基于刚柔耦合的汽车多连杆后悬架性能分析

文章介绍了采用模态综合法计算出拖曳臂的变形量和模态,然后生成模态中性文件,导入ADAMS/Car中建立刚柔耦合的汽车多连杆后悬架模型进行运动学分析,并通过仿真结果与实测数据的比较,证明了刚柔耦合悬架模型比刚体悬架模型更为合理,能在设计阶段更真实地预测与分析汽车悬架的性能,同时也说明拖曳臂的刚度是对多连杆后悬架运动学特性影响的重要因素.     

Simplified fatigue durability assessment for rear suspension structure

The eight-channel test rig is widely used in durability assessment of vehicle components while for some cases of rear suspension, this costly instrument is unnecessary. Based on the analysis of structure and forces, a simpler one-channel testing approach is presented for the durability calculation of a dependent rear suspension. Taking a punched rear shock tower as the study object, a FEA strain-stress analysis was first performed to determine the risk area. Then, the entire vehicle test system was created, and the proving ground tests were carried out so that the real strain on the part could be measured. Based on the road test data and the P-S-N curve of the component, the cumulative fatigue damage of a 15,000-kilometer proving ground test road was calculated, and the computational result indicates that the modified structure was safe for durability analysis. Moreover, a standard 50% S-N survival fraction curve was plotted using Corten and Dolan’s method, which can be utilized in the durability analysis for other similar components. Finally, the road test for this modified suspension structure was carried out, and the test result certified that the punched shock tower can be subjected to a 15,000-kilometer proving ground test road without the appearance of fatigue failure.     

城市客车短后悬结构的开发

论述了客车短后悬的优点,并针对现行的发动机后横置短后悬存在结构复杂、传动效率低、成本高的不足,开发了一种传动可靠的低成本客车短后悬结构.     

轻型车后悬架安全性和舒适性的设计

本文对后悬架的类型及纵悬 架开发设计中的安全性和舒适性的影响进行了介绍和分析。     

工程车断开式后悬架系统的强度分析

本文通过建立两种某工程车断开式后悬架系统的三维实体有限元模型,仿真计算载荷作用下后悬架系统的应力分布状况。通过对计算结果的对比分析,指出后悬架系统1为满足结构强度和轻量化要求下的较优结构。     

基于ADAMS／Insight的多连杆后悬架系统优化分析

在对某型轿车多连杆后悬架系统建立ADAMS多体动力学模型基础上,对该悬架系统进行了仿真分析,分析了轮跳对后轮定位参数的影响,并结合ADAMS／Insight模块对该悬架部分硬点的位置进行了DOE优化。优化结果表明,对该悬架系统所做的优化设计是正确有效的,改善了该悬架系统的运动特性。     

某车型前后桥制动器匹配设计

为满足整车制动性能要求,对主机厂提供的参数进行制动力匹配计算,并将计算结果与试验结果进行对比,其制动性能试验结果符合法规GB 12676—1999的相关要求。     

Development of a bushing with an active compliance chamber for variable displacement engines

In this paper a novel active compliance chamber is designed, which can be used to control the dynamic stiffness of a common hydraulic bushing. This chamber offers a simple and cost-effective solution for the variable displacement engine (VDE) isolation problem. A VDE system requires a soft bushing for the half cylinder mode and a regular one for normal engine operations. A magnetic actuator is used to produce mechanical pulses. The linearisation technique is used for simplifying the nonlinear equation of motion. Different current sources are used to feed the magnetic actuator. The pressure inside the chamber follows linearly the current input signal. The phase shift in various current inputs is used in the form of the transfer functions to create the required pressure response pattern in the frequency domain. Since the dynamic stiffness of a conventional hydraulic bushing is a direct function of the pressure inside it, the active compliance chamber can be used to alter the pressure and consequently produce the required dynamic stiffness response. As a result, it can address the engine vibration problem for VDE situation.     

Effect of rear slant angle on vehicle crosswind stability simulation on a simplified car model

It is important to know the effect of the aerodynamic forces and moments on driving stability because it is responsible for the excitation and influences the response of the vehicle. The purpose of this paper is to study the effect of rear slant angle of a surface vehicle on crosswind sensitivity for stability analysis. The vehicle mathematical model used to conduct a dynamic simulation was based on a simple reduced order lateral dynamics of sideslip and yaw rate motion coupled with aerodynamics model. The intention here is to compare the effect of rear slant angles response to crosswind and to rank the crosswind sensitivity ratings. The aerodynamic loads are defined as the function of the aerodynamic derivatives from the static wind tunnel tests. Result shows a 20° rear slant angle demonstrates the highest rating of crosswind sensitivity, while zero degree slant exhibits the least.     

