高速列车会车横向冲击的半主动控制研究

铁路高速化使得车辆在行驶过程中受到的气动冲击加剧,严重影响车辆的乘坐舒适性。为了改善高速列车乘坐的舒适性,研究了高速列车会车横向冲击的半主动控制方法。建立车辆系统动力学模型,分析会车振动的传递特性和天棚阻尼控制方法的局限性,针对会车横向振动特性提出会车横向冲击半主动控制方法,对车辆气动冲击进行控制。利用计算机仿真方法验证会车控制的效果。结果显示,控制后由会车气动冲击引起的车辆横向振动平均减幅达到35%～45%。     

商用车驾驶室悬置系统非线性阻尼系数的匹配

驾驶室悬置系统中的减振器阻尼直接影响卡车行驶的平顺性,在国内卡车设计中,其确定方法尚未得到较好的解决.针对此问题,建立了非线性阻尼的数学模型,分析了阻尼参数对驾驶室振动的影响,经过对比分析可知,阻尼特性指数n<1时,对于提高卡车乘坐舒适性是比较有效的.因此,在设计样车的悬置减振器时,我们采用n<1的粘性阻尼,并进行了多次的调整和试验,有效的改善了驾驶室乘坐舒适性问题.     

驾驶室悬架参数对拖拉机振动特性影响的研究

以CF700型拖拉机为研究对象,以MATLAB/SIMULINK为研究平台,建立了带驾驶室拖拉机4自由度振动仿真模型。以GB/T 10910—2004中较平滑跑道为激励,对拖拉机振动特性进行了仿真研究,在此基础上得到驾驶室前、后悬架刚度和阻尼系数。研究结果表明,驾驶室前、后悬架刚度和阻尼系数分别取20 k N/m,1 233 N·s/m和20 k N/m,1 726 N·s/m时,座椅处垂向振动加速度均方根值和驾驶室俯仰振动加速度均方根值分别较无驾驶室悬架时减小50%和61%,拖拉机的乘坐舒适性明显改善。     

基于振动响应工程车辆驾驶室乘坐舒适性分析

工程车辆工作环境恶劣,为保证驾驶员能够高效迅速的对复杂行驶路况做出准确反映,需要设计具备良好的乘坐舒适性的驾驶室。根据工程车辆工作环境恶劣的现状,采用计算振动响应的方法研究车辆驾驶室的乘坐舒适性。建立八自由度二分之一车动力学模型,运用拉格朗日方程求解系统的运动微分方程,获得驾驶室在随机路面激励下的振动响应。在驾驶室的竖直方向建立"驾驶员—座椅"分析子系统,驾驶室受到的竖直方向的激励作为子系统的输入,根据驾驶员受到的振动加速度的加权值,对驾驶室的乘坐舒适性进行评价。分析结果可知:评价驾驶员的主观感受为:没有不舒适;减小座椅刚度,能有效的提高驾驶员的舒适性;为同类设计研究提供参考。     

汽车阻尼比及振动响应的分析

应用MATLAB对某款轿车进行了汽车振动控制仿真,分析了汽车阻尼对汽车行驶速度控制的影响,得到汽车阻尼有利于汽车当前速度迅速收敛于期望速度。进而对不同阻尼比在同级路面下的车身加速度进行了分析,并绘制了相应的影响曲线。然后将轿车简化为四自由度动力学模型,通过受力分析得到了一般粘性有阻尼多自由度系统的振动方程,且仿真分析了车身垂直振动、俯仰振动、前轴和后轴振动对汽车前后轮激励的频率响应曲线,最后导出了轴距与汽车俯仰振动的关系,为汽车乘坐舒适性的提高提供了相关的理论参考。     

