汽车磁流变半主动座椅悬架动态特性的试验研究

为进一步提高汽车的乘坐舒适性,研发了一种汽车座椅半主动悬架用磁流变减振器,并对其进行阻尼特性试验,通过分析其受力情况,建立了汽车半主动座椅悬架动力学模型,设计了用于座椅磁流变半主动悬架的天棚控制策略,并在随机和正弦激励输入下进行了座椅天棚控制仿真计算,试制了磁流变半主动座椅物理样机及试验台架系统,开展了磁流变半主动座椅悬架的台架试验研究。结果表明,理论仿真和试验结果基本吻合,磁流变减振器阻尼可控性好;相对于被动座椅悬架,采用磁流变半主动座椅悬架后,座椅动态性能改善了30%左右,磁流变半主动座椅悬架减振效果显著。     

磁流变半主动悬架的天棚控制方法研究

研究天棚控制方法对磁流变半主动悬架动力学的影响.根据磁流变减振器的力学特性,建立了二自由度磁流变半主动悬架模型,分析了在天棚控制方法下悬架的频率响应特性,并通过仿真分析了被动悬架和天棚控制悬架的平顺性.结果表明,天棚控制方法能有效降低簧载质量加速度和悬架动挠度,但是增大了轮胎动载荷.     

基于半主动自适应悬架系统的整车道路友好性研究

为了提高车辆的道路友好性与平顺性,设计了以磁流变减振器为控制对象的整车自适应模糊控制半主动悬架系统。在试验测试和理论分析的基础上,建立了基于磁流变减振器的整车半主动悬架模型及其状态方程,并用该模型对自适应模糊控制方法进行了研究。模型的输入采用B级和C级路面谱;道路友好性评价指标采用动载荷系数和动载荷应力因子;使用MATLAB/Simulink建立基于2个自适应模块的模糊控制器控制系统,模糊控制器的输入均采用车身与车桥的相对速度和相对加速度。仿真结果表明:与被动悬架相比,在B级和C级路面、不同速度下,半主动自适应悬架动载荷系数均降低30%左右,动载荷应力因子均降低40%以上,同时也提高了车辆的运行平顺性和稳定性。     

基于磁流变阻尼器的半主动车辆座椅悬架模糊控制研究

设计基于磁流变阻尼器的半主动车辆座椅悬架系统的模糊控制器。用ADAMS对系统建立三维多刚体动力学模型,用MATLAB设计系统模糊控制器,并联合两者对整个系统进行仿真。仿真和台架试验结果表明,模糊控制策略能使该系统较好抑制垂直振动加速度,提高乘坐的舒适性。     

半主动悬架车辆的整车模糊控制仿真研究

对半主动悬架整车进行动力学分析，以建立的半主动悬架整车模型为研究对象，将整车划分成8个板块，针对车身的垂直、侧倾、俯仰3种运动设计不同的模糊控制策略，控制磁流变阻尼器的电流输出，达到改善车辆垂直、侧倾和俯仰振动的综合减振目的；以某型车的参数进行仿真分析，仿真结果表明采用文中提出的整车模糊控制策略能很好地改善车辆的舒适性。     

汽车磁流变非线性悬架模糊控制

建立了整车悬架系统的三维模型,根据试验数据得出了前后悬架弹簧的非线性特性曲线。前后悬架减振器均采用磁流变减振器,采用Bouc-Wen参数化模型为其阻尼力模型。采用模糊控制算法为整车半主动控制算法,采用ADAMS和Matlab联合对整车平顺性进行仿真。结果表明,采用模糊控制算法控制磁流变非线性悬架可提高整车的平顺性。     

磁流变半主动悬架试验研究

针对磁流变半主动悬架存在的控制策略设计和磁流变阻尼器逆模型求解复杂繁琐的问题,采用天棚控制、SH-ADD控制和频域控制3种典型的开关控制策略,基于具有并联旁通孔的磁流变阻尼器,在1/4车辆悬架试验台上进行半主动振动控制对比试验。结果表明,具有并联旁通孔的磁流变阻尼器与开关控制策略相结合可有效地抑制悬架振动,且控制过程简单,具有较好的实际应用价值。     

整车磁流变减振器半主动悬架模糊滑模控制研究

针对八自由度整车悬架模型,以改进天棚阻尼系统为参考模型,运用模糊滑模控制方法设计了半主动整车悬架的模糊滑模控制器;将滑模切换函数及其导数进行滑模控制量划分,形成二维模糊控制规则表,以此来提高系统控制的灵敏度,并降低系统的抖振;将整车分块成四部分,对每个版块进行独立控制,使系统具有滑模特点同时也能克服抖振,最后利用李亚普诺夫方法来保证系统的稳定性。仿真结果表明,模糊滑模控制整车半主动悬架的减振效果优于被动控制和PID控制的悬架,且具有很好的稳定性。     

