共查询到20条相似文献,搜索用时 62 毫秒
1.
《汽车生活》2008,(2):26-27
0.61803398874989484820……很多人认得这串数字,是传说中的黄金分割值。不用去深究它是怎么得来的,反正你拿把尺子量一量自己肚脐的位置就知道这里的神奇了。车也是一样,都知道门开得越多越实用,可双门的造型就像是汽车设计中的黄金分割法则一样,深深地激发着设计师的灵感和人们的审美情趣。所以在我们的汽车工业朝着越来越实用的方向发展的时候,Coupe作为一种独具魅力的车型,长久地保存在了我们的视线之中。但我们还是会有一些解不开的疑惑。留存至今的经典老爷车型门乎每一辆都是双门,这是为什么?阿尔法·罗密欧几乎每次都把后车门把手刻比普通版好看,为什么?奥迪A5刚出来不久,双门的S5紧随其后更受关注,为什么?是什么让那么多人为Coupe这种超级不实用的车型而倾倒?小小的汽车里,0.618后面的这串密码,究竟要怎样才能破解呢? 相似文献
2.
例1 一辆东风12 V汽油车改装成24 V柴油车时,由于一时购买不到24 V稳压器,只好就用原车12 V仪表、稳压器.原车12 V仪表工作原理接线图见图1. 相似文献
3.
4.
"产品同质化"如同一个幽灵在中国客车市场中游荡,几乎所有的客车制造商都为其所困绕,因此,如何驱除这个幽灵当然也成为业界普遍关心的问题.仔细分析一下当前国内所有客车销售的热点细分市场,配置相同、功能相近、外形相似的产品都扎成了堆,在中低端产品上"你有我也有,现在没有3个月后也能有"的状况,已经成为中国客车市场一道独特的风景. 相似文献
5.
6.
7.
8.
Magic Formula轮胎模型参数辨识的一种混合优化方法 总被引:1,自引:0,他引:1
Magic Formula(MF)轮胎模型能够准确描述轮胎的侧偏特性,广泛应用于车辆动力学的研究。由于MF轮胎模型参数多,且高度非线性,从大量的试验数据中准确辨识这些参数相当困难。提出一种基于遗传算法和数值优化算法的混合优化方法,采用由粗到精的辨识过程,先利用遗传算法得出近似最优解,再利用数值优化算法辨识出精确的参数。利用辨识出的参数计算轮胎的侧偏特性,计算结果与试验数据吻合良好,表明该方法是辨识MF轮胎模型参数的有效手段。 相似文献
9.
An Alternative Method to Determine the Magic Tyre Model Parameters Using Genetic Algorithms 总被引:2,自引:0,他引:2
J. A. Cabrera A. Ortiz E. Carabias A. Simon 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2004,41(2):109-127
Summary Tyre behavior plays an important role in vehicle dynamics research. Knowledge of tyre properties is necessary to properly design vehicle components and advance control system. For that purpose mathematical models of the tyre are being used in vehicle simulation models. The Magic Formula Tyre Model is a semi-empirical tyre model which describes tyre behavior quite accurately. The Magic Formula Tyre Model needs a set of parameters to describe the tyre properties; the determination of these parameters is dealt with in this paper. A new method based on genetic techniques is used to determine these parameters. The main advantages of the method are its simplicity of implementation and its fast convergence to optimal solution, with no need of deep knowledge of the searching space. So to start the search, it is not necessary to know a set of starting values of the Magic Formula parameters. The comparison between analytical optimization methods and the method proposed is discussed in this paper. 相似文献
10.
《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(2):109-127
Summary Tyre behavior plays an important role in vehicle dynamics research. Knowledge of tyre properties is necessary to properly design vehicle components and advance control system. For that purpose mathematical models of the tyre are being used in vehicle simulation models. The Magic Formula Tyre Model is a semi-empirical tyre model which describes tyre behavior quite accurately. The Magic Formula Tyre Model needs a set of parameters to describe the tyre properties; the determination of these parameters is dealt with in this paper. A new method based on genetic techniques is used to determine these parameters. The main advantages of the method are its simplicity of implementation and its fast convergence to optimal solution, with no need of deep knowledge of the searching space. So to start the search, it is not necessary to know a set of starting values of the Magic Formula parameters. The comparison between analytical optimization methods and the method proposed is discussed in this paper. 相似文献
11.
13.
《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(2):154-178
Tyre models are a prerequisite for any vehicle dynamics simulation. Tyre models range from the simplest mathematical models that consider only the cornering stiffness to a complex set of formulae. Among all the steady-state tyre models that are in use today, the Magic Formula tyre model is unique and most popular. Though the Magic Formula tyre model is widely used, obtaining the model coefficients from either the experimental or the simulation data is not straightforward due to its nonlinear nature and the presence of a large number of coefficients. A common procedure used for this extraction is the least-squares minimisation that requires considerable experience for initial guesses. Various researchers have tried different algorithms, namely, gradient and Newton-based methods, differential evolution, artificial neural networks, etc. The issues involved in all these algorithms are setting bounds or constraints, sensitivity of the parameters, the features of the input data such as the number of points, noisy data, experimental procedure used such as slip angle sweep or tyre measurement (TIME) procedure, etc. The extracted Magic Formula coefficients are affected by these variants. This paper highlights the issues that are commonly encountered in obtaining these coefficients with different algorithms, namely, least-squares minimisation using trust region algorithms, Nelder–Mead simplex, pattern search, differential evolution, particle swarm optimisation, cuckoo search, etc. A key observation is that not all the algorithms give the same Magic Formula coefficients for a given data. The nature of the input data and the type of the algorithm decide the set of the Magic Formula tyre model coefficients. 相似文献
14.
