Adaptive control of a vehicle-seat-human coupled model using quasi-zero-stiffness vibration isolator as seat suspension

We propose the quasi-zero-stiffness (QZS) vibration isolator as seat suspension to improve vehicle vibration isolation performance. The QZS vibration isolator is composed of vertical spring and two symmetric negative stiffness structures used as stiffness correctors. A vehicle-seat-human coupled model considering the QZS vibration isolator is established as a three degree-of-freedom (DOF) model; it is composed of a quarter car model and a simplified 1 DOF model combined vehicle seat and human body. This model considers the changing mass of the passengers and sets the total mass of the vehicle seat and human body as an uncertain parameter, which investigates the overload and unload conditions in practical engineering. To further improve the vehicle ride comfort, a constrained adaptive backstepping controller law based on the barrier Lyapunov function (BLF) is presented. The dynamic characteristic of the active vehicle-seathuman coupled model under shock excitation was analyzed using numerical method. The results show that the designed controller law can isolate the shock excitation transmitted from the road to the passengers effectively, and both the vehicle and seat suspension strokes remain in the allowed stroke range.     

Simulation of PID and fuzzy logic controller for integrated seat suspension of a quarter car with driver model for different road profiles

Passenger travel comfort is important while analyzing the vibration control of a quarter car model. To achieve the same, various control strategies are employed by the researchers for a 2 Degree of freedom (DOF) quarter car model. We analyzed travel comfort of the passenger by designing and simulating the PID controller and Fuzzy logic controller (FLC) for an 8 DOF quarter car with integrated seat suspension and driver model. While testing the performance of the controllers, the system was subjected to four types of road disturbance individually. The responses were compared with each other along with the passive system. The results show that FLC increases the ride quality better than the PID and passive system.

     

考虑路面时变的整车主动悬架的改进模糊PID集成控制策略

为提升某汽车的行驶平顺性及其适应路面时变的能力,提出一种座椅主动悬架和底盘主动悬架的改进模糊PID集成控制策略。相比于一般模糊PID控制方法,该控制策略能够根据轮胎所受路面激励和驾驶员座椅垂向速度的实时变化,在线调整控制器的量化因子、比例因子及PID参数值,以实现对控制力更精确的实时调控。建立八自由度整车平顺性模型,在MATLAB/Simulink软件中模拟汽车在A级、B级、C级和D级路面行驶的状况,结果表明:整车主动悬架改进模糊PID集成控制能够大幅提升汽车行驶平顺性和操纵稳定性,且效果明显优于模糊PID控制。     

Reducing the seat vibration of vehicle by semi active force control technique

This article focusses on reducing the axis acceleration and minimizing the vertical displacement by using an air spring actuator and active force control as a main control element. In active force control loop track the developed force of an air spring actuator is fed as a feedback to the actuator. Mamdani and sugeno type fuzzy interference system are used to develop a desired force and to estimate mass of the system respectively. The performance of the system is analyzed for both time and frequency domains and contrasted with passive suspension due to the irregular road disturbances. While developing the simulation model, quarter car suspension with seat as three degree of freedom and an air spring actuator acting as a force generator are modeled as non-linear system. The simulation result shows the effectiveness of the proposed control scheme in suppressing the undesirable effects of the suspension system.     

轿车八自由度平顺性动力学仿真与实验研究

建立了轿车八自由度平顺性动力学模型,推导了八自由度轿车模型拉格朗日方程,并应用仿真软件MATLAB/S imu link建立了轿车平顺性的仿真模型,对驾驶员座椅、副驾驶员座椅和后排左侧座椅的垂直加速度信号进行了仿真,得出了频域内的仿真结果,并与实验结果进行了对比。     

Simulation and experimental validation of vehicle dynamic characteristics for displacement-sensitive shock absorber using fluid-flow modelling

In this study, a new mathematical dynamic model of shock absorber is proposed to predict the dynamic characteristics of an automotive system. The performance of shock absorber is directly related to the car behaviours and performance, both for handling and ride comfort. Damping characteristics of automotive can be analysed by considering the performance of displacement-sensitive shock absorber (DSSA) for the ride comfort. The proposed model of the DSSA is considered as two modes of damping force (i.e. soft and hard) according to the position of piston. For the simulation validation of vehicle-dynamic characteristics, the DSSA is mathematically modelled by considering the fluid flow in chamber and valve in accordance with the hard, transient and soft zone. And the vehicle dynamic characteristic of the DSSA is analysed using quarter car model. To show the effectiveness of the proposed damper, the analysed results of damping characteristics were compared with the experimental results, which showed similar behaviour with the corresponding experimental one. The simulation results of frequency response are compared with the ones of passive shock absorber. From the simulation results of the DSSA, it can be concluded that the ride comfort of the DSSA increased at the low-amplitude road condition and the driving safety was increased partially at the high-amplitude road condition. The results reported herein will provide a better understanding of the shock absorber. Moreover, it is believed that those properties of the results can be utilised in the dynamic design of the automotive system.     

