optimal design of concrete-steel platforms.

一种基于约束规则的航天器全相位交会对接程序规划方法

针对载人航天领域交会对接过程,设计了一种基于约束规则的程序规划方法,将飞行程序按照相关性划分为飞控事件,将事件约束与时间或圈次解耦,形成适用全相位交会对接的规划配置体系,通过一套配置实现各正常、应急分支程序的规划生成,相比传统基于时序的程序设计方法,提高配置的适应性,提高程序设计效率,为后续交会对接程序规划设计提供参考。