The research and design using CAD system for the clutch of automobile
Clutch is used to transfer and switch of the powers which are coming from the engine. In automobile, clutch is connected with engine and derailleur. It can shut of and stably transfer the power between them. How to reasonably, effectively and speedily design clutch always is the pursuing destination of all clutch factories. The appearance of CAD which is the abbreviation of computer aided design make it possible. Automobile CAD is the forerunner of CAD all the times. CAD is fist used in automotive industry and become more and more indivisible with CAM, CAE and CAP furthermore, integration is becoming to reality. Researching how to use computer to aid us design the automobile clutch and how to develop a useful and advanced automobile clutch computer aided design system-abbreviation is ACCAD that can make a steady system framework for automobile cultch integrated design and manufacture system. are the destination of this thesis.
ACCAD system should firstly be able to aid engineer design clutch, secondly to aid engineer analyze the designed clutch, finally to organize and manage the data of design. From the long-term consideration it should also be able to aid workshop manufacture clutch and help manager supervise all the life cycle of clutch. So it should have a core which can integrate all these subsystem. Engineering database (EDB) is just for this use and Using EDB to construct CIMS become an inevitable current. In order to expand ACCAD and realize clutch CIMS in the future ACCAD system also need EDB as the core to integrate each design and management subsystem into a whole system. At the third chapter of this thesis the technology of EDB and how to design automobile clutch EDB are researched and automobile clutch EDB is set up according to the framework of entire database, project database and design database.
The traditional procedures of the design of automobile clutch are: selecting storing confident, designing clutch structure type, friction flat, clutch sketch, assembled module and each part of clutch. In our country, all these procedure are handmade, but in the coming years with the application of computer aided drawing software such as Auto CAD of Auto Desk corp. engineering drawing can basically be done by computer. But the depicting capability of this two-dimension engineering drawing module is so deficient that it can only be used as drawings and can’t be used to analyze by computer. Along with the appearance of B-P modeling and curve-based or solid-based modeling, mechanic parts are denoted by three-dimension module which can better aid engineer design and analyze them. But this module loses parts of the whole information of them, so it results in much difficulty to integrate aided design subsystem, aided manufacture subsystem and computer analyzing subsystem. Feature-based modeling can just make up this shortcoming, and also if it combines with parameter design technology it can enhance the capability not only of depicting but also of fast amending. At the forth chapter of this thesis the technology of feature-based is researched and the parametric feature-based solid models are created upon MDT that is belonging to Auto Desk corporation.
In order to aided engineers to design clutch faster computer is used to simulate engineers to use variant design technology to design clutch products that are based on original models. Variant design technology has some intelligence. Intelligent CAD is a direction of developing CAD. At the fifth chapter of this thesis the technology of variant design is researched and variant design of automobile clutch is achieved on MDT by the technology of parameter table-driven and feature restrained
Besides some degree of integrity and intelligence ACCAD system should have some degree of automation, that is to say that ACCAD can automatically design clutch according to primitive design requests, analyze, check and optimize some basic parameters of clutch. At the sixth chapter of this thesis the combining model of clutch is analyzed, some formulas of designing and calculating basic parameter are deduced, the working instances of diaphragm spring are analyzed and the characters of load-distortion and stress-strain are calculated simulatively by the formulas of A-L which are approbatory internationally nowadays. The optimizations of some basic parameters and diaphragm spring are carried out by muti-body arithmetic in which design destinations, design restrictions and the primitive value of design variables can be changed according to real demands. Instances deduction and design templates are used to design the model of each part of clutch and all these models are assembled automatically after that basic parameters and structure type are completed according to primitive design demands. The design templates are deduced in existing design instance of clutch product by inter gent instance-deducing technology. Then designers can mend and to-and-fro design them till they can meet the design demands. So computer aided function and man’s initiative can be fully enlarged, automatic design and mutual design are combined indeed .
It needs not only much knowledge of automobile clutch design and CAD but also much high lever of software design and computer application to really realize such a complicate and advanced ACCAD system. So I also researched the method of object-oriented and the operation system of Windows and study many sorts of program design language. The theory of software engineering is used to analyze ACCAD system in requirement, function structure, flow chart, project design and module design. The software developing tools of Visual Basic and Visual C++ are used to design and implement the ACCAD system. Yi-Dong clutch corporation have applied it to design clutch. Practice proves that the ACCAD system can aid designers to design clutch well, remarkably improve the ability of clutch product design, greatly shorten the design cycle and also it has very high stability and extensibility.
INVESTIGATION TO DYNAMICS AND CONTROL OF VEHiCLE AMT CLUTCHES DURiNG ENGAGEMENT
China Automotive Parts enterprises face more and more pressure and challenge with China joining WTO.The global Automotive and Parts MNC are gradually entering the lastly and largest potential market of the world.The local automotive industry especially parts is not so good as MNC no matter in scale, capital capacity, products technical level and marketing level.So in order the to exist,the local automotive parts enterprises must improve themselves as quickly as possible in some the fields. One of the important reasons for this risk is the slow Product Engineering with low technical content.It is caused by several reasons that are outdated engineering method，insufficient working experiences，low quality of the working people and the outdated methodology of product Engineering，and the last one is the most important reason.