基于多自由度车辆模型的主动悬架研究

通过对模型频域特性的分析，研究了发动机及前后座椅对车辆模型的影响，提出了一种新的多自由度车辆模型，基于该模型应用LQ理论对主动悬架的控制器进行设计，对基于不同车辆模型设计的不同控制器的控制效果进行比较研究，提出了一种较理想的主动悬架控制策略。     

Intelligent semi-active vibration control of eleven degrees of freedom suspension system using magnetorheological dampers

A novel intelligent semi-active control system for an eleven degrees of freedom passenger car’s suspension system using magnetorheological (MR) damper with neuro-fuzzy (NF) control strategy to enhance desired suspension performance is proposed. In comparison with earlier studies, an improvement in problem modeling is made. The proposed method consists of two parts: a fuzzy control strategy to establish an efficient controller to improve ride comfort and road handling (RCH) and an inverse mapping model to estimate the force needed for a semi-active damper. The fuzzy logic rules are extracted based on Sugeno inference engine. The inverse mapping model is based on an artificial neural network and incorporated into the fuzzy controller to enhance RCH. To verify the performance of the NF controller (NFC), comparisons with existing semi-active techniques are made. The typical control strategy are linear quadratic regulator (LQR) and linear quadratic Gaussian (LQG) controllers with clipped optimal control algorithm, while inherent time-delay and non-linear properties of MR damper lie in these strategies. Simulation results demonstrated that the NFC has better control performance and less control effort than the optimal in improving the service life of the suspension system and the ride comfort of a car.     

Development and application of new evaluation system for ride comfort and vibration on railway vehicles

Vibrations related to ride comfort should be considered at the beginning of design stage. In general, ride comfort of human is mainly affected by vibration transmitted from the floor and seat. Also, vibration level is very important regarding with running safety on freight wagon. To ensure ride comfort for passenger coach and vibration level for freight wagon, tests had been repeated by different test procedures with several equipments. With different measuring and evaluations for these results, it took much time to evaluate test results. In this paper, a new evaluation procedure was developed combining several software for ride comfort and vibration level test on railway vehicles. In addition, this developed system is capable of ride comfort test and vibration test by a single integrated system that is capable of immediate reporting the test result. With this developed system, the comfort in a passenger coach and the vibration in a freight car were evaluated. And the simulation results from the proposed system are verified by a field test.     

汽车磁流变半主动悬架仿人智能控制研究

在建立整车动力学模型的基础上，设计了基于整车分姿态协调控制的仿人智能控制器。将汽车看成快速移动的机器人，把汽车运动姿态划分为八种姿态，对不同的运动姿态采用不同的控制模态，并在MATLAB平台上进行了仿真。选用某型号轿车作为试验车辆，用磁流变半主动悬架替代原车被动悬架，在多种条件下进行了实车道路试验，试验结果与仿真结果吻合，表明对整车进行分姿态协调控制是可行的。与被动悬架相比较，仿人智能控制可提高平顺性能近20％，能有效抑制车身的俯仰和侧倾运动，改善轮胎的接地性能，其控制效果优于对各悬架进行独立控制的天棚控制策略。     

基于随机次优控制的汽车电动助力转向与主动悬架集成控制

将汽车电动助力转向系统(EPS)模型、转向模型和主动悬架系统(ASS)模型相结合，建立了整车系统的动力学模型。设计了输出反馈随机次优控制策略，实现了汽车EPS和ASS的集成控制。在Matlab／Simulink环境下进行了仿真计算，仿真结果表明，采用所提出的集成控制策略，不仅能有效改善EPS的轻便性，而且使得ASS具有很好衰减路面振动、抗侧倾和抗俯仰的能力，从而显著提高了汽车操纵稳定性、安全性和平顺性等综合性能。     

基于免疫进化的汽车主动悬架的控制及其鲁棒性

基于免疫系统的克隆选择理论，提出了一种具有多样识别能力、鲁棒性强和具有免疫记忆功能的免疫进化控制方法。仿真结果表明，免疫控制器能有效改善汽车的平顺性和操纵稳定性，对系统参数的不确定性具有自适应性和较强的鲁棒性。     

手扶拖拉机非线性座椅的研究

给出一种预紧的非线性座椅,用以改善手扶拖拉机驾驶员的乘坐舒适性,并对该座椅进行了理论分析,测定了它的静态特性、手扶拖拉机在凹凸不平道路上行驶时的隔振性能,同时与手扶拖拉机原海棉弹簧座垫及ＩＳＯ２６３１中的振动规范曲线进行了比较。     

B级和C级路面下汽车行驶平顺性的仿真分析

根据多体动力学理论,利用A dam s的专业模块A dam s/car建立完整的整车样机模型。在B级和C级路面的行驶状况下,对整车在40 km/h、60 km/h、80 km/h、100 km/h速度下进行平顺性仿真分析,研究B级和C级路面情况下速度对车辆行驶平顺性的影响。     

