基于虚拟样机技术的多轴转向车辆建模与仿真分析

为提高目前多轴转向车辆模型的精确度,以三轴车辆为研究对象,利用虚拟样机技术,在ADAMS/CAR中建立了三轴全轮转向车辆的动力学模型,依据三轴全轮转向车辆的零质心侧偏角转角控制策略,对全轮转向进行了相应设置。为验证车辆的操纵稳定性能,对其进行了仿真分析,主要考查其在低速大转角和高速小转角行驶情况下的响应特性,并与传统的前轮转向车辆进行了对比,结果表明全轮转向车辆在低速转弯时机动性高,中高速转向时稳定性好。     

虚拟样机技术在工程车辆中的应用

论述工程车辆虚拟样机技术的概念、体系结构、样机开发流程和关键技术，对虚拟样机在工程车辆中的应用进行了有益的初探。     

虚拟样机技术初探

阐述了虚拟样机技术的概念、特点及其关键技术;简要介绍了虚拟样机技术在国内外的应用现状;指出了我国发展虚拟样机技术的迫切性。     

某轿车整车虚拟样机模型的操纵稳定性建模与仿真试验

依据某轿车的数模,首先在ADAMS/Car软件中建立该车的整车虚拟样机模型,然后对其进行操纵稳定性仿真试验,并对仿真结果进行了处理.这对于利用ADAMS/Car建立汽车整车虚拟样机模型及对所建模型进行仿真测试及后处理仿真结果求解性能指标提供了实践经验,并为建立面向总成性能动力学模型开辟了新的途径.     

基于虚拟样机技术的乳化液泵仿真研究

为了对乳化液泵的特性进行研究,以ADAMS为平台,结合Pro/E中建立的三维模型,建立了RB315/31.5型乳化液泵的虚拟样机,对连杆、柱塞运动特性进行了分析.基于虚拟样机技术的仿真研究,物理意义明晰,分析灵活方便,对于研究分析乳化液泵性能具有重要意义.     

基于虚拟样机技术的轴向柱塞泵特性仿真

为了对柱塞泵的特性进行研究,以ADAMS为平台,结合Pro/E中建立的三维模型、ANSYS柔性化处理和AMESim中建立的液压系统模型,建立了HAWE V30型柱塞泵的虚拟样机.对配流盘位置与压力冲击,泵出口容积与压力脉动,柱塞运动特性和主轴应力应变进行了分析.基于虚拟样机技术的仿真研究,物理意义明晰,分析灵活方便,对于研究分析柱塞泵性能具有重要意义.     

基于ADAMS与Matlab的车辆稳定性控制联合仿真研究

通过ADAMS/Car软件建立车辆虚拟样机模型,设计出一种基于横摆角速度反馈的稳定性控制系统,此系统由四轮制动逻辑控制器和单轮制动力PID控制器组成,并同防抱死刹车系统(Anti-locked braking system,ABS)的轮胎滑移率控制相结合以防止车轮失稳,进行ADAMS与Matlab联合仿真分析。控制系统中,逻辑控制器只需两路信号,不需要对四个车轮进行独立控制,PID控制器设计为使能子系统,接收逻辑控制器发出的激活信号,而ABS控制器当车轮滑移率小于限定值时方解除控制状态,执行稳定性控制逻辑。理论分析和仿真结果表明,构建的车辆稳定性控制系统是一个行之有效的进行综合仿真和优化控制的系统,所采用的联合仿真方法是正确有效的,由ABS系统和PID控制策略组成的控制系统有效提高了车辆的稳定性,所得结果为稳定性控制在车辆工程中的实际应用提供了参考。     

基于虚拟样机技术的攀爬机器人仿真分析

随着攀爬类机器人技术的不断发展,对能够攀爬复杂三维钢架结构的机器人的需求日益增多。针对一种带脚钉的特殊钢材塔架,提出了一种气动攀爬机器人本体设计方案。利用SolidWorks建立设计方案的三维模型,将其导入Adams中建立虚拟样机模型,并进行运动学及动力学的仿真,测量分析了重要的动力学参数,并运用Adams的二次开发技术,追踪了机器人模型总质心的坐标轨迹。验证了方案的可行性,研究了其运动及动力学性能,为物理样机的研制提供了重要的理论依据。     

基于虚拟样机技术的弹射发射装置动力学仿真

在UG中建立某型弹射发射装置三维装配模型,然后把模型导入ADAMS.利用Matlab计算出的系统动力曲线,在ADAMS中进行弹射发射装置的解锁机构和分离机构动力学仿真分析.     