In comparison with hydraulic Automatic Transmission (AT) and Continuously Variable Transmission (CVT), Automatic Mechanical Transmission (AMT) has advantages of much lower cost in manufacturing and easier installation in driveline system .This means that there exists a vast potential market for development of such a mechanical technology. As an important functional module in AMT vehicles, however, the automatic clutches developed by far still have some shortcomings, for example, of road startup failure, considerable shock, unstable shifting, friction-caused service life reduction, and time-delay response. The key concern is therefore concentrated in this dissertation on real implementation of optimal transient responses and control laws during engagement of the clutches, and detailed investigations are made both in theory and experiment.
Strong nonlinearities exist in such component systems as engine, clutch membrane spring and servo actuator and consequently difficulties are encountered in design of the optimal control for improving transient responses of the automatic clutch. A system synthesis is proposed herein for the study of nonlinear dynamics and control of AMT automatic clutches. Based on principles of automotive powertrain systems, the main system under consideration can be decomposed into two sub-systems, engine and transmission systems. The Popov super stability theory has adopted for the first time in association with reference, model following adaptive control for the engine. monitoring. The engine monitor requires accurate predictions of rational velocities. A prediction model is constructed on the basis of flat neural network A fast recursive algorithm is used
to improve the learning speed by forgetting factor. Accordingly, the present neural network algorithm leads to considerable reduction of effort in network weighting matrix as well as increase of self-learning and adaptability of neural network algorithms to nonlinear and nonstationary systems. It has been shown by comparison of the numerical results with experiments that the modified algorithm is proved to be reliable and effective in the engine condition monitoring. In modeling the system, the load-deflection relationship of the clutch membrane spring is generally treated as a black box, and as a result many advanced control methods can not be applied. A new approach for the black box is required nevertheless in development of the accurate model. The nonlinear relationship is mathematically derived out for the clutch system during engagement and a further progress is thus made to certain extent for the Almen-Lazslo method. By matching control inputs of the two subsystems, a synthetically optimal performance of the system can be achieved. It can be seen that by the system synthesis, not only the design of a feedback controller is accommodated according to longitudinal dynamic requirements of the whole vehicle, but an effective procedure is established for solving problems of time-delay and inaccuracy due to the use of the analysis method of upper-lower layers.
Differential geometry provides a powerful tool for the analysis of nonlinear dynamic systems. With consideration of the automatic clutch which is a typical a fine nonlinear system, the differential manifold and corresponding a companion form to the original system with nonlinearities can be constructed by using feedback linearization approach. It is demonstrated by simulations and experiments that this method simplifies the design of the controller, and is of practical significance for real engineering applications. In this dissertation, ∮ operator and its transform in frequency domain are introduced for the first time into the field of automotive electronics technology. In comparison with the conventional z operator, digital iterations of ∮ operator are featured by higher precision and more stability while sample time T -4 0.The nonlinear sliding mode controller is taken as an example, the implementation form of ∮ operator discretion control, the error analysis and the algorithms stability are studied both theory and engineering application. In high frequency sampling systems the approach has advantages in industrial applications and enriches its new fields of application, especially in vehicle electronics.
Based upon the minimum value principle, a muti-objective optimal control is applied to derive out for the first time the optimal response in analytic form by compromising longitudinal shock and plane slippage of the automatic clutch related with each other in the transmission sub-systems. The real significance of the synthetic optimal control lies in expression of the theoretical optimal performance. For preventing the control system from system uncertainties and external perturbations the robust sliding mode controller is designed to guarantee the system to trace the optimal trajectory. Since dynamic properties of the sliding mode is invariant to extraneous disturbance, the SMC method may apply for
a kind of complicated systems with nonlinearities and uncertainties like the automatic clutch. It is shown through numerical simulations that errors of the SMC in reference model following are far less than the PID control whenever the damping orifice flux coefficient of an on-of solenoid, the frictional plate wear quality, friction coefficient and the driveline elastic coefficient may be deviated in a permissible range, respectively. Hence, the present work possesses of significant value in engineering application.
As an important part of the dissertation, the virtual mechanical prototyping and real on-vehicle experiments for the automatic clutch system are made, respectively. The virtual machine is modeled in ADAMS software and verified by real vehicle experiments. Therefore, through comparison of the virtual experiments within ADAMS environment with theoretical predictions for transient responses of the clutch during engagement, reliable and effective instructions are provided for design of the hydraulic actuator and PC controller required in real vehicle experiments. The control apparatus for automatic clutch
include sensors, microcomputer and their interfaces. All experiments are carried out on the Santana LX car, and much attention is focused to typical difficult working conditions, such as small through angle, heavy load, high gear and steep ramp. It is shown by the results obtained from the experiments that fairly good transient responses during the clutch engagement are achieved. By the control strategies presented in this dissertation, the engine is prevented from flameout, moreover, vehicle startup and gear shift smoothly can be adjusted with short friction duration and quick response of the actuator. All these mean that the adaptability for subjective will, time varying driving conditions of vehicle and complicated surroundings. In a word, on the basic of theoretical research and control technology, the performance of AMT automatic clutch is improved markedly, moreover, the apparatus for experiments establishes a massy foundation for future product development.
