Semi-active vibration control of an eleven degrees of freedom suspension system using neuro inverse model of magnetorheological dampers

A semi-active controller-based neural network for a suspension system with magnetorheological (MR) dampers is presented and evaluated. An inverse neural network model (NIMR) is constructed to replicate the inverse dynamics of the MR damper. The typical control strategies are linear quadratic regulator (LQR) and linear quadratic gaussian (LQG) controllers with a clipped optimal control algorithm, while inherent time-delay and non-linear properties of MR damper lie in these strategies. LQR part of LQG controller is also designed to produce the optimal control force. The LQG controller and the NIMR models are linked to control the system. The effectiveness of the NIMR is illustrated and verified using simulated responses of a full-car model. The results demonstrate that by using the NIMR model, the MR damper force can be commanded to follow closely the desirable optimal control force. The results also show that the control system is effective and achieves better performance and less control effort than the optimal in improving the service life of the suspension system and the ride comfort of a car.     

基于磁流变减振器的汽车半主动悬架非线性控制方法

考虑磁流变减振器阻尼力和悬架弹性元件非线性特性,建立车辆半主动悬架非线性动力学模型。应用微分几何非线性控制,经过适当的非线性状态和反馈变换,实现半主动悬架非线性系统的精确线性化,并对系统实施非线性状态反馈控制;根据预定的控制目标及模糊控制策略调节控制参数,设计模糊控制器,对悬架系统进行了控制仿真研究;利用神经网络模式识别能力对输入数据处理辨别,设计控制网络层,从而达到提高悬架工作性能,改善汽车行驶舒适性的目的。将三种非线性控制方法的仿真结果进行分析比较表明:经模糊控制或神经网络控制后的悬架承受的冲击响应小、振动强度低,比微分几何控制能获得更优异的性能。     

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.     

基于模糊PID算法的汽车半主动悬架振动控制

选择了某微型汽车悬架的磁流变减震器为研究对象,运用汽车动力学理论建立了1/4汽车半主动悬架控制系统动力学模型,基于模糊PID控制算法设计了模糊PID控制器.车辆在不同路面输入谱和不同行驶速度下,以悬架的簧载质量加速度、悬架动挠度和轮胎动载荷3个基本参数来表征磁流变半主动悬架系统的振动特性,运用Matlab/Simulink软件对该悬架系统进行仿真研究,仿真结果表明,当汽车在不同等级的路面上行驶时,随着车速的提高,采用模糊PID控制半主动悬架汽车的簧载质量加速度和悬架动挠度的幅值相对于被动悬架均明显减小,表现出了良好的控制效果.轮胎动载荷与被动悬架的幅度大体相当,偶尔还比被动悬架幅值高,但综合来看,模糊PID控制器能更好地减小汽车振动,进一步提高汽车的乘坐舒适性.结果同时也说明了模糊PID控制具有很好的鲁棒性.采用磁流变减振器的半主动悬架系统有效地改善了汽车乘坐舒适性和操纵稳定性.     

基于磁流变减振器的汽车悬架振动控制

分析了磁流变减振器特性,为了抑制汽车磁流变悬架的振动,提出了一种含有控制级和协调级的分级模糊控制。在控制级,把天棚、地棚混合控制策略与模糊智能控制策略相结合,设计了1/4车辆垂直振动的半主动模糊智能控制器;在协调级,设计了整车控制的协调器,根据反馈变量对整车4个独立模糊智能控制器输出参数进行调整。把某微型汽车的4只被动减振器改装成磁流变减振器,搭建了磁流变悬架全车测控系统,运用设计的分级模糊控制器,进行了平顺性随机输入实车道路试验。试验结果表明对汽车磁流变悬架的垂直振动进行分级模糊控制是可行的,能有效提高汽车的乘坐舒适性和操纵稳定性。     

