Decentralized Dynamic Event-Triggered Communication and Active Suspension Control of In-Wheel Motor Driven Electric Vehicles with Dynamic Damping

This paper addresses the co-design problem of decentralized dynamic event-triggered communication and active suspension control for an in-wheel motor driven electric vehicle equipped with a dynamic damper. The main objective is to simultaneously improve the desired suspension performance caused by various road disturbances and alleviate the network resource utilization for the concerned in-vehicle networked suspension system. First, a T-S fuzzy active suspension model of an electric vehicle under dynamic damping is established. Second,a novel decentralized dynamic event-triggered communication mechanism is developed to regulate each sensor's data transmissions such that sampled data packets on each sensor are scheduled in an independent manner. In contrast to the traditional static triggering mechanisms, a key feature of the proposed mechanism is that the threshold parameter in the event trigger is adjusted adaptively over time to reduce the network resources occupancy. Third, co-design criteria for the desired event-triggered fuzzy controller and dynamic triggering mechanisms are derived. Finally, comprehensive comparative simulation studies of a 3-degrees-of-freedom quarter suspension model are provided under both bump road disturbance and ISO-2631 classified random road disturbance to validate the effectiveness of the proposed co-design approach. It is shown that ride comfort can be greatly improved in either road disturbance case and the suspension deflection, dynamic tyre load and actuator control input are all kept below the prescribed maximum allowable limits, while simultaneously maintaining desirable communication efficiency.     

Robust active suspension design subject to vehicle inertial parameter variations

This paper presents an approach in designing a robust controller for vehicle suspensions considering changes in vehicle inertial properties. A four-degree-of-freedom half-car model with active suspension is studied in this paper, and three main performance requirements are considered. Among these requirements, the ride comfort performance is optimized by minimizing the H∞ norm of the transfer function from the road disturbance to the sprung mass acceleration, while the road holding performance and the suspension deflection limitation are guaranteed by constraining the generalized H2 (GH2) norms of the transfer functions from the road disturbance to the dynamic tyre load and the suspension deflection to be less than their hard limits, respectively. At the same time, the controller saturation problem is considered by constraining its peak response output to be less than a given limit using the GH2 norm as well. By solving the finite number of linear matrix inequalities (LMIs) with the minimization optimization procedure, the controller gains, which are dependent on the time-varying inertial parameters, can be obtained. Numerical simulations on both frequency and bump responses show that the designed parameter-dependent controller can achieve better active suspension performance compared with the passive suspension in spite of the variations of inertial parameters.     

Observer‐Based Adaptive L2 Disturbance Attenuation Control of Semi‐Active Suspension with MR Damper

A novel nonlinear observer‐based adaptive disturbance attenuation control strategy was proposed for a quarter semi‐active suspension system with a magneto‐rheological (MR) damper in light of the intrinsic nonlinearity, parameter uncertainty, state immeasurability and road randomness. Adaptive adjusting parameters were adopted to avoid the curve fitting and identification of the system parameters by a great deal of experimental data for shortening the development cycle of the control system. Based on the reduced‐order observer, the system states including the immeasurable virtual state of MR damper and inconveniently measured states of suspension system were estimated for the realistic frame of the proposed controller in practice. The dissipative system theory was utilized to reduce the influence of the road disturbance on the system control performance. Simulation results in the bump road and B‐class road indicate that, whether there are perturbations of the system parameters or not, the proposed control scheme always ensures a better performance on the suspension travel, ride comfort and handling stability in comparison with other existing methods.     

基于模糊控制的汽车主动悬架系统仿真研究

汽车悬架直接影响汽车在行驶过程中抑制不平路面对车身的冲击力及车身倾斜度,传统被动悬架遇冲击自动调节能力较差,抗振能力不强,针对上述问题,通过对悬架受力特点分析,建立了1/4车体二自由度主动悬架数学模型,结合自动控制理论,设计车辆的主动悬架模糊控制器,利用MATLAB/Simulink模糊工具箱对其进行仿真,在相同输入的情况下,对主动悬架与被动悬架模型部分性能参数分析比较,仿真结果表明采用此模糊控制器的主动悬架在提高车辆乘坐的舒适性和操纵的稳定性方面明显优于被动悬架。实验证明,研究结果对汽车主动悬架系统的设计具有一定参考价值。     

