智能车转向系统模糊控制器设计研究

提出一种参数自整定的模糊控制方法,对智能车的转向控制进行了优化.介绍了模糊控制器的设计与实现方法,并通过实验得出模糊参数自整定规则,改善了智能车转弯时巡线不准确、超调等问题.采用此方法的智能车转向控制系统具有较好的适应性和良好的鲁棒性.     

4WS整车虚拟样机建模与动力学仿真

为了改善汽车在高速行驶转弯时的操纵稳定性，运用动力学仿真软件ADAMS，在其专业汽车模块ADAMS/CAR下研究了4WS汽车建模及其瞬态和稳态操纵动力学特性。以质心侧偏角和横摆角速度响应为评价指标，在角阶跃输入下高速转弯时，对前后轮转角成比例关系的4WS汽车和FWS汽车分别做了动力学仿真研究。对比分析了两者的质心侧偏角和横摆角速度响应特性，从分析结果得出，后轮主动参与转向，总体上有助于改善汽车在高速行驶转弯时的动力学响应特性，但是不同的因素也会对操纵稳定性产生不利的影响。     

非同轴前后轮自平衡车非线性转弯平衡控制

针对非同轴前后轮自平衡车转弯平衡控制问题,提出一种基于非线性动力学模型的转弯平衡控制方法.在分析自平衡车稳定转弯原理的基础上,以自平衡车车体左右倾斜角、转向角、陀螺进动角为广义坐标,利用拉格朗日法建立平衡车转向的MIMO仿射非线性动力学模型;基于反馈精确线性化理论设计PID控制器,进行自平衡车的转弯平衡控制以及对输入的...     

前移式叉车转向稳定性分析

为提高前移式叉车运行和作业时的转向稳定性,需深入分析其转向稳定性机理。首先利用方位角概念将转弯动态过程等效为叉车静止在坡度不断变化的斜坡上进行失稳特征分析;接着通过侧偏角下的最小转弯半径、侧翻临界速度等对前移式叉车进行运动学分析;最后以CQD15-GA2R型号为实验对象,对其横向稳定性作具体计算,得出该机型在额定工况下,满足转弯稳定性的重心最大高度不超过656.6mm。分析结果对优化前移式叉车的结构、载荷分布、转弯半径与速度以及提高车辆运行和作业过程的转向稳定性有一定指导意义。     

异构模块型可变形机器人狭窄空间转向性能研究

围绕异构模块型可变形机器人在狭窄环境的通过性问题,在分析直线构型转向性能和狭窄环境安全通过范围的基础上,提出一种基于能量最优的狭窄环境下转向控制方法.首先在转向运动学和转向动力学模型基础上,构建了状态角度、驱动速度等控制参数与转弯半径等转向性能的关系;进而以能量消耗最小为目标、以安全转弯范围为约束条件,优化机器人直线构型转向下各运动参数的选择和调整.最终通过仿真分析验证了运动控制参数对转向性能的影响,并提出了不同转向方式、不同转向控制参数的特点和优势.     

基于序列图像处理法的机器鱼转向机动性能研究

基于序列图像处理法，对机器鱼的转向性能进行了初步研究．利用高速摄像机记录机器鱼运动过程， 对游动序列图像进行处理，提取机器鱼体干曲线，获取机器鱼转向运动中角度、角速度、角加速度的动态特性．根 据实验结果，给出了机器鱼C 形转向运动的3 个阶段的运动特征，并对理论值和实验测定值之间的差异进行分析． 同时，对静止和运动两种C 形转向运动进行比较，分析了影响C 形转向效果的因素：初始动能以及保持阶段角度大 小，在此基础上，给出了提高机器鱼转向性能的方法．     

视觉AGV的差速转向控制器设计

简要地介绍了基于机器视觉导向的AGV两轮差速转向的原理和组成，并对计算机控制系统设计，图像信息识别等AGV控制问题进行了阐述，提出了一种采用模糊控制方法对AGV两轮差速转向进行控制。仿真和实验结果均表明，采用模糊控制方法对两轮差速转向进行控制，样车运行过程稳定，路径跟踪可靠，控制性能良好。     

匀变速工况下汽车的转向特性仿真研究

为了研究转向工况下的汽车操纵稳定性问题,由于受到外界环境干扰和转弯离心力的影响,为保证行驶的稳定性,需准确获得变速转向工况下的动力特性,建立汽车转向工况下匀变速运动的线性二自由度动力学模型,并从整车控制的角度出发,以横摆角速度作为判据,用仿真分析模型。为提高汽车的响应特性,进行了匀变速工况下汽车的转向仿真研究。仿真结果表明,在匀加速转向时,汽车的横摆角速度响应是逐渐增加;在匀减速转向时,汽车的横摆角速度响应逐渐减小,可为汽车在转向工况下的操纵控制提供有益的参考。     