离合器是用来传递和切断从发动机传来的动力的一种机构。在汽车上， 它和发动机的飞轮相连接，切断和平稳地实现发动机和变速器之间的动力传递。如何合理、高效、快捷地设计离合器一直是国内外离合器厂家追求的目标，CAD (Computer Aided Design)的诞生将此希望变为可能。汽车CAD一直是CAD技术的先驱，CAD技术最先是应用在汽车工业上，而且与CAM. CAE和CAPP越来越不可分割，集成化正成为现实。研究如何应用计算机来辅助设计汽车离合器，以及如何设计开发出一个实用的、先进的汽车离合器CAD系统— 简称ACCAD (Automotive Clutch CAD)，为实现汽车离合器集成设计制造系统打下一个坚实的系统框架，正是本文的目的。
传统的汽车离合器设计基本上是选择后备系数、离合器型式、设计摩擦片、设计草图、设计装配总成、设计各零件。在国内，这些过程基本上都是人工进行的，但近些年来，随着计算机辅助绘图软件如Auto Desk公司的Auto CAD的应用，工程图的绘制基本上可在计算机上进行。用这种二维工程图的模型，计算机只能辅助工程设计人员绘制工程图纸，无法对零部件进行分析，这种模型描述能力低下。随着线框建模技术、基于曲面或实体建模技术的出现，零部件在计算机中将以三维的方式表示，它能够很好地辅助工程设计人员设计和分析零部件。但这种模型缺乏对产品零部件信息的完整描述， 从而导致计算机辅助设计系统、制造系统和分析系统集成困难。特征建模技术正好能够弥补这种缺陷，而将特征建模技术和参数化建模技术结合起来则
如何真正地实现如此复杂和先进的汽车离合器CAD系统，这不仅需要许多的汽车离合器设计和CAD方面的专业知识，更需要很高的计算机软件设计和计算机应用水平。本人还对面向对象的程序设计方法和当前的Windows操作系统进行了研究，学习了多种程序设计语言和一些软件开发工具。运用软件工程的理论对ACCAD系统进行了需求分析、功能结构分析、流程图分析、方案设计、模块设计。运用面向对象的程序设计方法、多种程序设计语言，用Visual Basic和Visual C++开发工具设计并实现了汽车离合器CAD系统。一汽东光离合器厂已经大量应用该系统，实践证明ACCAD 系统能够很好的辅助设计人员设计离合器、能显著地提高离合器产品的设计能力、大大缩短离合器产品的开发周期，而且系统具有很高的稳定性和可扩充性。
随着中国加入WTO，中国汽车零部件企业面临着越来越大的压力和挑战， 全球性的跨国汽车及零部件公司正逐渐地入侵中国这一个世界上最大也是最后一个潜在汽车市场。国内汽车行业尤其是汽车零部件与跨国公司相比，无论是从规模、资金实力、研发能力、还是管理水平上看，都不在一个数量级上。国内零部件企业为了生存下去，必须从某个方面有所突破，形成一定的竞争优势。过去，一直在国家关税政策保护卜生存的中国汽车这一竞争行业的企业， 面临着生存的危机，竞争力弱的很重要的一个原因就是产品开发速度慢，水平低。究其原因，有的是开发手段落后，有的是经验不足，有的是开发人员素质达不到客观要求，还有一个重要的原因，就是我们产品开发的方式的落后。
作为本项工作的重点之一，本文分别对自动离合器系统的虚拟样机仿真和实车试验。利用大型系统动力学分析软件ADAMS，开发出自动离合器系统的虚拟样机模型，通过虚拟试验分析离合器接合过程瞬态响应的理论预测结果，为实车试验所需的液压执行器和计算机控制器的设计提供了可靠而有效的依据。自动离合器控制器包括传感器、微处理器及其接口;执行器为液压机构。所有试验都在Santana LX 轿车上实车进行，重点考察小油门、大载荷、高档位、上坡等高难度工况。试验结果表明，本文实施的控制策略使自动离合器的接合过程具有良好的动态特性，对人的主观意图、汽车多变的工况和复杂的行驶环境具有自适应能力，能够保证发动机不熄火，车辆平稳起步和换档，滑磨过程缩短，执行机构响应迅速。仿真和实验结果均表明，本文提出的分析方法和控制技术能够显著提高AMT自动离合器的工作性能，为该技术的进一步产品化开发奠定了基础。