基于模糊算法的车辆半主动悬架控制

以汽车二自由度悬架系统为研究对象,针对半主动悬架系统,提出以车身加速度为控制目的的模糊控制策略。以白噪声随机响应谱作为B级路面的激励输入,对被动悬架和半主动悬架系统进行仿真研究。仿真后的被动悬架与半主动悬架对结果表明,所提出的模糊控制策略有效的降低了悬架系统被击穿的可能性,提高了汽车乘坐的舒适性。     

基于磁流变阻尼器的半主动悬架研究

为提高商用车乘坐舒适性,文章结合某款商用载货汽车进行半主动悬架系统的设计研究。首先进行磁流变阻尼器结构设计,并使用Ansoft有限元分析软件对阻尼器进行结构优化,避免磁流变（MR）阻尼器磁场强度的欠饱和与过饱和;其次采用模糊控制与比例-积分-微分（PID）控制相结合的方式对阻尼器阻尼力大小进行控制输出,使得阻尼力始终等于或接近最佳舒适性与安全性要求下的阻尼力大小;最后基于Matlab/Simulink数值分析软件对阻尼器减振性能进行仿真,完成了一款基于磁流变阻尼器的半主动悬架系统设计。此研究中的磁流变阻尼器结构紧凑,易于集成化设计,通过最终仿真结果表明,与传统被动悬架相比较,此半主动悬架减振效果更为优秀,响应速度更快,使得车辆具有更好的平顺性、舒适性与行驶安全性。     

Semi-active control of tracked vehicle suspension incorporating magnetorheological dampers

In past years, the application of magnetorheological (MR) and electrorheological dampers in vehicle suspension has been widely studied, mainly for the purpose of vibration control. This paper presents theoretical study to identify an appropriate semi-active control method for MR-tracked vehicle suspension. Three representative control algorithms are simulated including the skyhook, hybrid and fuzzy-hybrid controllers. A seven degrees-of-freedom tracked vehicle suspension model incorporating MR dampers has been adopted for comparison between the performance of the three controllers. The model differential equations are derived based on Newton's second law of motion and the proposed control methods are developed. The performance of each control method under bump and sinusoidal road profiles for different vehicle speeds is simulated and compared with the performance of the conventional suspension system in time and frequency domains. The results show that the performance of tracked vehicle suspension with MR dampers is substantially improved. Moreover, the fuzzy-hybrid controller offers an excellent integrated performance in reducing the body accelerations as well as wheel bounce responses compared with the classical skyhook and hybrid controllers.     

Generalized magnetorheological (MR) damper model and its application in semi-active control of vehicle suspension system

In this paper, analytical characterization of the magneto-rheological (MR) damper is done using a new modified algebraic model. Algebraic model is also more preferable because of its low computational expenses compared to differential Bouc-Wen’s model which is highly computationally demanding. This model along with the obtained model parameters is used as a semi-active suspension device in a quarter car model and the stationary response of the vehicle traversing on a rough road is obtained. The control part consists of two nested controllers. One of them is the system controller which generates the desired damping force and the other is the damper controller which adjusts the voltage level to MR damper so as to track the desired damping force. For the system controller a model reference skyhook Sliding Mode Controller (SMC) is used and for the damper controller a continuous state algorithm is built to determine the input voltage so as to gain the desired damping force. The analytical model is subsequently used in the quarter car vehicle model and the vehicular responses are studied. A simulation study is performed to prove the effectiveness and robustness of the semi-active control approach. Results show that the semi-active controller can achieve compatible performance as that of active suspension controller except for a little deterioration.     

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。     

Comparison between different sets of suspension parameters and introduction of new modified skyhook control strategy incorporating varying road condition

This study examines the uncertainties in modelling a quarter car suspension system caused by the effect of different sets of suspension parameters of a corresponding mathematical model. To overcome this problem, 11 sets of identified parameters of a suspension system have been compared, taken from the most recent published work. From this investigation, a set of parameters were chosen which showed a better performance than others in respect of peak amplitude and settling time. These chosen parameters were then used to investigate the performance of a new modified continuous skyhook control strategy with adaptive gain that dictates the vehicle's semi-active suspension system. The proposed system first captures the road profile input over a certain period. Then it calculates the best possible value of the skyhook gain (SG) for the subsequent process. Meanwhile the system is controlled according to the new modified skyhook control law using an initial or previous value of the SG. In this study, the proposed suspension system is compared with passive and other recently reported skyhook controlled semi-active suspension systems. Its performances have been evaluated in terms of ride comfort and road handling performance. The model has been validated in accordance with the international standards of admissible acceleration levels ISO2631 and human vibration perception.     

Active Suspension Control to Improve Vehicle Ride and Handling

In practice most active vehicle suspension work can be traced to two sources, Lotus' modal control and Karnopp's skyhook damper. A model is developed which allows comparison of different active suspension control algorithms. The Lotus modal control algorithm is reviewed, and compared with Karnopp's skyhook damper. It is shown that a tight inner closed loop allows the Lotus algorithm to achieve the inertial damping described by Kamopp for a single comer or quarter car. It is suggested that to achieve simultaneously high inertial damping and good disturbance rejection an inner force loop is desirable. A vehicle control scheme is presented which combines the Lotus modal decomposition with Karnopp's skyhook damper, allowing nearly optimal ride and simultaneously permitting modification of vehicle handling properties.     