基于神经网络的半主动悬架自适应模糊控制研究

在建立了五自由度车辆半主动悬架系统模型的基础上，将神经网络与模糊控制结合起来，提出一种基于神经网络的自适应模糊控制半主动悬架系统，其控制器由模糊神经网络控制器和模糊网络组成，采用快速的变斜率梯度下降算法学习，具有自适应学习功能。仿真计算表明，与被动悬架相比，神经网络自适应模糊控制性能明显优于一般的Fuzzy控制，半主动悬架系统在减小振动，提高车辆平顺性方面优于被动悬架，且车轮动载荷和悬架动挠度也得到明显改善。台架试验同样表明了半主动悬架的优良减振性能。     

汽车磁流变半主动悬架反步自适应控制研究

针对1/2车4自由度汽车震动模型和磁流变阻尼器力学简化模型,提出了汽车半主动悬架系统的自适应Backstepping控制器设计方法。该方法所设计的控制器能自动调节控制器参数,以适应汽车悬架系统中某些参数在一定范围内的变化。仿真结果表明,与被动悬架相比,所设计的控制器不仅增加了悬架系统的快速稳定性,而且汽车的平顺性也得到了明显改善。     

Neuro-fuzzy control strategy for an offshore steel jacket platform subjected to wave-induced forces using magnetorheological dampers

Magnetorheological (MR) damper is a prominent semi-active control device to vibrate mitigation of structures. Due to the inherent non-linear nature of MR damper, an intelligent non-linear neuro-fuzzy control strategy is designed to control wave-induced vibration of an offshore steel jacket platform equipped with MR dampers. In the proposed control system, a dynamic-feedback neural network is adapted to model non-linear dynamic system, and the fuzzy logic controller is used to determine the control forces of MR dampers. By use of two feedforward neural networks required voltages and actual MR damper forces are obtained, in which the first neural network and the second one acts as the inverse dynamics model, and the forward dynamics model of the MR dampers, respectively. The most important characteristic of the proposed intelligent control strategy is its inherent robustness and its ability to handle the non-linear behavior of the system. Besides, no mathematical model needed to calculate forces produced by MR dampers. According to linearized Morison equation, wave-induced forces are determined. The performance of the proposed neuro-fuzzy control system is compared with that of a traditional semi-active control strategy, i.e., clipped optimal control system with LQG-target controller, through computer simulations, while the uncontrolled system response is used as the baseline. It is demonstrated that the design of proposed control system framework is more effective than that of the clipped optimal control scheme with LQG-target controller to reduce the vibration of offshore structure. Furthermore, the control strategy is very important for semi-active control.     

采用磁流变阻尼器的人体座椅悬架系统模糊ANFIS-PID复合控制技术研究

对座椅悬架用单出杆式磁流变阻尼器进行阻尼特性试验,并借助MATLAB多项式拟合工具箱对改进多项式模型中未知参数进行辨识。分析人体振动特性,建立五自由度人体座椅悬架模型。综合模糊控制器与自适应模糊神经推理系统(Adaptive Neuro-Fuzzy Inference System,ANFIS)整定PID控制器的优点,提出一种模糊ANFIS-PID复合控制策略。采用正弦信号作为外界激励,分别对被动悬架、传统模糊控制、ANFIS-PID控制及模糊ANFIS-PID复合控制人体座椅悬架系统进行仿真分析。结果表明,辨识得出的参数和建立的改进多项式模型均可满足后续仿真要求;采用模糊ANFIS-PID复合控制策略的隔振效果明显优于传统模糊控制及ANFIS-PID控制,能有效改善人体座椅悬架系统的行驶平顺性及驾乘人员乘坐舒适性。     

Skyhook-based semi-active control of full-vehicle suspension with magneto-rheological dampers