基于虚拟样机技术的挖掘机器人节能控制仿真研究

针对传统基于反复试验的挖掘机器人节能控制研究的缺点,提出了将虚拟样机技术应用于节能控制开发的方案.在分析典型节能控制模型的基础上,在挖掘机器人虚拟样机上对各种控制方式进行仿真试验,通过分析仿真结果得出各种控制方案的特性,据此进行实际节能控制的优选和参数调整,从而达到减少实际试验次数,提高控制精度和效果的目的.     

Nonlinear observer and robust controller design for enhancement of vehicle lateral stability

This paper describes the design of a sliding mode controller to control wheel slip. A yaw motion controller (YMC), which uses a PID control method, is also proposed for controlling the brake pressure of the rear and inner wheels to enhance lateral stability. It induces the yaw rate to track the reference yaw rate, and it reduces a slip angle on a slippery road. A nonlinear observer is also developed to estimate the vehicle variables difficult to measure directly. The braking and steering performances of the anti-lock brake system (ABS) and YMC are evaluated for various driving conditions, including straight, J-turn, and sinusoidal maneuvers. The simulation results show that developed ABS reduces the stopping distance and increases the longitudinal stability. The observer estimates velocity, slip angle, and yaw rate very well. The results also reveal that the YMC improves vehicle lateral stability and controllability when various steering inputs are applied. In addition, the YMC enhances the vehicle safety on a split-μ road.     

基于LQG的车辆悬架系统控制仿真

将线性二次型高斯控制（LQG）的理论应用到了车辆半主动悬架系统的控制中,通过仿真分析了其特性,LQG控制的半主动悬架系统,在悬架弹性元件支撑的所有部件的质量（简称簧上质量）的固有频率附近,悬架的平顺性和动挠度不能同时得到改善,而在中频段可以使二者同时得到改善,在低频段和接近非簧载质量的固有频率段内,改善悬架的平顺性则必然会增加悬架的动挠度．     

汽车稳定性控制虚拟样机和试验研究

首先,采用自制的简易三坐标测量仪对样车的各铰点(硬点)进行实测,并通过实测或辨识方法确定减振器、转向系统等部分的特征参数;然后,在多体动力学软件中建立该样车整车虚拟样机模型,并建立基于横摆和侧偏的车身稳定性控制系统模糊控制器,其仿真结果表明所建控制器控制效果良好。最后,为了探析样车原装稳定性控制系统控制算法等,对样车进行了冬季试验,并得出了一些有益的启示,这为下阶段自主开发汽车稳定控制系统提供了参考。     

汽车动态稳定性仿真与试验研究

在分析和简化大客车基本结构和载荷分布的基础上,利用人体工效学和汽车系统动力学原理,分别建立了轮胎、悬架系统、乘客人体等模型,并最终建立起9自由度的客车动力学模型.同时,采用SX6120A型客车进行了实车试验.将仿真结果与试验数据进行对比,结果表明所建动力学模型是正确的.应用此模型,仿真分析了高速回避障碍物工况下客车操纵稳定性响应特性.     

Vehicle lateral stability management using gain-scheduled robust control

This paper deals with the design of a yaw rate controller based on gain-scheduled H_∞ optimal control, which is intended to maintain the lateral stability of a vehicle. Uncertain factors such as vehicle mass and cornering stiffness in the vehicle yaw rate dynamics naturally call for the robustness of the feedback controller and thus H_∞, optimization technique is applied to synthesize a controller with guaranteed robust stability and performance against the model uncertainty. In the implementation stage, the feed-forward yaw moment by driver’s steer input is estimated by the disturbance observer in order to determine the accurate compensatory moment. Finally, HILS results indicate that the proposed yaw rate controller can satisfactorily improve the lateral stability of an automobile.     

