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1、液压动力系统中英文对照外文翻译文献中英文对照外文翻译文献 (文档含英文原文和中文翻译) 原文： FEATURE-BASED COMPONENT MODELS FOR VIRTUAL PROTOTYPING OF HYDRAULIC SYSTERM Abstract: This paper proposes a feature-based approach for the virtual prototyping of hydraulic systems. It presents a framework which allows the designer to develop a virtual
2、hydraulic system prototype in a more intuitive manner, i.e. through assembly of virtual components with engineering data. The approach is based on identifying the data required for the development of the virtual prototypes, and separating the information into behaviour, structural, and product attri
3、butes. Suitable representations of these attributes are presented, and the framework for the feature-based virtual prototyping approach is established,based on the hierarchical structure of components in a hydraulic system. The proposed framework not only provides a precise model of the hydraulic pr
4、ototype but also offers the possibility of designing variation classes of prototypes whose members are derived by changing certain virtual components with different features. Key words: Computer-aided engineering; Fluid power systems;Virtual prototyping 1.Introduction Hydraulic system design can be
5、viewed as a function-to-form transformation process that maps an explicit set of requirements into a physical realisable fluid power system. The process involves three main stages: the functional specification stage,the configuration design stage, and the prototyping stage.The format for the descrip
6、tion of the design in each stage is different. The functional specification stage constitutes the initial design work. The objective is to map the design requirements. To achieve this, the design problems are specified Correspondence and offprint requests to: Dr S. C. Fok, Schoool of Mechanical and
7、Production Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798. The designer must identify the performance attributes, which can include pressure, force, speed, and flowrate, with the required properties such as size, cost, safety and operating sequence. performance requi
8、rements for each attribute. In this stage, the design is abstracted in terms of the performance attributes with associated values. The objective of the configuration design stage is to synthesise a hydraulic circuit that performs the required functions conforming to the performance standards within
9、defined constraints. A typical hydraulic system is made up of many subsystems. The smallest building block in a subsystem is the standard hydraulic component (such as valves, cylinders,pumps, etc.). Each type of standard component serves a specific elemental function. The design effort in the config
10、uration design stage is fundamentally a search for a set of optimal arrangements of standard components (i.e. hydraulic circuit) to fulfil the functional requirements of the system. Based on this framework, the designers would normally decompose the overall system functions in terms of subfunctions.
11、 This will partition the search space and confine the search for smaller hydraulic subcircuits to perform the subfunctions. Computers are often used to support the configuration design process. For example, Kota and Lee devised a graph-based strategy to automate the configuration of hydraulic circui
12、ts. After the development of the hydraulic circuits, digital simulation tools are often used to study and evaluate these configurations. With these tools, designers can compare the behaviour of different circuits and also analyse the effects when subcircuits are combined. In the configuration design
13、 stage, the design is traditionally represented as a circuit drawing using standard icons to symbolise the type of standard component. This is a form of directed graph S(C,E) where the circuit S contains components C in the form of nodes with relations between components denoted by edges E. The prot
14、otyping stage is the verification phase of the system design process where the proposed hydraulic circuit from the configuration design stage is developed and evaluated. Physical prototyping aims to build a physical prototype of the hydraulic system 666 S. C. Fok et al. using industrial available co
15、mponents. The process of physical prototyping involves the following: Search for appropriate standard components from different manufacturers. Pre-evaluation and selection of components based on individual component cost, size, and specification, and compatibility factors between components. Procure
16、ment and assembly of the selected components.Test and evaluate the physical prototype based on the overall system requirements. Use other components or redesign the circuit (or subcircuits) if necessary.Besides dynamics, the development of the physical prototype must take into consideration other fa
17、ctors including structure,cost, and weight. The dynamics data are used to confirm the fluid power system behaviour whereas the geometric information is used to examine the assembly properties. The development of the physical prototype will provide the actual performance,structure, and cost of the de
18、sign. The main disadvantage of physical prototyping is that it is very tedious and time consuming to look for a set of suitable combinations of standard components from among so many manufacturers. Although the basic functions of the same types of standard component from different manufacturers do n
19、ot differ, their dynamics, structural and cost characteristics may not be similar, because of design variation. Hence, for a given hydraulic circuit, different combinations of parts from different manufacturers can have implications on the resulting system,in terms of dynamics, structure, and cost.
