Car Parameters Identification by Handling Manoeuvres

A methodology is presented for identifying car parameters by studying the vehicle's handling. The methodology is based on the Kalman filter and makes it possible to determine the parameters on the basis of the results obtained from standard, on-road handling manoeuvres.     

Effect of vehicle model on the estimation of lateral vehicle dynamics

A methodology is presented for estimating vehicle handling dynamics, which are important to control system design and safety measures. The methodology, which is based on an extended Kalman filter (EKF), makes it possible to estimate lateral vehicle states and tire forces on the basis of the results obtained from sinusoidal steering stroke tests that are widely used in the evaluation of vehicle and tire handling performances. This paper investigates the effect of vehicle-road system models on the estimation of lateral vehicle dynamics in the EKF. Various vehicle-road system models are considered in this study: vehicle models (2-DOF, 3-DOF, 4-DOF), tire models (linear, non-linear) and relaxation lengths. Handling tests are performed with a vehicle equipped with sensors that are widely used by vehicle and tire manufacturers for handling maneuvers. The test data are then used in the estimation of the EKF and identification of lateral tire model coefficients. The accuracy of the identified values is validated by comparing the RMS error between experimentally measured states and regenerated states simulated using the identified coefficients. The results show that the relaxation length of the tire model has a notable impact on the estimation of lateral vehicle dynamics.     

Objectification of on-center handling characteristics based on spring-mass-damper system

As one of the major handling performance factors of vehicles and tires, on-center handling is very important at high speeds where safety and refinement are major concerns for the driver. In this paper, the steering wheel torque and vehicle response characteristics that play an important role in on-center handling performance were quantified using a spring-mass-damper (SMD) system. Using this system, the characteristics of steering wheel torque and vehicle response could be objectified with SMD parameters such as those for the spring and damping. Experimental objective tests were performed by considering the process by which the on-center handling is evaluated subjectively, and the SMD parameters were extracted from the measurement data. From a statistical analysis of the subjective and SMD parameters for several vehicles and professional drivers, it was found that the subjective assessment of on-center handling could be successfully explained using the suggested parameters.     

Analysis of handling performance based on simplified lateral vehicle dynamics

In this article, the analysis methods for vehicle handling performance are studied. Using simple models, dynamic characteristic parameters such as yaw, natural frequency, and the damping coefficient of a vehicle can be theoretically formulated. Here, the vehicle is simplified by a bicycle (single-track) model, and the tire is modeled by an equivalent cornering stiffness and first order lag. From the experimental road data, the tire model parameters (equivalent cornering stiffness and time lag constant) are extracted. These parameters are then inserted into the theoretically formulated equations of dynamic characteristic parameters. For the purpose of validating the efficiency of the suggested methods, experimental road tests (where the cars have different handling performances) are performed. The results show that vehicle handling performance can be sufficiently represented by the suggested dynamic characteristic parameters. So, it is concluded that the proposed method has practical use for the development of new cars or for the comparison of similar cars since the evaluations of the vehicle handling performance can be efficiently determined by the suggested dynamic characteristic parameters.     

Handling and safety enhancement of race cars using active aerodynamic systems

A methodology is presented in this work that employs the active inverted wings to enhance the road holding by increasing the downward force on the tyres. In the proposed active system, the angles of attack of the vehicle's wings are adjusted by using a real-time controller to increase the road holding and hence improve the vehicle handling. The handling of the race car and safety of the driver are two important concerns in the design of race cars. The handling of a vehicle depends on the dynamic capabilities of the vehicle and also the pneumatic tyres’ limitations. The vehicle side-slip angle, as a measure of the vehicle dynamic safety, should be narrowed into an acceptable range. This paper demonstrates that active inverted wings can provide noteworthy dynamic capabilities and enhance the safety features of race cars. Detailed analytical study and formulations of the race car nonlinear model with the airfoils are presented. Computer simulations are carried out to evaluate the performance of the proposed active aerodynamic system.     