The control study of vehicle semi-active suspension with magneto-rheological (MR) dampers has been attracted much attention internationally. However, a simple, real time and easy implementing semi-active controller has not been proposed for the MR full-vehicle suspension system, and a systematic analysis method has not been established for evaluating the multi-objective suspension performances of MR full-vehicle vertical, pitch and roll motions. For this purpose, according to the 7-degree of freedom (DOF) fullvehicle dynamic system, a generalized 7-DOF MR and passive full-vehicle dynamic model is set up by employing the modified Boucwen hysteretic force-velocity (F-v) model of the MR damper. A semi-active controller is synthesized to realize independent control of the four MR quarter-vehicle sub-suspension systems in the full-vehicle, which is on the basis of the proposed modified skyhook damping scheme of MR quarter-vehicle sub-suspension system. The proposed controller can greatly simplify the controller design complexity of MR full-vehicle suspension and has merits of easy implementation in real application, wherein only absolute velocities of sprung and unsprung masses with reference to the road surface are required to measure in real time when the vehicle is moving. Furthermore, a systematic analysis method is established for evaluating the vertical, pitch and roll motion properties of both MR and passive full-vehicle suspensions in a more realistic road excitation manner, in which the harmonic, rounded pulse and real road measured random signals with delay time are employed as different road excitations inserted on the front and rear two wheels, by considering the distance between front and rear wheels in full-vehicle. The above excitations with different amplitudes are further employed as the road excitations inserted on left and right two wheels for evaluating the roll motion property. The multi-objective suspension performances of ride comfort and handling safety of the proposed MR full-vehicle suspensi     

半主动悬架模糊控制系统的仿真

建立汽车的1/4车二自由度动力学模型,利用模糊控制工具箱设计了用于汽车半主动悬架的模糊控制器,通过应用MATLAB/Simulink对比仿真,结果显示传统的被动悬架在行驶平顺性方面不如使用模糊控制器的半主动悬架,应用模糊控制的半主动悬架系统可以有效提高汽车的行驶平顺性.     

自适应磁流变悬架半主动控制研究

针对目前应用于汽车悬架系统的磁流变减振器工作时需要外部电源和控制设备的问题,设计了一种新型磁流变减振器,该减振器在无需外部电源和控制设备的条件下实现了对振动的自适应控制。研究了该减振器的结构特征和电能收集理论模型,并进行了模拟仿真。利用该减振器构建了无需外部电源和控制设备的汽车自适应磁流变悬架半主动控制系统,在1/4悬架实验台上进行了实验研究,实验结果表明,该控制系统是可行的,明显提高了汽车行驶的平顺性。     

汽车磁流变悬架垂直振动控制与试验研究

在对整车振动系统进行分解和简化的基础上,提出一种分级智能控制系统,设计了用仿人智能思想来在线修改模糊控制器参数的1/4车磁流变悬架振动模糊自适应局部控制器,设计了整车悬架垂直振动的协调控制规则用于调整4个局部控制器的输出值。在MATLAB平台上对分级控制系统进行仿真,构建了磁流变悬架系统垂直振动的整车测控与评价系统,在不同条件下进行了道路试验。相对于被动悬架,分级控制的磁流变悬架使汽车底板振动加速度下降了约15％,使座椅振动加速度下降了约23％,表明用分级控制来减小磁流变悬架系统的垂直振动是可行的,可降低因模型的简化带来的影响,提高汽车的平顺性。     

时滞半主动悬架大系统递阶控制研究

建立了含时滞半主动悬架整车数学模型,解决了传统半主动悬架整车模型无法考虑时滞的难题;设计了模糊神经网络自适应子控制策略及大系统递阶协调控制策略,开发了以ARM单片机为核心元件的半主动悬架控制器。在仿真的基础上进行了实车道路试验,结果表明,模糊神经网络自适应子系统控制器改善了车辆的局部性能,递阶控制协调了车辆的整体性能,调整了车辆行驶姿态,二者联合控制,提高了半主动悬架控制的有效性、实时性,协调了车辆安全性与平顺性之间的矛盾。研究结果为整车半主动悬架系统时滞及其控制研究提供了新的方法。     

基于变论域模糊控制的车辆半主动悬架控制方法

针对车辆半主动悬架系统,提出了一种基于变论域模糊PID控制方法,目标是提高车辆在随机路面激励作用下的平顺性。通过将变论域方法与模糊PID控制器相结合来解决模糊PID存在的因模糊规则制定盲目性而产生的在线调节时间过长等问题。由仿真和实验研究对比可知,变论域模糊PID控制下的半主动悬架系统中的车身垂直振动速度和加速度比常规PID控制下的车身垂直振动速度和加速度分别减小了46.56%和29.21%,相比被动悬架系统的车身垂直振动速度和加速度分别减小了58.05%和49.74%。使用该车辆半主动悬架模糊控制方法可提高车辆的平顺性。     