Control and evaluation of active suspension for MDOF vehicle model

The current method for solving the problem of active suspension control for a vehicle often uses a quarter car or a half car model. This kind of model is not suitable for practical applications. In this paper, based on considering the influence of factors such as the engine, seat and passengers, a MDOF (multi-degree-of-freedom model) describing the vehicle motion has been set up, and a controller for this model is designed by using LQ control theory. Furthermore the appropriate control scheme is selected by testing various performance indexes.     

Active controller design for an electromagnetic energy-regenerative suspension

In this paper, with the parameters acquired from measured and tested data, a three-phase mathematical model is applied to the motor component of the developed electromagnetic suspension actuator. A main/inner-loop structure is used for its active control, and the constraints of the control current and energy flow states of actuator are analyzed by simplifying the inner-loop control system. Two different control modes, i.e., Consumptive Full Active (CFA) and Regenerative Semi Active (RSA) modes, which emphasize vibration control of sprung mass and vibration energy regeneration caused by road roughness, respectively, are proposed. Simulations are carried out using different road conditions, and the results demonstrate that the CFA mode can improve vehicle ride comfort by more than 30 percent, despite battery energy consumption; in RSA mode, the ride comfort can be improved by up to 10 percent with the battery charged by regenerated energy.     

Road disturbance estimation for the optimal preview control of an active suspension systems based on tracked vehicle model

This research investigates stochastic estimation of a look-ahead sensor scheme using the optimal preview control for an active suspension system of a full tracked vehicle (FTV). In this scheme, wheel disturbance input to the front wheels are estimated using the dynamic equations of the system. The estimated road disturbance input at the front wheels are utilized as preview information for the control of subsequently following wheels of FTV. The design of optimal preview control is used as a classical linear quadratic Gaussian problem by combining dynamics of the original system and estimation of previewed road inputs. The effectiveness of the preview controller is evaluated by comparing the estimated information with the measured information for different road profiles, where Kalman filter is used for the state-variables estimation of the FTV. This research also considers the reduced order estimation using commonly available sensors in order to decrease the number of sensors and measurements. The simulation results’ using an active suspension system with different preview information shows that the proposed system can be beneficial for the improvement of ride comfort of tracked vehicles without using any specialized sensors for preview information calculation.     

富康轿车随动悬架中横向稳定杆的设计分析

对富康轿车随动悬架结构中横向稳定杆的设计进行了分析，讨论了横向稳定杆结构对于富康轿车行驶稳定性的影响。     

Lateral handling improvement with dynamic curvature control for an independent rear wheel drive EV

The integrated longitudinal and lateral dynamic motion control is important for four wheel independent drive (4WID) electric vehicles. Under critical driving conditions, direct yaw moment control (DYC) has been proved as effective for vehicle handling stability and maneuverability by implementing optimized torque distribution of each wheel, especially with independent wheel drive electric vehicles. The intended vehicle path upon driver steering input is heavily depending on the instantaneous vehicle speed, body side slip and yaw rate of a vehicle, which can directly affect the steering effort of driver. In this paper, we propose a dynamic curvature controller (DCC) by applying a the dynamic curvature of the path, derived from vehicle dynamic state variables; yaw rate, side slip angle, and speed of a vehicle. The proposed controller, combined with DYC and wheel longitudinal slip control, is to utilize the dynamic curvature as a target control parameter for a feedback, avoiding estimating the vehicle side-slip angle. The effectiveness of the proposed controller, in view of stability and improved handling, has been validated with numerical simulations and a series of experiments during cornering engaging a disturbance torque driven by two rear independent in-wheel motors of a 4WD micro electric vehicle.     

Designing a non-linear tracking controller for vehicle active suspension systems using an optimization process

In this paper, a new non-linear tracking controller for vehicle active suspension systems is analytically designed using an optimization process. The proposed scheme employs a realistic non-linear quarter-car model, which is composed of a hardening spring and a quadratic damping force. The control input is the external active suspension force and is determined by minimizing a performance index defined as a weighted combination of conflicting objectives, namely ride quality, handling performance and control energy. A linear skyhook model with standard parameters is used as the reference model to be tracked by the controller. The robustness of the proposed controller in the presence of modeling uncertainties is investigated. The performed analysis and the simulation results indicate that both vehicle ride comfort and handling performance can be improved using the minimum external force when the proposed non-linear controller is engaged with the model. Meanwhile, a compromise between different objectives and control energy can easily be made by regulating their respective weighting factors, which are the free parameters of the control law.     