基于烦恼率的悬架振动舒适性评价方法

现有针对汽车乘坐舒适性评价的研究主要包括人体对振动的感受程度。人体对振动的感受程度受多种因素的影响,根据普通概率统计和简单二值逻辑原则给出的振动舒适性无法反映这些不确定因素。因此,采用人对振动主观反应的模糊随机评价模型,从心理物理学的角度对这些不确定性进行分析。对传统车辆振动时的乘坐舒适性评价方法进行讨论。提出一个以烦恼率为基础的模糊随机评价模型用于人体对振动的主观响应。借助于Matlab/Simulink软件,表述一个四自由度的受到不规则路面激励的半车模型。提出一种关于汽车乘坐舒适性的新的评价方法——烦恼率评价方法。采用遗传算法神经网络与神经网络控制算法对系统进行控制。分别基于ISO 2631/1(1982)、ISO 2631-1(1997)和所提烦恼率评价方法进行仿真模拟,包括控制前后人体对振动的反应对比、烦恼率随着振动频率与加权加速度均方根值的变化。模拟评价结果表明,所提出的主动悬架系统在振动控制方面是有效的,可以将人的生观反应由十分不舒适提升到略有不舒适,而且基于烦恼率的新评价方法可以进一步定量地估计由于振动感到不适的乘客人数。提山了一个关于汽车行驶平顺性的新的分析方法。     

半主动悬架控制与整车性能匹配研究

建立了两自由度汽车半主动悬架系统的数学模型，以提高乘坐舒适性而不损害行车安全性作为控制策略的出发点，采用自适应模糊控制方法，该控制方法将模糊系统辩识和模糊控制结合起来，针对自适应算法的复杂性，采用最大隶属度法对控制规则进行修正，简化了运算。仿真表明，与被动悬架和模糊控制相比，可显著地减少汽车振动及干扰，操纵稳定性得到改善，可较好解决乘坐舒适性和操纵稳定性矛盾，使汽车在各种行驶条件下舒适性和安全性最佳匹配。     

某商用车驾驶室振动问题的改进研究

针对某商用车驾驶室振动过大的问题,使用LMS振动测试系统进行测试.通过振动传递路径分析(TPA),发现板簧固有频率与激励源频率重叠是引起驾驶室振动过大的主要原因.通过减小板簧刚度从而降低板簧固有频率,改进后再次进行实车测试.数据分析表明,振动加速度显著减小,提高了乘坐舒适性,驾驶室振动过大问题得到解决,证明减小板簧刚度对降低驾驶室振动的有效性.     

基于MATLAB的半主动悬架可变刚度座椅的研究

为进一步改善汽车的乘坐平顺性,利用MATLAB建立了1/2车动力学微分方程;以半主动悬架天棚阻尼控制为基础,设计一种可以改变刚度的座椅系统;以线性滤波得到的B级路面为输入进行仿真分析,对比了3种情况下的汽车平顺性。结果表明:相比于被动悬架,天棚阻尼控制有效改善了汽车的平顺性,同时附加变刚度座椅的半主动天棚阻尼控制悬架能进一步提高乘坐舒适性。     

重型卡车驾驶室乘坐舒适性研究

建立了包含车架弹性振动的15自由度重型卡车整车振动模型，通过计算机仿真模拟了路面随机输入响应；通过改进驾驶室悬架参数，显著改善了驾驶室的乘坐舒适性。     

基于灰狼算法的矿用自卸车油气悬架半主动控制

为解决矿用自卸车乘坐舒适性与道路友好性相矛盾的问题,提出了一种可控阻尼阀式半主动油气悬架系统。搭建了包含摩擦力的油气弹簧AMESim物理模型,建立了可控阻尼阀的多项式力学模型;设计了一种以可控阻尼阀驱动电压为半主动控制对象的改进天棚控制策略,并基于灰狼优化算法对改进天棚策略关键控制参数进行优化。联合仿真结果表明：D级随机路面下,半主动油气悬架的车身加速度相比被动悬架减小了11.4%,而轮胎动载荷仅增加了1.1%,相比传统天棚控制策略,更好地兼顾了矿用自卸车的乘坐舒适性和道路友好性。硬件在环试验结果也验证了该控制策略的有效性和可行性。     