Study on vehicle active suspension system control method based on homogeneous domination approach

In an active suspension system, there is an actuator mounted between the sprung mass and the unsprung mass to change the stiffness and damp of the suspension for ride comfort and handling stability. Because the active suspension control system is an under‐actuated system, the control problem of the active suspension is challenging but interesting. In order to solve this issue, a novel vehicle active suspension control method based on homogeneous domination approach is proposed in this paper. Firstly, a groundhook control model is constructed according to the general active suspension dynamic model. In order to deal with the additional terms of the control system which are harmful for convergence, a homogeneous domination approach is used to construct an active suspension homogeneous controller (ASHC). A useful technical theorem is proposed in the stability analysis to show that the proposed ASHC can guarantee the states of the active suspension system being stabilized. Compared with the SMC method and without any controller (passive suspension), the simulation results indicate that the proposed ASHC is effective.     

A New SSUKF Observer for Sliding Mode Force Tracking H∞ Control of Electrohydraulic Active Suspension

Compared to passive and semi‐active suspensions, active suspensions have the capacity to overcome the tradeoff design of vehicle ride comfort and handling performance. In this paper, a new control system with modified spherical simplex UKF (SSUKF) observer and sliding mode force tracker is proposed for electrohydraulic active suspensions. The estimated states obtained from the SSUKF observer are used to derive the mode energy of body motion and design the target demanded forces for suspension actuators. A sliding mode controller is presented to drive electrohydraulic actuators to track the demanded forces. Based on a robust H∞ control method, a new control strategy depending on body mode energy is proposed to restrict body motion. The performance comparisons between passive and active suspensions under three typical excitations are presented, and the obtained results indicate that the proposed control system can significantly depress body motion and decrease the mode energy to improve ride comfort and also effectively enhance the road hold abilities.     

非线性油气悬架的平顺性仿真研究

该文针对某工程车辆油气悬架系统建立了单气室油气弹簧的非线性刚度模型，在传统的定刚度车辆两自由度振动模型中加入了非线性的因素，使计算机仿真更接近工程实际。在Maflab／Simulink的环境下，对油气弹簧的刚度非线性、D级随机路面输入以及在随机路面输入下的车辆平顺性进行了计算机仿真。最后将油气悬架平顺性仿真结果和线性二次型最优主动控制悬架以及钢板弹簧被动悬架进行了比较，证明了油气悬架在降低车身加速度、改善轮胎接地性等方面具有显著的优越性和工程应用价值。     

基于电流变阻尼器的履带式车辆悬架振动控制

提出一种基于电流变阻尼器的半主动悬架系统,建立了某履带式车辆悬架的1/4车体动力学模型,在此基础上给出了悬架系统的运动方程和状态方程,分析了某种剪切模式电流变阻尼器的阻尼力并作为悬架系统半主动控制的制动器.将随机最优控制理论应用到车辆悬架的控制中,以车身加速度、悬架动行程和轮胎动位移的加权二次型最小为控制性能指标,设计了线性二次型高斯(LQG)控制器,通过被动悬架与LQG控制悬架的仿真比较,在轮胎动位移基本相同的情况下,LQG控制能有效的降低车身加速度,充分利用悬架的工作空间,提高车辆的舒适性和安全性.     

Novel Optimal Design Approach for Output‐Feedback H∞ Control of Vehicle Active Seat‐Suspension System

In this paper, the output‐feedback control problem of a vehicle active seat‐suspension system is investigated. A novel optimal design approach for an output‐feedback H_∞ controller is proposed. The main objective of the controller is to minimize the seat vertical acceleration to improve vehicle ride comfort. First, the human body and the seat are considered in the modeling of a vehicle active suspension system, which makes the model more precise. Other constraints, such as tire deflection, suspension deflection and actuator saturation, are also considered. Then the output‐feedback control strategy is adopted since some state variables, such as body acceleration and body deflection, are unavailable. A concise and effective approach for an output‐feedback H_∞ optimal control is presented. The desired controller is obtained by solving the corresponding linear matrix inequalities (LMIs) and by the calculation of equations proposed in this paper. Finally, a numerical example is presented to show the effectiveness and advantages of the proposed controller design approach.     