Semi-active control to reduce carbody vibration of railway vehicle by using scaled roller rig

As train operating speeds increase, upgrading the performance of the railway vehicle has been required. To improve the ride comfort related to vibration, researches to replace the conventional passive suspension with (semi)active suspension have been carried out. For the purpose of vibration reduction, the magneto-rheological (MR) damper has been widely applied in automobile or anti-vibration areas, but it hasn??t yet been applied to railway vehicles. In this study, skyhook control with the MR damper was applied to the 1/5 scaled railway vehicle model on roller rig to suppress the lateral vibration of the carbody. For the 1/5 scaled prototype model of the railway vehicle, the dimensions of railway vehicle were scaled down by similarity method. Both numerical analysis and experiments to control the carbody lateral vibration were conducted and compared. The possibility of improving both the ride comfort and running stability of the railway vehicle by using the semi-active control was discussed in detail.     

高速机车悬架系统磁流变阻尼器试验建模与半主动控制

针对磁流变阻尼器的高速机车横向半主动悬架系统,设计并制作了一个剪切阀式磁流变阻尼器,在液压伺服试验机上对磁流变阻尼器的阻尼特性进行了试验研究;提出了一种修正的Bouc-Wen模型,并用优化方法确定了模型的参数:建立了采用磁流变阻尼器的高速机车横向半主动悬架系统模型,运用中心流形定理分析了半主动悬架系统的稳定性;提出了一种半主动控制策略,仿真验证了采用磁流变阻尼器的高速机车横向半主动悬架系统的有效性。     

能量可再生的新型汽车半主动悬架系统研究

介绍了一种采用功率电传方式的作动器,提出了基于EHA的可能量再生的新型汽车半主动悬架样机结构。同时,建立了1/4汽车半主动悬架动力学模型,设计了用于EHA半主动悬架系统的模糊控制器和天棚控制算法,并进行了仿真试验研究。结果表明,基于EHA的半主动悬架采用模糊控制方法能够兼顾不同频率路面以及有效降低车体加速度、悬架动挠度、轮胎动载荷,从而提高了汽车的乘坐舒适性和操纵稳定性。     

Performance evaluation of a quarter-vehicle MR suspension system with different tire pressure

This paper evaluates performance of a quarter-vehicle magneto-rheological (MR) suspension system with respect to different tire pressure. In order to achieve this goal, controllable MR damper that satisfies design specifications for a midsized commercial passenger vehicle is designed and manufactured based on the optimized damping force levels and mechanical dimensions. After experimentally evaluating the field-dependent characteristics of the manufactured MR damper, the quarter-vehicle suspension system consisting of sprung mass, spring, tire and the MR damper is constructed in order to investigate the ride comfort. After deriving the equations of the motion for the proposed quarter-vehicle MR suspension system, vertical tire stiffness with respect to different tire pressure is experimentally identified. The skyhook controller is then implemented for the realization of quarter-vehicle MR suspension system. Ride comfort characteristics such as vertical acceleration RMS (root mean square) and WRMS (weighted RMS) of sprung mass are evaluated under bump and random road conditions using a quarter-vehicle test facility.     

某越野汽车磁流变半主动悬架变论域模糊控制

为了解决半主动悬架传统变论域模糊控制器过度依赖经验规则的问题,提出了一种基于模糊神经网络的变论域T-S模糊控制策略。首先,根据磁流变减振器阻尼特性的实验结果,建立基于自适应模糊神经网络的减振器阻尼力模型及1/2车辆半主动悬架动力学模型;其次,建立悬架系统T-S模糊控制器,同时为了实时调节T-S模糊控制器变量的论域,采用模糊神经网络结构描述伸缩因子的变化。仿真结果表明,笔者提出的变论域模糊控制策略能够有效提高车辆行驶平顺性和操作稳定性。