Load-leveling suspension system with a magnetorheological damper

In this paper, a load-leveling suspension system with a magnetorheological (MR) damper is investigated. In this suspension system, the MR damper is connected to a spring to form a load-leveling suspension system. The system effective stiffness and damping can be adjusted by controlling the MR damper. The characteristics of a load-leveling suspension system are studied first. When the linear damper is replaced with an MR damper, the averaging method is adopted to obtain the steady-state response of the nonlinear system. A comparison demonstrates that the results of the averaging method are in good agreement with those obtained by numerical simulations. The analytical results are then verified experimentally. The load-leveling suspension system studied here is able to adjust both suspension stiffness and damping and, hence, it may provide more effective vibration control in a wider frequency range, when the damper is controlled.     

A study of locomotive driver's seat vertical suspension system with adjustable damper

This paper shows that laboratory measurements can be used for the identification of structure and parameters of commercial seat vertical suspension system model. A commonly used single-degree-of-freedom suspension model does not suffice. The system model presented is based on Zener's structure and clearly describes the dynamic properties of a vertical seat suspension with an adjustable damper. The model introduced, augmented with seat cushion dynamic model, predicts the seat vertical vibration mitigation properties under field conditions with a reasonable accuracy. Optimisation of the adjustable damper setting is performed using a two-objective function optimisation technique. This enables us to optimise not only the exerted vertical vibration acceleration but also the seat relative vertical displacement (stroke). Optimisation was facilitated for the particular suspended seat without the requirement of further field measurements. In addition, a two-parameter optimisation was performed showing possible further improvement in both objectives at the manufacturer's discretion. This study could be representative of driver's seats equipped with vertical seat suspension system using an air-spring and an adjustable damper.     

Semi-active suspension systems for railway vehicles using magnetorheological dampers. Part I: system integration and modelling

In this paper, it is aimed to investigate semi-active suspension systems using magnetorheological (MR) fluid dampers for improving the ride quality of railway vehicles. A 17-degree-of-freedom (DOF) model of a full-scale railway vehicle integrated with the semi-active controlled MR fluid dampers in its secondary suspension system is proposed to cope with the lateral, yaw, and roll motions of the car body, trucks, and wheelsets. The governing equations combining the dynamics of the railway vehicle integrated with MR dampers in the suspension system and the dynamics of the rail track irregularities are developed and a linear quadratic Gaussian (LQG) control law using the acceleration feedback is adopted, in which the state variables are estimated from the measurable accelerations with a Kalman estimator. In order to evaluate the performances of the semi-active suspension systems based on MR dampers for railway vehicles, the random and periodical track irregularities are modelled with a uniform state-space formulation according to the testing data and incorporated into the governing equation of the railway vehicle integrated with the semi-active suspension system. Utilising the governing equations and the semi-active controller developed in this paper, the simulation and analysis are presented in Part II of this paper.     

磁流变阻尼器在汽车悬架减振系统中的应用

为了提高汽车的舒适性和操纵性,在汽车悬架减振系统中安装磁流变阻尼器。基于磁流变液的组成部分, 对其工作原理进行分析,并阐述了磁流变阻尼器的三种工作模式。接着研究了汽车悬架半主动减振系统的控制和测 试方法,为磁流变阻尼器在汽车悬架中的应用提供了理论支撑。文章介绍了磁流变阻尼器在国内外汽车领域中的应用,阐述了磁流变液在汽车悬架减振系统中的重要作用。     

Semi-active suspension systems for railway vehicles using magnetorheological dampers. Part II: simulation and analysis

In this paper, the semi-active suspension system for railway vehicles based on the controlled (MR) fluid dampers is investigated, and compared with the passive on and passive off suspension systems. The lateral, yaw, and roll accelerations of the car body, trucks, and wheelsets of a full-scale railway vehicle integrated with four MR dampers in the secondary suspension systems, which are in the closed and open loops respectively, are simulated under the random and periodical track irregularities using the established governing equations of the railway vehicle and the modelled track irregularities in Part I of this paper. The simulation results indicate that (1) the semi-active controlled MR damper-based suspension system for railway vehicles is effective and beneficial as compared with the passive on and passive off modes, and (2) while the car body accelerations of the railway vehicle integrated with semi-active controlled MR dampers can be significantly reduced relative to the passive on and passive off ones, the accelerations of the trucks and wheelsets could be increased to some extent. However, the increase in the accelerations of the trucks and wheelsets is insignificant.     

