轮毂电机驱动电动汽车行驶平顺性研究

为研究轮毂电机对车辆平顺性的影响,文章建立了1/4车辆二自由度振动系统模型和随机路面输入模型,以MATLAB/Simulink为仿真平台建立了相应仿真模型,通过仿真得到了不同非簧载质量情况下车身加速度、车轮相对动载荷以及悬架动挠度对路面速度激励的响应.最后,分别从频域和时域角度对振动系统响应进行分析,结果表明,随着非簧...     

基于LMS的履带车辆多体动力学建模与仿真

本文研究履带车辆在路面行驶时受到的振动,使用Track builder在LMS中建立了某履带车辆动力学模型,应用多体动力学理论分析了车体、悬挂系统、负重轮、履带、路面之间的相互作用,给出了与各参数相对应的关系表达式,并描述了履带车辆运动学方程以及动力学方程。以标准梯形障碍物作为路面输入选取的各种参数进行了仿真,可为设计提供参考。     

履带车辆台架试验台控制方法研究与仿真

履带车辆在台架试验过程中,车辆实际行驶工况在试验台架的模拟是试验成功的关键。本文通过对履带车辆动力学理论和台架试验台结构的研究和分析,完成了车辆的纵向动力学模型和台架系统的时域数学模型的建模仿真。从试验加载精度和实时性出发,提出了台架试验台的速度跟踪控制算法,并通过实车试验台试验结果与理论计算结果的对比分析,验证了此控制方法在履带车辆台架试验中模拟实际路面工况的可行性和准确性。     

基于客车空气悬架控制系统的仿真分析

由于电控空气悬架振动控制系统为复杂的非线性系统,本文采用了不依赖于被控对象精确数学模型的模糊控制策略对空气悬架控制系统进行了仿真分析。在仿真分析过程中,建立了两自由度的1/4空气悬架动力学模型;同时考虑到路面扰动输入对汽车悬架控制的影响,建立了随机路面不平度的数学模型,并在时域内对其仿真。仿真结果表明,使用模糊控制算法可以有效衰减簧载质量垂直加速度,改善了汽车的行驶平顺性。     

无线电引信虚拟样机技术研究

介绍了虚拟样机的设计环境和引信系统及部件模型的设计方法,针对无线电引信建立了其虚拟样机系统模型,通过相同条件下虚拟试验仿真结果和物理样机实测结果的对比,验证了该虚拟样机系统模型的可靠性,为引信总体性能提供了一种快速有效的预估手段。     

雷达机械系统虚拟样机技术实现方法研究

在分析了雷达机械系统性能的基础上,提出了雷达机械系统虚拟样机技术实现途径.系统研究了雷达机械系统的各子系统建模及模型集成技术.利用ProE和Matlab软件建立了机械子系统、液压子系统及控制子系统,并在虚拟样机环境中利用相关集成技术,将各个子系统模型集成,构成雷达机械系统虚拟样机模型.     

基于VEGA的车辆自动驾驶仿真研究

在研究车辆自动驾驶特性的基础上,采用虚拟现实仿真技术,利用Creator和Vega完成了实体模型的建立和虚拟场景的渲染,完成了仿真系统的开发,完整地演示了从建模、路径导航设置,碰撞检测到最终实现车辆自动模拟驾驶的全过程,并在仿真测试中取得了较好的效果.该系统可以真实的模拟交互式的车辆行驶过程,提供了一个通用的仿真平台,可以大大降低车辆行驶视景仿真建模中的开发成本,并对同类虚拟仿真的研究也具有重要的指导意义.     

基于车路耦合安全度模型的公路弯道设计研究

车辆通过弯路时的安全性是车辆设计参数与路面的共同作用。基于此,文章通过设计一套有效的评价模型对车路耦合安全度进行综合评价,分别对车辆侧翻状态与侧滑状态进行受力分析,并建立参数模型,后利用Carsim软件对实际车路耦合情况进行仿真分析,希望能够为后续的车辆设计或道路设计提供安全性保障。     

空空导弹制导控制系统虚拟样机的研究与实现

为克服物理样机研制周期长、代价大、效率低的缺点,利用虚拟样机技术及计算机技术,以研究导弹制导控制系统的性能为核心,建立了制导控制系统的各个子模型.介绍了各个子模型的功能及特点,集成制导控制系统虚拟样机仿真平台,验证了虚拟样机平台的合理性.利用该平台在系统开发和运行环境中对导弹制导控制系统进行稳定算法参数优化设计、滤波算...     