Design of robust discrete control with desirable quadratic stability

In this paper, a design of robust discrete control with desirable quadratic stability is proposed. The design procedure is the extended discrete version of the continuous robust quadratic stabilization technique proposed by Gu et al. [K. Gu, Y.H. Chen, M.A. Zohdy, N.K. Loh, Quadratic stabilizability of uncertain systems: a two level optimization setup, Automatica 27 (1) (1991) 161–165.]. The effect of the sampling time selection, and the effect of the domain on the robustness, is examined. The presented algorithm is applied to a discrete mass spring system, and a discrete simplified car steering system to demonstrate the feasibility of the procedure, and the effect of the time sampling on the robustness. The robustness increases in both examples considered, as the sampling time decreases to some degree.     

SISO extended predictive control: implementation and robust stability analysis

The proposed algorithm of extended predictive control (EPC) represents an exact method for removing the ill-conditioning in the system matrix by developing a unique weighting structure for any control horizon. The main feature of the EPC algorithm is that it uses the condition number of the system matrix to evaluate a single tuning parameter that provides a specified closed-loop response. Robust analysis demonstrated that EPC is more robust in comparison with move-suppressed and m-shifted predictive controllers in all aspects of process variation in gain, delay, and time-constant ratios. Tuning of EPC is effective and simple since there is a direct relationship between closed-loop performance and its tuning parameter.     

Study on modeling of vehicle dynamic stability and control technique

In order to solve the problem of enhancing the vehicle driving stability and safety,which has been the hot question researched by scientific and engineering in the vehicle industry,the new control method was investigated.After the analysis of tire moving characteristics and the vehicle stress analysis,the tire model based on the extension pacejka magic formula which combined longitudinal motion and lateral motion was developed and a nonlinear vehicle dynamical stability model with seven freedoms was made.A new model reference adaptive control project which made the slip angle and yaw rate of vehicle body as the output and feedback variable in adjusting the torque of vehicle body to control the vehicle stability was designed.A simulation model was also built in Matlab/Simulink to evaluate this control project.It was made up of many mathematical subsystem models mainly including the tire model module,the yaw moment calculation module,the center of mass parameter calculation module,tire parameter calculation module of multiple and so forth.The severe lane change simulation result shows that this vehicle model and the model reference adaptive control method have an excellent performance.     

汽车操纵稳定性仿真用轮胎模型的研究

介绍了四种常见的车辆操纵稳定性仿真用轮胎模型,即简单非线性轮胎模型、半经验公式轮胎模型、魔术公式轮胎模型和分析轮胎模型。通过对含上述四种轮胎模型的车辆动力学系统进行C级不平路面上转向盘角阶跃输入仿真试验,结果表明车辆系统响应总体趋势一致。以简单非线性轮胎模型为例,对比了车辆在水平路面与正弦路面上的响应,分析了不平路面的频率和幅值及车速对车辆操稳性的影响。     

Side slip angle based control threshold of vehicle stability control system

Vehicle Stability Control (VSC) system prevents vehicle from spinning or drifting out mainly by braking intervention. Although a control threshold of conventional VSC is designed by vehicle characteristics and centered on average drivers, it can be a redundancy to expert drivers in critical driving conditions. In this study, a manual adaptation of VSC is investigated by changing the control threshold. A control threshold can be determined by phase plane analysis of side slip angle and angular velocity which is established with various vehicle speeds and steering angles. Since vehicle side slip angle is impossible to be obtained by commercially available sensors, a side slip angle is designed and evaluated with test results. By using the estimated value, phase plane analysis is applied to determine control threshold. To evaluate an effect of control threshold, we applied a 23-DOF vehicle nonlinear model with a vehicle planar motion model based sliding controller. Controller gains are tuned as the control threshold changed. A VSC with various control thresholds makes VSC more flexible with respect to individual driver characteristics.