电控空气悬架载荷平衡系统仿真

结合当代最新设计理念,利用MATLAB和ADAMS/Car软件的联合仿真,设计了电控空气悬架载荷平衡系统,并对整体系统进行了几个工况的模拟仿真。结果表明:所设计的空气悬架载荷平衡系统性能良好;联合MATLAB和ADAMS软件的长处来设计系统,能够使产品开发过程加快,同时产品开发成本也相应下降。     

Ride quality evaluation of a vehicle with a planar suspension system

The longitudinal connection between a chassis and a wheel in a conventional vehicle suspension system is commonly very stiff than the vertical connection. Such a mechanism can efficiently isolate vibrations and absorb shocks in the vertical direction but cannot sufficiently attenuate the impact in the longitudinal direction. In order to overcome such a limitation, a planar suspension system (PSS) with spring–damper struts in both the longitudinal and vertical directions is proposed so that the vibration along any direction in the wheel rotation plane can be isolated. In this paper, the dynamic responses of a vehicle with PSS due to a single bump and random road unevenness are investigated. The ride quality of the vehicle with PSS is evaluated in accordance with ISO 2631. A comparison with that of a similar conventional vehicle is conducted to demonstrate the promising potentials of the PSS in improving the vehicle ride quality.     

基于ILMI算法的车辆半主动悬架静态输出反馈控制

针对采用磁流变阻尼器的1/4汽车半主动悬架模型进行振动控制分析。利用迭代线性矩阵不等式(ILMI)算法在输出反馈控制中的求解优势,提出基于ILMI算法的半主动悬架静态输出反馈控制方法。仿真结果表明,结合合适的控制算法,采用磁流变阻尼器的半主动悬架系统有效地改善了汽车驾驶平顺性和乘坐舒适性。     

客车用可升降空气悬架系统

近几年空气悬架在客车上的应用日益广泛。功能也不断增加。简要介绍了由机械控制和电子控制的客车用可升降空气悬架的控制方式、组成、工作原理及在车辆上匹配时的注意事项。     

主动悬架系统对汽车侧翻稳定性改善分析

针对被动悬架系统侧翻稳定性比较差的问题,提出采用主动悬架系统的方法进行改善。通过汽车侧倾运动状态分析,建立了被动悬架系统、主动悬架系统和控制系统模型。模拟分析得到主动悬架系统使得汽车在弯道行驶时的侧倾角有效值下降了92.8%,侧倾角加速度有效值下降了78.2%,侧翻因子有效值下降了92.6%。结果表明:利用主动悬架系统可以有效地降低汽车非直线行驶时的侧倾角以及侧倾角加速度,提高汽车的侧翻稳定性,是提高汽车非直线行驶状态下安全性的一个合理的解决方案。     

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.     

Dual objective active suspension system based on a novel nonlinear disturbance compensator

This paper proposes an active suspension system to fulfil the dual objective of improving ride comfort while trying to keep the suspension deflection within the limits of the rattle space. The scheme is based on a novel nonlinear disturbance compensator which employs a nonlinear function of the suspension deflection. The scheme is analysed and validated by simulation and experimentation on a laboratory setup. The performance is compared with a passive suspension system for a variety of road profiles.     

Identification of nonlinear systems using modified particle swarm optimisation: a hydraulic suspension system

This paper presents a novel modified particle swarm optimisation (MPSO) algorithm to identify nonlinear systems. The case of study is a hydraulic suspension system with a complicated nonlinear model. One of the main goals of system identification is to design a model-based controller such as a nonlinear controller using the feedback linearisation. Once the model is identified, the found parameters may be used to design or tune the controller. We introduce a novel mutation mechanism to enhance the global search ability and increase the convergence speed. The MPSO is used to find the optimum values of parameters by minimising the fitness function. The performance of MPSO is compared with genetic algorithm and alternative particle swarm optimisation algorithms in parameter identification. The presented comparisons confirm the superiority of MPSO algorithm in terms of the convergence speed and the accuracy without the premature convergence problem. Furthermore, MPSO is improved to detect any changes of system parameters, which can be used for designing an adaptive controller. Simulation results show the success of the proposed algorithm in tracking time-varying parameters.     

