Mathematical Transforms in Design: Case Study on Feedback Control of a Customizable Automotive Suspension

Engineering design and analysis is replete with examples of mathematical transforms. This paper discusses the use of mathematical transforms at the operational stage implemented by superimposing the system with a control system to (1) convert a decoupled or coupled system to uncoupled, (2) achieve robustness to noise factors and (3) eliminate imaginary complexity. This paper proves with examples that such controller design and implementation is much easier for an uncoupled or decoupled design as compared to a coupled design. The case study presents a new customizable automotive suspension with independent control of stiffness, damping and ride-height. This system was proposed, designed and built using axiomatic design principles. The mechanical design is decoupled with respect to the functional requirements (FRs) of stiffness and ride-height; moreover ride-height is affected by the load on the vehicle (noise factor). This paper presents the design and implementation of a feedback control system for the customizable suspension to uncouple the system and to make it robust to the noise factor.     

Simulation Within the Axiomatic Design Framework

Creating systems with axiomatic design involves conception of physical embodiments and selection of design parameters to satisfy functional requirements at every level of the decomposition process. Simulation models characterize the system using accurate representations of system behavior, allowing the designer to make better decisions about which variables to use as design parameters, and best values for constants in the design. This paper describes a method of simulating designs created using axiomatic design so that the final system performance can be predicted. Simulation in tandem with axiomatic design allows the creation of systems with the best probability of satisfying the functional requirements.     

Three typical failure scenarios of the mind process of design from the Axiomatic Design perspective

Review of several failure databases from software, hardware, and service industries and analysis of the failure cases from the Axiomatic Design perspective led to identifying three typical failure scenarios of the mind process of design; uncoupled but unrealized, coupled but over-simplified, and coupled and complex designs. Failure due to coupled and complex design occurred in all databases at rates of 10-40%. Recent large-scale computer systems have especially expanded the number of functional requirements beyond human capability of recognizing their interference, and failure from such causes amounted to 30-40% of all cases of software industry.     

Axiomatic functional and object-oriented product design framework

This paper describes an axiomatic functional and object-oriented design framework for co-design and co-analysis of product functions, physical structures, and their mapping relations. This design framework consists of function model, object model, information flow model, and axiomatic design model. These models are constructed level-by-level and side-by-side to form a concurrent and coordinated design paradigm. The components of the resulting design are reviewed by the design team, summarized in a task assignment table, and allocated to respective disciplinary engineers for detail design. This methodology enables mechanical, electronic, and software engineers to collaborate and develop mechatronic products in a concurrent and integrated fashion.     

An Axiomatic Approach for “Target Cascading” of Parametric Design of Engineering Systems

Complex engineering system realization involves finding out design specifications that simultaneously achieve performance objectives at different levels. A common practice in industry is to adopt “Target Cascading” to obtain proper settings of the performance objectives, and find out those design specifications, not necessarily optimal, but satisfying all the desirable component-level, subsystem-level and system-level performance objectives. In this paper, an Axiomatic Approach to “Target Cascading” (AATC) is presented to improve the current “Target Cascading” process. AATC uses axioms to guide the decompositions of performance objectives, and an integration of a hybrid meta-modeling tool and direct synthesis method to enhance both robustness and efficiency. The preliminary results of AATC's industrial applications demonstrate its advantage in improving productivity at the early stage parametric design, especially for complex engineering systems.     

Incorporating Lifecycle Considerations in Axiomatic Design

At the outset of designing a new product, knowledge about the product is limited, but the designer has a considerable amount of design freedom. Considering the environmental implications of a product design early in the design phase is a crucial step in achieving an environmentally efficient product. By applying the axiomatic approach to a product's design, the designer can ensure that the final embodiment of the product or service satisfies the obligatory and necessary set of functional requirements and constraints, including environmental issues. In this paper we show how the integration of environmental considerations early in the process of axiomatic design can lead to the development of an environmental-friendly product or service. The paper demonstrates an artificial case study of designing a modern manufacturing system. A major issue investigated in this work is the possibility of assessing environmental performance (or environmental-related information) already in the preliminary stages of the design process. An upper bound for the probability of a product failing to satisfy environmental requirements is introduced. In addition, the suitability of lifecycle analysis to the assessment of products during the process of axiomatic design is discussed.     