Finite Frequency Fuzzy H∞ Control for Uncertain Active Suspension Systems With Sensor Failure

This paper investigates the problem of finite frequency fuzzy H_∞ control for uncertain active vehicle suspension systems, in which sensor failure is taken into account. TakagiSugeno (T-S) fuzzy model is established for considered suspension systems. In order to describe the sensor fault effectively, a corresponding model is introduced. A vital performance index, H_∞ performance, is utilized to measure the drive comfort. In the framework of Kalman-Yakubovich-Popov theory, the H_∞ norm from external perturbation to controlled output is optimized effectively in the frequency domain of 4 Hz-8 Hz to enhance ride comfort level. Meanwhile, three suspension constrained requirements, i.e., ride comfort level, manipulation stability, suspension deflection are also guaranteed. Furthermore, sufficient conditions are developed to design a fuzzy controller to guarantee the desired performance of active suspension systems. Finally, the proposed control scheme is applied to a quarter-vehicle active suspension, and simulation results are given to illustrate the effectiveness of the proposed approach.      

基于模糊神经网络的二自由度主动悬架滑模控制系统设计

主动悬架滑模控制系统受到行驶路面影响,车体震动加速度功率谱密度与实际密度不一致,导致系统控制效果不佳,提出基于模糊神经网络的二自由度主动悬架滑模控制系统设计;基于二自由度硬件结构,在主动悬架液压伺服系统中安装蓄能器,减小空间内存;采用磁流变阻尼器,调整电流大小控制阻尼;设计自适应减振座椅悬架并计算阻尼值,实现了主动悬架的控制;考虑路面不规则度,构建二自由度主动悬架滑模控制模型,依据牛顿定律计算悬架弹性元件受力;采用模糊控制规则校正控制误差,采用模糊神经网络设计主动悬架滑膜控制方案,经迭代处理得到满足优化要求的解,实现滑膜控制;由试验结果可知,车体震动加速度功率谱密度与实际密度一致,从最初的0 ms^(-2)到最终的1.5 ms^(-2),具有良好控制效果,确保乘车的舒适性。     

兼顾平顺性与车高调节的重型车空气悬架控制

空气悬架由于质量轻、刚度以及高度可调等优点在重型车中得到了广泛的应用.空气悬架可以实现重型车的两项重要功能:平顺性保证以及车身高度调节,但是空气悬架的平顺性以及车身高度调节均通过空气弹簧气压腔的气压改变来实现,因此二者是彼此制约和冲突的.然而,目前对空气悬架车高调节的研究追求控制的精确性与稳定性而忽略了平顺性,而对平顺性的研究又几乎不考虑车高变化造成的影响.基于上述动机,本文提出了兼顾平顺性的空气悬架重型车车高调节鲁棒控制方法,实现了平顺性保障下的车高调节曲线精确跟踪控制,提升了重型车空气悬架系统的整体性能.实车参数仿真验证了所提出方法在平顺性与车高调节两项指标中的优越性.     

Vibration control of vehicle active suspension system using a new robust neural network control system

The main problem of vehicle vibration comes from road roughness. For that reason, it is necessary to control vibration of vehicle’s suspension by using a robust artificial neural network control system scheme. Neural network based robust control system is designed to control vibration of vehicle’s suspensions for full suspension system. Moreover, the full vehicle system has seven degrees of freedom on the vertical direction of vehicle’s chassis, on the angular variation around X-axis and on the angular variation around Y-axis. The proposed control system is consisted of a robust controller, a neural controller, a model neural network of vehicle’s suspension system. On the other hand, standard PID controller is also used to control whole vehicle’s suspension system for comparison.Consequently, random road roughnesses are used as disturbance of control system. The simulation results are indicated that the proposed control system has superior performance at adapting random road disturbance for vehicle’s suspension.     