Fault detection of vehicle suspension system using wavelet analysis

This paper presents a method based on continuous wavelet transform to detect the faults of vehicle suspension systems. The Morlet wavelet functions are employed to approach the natural frequencies of the system and the frequency components of the signal with relative maximum energy. To evaluate our method, we use a full vehicle dynamic model which has been simulated in ADAMS/CAR and validated by laboratory test results. The suspension faults have been considered due to the damage of shock absorbers (dampers) and upper damper bushings (UDBs) and assumed as the decrease in damping force and loose joints, respectively. In this paper, the incapability of the spectral analysis by using fast Fourier transform in analysis of the signals is revealed through applying the inputs that include transient characteristics and then wavelet transform employed to achieve more proper results. A swept frequency is applied as an input to the wheels that simulates the road irregularities. After detection of faulty sections of the system using signal energy distribution, the defects of damper and UDBs are distinguished from each other through observing the changes of natural frequencies and corresponding energy amplitudes.     

Multi-objective optimization of quarter-car models with a passive or semi-active suspension system

A systematic methodology is applied in an effort to select optimum values for the suspension damping and stiffness parameters of two degrees of freedom quarter-car models, subjected to road excitation. First, models involving passive suspension dampers with constant or dual rate characteristics are considered. In addition, models with semi-active suspensions are also examined. Moreover, special emphasis is put in modeling possible temporary separations of the wheel from the ground. For all these models, appropriate methodologies are employed for capturing the motions of the vehicle resulting from passing with a constant horizontal speed over roads involving an isolated or a distributed geometric irregularity. The optimization process is based on three suitable performance criteria, related to ride comfort, suspension travel and road holding of the vehicle and yielding the most important suspension stiffness and damping parameters. As these criteria are conflicting, a suitable multi-objective optimization methodology is set up and applied. As a result, a series of diagrams with typical numerical results are presented and compared in both the corresponding objective spaces (in the form of classical Pareto fronts) and parameter spaces.     

Actively controlled vehicle suspension with energy regeneration capabilities

The paper presents an innovative dual purpose automotive suspension topology, combining for the first time the active damping qualities with mechanical vibrations power regeneration capabilities. The new configuration consists of a linear generator as an actuator, a power processing stage based on a gyrator operating under sliding mode control and dynamics controllers. The researched design is simple and energetically efficient, enables an accurate force–velocity suspension characteristic control as well as energy regeneration control, with no practical implementation constraints imposed over the theoretical design. Active damping is based on Skyhook suspension control scheme, which enables overcoming the passive damping tradeoff between high- and low-frequency performance, improving both body isolation and the tire's road grip. The system-level design includes configuration of three system operation modes: passive, semi–active or fully active damping, all using the same electro-mechanical infrastructure, and each focusing on different objective: dynamics improvement or power regeneration. Conclusively, the innovative hybrid suspension is theoretically researched, practically designed and analysed, and proven to be feasible as well as profitable in the aspects of power regeneration, vehicle dynamics improvement and human health risks reduction.     

Level and attitude control of the active suspension system with integral and derivative action

A 7-DOF full-car model with optimal active control suspension is utilized to evaluate the vehicle dynamic performances which are achieved through proposed controllers. The optimal controller, which includes the integral action for the suspension deflection, considerably improves the attitude control of a vehicle because the rolling and pitching motion in cornering and braking maneuvers are reduced, respectively. In the viewpoint of level control, the integral control acting on the suspension deflection results in the zero steady-state deflection in response to static body forces and ramp road input. The dynamic characteristics of the suspension control system are evaluated in terms of time domain and frequency domain. The simulations in the time domain demonstrate the advantages of the active suspension system obtained by penalizing the integral and derivative of suspension deflections and the derivative of roll and pitch angles in the performance index. The frequency characteristic curves obtained by simulations regarding integral action or derivative action show the increase of both ride comfort and road-holding performances by maximizing the use of suspension deflections. The potential of derivative control is shown by the performances of the car traveling over a bump and braking.     

SX5624ZPV364非公路自卸车的悬挂系统侧倾角分析及计算

本文对SX5624ZPV364非公路自卸车的悬挂系统的侧倾角刚度进行了详尽的分析及计算,为SX5624ZPV364非公路自卸车悬挂系各总成的设计提供理论依据。     

汽车转向与悬架系统的集成控制研究

在建立了汽车转向与悬架系统的综合模型的基础上,运用一种具有扩展的调节器结构LQG控制方法,设计了 主动悬架控制器,实现对车身横摆角速度、车身垂直加速度、车身侧倾角和俯仰角的集成控制,从而显著提高汽车的 平顺性、操纵稳定性和安全性。