基于公理化设计的产品需求分析研究

本文建立了基于公理化设计理论的产品需求分析过程模型,讨论了用户需求的获取、理解、分析和评价的过程和方法,以及从用户需求转化为产品功能要求的策略,介绍了质量功能配置(QFD)中质量屋的建立过程。最后,以数控机床变速传动系统设计为例,对所述的需求分析方法进行了阐述。     

XML相关技术在基于公理化设计的概念设计产品模型中的研究

提出用XML相关技术解决了基于公理化设计的概念设计产品模型的实现、产品开发过程中的约束及其应用框架问题。借助XML Schema给出了相应的产品模型和产品开发过程中的约束；应用XML技术实现了产品的域结构模板；研究并实现了产品模型的应用框架。最后将所述的应用框架应用到工业缝纫机概念设计工具中来指导概念设计过程。     

Improving the requirements process in Axiomatic Design Theory

This paper introduces a model to integrate the traditional requirements process into Axiomatic Design Theory and proposes a method to structure the requirements process. The method includes a requirements classification system to ensure that all requirements information can be included in the Axiomatic Design process, a stakeholder classification system to reduce the chances of excluding one or more key stakeholders, and a table to visualize the mapping between the stakeholders and their requirements.     

A New Approach for Robust Design of Mechanical Systems

Robust product design aims to develop a product that satisfies design requirements while ensuring minimal effects of environmental variability on product performance. Environmental variations may come from raw materials, manufacturing processes, and/or operational environments, which can cause deviations of product functions. This research can verify that the independence axiom can lead to a robust design, while robust designs do not necessarily require functional independence. Thus, designs can be divided into three categories - feasible designs, robust designs and ideal designs. In the first level of the design process, the designers should generate a feasible design, then seek to acquire robustness, and finally determine the possibility of independence. Axiomatic design aims to achieve the independent design; the traditional robust design is an experimental method that may not reach design independence. The proposed approach introduces the integration of the independent analysis that is based on axiomatic design, with the robust analysis that is based on the traditional robust technique. It can help the designer to seek an ideal design or a robust design in respect to the specific design conditions.     

车用电磁悬架系统的结构设计与优化

针对汽车传统被动悬架道路适应性差、安全性不高、减振效果不理想的缺陷,设计一种新型的车用电磁悬架系统。在被动悬架系统中加入车用电磁悬架系统作动器,与汽车弹簧和液压阻尼器并联,可以增加悬架系统的阻尼力,极大程度降低汽车车身由于路面起伏而引起的振动,提升汽车的安全性以及驾驶平顺性。设计车用电磁悬架系统作动器的3种初始结构,结合Ansys/Maxwell磁场分析软件,研究了不同结构对车用电磁悬架系统作动器产生主动力的影响。结合正交试验法,分析车用电磁悬架系统作动器各部分尺寸参数对主动力的影响,然后对仿真结果进行极差分析,选出该作动器产生主动力最大的一组尺寸参数为：线圈1径向长度8 mm,线圈2轴向长度42 mm,线圈1、3轴向长度20.5 mm,导磁环2轴向长度13 mm,导磁环1、3轴向长度5 mm,使其结构达到相对最优。     

Two design problems identified in consumer product recalls: Degradation over extended use and scarce FR-coupling

One hundred recalls of consumer products, e.g., home electronics, in the Japanese market identified two design problems; aging degradation causing failure to meet functional requirements (FR) over extended use and scarce FR-coupling failure that affect meeting other FRs. The former was found in 22% of the recalls with products used over 10 years. The designer could not foresee the long-term degradation in plastic or insulator. The latter contributed to 66% with an extremely low failure rate of less than 0.01% of all production. Rare design error affected by secondary FRs like cooling or friction is another hard-to-notice factor for designers.     