履带车辆肘内式半主动油气悬挂性能研究

肘内式油气悬挂与传统油气弹簧相比,能够以较小的体积和质量,提供更高的负载能力。将履带车辆肘内式油气悬挂单轮模型与半主动控制相结合,进行了半主动肘内式油气悬挂动态特性分析,提出了基于天棚算法的半主动双环控制策略,外环控制器计算目标阻尼力对应的阀芯位置,内环控制器控制阀芯跟踪目标位置,从而达到改善履带车辆平顺性的目的。探索了Virtual.Lab,AMESim和Matlab之间的集成接口,搭建了机电液耦合系统的联合仿真虚拟试验平台,并在该平台对控制算法进行了验证,结果表明肘内式油气悬挂半主动性能显著优于被动悬挂。     

汽车悬架系统的半主动追踪控制

在介绍了磁流体减振器阻尼力特性的基础上，提出了针对磁流体减振器特性的半主动追踪控制方法。试验验证了磁流体减振器阻尼力可调的减振性能及追踪控制方法的有效性。结果表明提出的半主动追踪控制方法不仅比被动控制方式优越，而且比天棚式反向控制方式有更佳的减振效果。     

高速列车弹性车体垂向振动控制

建立包含车体弹性的高速列车单车刚柔耦合动力学模型.针对车体垂向振动,分别在一系悬挂和二系悬挂系统中采用半主动控制策略,研究控制策略对车辆运行平稳性的影响.结果表明,二系天棚阻尼半主动控制与二系阻尼连续可调型半主动控制均能有效降低车体低频处的刚性振动,相对而言,前者对于低频振动抑制效果更佳,但对较高频率的弹性振动无明显作...     

具有非对称力学特性的汽车磁流变减振器设计与控制

为降低汽车磁流变悬架系统中传感器成本,提高系统可靠性,提出了一种具有非对称力学特性的汽车磁流变减振器结构设计方案及分级控制方法。根据结构设计方案,对其力学输出特性进行了理论分析,并进行了样机加工与试验测试。为分析分级控制算法在相应半主动悬架中的控制效果,建立了1/4车辆悬架动力学模型,进行了动力学仿真分析。研究结果表明,所设计的磁流变减振器具有连续输出非对称阻尼力的工作特性,验证了设计思路和方法的有效性;采用分级控制算法的半主动悬架在适应道路条件的变化方面比被动控制下的悬架具有更大的优越性;虽然分级控制的控制效果在部分路面下没有天棚控制的控制效果好,但基于分级控制的减振控制系统可以节约成本并提高可靠性,具有较好的应用前景。     

Multi-objective stability control algorithm of heavy tractor semi-trailer based on differential braking

Rollover and jack-knifing of tractor semi-trailer are serious threats for vehicle safety,and accordingly active safety technologies have been widely used to reduce or prevent the occurrence of such accidents.However,currently tractor semi-trailer stability control is generally only a single hazardous condition (rollover or jack-knifing) control,it is difficult to ensure the vehicle comprehensive stability of various dangerous conditions.The main objective of this study is to introduce a multi-objective stability control algorithm which can improve the vehicle stability of a tractor semi-trailer by using differential braking.A vehicle controller is designed to minimize the likelihood of rollover and jack-knifing.First a linear vehicle model of tractor semi-trailer is constructed.Then an optimal yaw control for tractor using differential braking is applied to minimize the yaw rate and lateral acceleration deviation of tractor,as well as the hitch articulation angle of tractor semi-trailer,so as to improve the vehicle stability.Second a braking scheme and variable structure control with sliding mode control are introduced in order to achieve the best braking effect.Last Fishhook maneuver is introduced to the active safety simulation and the active control system effect verification.The simulation results show that multi-objective stability control algorithm of semi-trailer could improve the vehicle stability significantly during the transient maneuvers.The proposed multi-objective stability control algorithm is effective to prevent the vehicle rollover and jackknifing.     