基于操纵稳定性的车辆悬架性能参数稳健设计方法

结合虚拟样机模型实例,介绍将Taguchi稳健优化设计方法应用于悬架参数设计,以提高车辆操纵稳定性能的稳健性方法.该方法只需要少量代表性的试验及简单的分析,即可得到可靠的设计结果.该结果可有效控制不可控因素对车辆操纵稳定性能的影响.     

Hierarchical optimisation of the design parameters of a vehicle suspension system

This paper presents a design methodology for the mechanical systems entitled First Design. It is based on a hierarchical organisation of the design, taking into account the notion of robustness at an early phase of the project. The aim is to improve the quality of the system in order to make it robust, less sensitive to the variability of the external parameters and design parameters. We distinguish two main stages of the design cycle: one concerning functional parameters and another concerning physical parameters. The methodology is based on simplified models, on sensitivity analysis and on robust multi-objective optimisation. As an example, the methodology will be applied to the optimisation of vehicle suspension system design parameters. For each stage of the hierarchical design, adapted simplified models, sensitivity analyses and optimisation processes will be studied and applied to our vehicle suspension system.     

麦佛逊悬架总成参数对整车操控性能的影响分析

基于悬架K&C特性试验数据、整车操纵稳定性道路试验客观评价数据库资源、车轮和悬架几何定位参数测试数据及CARSIM参数化仿真技术,针对麦佛逊式前悬架的设计开发,运用试验统计学中的DOE方法分别在时域和频域内进行整车操控性客观仿真试验,并对虚拟试验结果进行参数敏感性分析,得到了麦佛逊式前悬架影响整车性能的关键总成参数及其...     

Hierarchical optimisation of the design parameters of a vehicle suspension system

This paper presents a design methodology for the mechanical systems entitled First Design. It is based on a hierarchical organisation of the design, taking into account the notion of robustness at an early phase of the project. The aim is to improve the quality of the system in order to make it robust, less sensitive to the variability of the external parameters and design parameters. We distinguish two main stages of the design cycle: one concerning functional parameters and another concerning physical parameters. The methodology is based on simplified models, on sensitivity analysis and on robust multi-objective optimisation. As an example, the methodology will be applied to the optimisation of vehicle suspension system design parameters. For each stage of the hierarchical design, adapted simplified models, sensitivity analyses and optimisation processes will be studied and applied to our vehicle suspension system.     

伸缩臂式自装卸机构总体参数的优化设计

建立了伸缩臂式自装卸机械总体参数化设计的数学模型，以油缸受力最小为目标函数，满足最大纳向装卸角及尺寸２条件为约束条件，详述了结构优化设计过程，编制了优化计算软件。并以某型自装卸机械为优化设计计算，求得了机构最优参数。     

Identification of linear handling models for road vehicles

This study reports the identification of linear handling models for road vehicles starting from structural identifiability analysis, continuing with the experiments to acquire data on a vehicle equipped with a sensor set and data acquisition system, and ending with the estimation of parameters using the collected data. The model structure originates from the well-known linear bicycle model that is frequently used in handling analysis of road vehicles. Physical parameters of the bicycle model structure are selected as the unknown parameter set that is to be identified. Global identifiability of the model structure is analysed, in detail, and concluded according to various available sensor sets. Physical parameters of the bicycle model structure are estimated using prediction error estimation method. Genetic algorithms are used in the optimisation phase of the identification algorithm to overcome the difficulty in the selection of initial values for parameter estimates. Validation analysis of the identified model is also presented. The identified model is shown to track the system response successfully.     