模拟驾驶器山区道路虚拟驾驶研究

针对山区道路模拟驾驶体验的特点,提出了模拟驾驶场景中预定义和路面感应计算相结合的实时控制虚拟车辆运行方法。在虚拟场景中预定义自走车辆运动轨迹,通过时间控制位置和方位的线性插补方法使其运行。对于驾驶车辆模型,文中用方向盘信号和车辆轮胎在路面的空间位置坐标实时计算车辆的位置和方位姿态,使车辆行驶与山区路面的坡度、弯道倾斜、粗糙度等状况等相吻合,增强了山区道路安全驾驶的真实体验感。     

智能网联汽车测试方案研究与展望

对智能网联汽车开展全方位的测试评价,是智能网联汽车安全上路与产业顺利落地的重要保障。基于智能网联汽车的测试现状、测试技术路径、测试评价规范和标准,在满足智能网联汽车现有道路测试要求及未来多应用融合方面,创新性地提出智能网联汽车测试方案总体架构,并详细阐述虚拟仿真测试、网联测试、自动驾驶功能测试、大规模并发测试、互联互通测试5个业务应用。最后结合我国智能网联汽车的实际应用与行业需求,对智能网联汽车测试的未来发展方向进行展望。     

Design of a linear motor-based shaker rig for testing driver's perceived ride comfort

In autonomous vehicles the driver will become a passenger. By ensuring a high level of ride comfort through active suspensions, the driver's ability to perform various tasks such as reading, drawing and texting can be enhanced. A high-performance shaker rig can conveniently be used to test the ride comfort improvement by means of various active suspensions under laboratory conditions. The paper deals with the design of such a rig, which employs a linear electric servomotor to impose accurately controlled vertical vibrations of driver seat. The reference time profiles of seat acceleration, velocity and displacement are generated off-line by using a half-car vehicle model and LQR control with a road preview option. The selection of linear motor comes from assessment of three characteristic shaker rig drive designs (hydraulic and two electric ones). To ensure high-precision seat motion, the proposed shaker control system includes: acceleration feedforward and feedback control loops, a state controller-like compensator of accelerometer offset to prevent drift of seat position and velocity, and feedforward compensation of linear motor cogging force mode. The designed shaker rig application is demonstrated through a case study related to ride comfort evaluation of various active suspension configurations and a drawing task. The drawing task results are employed to determine the root-mean-square vertical seat acceleration threshold, below which the active suspension drawing task performance remains similar to that obtained under standstill conditions.     

Steering control of automated vehicles using absolute positioning GPS and magnetic markers

Steering control for passenger cars on automated highways is analyzed. The feasibility of an automatic steering system based on absolute positioning global positioning system (GPS) and a magnetic marker guidance system has been evaluated using computer simulations. State estimation and control algorithm issues are examined for such a control system. By use of GPS and a magnetic marker sensor, an accurate and real-time estimation of the vehicle's lateral displacements with respect to the road can be accomplished. A steering control algorithm based on road curvature preview for achieving good road tracking and providing ride comfort is also presented. The proposed estimation and control system are validated by simulation results.     

Semiactive Suspension Control of a Light Commercial Vehicle

This paper presents the design and implementation of a semi-active suspension control system for a light commercial vehicle using continuously varying dampers, accelerometers, and an onboard processor. The control algorithms such as sky-hook, ground-hook, and hybrid are designed based on the vertical velocities of each quarter of the car. These velocities are estimated from Kalman filter using quarter car vehicle model. The controllers are implemented in an actual vehicle equipped with the developed semiactive suspensions system and their performance are compared. Sky-hook control improved ride comfort by reducing body accelerations in the 1-3 Hz range, ground-hook control improved road holding by reducing wheel accelerations in the 10-15 Hz range, and hybrid control results were in between the sky-hook and ground-hook results. The main contribution of this paper is the successful implementation of the semiactive suspension control strategies on an actual vehicle with accompanying experimental results.     