20、Value engineering can be used at this stage to improve the system design by improving the attributes at the component level. This includes maximizing the performance-to-cost ratio and minimising the size-to-performance ratio. Virtual prototyping can be viewed as a computer-aided design process, whic
21、h employs modelling and simulating tools to address the broad issues of physical layout, operationalconcept, functional specifications, and dynamics analysis under various operating environments. The main advantage of virtual prototyping is that a hydraulic system prototype can be assembled, analyse
22、d, and modified using digital computers without the need for physical components, thus saving lead time and cost. The main requirement of a virtual hydraulic system prototype is to provide the same information as a physical prototype for the designer to make decisions.To achieve this, the virtual pr
23、ototype must provide suitable and comprehensive representations of different data. Furthermore, transformation from one representation to another should proceed formally. Xiang et al. have reviewed the past and current computer-aided design and prototyping tools for fluid power systems. The work rev
24、ealed that the current tools could not provide a complete representation of the design abstractions at the prototyping stage for design judgement. Most of the tools concentrate on the dynamics behaviour. Vital geometrical and product information that relates to the system prototype consideration and
25、 evaluation is frequently missing.To advance the development of computer-aided virtual prototyping tools for fluid power systems, there is a need to address the formal representations of different abstractions of behaviour,structural, and product data along with their integration. This paper focuses
26、 on these issues and proposes the formalism of a unified component model and the taxonomy based on the feature-based approach. In Section 2, we discuss the feature- based approach focusing on the key information and their representations required for hydraulic system prototyping. Section 3 presents
27、a formalism of the feature-based model and structure for the development of virtual hydraulic system prototypes.The structure is illustrated with an example. Future work and conclusions are given in Section 4. 2. Feature-Based Approach Features can be defined as information sets that refer to aspect
28、s of attributes that can be used in reasoning about the design, engineering or manufacturing processes. The concept of using features to integrate CAD/CAPP/CAM is not new and there are many papers on the application of this approach in CIM. In all these applications, the feature model is regarded as
29、 the basis whereas design by features is the key for the integration. To develop a feature model, the relevant information concerning the design must be identified and grouped into sets based on the nature of the information. The relevant information should contain sufficient knowledge for activitie
30、s such as design, analysis, test, documentation, inspection, and assembly, as well as support various administrative and logistic functions. Design by features is the process of building a model of the design using features as primitive entities. The feature model provides the standardisation of rel
31、evant data. Through the design by features approach, vital knowledge of the design will be generated and stored. Together, the feature model and the design by features approach will provide the essential information, which can be used, not only for the simultaneous consideration of many different co
32、ncerns with the design, but also to interface the many activities in the design realisation process, including the life cycle support operations. The main drawback of the feature-based design approach is that the feature model should be properly defined . This can be difficult, as features are sets
33、of knowledge that are application dependent. The organisation of the features can also be application specific. Non-trivial data-management problems could arise if the feature model is not properly defined. To avoid these problems, the type,representation and structure of the features should be reso
34、lved prior to using the feature-based design methodology. The main concern when developing a feature model is that it is application-specific. In the domain of virtual prototyping of hydraulic systems, the details of the constituent standard components must be able to be used to describe the overall