汽车电子助力转向的模糊PD控制器设计

本文针对汽车助力转向环境的非线性、参数时变性和模型不确定性的情况，考虑PD控制器不能在线进行参数自整定的问题，基于模糊控制技术，提出了一种模糊自整定PD参数的汽车电子助力转向系统的控制方法与控制策略。该方法采用DSP为核心，利用模糊控制规则在线调整PD控制器的参数。运用MATLAB进行仿真的结果表明模糊PD控制器既具有PD控制器高精度的优点，又具有模糊控制器适应性强的特点,能保证有更小的超调、鲁棒性强、更短的调整时间及更好的动、静态特性，在汽车电子助力转向领域具有较高的推广应用价值。     

四轮线控转向系统的转向控制策略研究

为了控制汽车的质心侧偏角,同时保持汽车的转向增益不变,研究了四轮线控转向系统的后轮转向控制策略和前轮转向控制策略.首先建立了四轮转向整车二自由度模型,然后基于稳态质心侧偏角为零得到两种后轮转向控制策略:与前轮转角成比例型和横摆角速度反馈型,前者不改变系统极点,后者改变系统极点.基于转向增益不随车速改变得到二者的前轮转向控制策略.仿真表明,提出的前轮转向控制策略可以保持固定转向增益,降低驾驶员负担;后轮转向控制策略可以实现零质心侧偏角稳态值,控制车辆姿态,改善操纵稳定性.     

采用2-自由度调节器结构的制动方向稳定性控制算法

结合直接横摆力矩控制和主动前轮转向控制,设计了一种提高制动方向稳定性的复合控制系统.控制器采用2-自由度调节器结构,将前轮转向角视为输入,将作用于车身的外部侧向干扰力视为扰动,通过2-自由度调节器将转向跟随控制和抗扰控制分离,并对制动控制参数进行了优化.文章对有转向输入和路面突变情况下的控制器控制性能进行了仿真研究,并与无方向稳定控制的仿真结果进行了对比.仿真试验证实这种控制方法在提高车辆制动稳定性方面有良好的效果.     

线控转向系统全状态反馈控制策略的研究

为了根据车况和驾驶员喜好实现最优的操纵特性(不足转向、过度转向和中性转向),需要主动控制前轮转角.线控转向系统利用车辆全状态(横摆角速度和质心侧偏角)反馈控制策略优化驾驶员的转向输入,主动控制前轮转角来优化车辆的转向特性,高速时具有适当的不足转向特性,低速时具有适当的过度转向特性,从而在反应快速和安全性之间很好的权衡.其中通过状态观测器估计侧偏角.结果表明,在紧急操纵时可以代替驾驶员协调使车辆保持稳定,正常操纵时补偿物理参数或操纵条件的变化而保持操纵特性的一致.     

Visual strategies for the control of steering toward a goal

We have shown that people steer toward a target by aligning their heading with the target when target egocentric direction is not available for steering [24]. Here we examined what visual strategies people use to steer toward a target when target egocentric direction is available for steering. The display simulated a participant walking over a ground plane with a target placed off to one side. The participant’s simulated heading in the display was displaced 10° away from the participant’s straight ahead. A textured ground display that provided dense global optic flow and an empty ground display that provided nearly no flow were tested. Participants were instructed to use a joystick to control their simulated self-motion in the display to (a) steer toward the target, (b) center the target at their straight ahead, or (c) minimize the target drift on the screen. We found that participants produced similar heading error profiles when they were instructed to steer toward the target or to center the target straight ahead, but not when they were instructed to minimize the target movement on the screen. Furthermore, regardless of the instructions received, final heading errors were about 5° smaller with the textured than with the empty ground display, indicating the effect of optic flow on the control performance. We conclude that when target egocentric direction is available for steering, people do not steer toward the target by canceling its optical drift. Optic flow contributes to steering toward a target even when control could be based on egocentric direction alone.     

A Nonlinear Observer Based Analytical Redundancy for Predictive Fault Tolerant Control of a Steer‐by‐Wire System

In this paper, a nonlinear sliding mode observer, along with a long range linear predictor, is presented for fault tolerant control of a steer by wire system. The long‐range predictor is based on Diophantine identity aimed at improving the fault detection efficiency. The overall predictive fault tolerant control strategy was then implemented and validated on a steer by a wire hardware in loop bench. The experimental results show that the overall robustness of the steer by wire system was not sacrificed through the usage of analytical redundancy for sensors along with the designed fault detection, isolation, and identification algorithm. Moreover, the experimental results indicated that the fault detection speed is improved using the proposed analytical redundancy‐based algorithms for both attenuating and amplifying type faults. The proposed fault detection algorithm was also found to be robust against a wide range of fault types.     