汽车主动悬架系统的有限频域输出反馈控制

为进一步提升汽车悬架系统动力学性能,提出一种基于启发式两步法的静态输出反馈控制方法。为了更好地研究悬架动力学行为,建立一种经典的1/4车主动悬架系统模型用于控制分析与设计。考虑到人体对4~8 Hz频内的垂直振动异常敏感,给出一种有限频域下的性能判据作为控制设计的指导。同时,在控制设计中考虑了悬架行程和轮胎动位移两种机械硬约束,以保证悬架系统的动力学稳定性。由于难以在线获取实际悬架系统中所有状态信息,提出一种新的基于启发式两步法的有限频域输出反馈控制方法。数值仿真及台架试验结果表明：与传统的全频域输出反馈方法相比,该方法具有更好的控制性能。     

两种轮毂电机悬架系统构型比较研究

针对轮毂电机驱动的电动汽车非簧载质量增加,汽车垂向振动现象加剧的问题,设计多级隔振型和动力吸振型两种含电机悬架装置的悬架系统构型,并建立相应的车辆垂向振动数学模型.以电机悬架刚度与阻尼为优化变量,确定其位移约束与边界约束条件,建立多目标优化函数.利用MATLAB软件建立仿真模型,在分析电机悬架刚度与阻尼对悬架系统性能影...     

Knowledge Brokering for Assisting the Generation of Automotive Product Design

The aim of this paper is to present a pragmatic model for the systematic transfer of ideas and knowledge at the early stage of product design in a company environment. In using the model, the basic premise is not to build a new product ‘from scratch’ but to reuse existing ideas and knowledge from other objects and products developed previously. This new approach is called Knowledge Brokering (KB).The developed KB model consists of four sequential steps, which cover the collection and clustering of explicit design knowledge, the systematic learning process, retention and transfer of tacit design knowledge. The premises for using the KB model and case study results from the automotive industry on the advantages and limitations of the new approach are also described.     

醇基涂料悬浮性的探讨

介绍了原材料及处理工艺对醇基涂料悬浮性的影响，使用优良有机膨润土作悬浮剂，配以粒度较细但具有适当颗粒级配的耐火粉料，使涂料具有良好的悬浮性和再分散性能。     

一种六自由度汽车悬架测试控制系统的设计

主要介绍了基于施耐德LXM32A系列的六自由度汽车悬架测试控制系统以及整体机械机构的设计。通过CANOPEN通信协议控制伺服电机的运动,从而推动平台模拟各种路面的路谱信息。系统硬件主要由六路伺服电动缸、运动平台和汽车悬架组成,并通过加载不同的路谱信息验证六自由度汽车悬架测试系统的可行性。     

磁悬浮永磁直线电动机悬浮系统模糊 PID控制器的设计

为消除直线电动机驱动的数控机床进给系统的摩擦阻力,实现无摩擦进给,采用一种新型的磁悬浮永磁直线同步电动机,将矢量控制分别应用于两套绕组,可以实现推力与悬浮力的解耦,进而实现对电动机悬浮子系统的独立控制.针对悬浮子系统为非线性被控对象以及存在不确定性未知扰动的特性,设计模糊PID控制器,并将其应用到悬浮子系统位移环中,以满足悬浮系统控制高精度、高鲁棒性的要求.仿真结果表明:该控制器能起到良好的抗干扰作用,系统的跟踪误差小,可以保持悬浮系统的稳定性.     

汽车变速箱悬置断裂原因分析

汽车变速箱悬置做Z向冲击试验时支臂断裂，抽取库存件进行冲击试验未再发生断裂。为了分析支臂断裂的原因和机理，对零件进行外观分析、金相组织分析、硬度检测、宏观断口分析、断口SEM分析。结果表明:支臂在压铸过程中产生初始裂纹，在冲击性试验载荷作用下发生过载断裂。通过铸件冷却模流图以及再现性试验可知，铸件冷却过程中，由于保压时间不足，铝液尚未完全凝固、脱模，导致在最后凝固区域产生裂纹。     

基于LabVIEW的气压肌肉主动式悬架测试系统设计

针对主动式车辆悬架系统中以液压缸及气压缸作为致动器存在诸多缺点,开发气压肌肉主动式车辆悬架测试系统。设计该测试系统时,利用NI公司的Lab VIEW及c RIO的软硬件资源,搭建硬件模拟系统,模拟路面系统采用以基因算法辅助的模糊控制算法、主动式悬架控制系统采用Haar小波变换的H_∞追踪性能的自适应性滑动模式控制器算法。测试结果证明:与被动式悬架相比,气压肌肉主动式悬架系统对各种不同的路况具有更好的抑振效果。