STATISTIC LINEARIZATION CONTROL FOR HYDRAULIC ACTIVE DAMPING SUSPENSION

0INTRODUCTIONActivedamping suspension systems mainly take the quantified value of ride comfort and vehicle handling as a performance index,in which the damping coefficient of suspension is adjusted to optimize the performance index according to the road roughness and vehicle load.An ideal scheme of active damping control is to realtimely regulate the damping coefficient according to the vehicle run states,but which is difficulty in practice［1，2］.On one hand,the road disturbance is a…     

Semi-active Sliding Mode Control of Vehicle Suspension with Magneto-rheological Damper

The vehicle semi-active suspension with magneto-rheological damper(MRD) has been a hot topic since this decade, in which the robust control synthesis considering load variation is a challenging task. In this paper, a new semi-active controller based upon the inverse model and sliding mode control(SMC) strategies is proposed for the quarter-vehicle suspension with the magneto-rheological(MR) damper, wherein an ideal skyhook suspension is employed as the control reference model and the vehicle sprung mass is considered as an uncertain parameter. According to the asymptotical stability of SMC, the dynamic errors between the plant and reference systems are used to derive the control damping force acquired by the MR quarter-vehicle suspension system. The proposed modified Bouc-wen hysteretic force-velocity(F-v) model and its inverse model of MR damper, as well as the proposed continuous modulation(CM) filtering algorithm without phase shift are employed to convert the control damping force into the direct drive current of the MR damper. Moreover, the proposed semi-active sliding mode controller(SSMC)-based MR quarter-vehicle suspension is systematically evaluated through comparing the time and frequency domain responses of the sprung and unsprung mass displacement accelerations, suspension travel and the tire dynamic force with those of the passive quarter-vehicle suspension, under three kinds of varied amplitude harmonic, rounded pulse and real-road measured random excitations. The evaluation results illustrate that the proposed SSMC can greatly suppress the vehicle suspension vibration due to uncertainty of the load, and thus improve the ride comfort and handling safety. The study establishes a solid theoretical foundation as the universal control scheme for the adaptive semi-active control of the MR full-vehicle suspension decoupled into four MR quarter-vehicle sub-suspension systems.     

强非线性颤振分析的增量谐波平衡法

将增量谐波平衡法推广应用于二元机翼的颤振问题 ,为强非线性颤振分析提供了一条有效的新途径。对含有粘性阻尼项和强非线性立方俯仰刚度项的二元机翼颤振方程 ,采用振幅作为控制参数应用谐波平衡过程 ,求得方程解的表达式 ,并由此分析系统的分岔现象和极限环颤振现象 ,得到了极限环的大小。用龙格 库塔法进行数值计算验证 ,结果表明 :推广后的增量谐波平衡法在强非线性颤振分析中合理可靠 ,且具有足够的精度     

Vehicle active suspension system using skyhook adaptive neuro active force control

This paper aims to highlight the practical viability of a new and novel hybrid control technique applied to a vehicle active suspension system of a quarter car model using skyhook and adaptive neuro active force control (SANAFC). The overall control system essentially comprises four feedback control loops, namely the innermost proportional-integral (PI) control loop for the force tracking of the pneumatic actuator, the intermediate skyhook and active force control (AFC) control loops for the compensation of the disturbances and the outermost proportional–integral–derivative (PID) control loop for the computation of the optimum target/commanded force. A neural network (NN) with a modified adaptive Levenberg–Marquardt learning algorithm was used to approximate the estimated mass and inverse dynamics of the pneumatic actuator in the AFC loop. A number of experiments were carried out on a physical test rig using a hardware-in-the-loop configuration that fully incorporates the theoretical elements. The performance of the proposed control method was evaluated and compared to examine the effectiveness of the system in suppressing the vibration effect on the suspension system. It was found that the simulation and experimental results were in good agreement, particularly for the sprung mass displacement and acceleration behaviours in which the proposed SANAFC scheme is found to outperform the PID and passive counterparts.