Handling stability improvement through robust active front steering and active differential control

The design of the integrated active front steering and active differential control for handling improvement of road vehicles is undertaken. The controller design algorithm is based on the solution of a set of linear matrix inequalities that guarantee robustness against a number of vehicle parameters such as speed, cornering and braking stiffnesses. Vehicle plane dynamics are first expressed in the generic linear parameter-varying form, where the above-stated parameters are treated as interval uncertainties. Then, static-state feedback controllers ensuring robust performance against changing road conditions are designed. In a first series of simulations, the performance of the integrated controller is evaluated for a fishhook manoeuvre for different values of road adhesion coefficient. Then, the controller is tested for an emergency braking manoeuvre executed on a split-μ road. In all cases, it is shown that static-state feedback controllers designed by the proposed method can achieve remarkable road handling performance compared with uncontrolled vehicles.     

Possible experimental method to determine the suspension parameters in a simplified model of a passenger car

Currently, as well as in the past, researchers have shown great interest in developing suspension systems for vehicles and especially in the design and optimization of the suspension parameters, such as the stiffness and the damping coefficient. These parameters are considered to be important factors that have an influence on safety and improve the comfort of the passengers in the vehicle. This paper describes a simplified methodology to determine, in a quick manner, the suspension parameters for different types of passenger cars equipped with passive suspension systems. Currently, different types of passenger cars are produced with different types of suspension systems. Finding a simplified methodology to determine these parameters with sufficient accuracy would contribute a simplified and quick method to the inspection of the working conditions of a suspension system. Therefore, a simple system to determine these parameters is needed. An analysis of the suspension parameters is performed using mathematical modeling and numerical analysis conducted using the Working Model software. The result derived from the developed methodology shows small errors when compared with the generic values, and it can be concluded that the design of the suspension parameter measurement device using the developed methodology is useful, simple, and has sufficient accuracy.     

摩擦片式防滑差速器转矩特性对汽车操纵稳定性的影响研究

进行了摩擦片式防滑差速器防滑转矩输出特性测定试验,并分别对装有摩擦片式防滑差速器和普通差速器的汽车,通过试验测定的车厢侧倾角、转弯半径比、前后轴侧偏角差值、横摆角速度及侧向加速度作为对比参数,研究了摩擦片式防滑差速器转矩特性对汽车操纵稳定性的影响。结果表明,摩擦片式防滑差速器能够显著提高汽车的动力性、通过性,改善汽车的操纵稳定性。     

基于2阶响应面模型的汽车前轮定位参数设计研究

综合考虑轮胎磨损及车辆操纵稳定性的要求,运用正交试验方法对某型汽车烛式悬架-整体式转向系统的定位参数进行了设计研究。建立了基于2阶响应面的前轮定位参数设计模型,并应用该模型对前轮定位参数进行了优化设计。通过与经验公式设计结果的对比,验证了该方法的先进性和有效性,     

道路几何参数对车辆操纵稳定性影响

为研究道路几何参数对车辆操纵稳定性的影响,本文采用MATLAB/Simulink建立了3自由度整车动力学模型,通过数值仿真模拟,研究了车辆在不同超高、纵坡坡度以及合成纵坡下动力响应,在此基础上进一步分析了在不同车速以及前轮转角输入下,道路几何参数对车辆操纵稳定性的影响.结果表明:与水平路面相比,道路超高和纵坡坡度对车辆...     

利用ADAMS对双横臂独立悬架进行仿真分析

通过某商务车的独立悬架的数学建模和仿真模型,利用ADAMS软件精确地计算汽车运动中悬架定位参数的变化,分析了该悬架定位参数对操纵稳定性的影响,以提高产品开发质量。     

汽车四轮定位分析及检测

采用完全四轮定位方法和电脑四轮定位仪可使车辆定位参数得到最佳的测量，从而使车辆保证原设计功能。阐述了定位参数对转向操纵的稳定性，转向控制及轮胎磨损的影响，另外，介绍了四轮定位的优点。     

五连杆后悬架仿真研究

应用多体运动学与动力学仿真软件ADAMS中的CAR专业模块建立该车的前后悬架多刚体模型,对悬架的各种性能进行了仿真分析,研究了悬架几何参数对汽车操纵稳定性的影响,在理论验证的基础上揭示了该悬架的运动规律。