35、 system. The component features are bearers of knowledge about that part. To create a suitable feature model for hydraulic system design based on the assembly of standard components, the relevant information associated with various standard components must be identified and classified. This definiti
36、on Feature-Based Component Models 667 of the component feature set can then be extended to encompass the subsystem feature set based on the hierarchical structure between the components in the subsystem. In the same manner, a hierarchical structure for the hydraulic system feature representation wou
37、ld evolve by considering the system as a hierarchy of subsystems. The necessary information required for a proper description of the virtual prototype must be no less than that derived by the designer from a physical prototype for decision making. These data should generally include the shape, weigh
38、t, performance properties, cost, dimensions, functionality data, etc. Comparison with the physical prototyping process, the information required for each standard component could be separated into three distinct groups: behaviour attributes, structural attributes, and product attributes. 2.1 Behavio
39、ur Attributes The behaviour of a hydraulic component can be defined in terms of the dynamics characteristics used to satisfy the functional requirements. Consider a hydraulic cylinder connected to a load. Its function is to transmit a force from the stroke of the piston to the load. The maximum forc
40、e it can transmit can be used to define the functionality and the behaviour requirements can be specified in terms of the desired load acceleration characteristics. Hence for a hydraulic component, behaviour attributes express functionality and can be reflected in the dynamics characteristics. The d
41、esigner is responsible for the proper definition of the overall system behaviour characteristics in terms of the desired dynamics. A standard component will have its own behaviour and provide a specific function.Complex functions that cannot be achieved by a single standard component are derived usi
42、ng a combination of components. Hence, the behaviour of the standard component will play an important role as the individual behaviours of components together with their arrangement can alter the overall system function . The behaviour of a standard component can be nonlinear and can be dependent on
43、 the operating conditions. When two components are combined, it is possible that their behaviours can interact and produce undesired or unintended characteristics. These unwanted behaviours are assumed to have been resolved during the configuration design stage. The hydraulic circuit used in the pro
44、totyping stage is assumed to be realisable and without any undesirable interacting behaviours. This means that the output behaviour of a component will provide the input to the subsequent component. The representation of behaviours for hydraulic systems has been widely investigated. These representa
45、tions include transfer functions, state-space and bond graphs. Transfer functions (for single-inputsingle-output systems) and state-space equations (for multiple-inputmultiple-output systems) are based on the approximation of the dynamics about a nominal operating condition. The power bond graph mod
46、el is based on the causal effects that describe the energy transformations in the hydraulic system. This approach is appealing for hydraulic system analysis. The main disadvantage is that the derivation of the dynamics equation in a bond graph of a complicated fluid power system can become very tedi
47、ous. As a result, recent work has concentrated on the used of artificial intelligence to represent the nonlinear mapping between the input and output data, which can be obtained via experimental work. These nonlinear mappings can be accomplished using artificial neural networks . It is quite natural
48、 for a hydraulic system designer to use inputoutput data to describe the behaviour of a hydraulic component. The configuration design of a hydraulic system is often achieved through steps of function decomposition. To design a hydraulic system, the designer often tries to decompose the functions and
49、 their requirements down to the component level. 译文： 基于原型液压系统特征的机构模型 摘要：本文为原型液压系统的设计提出了一种基于特征的方法。它提出了一个框架,允许设计师以更加直觉的方式开发一个真实液压机构原型，例如， 通过真实的工程学数据进行设计。这种方法是在真正原型数据的基础上发展起来的， 它可以分离信息入行为，结构，和产品属性。这些属性被用适当的表示法提出， 并且框架为基于特点的真正原型 的方法建立，根据组分等级结构在一种液压机构。它所提出的框架不只是真实的液压系统的一个精确模型，而且为设计成员提供了当由于某些零件的一些特性改变导致系统改变而获得一个新的液压系统精确模型的可能性。 关键词: 计算机辅助工程; 液压动力系统;真实样机 1. 介绍 液压机构设计可能被看作是一个为映射明确套要求入物理可实现的液压能力系统的作用对形式变革过程。这个过程涉及三个主要阶段: 功能规划阶段，结构设计阶段， 和样机制造阶段。描述各个设计阶段的所用的格式是不同的。 功能的规划是所有设计中最初的工作。为了达到这个要求， 设计问题是以指定的书信和印成单行本发给新加坡南阳大