Actively translating a rear diffuser device for the aerodynamic drag reduction of a passenger car

This research aims to develop an actively translating rear diffuser device to reduce the aerodynamic drag experienced by passenger cars. One of the features of the device is that it is ordinarily hidden under the rear bumper but slips out backward only under high-speed driving conditions. In this study, a movable arc-shaped semi-diffuser device, round in form, is designed to maintain the streamlined automobile??s rear underbody configuration. The device is installed in the rear bumper section of a passenger car. Seven types of rear diffuser devices whose positions and protrusive lengths and widths are different (with the basic shape being identical) were installed, and Computational Fluid Dynamics (CFD) analyses were performed under moving ground and rotating wheel conditions. The main purpose of this study is to explain the aerodynamic drag reduction mechanism of a passenger car cruising at high speed via an actively translating rear diffuser device. The base pressure of the passenger car is increased by deploying the rear diffuser device, which then prevents the low-pressure air coming through the underbody from directly soaring up to the rear surface of the trunk. At the same time, the device generates a diffusing process that lowers the velocity but raises the pressure of the underbody flow, bringing about aerodynamic drag reduction. Finally, the automobile??s aerodynamic drag is reduced by an average of more than 4%, which helps to improve the constant speed fuel efficiency by approximately 2% at a range of driving speeds exceeding 70 km/h.     

Aerodynamic design optimization of rear body shapes of a sedan for drag reduction

This study proposes an aerodynamically optimized outer shape of a sedan by using an Artificial Neural Network (ANN), which focused on modifying the rear body shapes of the sedan. To determine the optimization variables, the unsteady flow field around the sedan driving at very fast speeds was analyzed by CFD simulation, and fluctuations of the drag coefficient (C _D ) and pressure around the car were calculated. After consideration of the baseline result of CFD, 6 local parts from the end of the sedan were chosen as the design variables for optimization. Moreover, an ANN approximation model was established with 64 experimental points generated by the D-optimal methodology. As a result, an aerodynamically optimized shape for the rear end of the sedan in which the aerodynamic performance is improved by about 5.64% when compared to the baseline vehicle is proposed. Finally, it is expected that within the accepted range of shape modifications for a rear body, the aerodynamic performance of a sedan can be enhanced so that the fuel efficiency of the sedan can be improved. The YF SONATA, a sedan manufactured by Hyundai Motors Corporate, played a major role in this research as the baseline vehicle.     

New model and simulation of Macpherson suspension system for ride control applications

The main purpose of this paper is to propose a new nonlinear model of the Macpherson strut suspension system for ride control applications. The model includes the vertical acceleration of the sprung mass and incorporates the suspension linkage kinematics. This two-degree-of-freedom (DOF) model not only provides a more accurate representation of the Macpherson suspension system for control applications in order to improve the ride quality, but also facilitates evaluation of the suspension kinematic parameters, such as camber, caster and king-pin angles as well as track alterations on the ride vibrations. The performances of the nonlinear and linearised models are investigated and compared with those of the conventional model. Besides, it is shown that the semi-active force improves the ride quality better than active force, while the opposite is true in terms of improving the performance of the kinematic parameters. The results of variations of the kinematic parameters based on the linear model subject to road disturbances are compared with those of a virtual prototype of Macpherson suspension in ADAMS software. The analytical results in both cases are shown to agree with each other.     

Kinematic and dynamic analysis of the McPherson suspension with a planar quarter-car model

McPherson suspension modelling poses a challenging problem due to its nonlinear asymmetric behaviour. The paper proposes a planar quarter-car analytical model that not only considers vertical motion of the sprung mass (chassis) but also: (i) rotation and translation for the unsprung mass (wheel assembly), (ii) wheel mass and its inertia moment about the longitudinal axis, and (iii) tyre damping and lateral deflection. This kinematic–dynamic model offers a solution to two important shortcomings of the conventional quarter-car model: it accounts for geometry and for tyre modelling. The paper offers a systematic development of the planar model as well as the complete set of mathematical equations. This analytical model can be suitable for fast computation in hardware-in-the-loop applications. Furthermore, a reproducible Simulink implementation is given. The model has been compared with a realistic Adams/View simulation to analyse dynamic behaviour for the jounce and rebound motion of the wheel and two relevant kinematic parameters: camber angle and track width variation.     

Drag reduction of a pickup truck by a rear downward flap

The drag reduction of a pickup truck by a rear flap add-on was examined through CFD simulations and wind tunnel experiments. When installed at the rear edge of the roof, the flap increased the cabin back surface pressure coefficient, causing the downwash of the bed flow to be inclined on the tailgate. Thus, the attachment of the bed flow to the tailgate was eliminated; consequently, the drag coefficient was reduced with increasing flap length and downward angle despite the enlarged reverse flow in the wake. However, the drag coefficient did not decrease any further after a specific downward angle was reached because the bed flow increased the drag force at the tailgate and the flap lowered the pressure field above the flap. To maximize the drag reduction effect, the rear downward flap should be designed to have an optimum downward angle.