A new active variable stiffness suspension system using a nonlinear energy sink-based controller

This paper presents the active case of a variable stiffness suspension system. The central concept is based on a recently designed variable stiffness mechanism which consists of a horizontal control strut and a vertical strut. The horizontal strut is used to vary the load transfer ratio by actively controlling the location of the point of attachment of the vertical strut to the car body. The control algorithm, effected by a hydraulic actuator, uses the concept of nonlinear energy sink (NES) to effectively transfer the vibrational energy in the sprung mass to a control mass, thereby reducing the transfer of energy from road disturbance to the car body at a relatively lower cost compared to the traditional active suspension using the skyhook concept. The analyses and simulation results show that a better performance can be achieved by subjecting the point of attachment of a suspension system, to the chassis, to the influence of a horizontal NES system.     

汽车磁流变半主动悬架的控制研究

为了改善汽车的乘坐舒适性和行驶安全性,提出了一种汽车磁流变半主动悬架的控制策略。首先,设计了磁流变减振器的工作模式,通过试验获得了其速度特性和力学特性,建立了磁流变减振器的数学模型;其次,建立了带磁流变减振器的二自由度车辆简化模型及其参数表;最后,基于双环控制理论,设计了一种控制系统,其外环产生理想的结构阻尼力,内环调节电流驱动器的电流,以使磁流变减振器实时地产生控制阻尼力。仿真结果表明:以磁流变减振器为基础,通过半主动控制技术,悬架系统的振动动态性能得到了有效的控制。     

On the achievable performance using variable geometry active secondary suspension systems in commercial vehicles

There is a need to further improve driver comfort in commercial vehicles. The variable geometry active suspension offers an interesting option to achieve this in an energy efficient way. However, the optimal control strategy and the overal performance potential remains unclear. The aim of this paper is to quantify the level of performance improvement that can theoretically be obtained by replacing a conventional air sprung cabin suspension design with a variable geometry active suspension. Furthermore, the difference between the use of a linear quadratic (LQ) optimal controller and a classic skyhook controller is investigated. Hereto, an elementary variable geometry actuator model and experimentally validated four degrees of freedom quarter truck model are adopted. The results show that the classic skyhook controller gives a relatively poor performance while a comfort increase of 17–28% can be obtained with the LQ optimal controller, depending on the chosen energy weighting. Furthermore, an additional 75% comfort increase and 77% energy cost reduction can be obtained, with respect to the fixed gain energy optimal controller, using condition-dependent control gains. So, it is concluded that the performance potential using condition-dependent controllers is huge, and that the use of the classic skyhook control strategy should, in general, be avoided when designing active secondary suspensions for commercial vehicles.     

New insights from fractional order skyhook damping control for railway vehicles

Active suspensions for railway vehicles have been a topic of research for a number of decades and while their applications in service operation are limited, it seems clear that they will in due course see widespread adoption. Railway suspension design is a problem of compromise on the non-trivial trade-off of ride quality versus track following (guidance), and the skyhook damping control approach has been paramount in illustrating the potential benefits. Since skyhook damping control, various advanced control studies appeared contributing to redefine the boundaries of the aforementioned trade-off. Yet there is no study on the impact of fractional order (FO) methods in the context of skyhook railway active suspensions and in particular related to skyhook damping control. This is the area to which this paper strongly contributes. We present findings from a current project on FO controllers for railway vehicles active suspensions, in particular work on the effect of FO methods in basic skyhook damping control schemes, i.e. pure and intuitively based skyhook. First, we present a brief review of conventional skyhook damping control and then proceed to a rigorous investigation of the impact of FO on the ride quality/track following trade-off. The relevant benefits from FO methods are appraised and new insights highlighted.     

Development of Preview Active Suspension Control System and Performance Limit Analysis by Trajectory Optimization

The main role of the suspension system is to achieve ride comfort by reducing vibrations generated by the road roughness. The active damper is getting much attention due to its reduced cost and ability to enhance ride comfort especially when the road ahead is measurable by an environment sensor. In this study a preview active suspension control system was developed in order to improve ride comfort when the vehicle is passing over a speed bump. The control system consists of a feedback controller based on the skyhook logic and a feedforward controller for canceling out the road disturbance. The performance limit for the active suspension control system was computed via trajectory optimization to provide a measure against which to compare and validate the performance of the developed controller. The simulation results indicated that the controller of this study could enhance ride comfort significantly over the active suspension control system employing only the skyhook feedback control logic. Also the developed controller, by displaying similar control pattern as the trajectory optimization during significant time portions, proved that its control policy is legitimate.