电动助力转向系统扭矩信号采集系统设计

电动助力转向系统是安装在汽车上的智能转向机构,通过其控制器获取方向盘输入扭矩的实时信号,以及车速信号等表征汽车运行状态的参数,确定助力电机所提供的助力转矩的大小和方向,辅助驾驶员进行转弯,同时保证汽车的操纵稳定性和安全性。为了保证助力的准确性和快速性,需要对方向盘输入扭矩信号进行检测,针对扭矩信号的采样要求,设计的扭矩信号采集系统主控芯片采用DSP,联合高精度4通道同步采样A/D转换芯片AD7864,可实现对扭矩信号的采样。     

Using feedback control of microflows to independently steer multiple particles

In this paper, we show how to combine microfluidics and feedback control to independently steer multiple particles with micrometer accuracy in two spatial dimensions. The particles are steered by creating a fluid flow that carries all the particles from where they are to where they should be at each time step. Our control loop comprises sensing, computation, and actuation to steer particles along user-input trajectories. Particle locations are identified in real-time by an optical system and transferred to a control algorithm that then determines the electrode voltages necessary to create a flow field to carry all the particles to their next desired locations. The process repeats at the next time instant. Our method achieves inexpensive steering of particles by using conventional electroosmotic actuation in microfluidic channels. This type of particle steering does not require optical traps and can noninvasively steer neutral or charged particles and objects that cannot be captured by laser tweezers. (Laser tweezers cannot steer reflective particles, or particles where the index of refraction is lower than (or for more sophisticated optical vortex holographic tweezers does not differ substantially from) that of the surrounding medium.) We show proof-of-concept PDMS devices, having four and eight electrodes, with control algorithms that can steer one and three particles, respectively. In particular, we demonstrate experimentally that it is possible to use electroosmotic flow to accurately steer and trap multiple particles at once.     

一种基于前馈－反馈复合控制方式的制动稳定性控制方法

设计了一种前馈—反馈复合控制结构，将直接横摆力矩控制和主动前轮转向控制相结合以提高制动稳定性．控制器将前轮转向角视为输入，将外部侧向干扰力和力矩作用视为扰动，通过前馈校正补偿转向角引起的状态变化；同时建立扰动状态观测器，采用反馈控制校正消除外部扰动引起的状态误差．仿真试验证实这种控制方法在提高制动稳定性方面有良好的效果．     

线控转向汽车传动比智能控制策略的研究

以线控转向汽车的传动比控制为重点进行研究,提出了传动比智能控制策略,旨在进一步改善系统的转向性能。针对转向系统的不确定性、非线性的特点,在原有基于模型控制方法的基础上,研究了模糊控制和模糊神经网络在传动比控制中的应用;首先利用模糊控制技术设计传动比控制器,然后研究了模糊神经网络的结构和算法,利用模糊神经网络对理想传动比控制进行改进,实现了输入变量隶属函数中心值和宽度的在线调节,进而对传动比进行优化;从仿真结果可以看出基于模糊神经网络的控制方法比单模糊控制扩大了传动比变化的车速范围,更加符合理想传动比的要求,表明基于模糊神经网络控制方法更具有可行性和有效性。     

Theoretical and Experimental Investigation of Driver Noncooperative-Game Steering Control Behavior

This paper investigates two noncooperative-game strategies which may be used to represent a human driver’s steering control behavior in response to vehicle automated steering intervention. The first strategy, namely the Nash strategy is derived based on the assumption that a Nash equilibrium is reached in a noncooperative game of vehicle path-following control involving a driver and a vehicle automated steering controller. The second one, namely the Stackelberg strategy is derived based on the assumption that a Stackelberg equilibrium is reached in a similar context. A simulation study is performed to study the differences between the two proposed noncooperative- game strategies. An experiment using a fixed-base driving simulator is carried out to measure six test drivers’ steering behavior in response to vehicle automated steering intervention. The Nash strategy is then fitted to measured driver steering wheel angles following a model identification procedure. Control weight parameters involved in the Nash strategy are identified. It is found that the proposed Nash strategy with the identified control weights is capable of representing the trend of measured driver steering behavior and vehicle lateral responses. It is also found that the proposed Nash strategy is superior to the classic driver steering control strategy which has widely been used for modeling driver steering control over the past. A discussion on improving automated steering control using the gained knowledge of driver noncooperative-game steering control behavior was made.      

基于DBF技术的星载SAR宽测绘带实现方法

在研究距离向使用数字波束形成(Digital Beanforming,DBF)实现星载SAR宽测绘带原理的基础上,分析了星载DBF-SAR距离模糊与传统星载SAR距离模糊的不同,并利用阵列天线零点指向技术实现宽零陷的原理,展宽模糊点所对应位置零陷宽度,从而在提高星载SAR宽测绘带基础上有效地减小距离模糊,提高成像质量.通过仿真和比较分析,表明使用具有宽零陷指向特性的DBF技术实现星载SAR宽测绘带模式的可行性.