具有执行器容错的汽车主动悬架系统有限频率H∞控制

本文研究了一类具有执行器容错的主动悬架系统有限频率H_∞控制问题.运用广义的Kalman-Yakubovich-Popov(KYP)引理,设计了有限频率H_∞控制器.该控制器不仅能够最大程度地减少路面在4～8 Hz范围内对乘客的影响,还能够保证汽车的悬架行程和车轮的动静载之比在它们允许的范围内.因此所设计的有限频率H_∞控制器不仅能够保证汽车驾驶的舒适性还能够保证汽车驾驶的安全性.为了解决系统状态不完全可测的问题,本文采用了动态输出反馈控制器策略.除此之外,在控制器的设计过程中还考虑了主动悬架系统的参数不确定性以及执行器随机故障的现象.最后,本文基于四分之一汽车主动悬架系统验证了控制器的有效性.     

基于电磁作动器的车辆座椅悬架最优控制研究

为了改善农用车、工程车等车辆座椅的减振性能,以电磁作动器为执行器,建立人体座椅—车辆两自由度的主动座椅悬架系统模型。通过对该系统的动力学模型进行线性化处理,并应用二次型最优控制理论,选取合适的加权系数,实现系统的最优控制。在Matlab/Simulink中以白噪声路面激励为系统输入,对主动控制和被动控制的座椅悬架系统仿真分析。结果表明：在不同的激励条件下,基于电磁作动器的主动座椅悬架系统减振效果显著,大幅降低了驾驶员所承受垂直振动加速度,提高了车辆的乘坐舒适性和操纵稳定性。     

最优控制理论在人车路磁流变半主动悬架中的应用

基于半主动悬架车辆的1/4动力学模型,论述了磁流变液特性及磁流变减振器的工作原理,推导了在随机最优控制理论下可调阻尼力和状态变量之间的关系,应用matlab/simulink编制了人车路模型的仿真程序,并以简化模型为例,考察了在磁流变阻尼器控制下的人车路平顺性问题.计算结果表明,与没有磁流变减振器的被动悬架相比较,该减振器的应用能够较好的改善汽车的平顺性,对提高人体的舒适性以及进一步深入研究该系统的振动,改善道路的振动特性有一定的指导意义.     

Intelligent feedback linearization control of nonlinear electrohydraulic suspension systems using particle swarm optimization

The core factors governing the performance of active vehicle suspension systems (AVSS) are the inherent trade-offs involving suspension travel, ride comfort, road holding and power consumption. In addition to this, robustness to parameter variations is an essential issue that affects the effectiveness of highly nonlinear electrohydraulic AVSS. Therefore, this paper proposes a nonlinear control approach using dynamic neural network (DNN)-based input–output feedback linearization (FBL) for a quarter-car AVSS. The gains of the proposed controllers and the weights of the DNNs are selected using particle swarm optimization (PSO) algorithm while addressing simultaneously the AVSS trade-offs. Robustness and effectiveness of the proposed controller were demonstrated through simulations.     

MotionView及HyperStudy在全地形车前悬架设计中的应用

为解决全地形车大行程前悬架的悬架跳动与前束角变化的协调问题,研究一款全地形车前悬架的运动学模型.在MotionView中建立该全地形车前悬架的运动学模型,借助HyperStudy对悬架跳动与前束角变化关系曲线进行优化,获得与理想曲线较接近的结果.     

Design of nonlinear controllers for active vehicle suspension with state constraints

Design of active vehicle suspension has tradeoffs between three main performance metrics (passenger comfort, suspension deflection and road holding ability). It has been known that each performance can be achieved by H _∞ controller and they can be gathered by LPV (Linear Parameter Varying) method. However, because the suspension deflection limit was not explicitly considered, this limit may be exceeded. In this paper, the authors propose a “reference shaping“ based method in order to improve the control performance. In this approach, a “virtual reference” signal is imposed to the system such that the suspension deflection is kept small. The effectiveness of the approach is examined by numerical simulations. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Robust H-infinity control for constrained uncertain systems and its application to active suspension

This paper presents an LMI based robust H-infinity control scheme for constrained systems with normbounded uncertainties.The uncertainties are incorporated in the evaluation of the H-infinity norm and the time-domain constraints.The robust closed-loop properties inclusive of stability,H-infinity performance and the satisfaction of the timedomain constraints are discussed.Analysis and simulation results for a 2 DOF quarter-car model show possible improvements on ride comfort,while robustly respecting safety related constraints such as good road holding,limited suspension strokes and actuator saturation.