Whole-body vibration analysis for assessment of railway vehicle ride quality

In this paper, a whole-body vibration analysis using a three-dimensional human biodynamic model is presented, and the dynamic behavior of the body exposed to vibration by a railway vehicle is investigated with respect to ride quality. Since a subject in a railway vehicle is exposed to multi-axial excitation conditions, the acceleration of the body is calculated by summing the accelerations in three directions. The equations for the acceleration response of the body are formulated as complex transfer functions multiplied by input accelerations from the three axes in the form of a frequency response function. Body behavior when exposed to random acceleration inputs measured at the floor of the railway vehicle is investigated across a frequency domain. Root Mean Square (RMS) values of the acceleration magnitudes in the body regions are calculated from the power spectral density (PSD) values of the acceleration responses. The absolute magnitude of the accelerations of the body is compared with the ride index, which is calculated using the input accelerations and standard methods. It is shown that the absolute magnitudes in the body regions are proportional to the standard ride index and that the ride index accurately reflects vibration damage to the body. A proposed seat design using the vibration magnitudes calculated with the human biodynamic model also is presented.     

磁流变半主动横向稳定杆对汽车侧倾的影响

由于智能材料磁流变液具有响应时间短、可控范围大等特性,基于磁流变液的半主动执行器件的应用越来越广泛。为同时保证车辆在高速转向时的行驶安全性（抗侧倾性能）和在通过不平路面时的行驶平顺性,提出一种磁流变半主动横向稳定杆。装有旋转式磁流变阻尼器的横向稳定杆可在车辆低速转向时提供较小的扭转力矩以提高平顺性,而在高速转向时提供大扭转力矩以提高安全性。为验证提出的半主动横向稳定杆的可行性和有效性,建立装有磁流变横向稳定杆的车辆侧倾数学模型,并基于整车动力学仿真软件CarSim对某型汽车整车模型进行半被动控制下的动力学仿真。以一种基于车身侧倾角速度的分段控制策略对磁流变横向稳定杆进行了初步的控制仿真,并与传统被动横向稳定杆对车辆侧倾的性能影响进行了对比、分析和评价。     

基于ADAMS／Car的整车平顺性仿真研究

以某轿车为研究对象．借助于ADAMS／Car仿真分析软件建立该车的多体系统动力学整车模型,根据路面理论生成脉冲和随机路面文件,根据国家标准对该车进行整车平顺性仿真并进行客观性评价．结果表明该车的平顺性较好。     

Robust control of nonlinear integrated ride and handling model using magnetorheological damper and differential braking system

The interaction of the ride and handling systems is one of the challenging topics in vehicle dynamics and control. In this study the dynamic behavior of a passenger car considering coupling among all the fourteen degrees of freedom is modeled using Boltzmann Hamel equations. In order to improve the ride quality and stability of the vehicle, a Magnetorheological damper and a differential braking system are used as control devices. Based on the nonlinear integrated ride and handling vehicle model, a nonlinear H-infinity controller is designed for an intermediate passenger car. The dynamic behavior of the controlled vehicle is simulated for single lane change and bump input, considering three different road conditions: Dry, rainy and snowy. The robustness of the designed controller is investigated when the vehicle is under these road conditions. The simulation results confirm the interactive nature of the ride and handling systems and the robustness of the designed control strategy.     

Passive control of railway vehicle car body flexural vibration by means of underframe dampers

To suppress vertical flexural vibration of a railway vehicle car body, a new passive control method by mounting dampers on the longitudinal beams of the car body underframe is proposed. The method is firstly studied by an Euler-Bernoulli beam model using Green’s functions, then it is further verified by a nonlinear dynamic model of the vehicle. Results show that the car body flexural vibration can be noticeably reduced by this method. It is better to mount the damper near the car body centre. The higher damping coefficient of the damper, the more effective in decreasing the car body first vertical bending vibration. The higher the rigidity of the damper bracket and rubber bush, the better performance of the damper. It is found that when mounting six dampers at proper positions, the damping coefficient of each damper is 1.33×10⁷ N·s/m, even if the first vertical bending frequency of the studied car body is only 7.2 Hz, a very good ride quality will be achieved when the vehicle runs at 250 km/h.     

基于随机路面的空气悬架平顺性研究

将空气弹簧的刚度特性曲线编写XML文件,与机械系统仿真分析软件ADAMS结合,建立了空气悬架的客车模型,并根据相关法规在ADAMS/Car Ride环境中对虚拟样机进行平顺性仿真,仿真结果在ADAMS/postprocessor环境中进行处理,给出了一种求得平顺性评价指标较为简便的方法。结果表明分析样车的悬架系统设计合理,虽舒适性随车速提高及路面等级的下降,加权加速度均方根值呈增大趋势,但仍然能保持在主观评价的舒适界限之内。