An output-feedback fuzzy approach to guaranteed cost control of vehicle lateral motion

This paper introduces a fuzzy guaranteed cost control approach for automated steering of a highway vehicle. The Takagi–Sugeno (T–S) fuzzy model is utilized to depict the dynamics of nonlinear time-varying lateral system. Based on the fuzzy model, an observer-based fuzzy controller is developed so that without knowing road’s curvature the vehicle can track center of the present lane on a curved highway section. Integrating H_∞ control and optimal control strategies, the fuzzy controller and observer are formulated by solving a minimization problem, which is to minimize a given quadratic performance function. Sufficient conditions to ensure minimum upper bound of the performance function are derived in terms of linear matrix inequalities (LMIs). Therefore, the designing work can be efficiently completed by applying the convex optimization techniques. Verified by computer simulation, the proposed method can perform well in driving safety and ride comfort.     

Real-time road edge following for mobile robot navigation

The authors describe the ongoing research at the University of Bristol to explore mobile robot road-following algorithms and suitable hardware architectures to run these algorithms. The prototype hardware, designed and built at the University, is a real-time frame grabber system based on transputers. Two approaches to real-time road edge following that have been tested to guide a small tracked vehicle around the paths of the University gardens are described     

Multi-objective control for uncertain nonlinear active suspension systems

Performance requirements for vehicle active suspensions include: (a) ride comfort, which means to isolate the body as far as possible from road-induced shocks and vibrations to provide comfort for passengers; (b) road holding, which requires to suppress the hop of the wheels for the uninterrupted contact between wheels and road; and (c) suspension movement limitation, which is restricted by the mechanical structure. In view of such situations, plus the parametric uncertainties, this paper suggests a constrained adaptive backstepping control scheme for active suspensions to achieve the multi-objective control, such that the resulting closed-loop systems can improve ride comfort and at the same time satisfy the performance constraints in the presence of parametric uncertainties. Compared with the classic Quadratic Lyapunov Function (QLF), the barrier Lyapunov function employed in this paper can achieve a less conservatism in controller design. Finally, a design example is shown to illustrate the effectiveness of the proposed control law, where different initial state values are considered in order to verify the proposed approach in detail.     

Nonlinear tracking control based on extended state observer for vehicle active suspensions with performance constraints

In this paper, a nonlinear tracking control strategy with extended state observer (ESO) is presented for vehicle active suspensions to improve the ride comfort, where suspension spaces, dynamic tire loads are considered as time-domain constraints to be guaranteed. The unique characteristic of the proposed approach lies in the independence on accurate mathematical model. More exactly, the unknown dynamics and external disturbances of the vehicle suspension are regarded as an augmented state of the system and are estimated using the designed ESO. The stability analysis shows that both the estimation error and the tracking error of the control output are bounded and that the upper bounds of the errors monotonously decrease with the increase of the observer bandwidth. Finally, a competitive experiment on a quarter-car suspension prototype is given to demonstrate the effectiveness of the proposed control schemes.     

GA-based fuzzy PI/PD controller for automotive active suspensionsystem

A genetic-algorithm (GA)-based fuzzy proportional-plus-integral-proportional-plus-derivative (PI/PD) controller is proposed for an automotive active suspension system (AASS). The fuzzy PI- and PD-type controllers are combined to cope with the different road conditions. By using the merit of GAs, the optimal decision-making rules for both types of controllers are constructed. The real-time simulation results demonstrate that the fusion of GAs and fuzzy controller for an AASS can provide passengers much more ride comfort     

基于单轮车辆悬架的Fuzzy-PID控制器设计和仿真

研究车辆主动空气悬架的控制问题,在车辆主动空气悬的常规PID控制器的基础上,运用模糊推理对常规PID控制器进行参数在线修订,设计了基于单轮车辆主动空气悬架的Fuzzy-PID控制器,并对Fuzzy-PID控制的单轮车辆主动空气悬架进行Matlab建模和仿真试验。仿真结果表明,与车辆被动空气悬架、常规PID控制的车辆主动空气悬架相比,Fuzzy-PID控制的车辆主动空气悬架可大大降低车身加速度和悬架动行程,提高车辆乘坐舒适性和操纵稳定性,具有良好的鲁棒性,从而验证了Fuzzy-PID控制器的有效性和实用性。