15.
Pacejka's Magic Formula Tyre Model is widely used to represent force and moment characteristics in vehicle simulation studies meant to improve handling behaviour during steady-state cornering. The experimental technique required to determine this tyre model parameters is fairly involved and highly sophisticated. Also, total test facilities are not available in most countries. As force and moment characteristics are affected by tyre design attributes and tread patterns, manufacturing of separate tyres for each design alternative affects tyre development cycle time and economics significantly. The objective of this work is to identify the interactions among various tyre design attributes-cum-operating conditions and the Magic Formula coefficients. This objective is achieved by eliminating actual prototyping of tyres for various design alternatives as well as total experimentation on each tyre through simulation using finite element analysis. Mixed Lagrangian–Eulerian finite element technique, a specialized technique in ABAQUS, is used to simulate the steady-state cornering behaviour; it is also efficient and cost-effective. Predicted force and moment characteristics are represented as Magic Formula Tyre Model parameters through non-linear least-squares fit using MATLAB. Issues involved in the Magic Formula Tyre Model representation are also discussed. A detailed analysis is made to understand the influence of various design attributes and operating conditions on the Magic Formula parameters. Tread pattern, tread material properties, belt angle, inflation pressure, frictional behaviour at the tyre–road contact interface and their interactions are found to significantly influence vehicle-handling characteristics. 相似文献
16.
17.
《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(6):431-448
The object of the study is to apply the Pacejka magic formula tyre model on a study of a hydraulic anti-lock braking system, especially applied to a light motorcycle. A sliding mode PWM controller is designed and tested. Both simulation and experimental studies of an anti-lock braking system are undertaken. The paper presents an analytical approach for estimating the longitudinal adhesive coefficient between a tyre and the road through the magic formula tyre model, the parameters of which are identified by a genetic algorithm. A dynamic analysis of a light motorcycle is carried out in detail. The experimental results show that the antilock braking system designed in the study is effective to prevent wheels locking during emergency braking. The proposed simulation results match experimental data well. 相似文献
18.
Chen-Yuan Lu Ming-Chang Shih 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2004,41(6):431-448
The object of the study is to apply the Pacejka magic formula tyre model on a study of a hydraulic anti-lock braking system, especially applied to a light motorcycle. A sliding mode PWM controller is designed and tested. Both simulation and experimental studies of an anti-lock braking system are undertaken. The paper presents an analytical approach for estimating the longitudinal adhesive coefficient between a tyre and the road through the magic formula tyre model, the parameters of which are identified by a genetic algorithm. A dynamic analysis of a light motorcycle is carried out in detail. The experimental results show that the antilock braking system designed in the study is effective to prevent wheels locking during emergency braking. The proposed simulation results match experimental data well. 相似文献
19.
《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(9):689-718
In 2004, a new searching algorithm for Magic Formula tyre model parameters was presented. Now, a summary of the results, for pure and combined slip, that this algorithm is able to achieve is presented. The Magic Formula tyre model needs a set of parameters to describe the tyre properties. The determination of these parameters is dealt with in this article. A new method, called IMMa Optimization Algorithm (IOA), based on genetic techniques, is used to determine these parameters. Here, we show the computational cost that has been used to obtain the optimum parameters of every characteristic of the Magic Formula tyre model, called Delft Tyre 96. The main advantages of the method are its simplicity of implementation and its fast convergence to optimal solution, with no need of deep knowledge of the searching space. Hence, to start the search, it is not necessary to know a set of starting values of the Magic Formula parameters (null sensitivity to starting values). The search can be started with a randomly generated set of parameters between [0, 1]. Nowadays, MF-Tool, an application developed by TNO, uses an optimization technique to fit Magic Formula parameters from Matlab toolbox [van Oosten, J.J.M. and Bakker, E., 1993, {Determination of magic tyre model parameters}. Vehicle System Dynamics, 21, 19–29; van Oosten, J.J.M., Savi, C., Augustin, M., Bouhet, O., Sommer, J. and Colinot, J.P., 1999, {Time, tire, measurements, forces and moments, a new standard for steady state cornering tyre testing}. EAEC Conference, Barcelona, 30 June–2 July.]. We refer to that algorithm as the starting value optimization technique. The comparison between the optimization technique employed by TNO and the proposed IOA method is discussed in this article. In order to give a relative idea of adjustment accuracy, the sum-squared error and the mean-squared error, from the curves of the tyre model with the parameters optimized by both applications compared with test data are evaluated. 相似文献