轮毂液驱重型汽车前桥差速协调控制问题探析,硕士论文.docx
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1、轮毂液驱重型汽车前桥差速协调控制问题探析,硕士论文重型车辆在社会基础设施建设和经济发展中具有举足轻重的地位。由于其多变的使用场合与复杂的工作环境,重型车辆在坏路面上的动力性和好路面上的经济性之间的矛盾日益突出。加装轮毂液压混合动力系统的重型车辆,在坏路面时利用前轮的路面附着力进行液压辅助驱动,在好路面时使用机械后轮驱动,能够实现分时全驱,拥有良好的应用前景。 但由于重型车辆行驶工况的复杂性和驾驶员操作的不确定性,进行液压辅助驱动时往往会出现单侧车轮陷入泥潭或转向等工况,此时前轮两液压马达的需求转速转矩不同,而一样的转速转矩输出势必会造成轮胎磨损等寄生功率,甚至会出现车辆侧滑跑偏等危险工况,故基
2、于前桥两液压马达的差速协调控制研究是完善轮毂液驱系统全工况适应性,提高其行驶安全性的关键。本文针对轮毂液驱重型车辆前桥差速协调控制问题,分别进行了基于路面附着系数辨识的工况适应层研究、基于节流阀设计和控制的执行子系统研究以及基于最优滑动率的逻辑门限差速控制策略研究,主要研究内容包括: 首先,针对本文的研究目的,提出了能够实现前桥两液压马达独立控制的轮毂液压混合动力系统构型方案,并分析其差速工作原理。根据系统构型方案分别进行机械系统和液压系统的建模分析,华而不实,七自由度车辆模型能够准确模拟车辆转向等工况下的动力学状态并提供所需的车辆运动学参数,Dugoff 轮胎模型的纵滑特性和侧偏特性为后文的
3、仿真分析研究提供理论参考。 其次,车辆差速控制策略的实现离不开对工况信息的感悟,针对路面附着系数辨识的工况适应层研究,开发了基于扩展卡尔曼滤波的路面附着系数估计算法;基于 TruckSim 重型车辆模型及工况模型和 Simulink 估计算法模型搭建联合仿真平台,然后分别在高附着系数路面、低附着系数路面、对开路面和对接路面进行仿真验证,结果显示开发的估计算法能够在合理误差范围内准确辨别路面条件,且时效性较好。 再次,针对节流阀设计和控制的执行子系统研究,首先基于液压系统的工作压力和液压马达的基本参数进行节流阀的选型和基本构造参数确实定;然后基于 AMESim 软件搭建节流阀控制模型,通过分析其
4、截面积影响因素,提取输入信号和输出流量关系的控制规则;最后基于 PID 反应控制和前馈+反应控制方式方法检验节流阀的响应效果,结果显示前馈+反应控制方式方法对节流阀出油口流量具有更好的控制效果。 吉林大学硕士学位论文II最后,针对最优滑动率的逻辑门限差速控制策略研究,首先基于阿克曼转向模型分析转向工况下各车轮的目的转速,并以此作为轮毂马达的控制输入,并基于各路面条件下不同的最优滑动率范围作为逻辑门限值开发差速协调控制算法;其次搭建基于 AMESim 机械传动系统模型和 Simulink 车辆模型及差速控制策略模型的联合仿真平台;最后基于转向工况、直行工况下的对开路面和对接路面工况设置仿真验证实
5、验,通过对车辆车速的跟随效果、轮速控制效果、滑动率控制效果和车辆行驶轨迹等效果的分析,证明了差速协调控制算法的准确性和有效性。 本文关键词语:重型车辆,轮毂液驱系统,路面附着系数,差速协调控制 ABSTRACT Research on Differential Coordinated Control of Hydraulic Hub-motor DriveSystem for Heavy Vehicle Front Axle 。 The heavy vehicle plays a pivotal role in social infrastructure construction and ec
6、onomicdevelopment. Due to its variable use occasions and complex working environment, thecontradiction between the power performance on bad roads and the economics of good roads ofheavy vehicle is increasingly prominent. The heavy vehicle equipped with a hub-motor hydraulichybrid system uses the roa
7、d surface adhesion of front wheels for hydraulic auxiliary drivingwhen the road surface is bad, and mechanical rear wheels driving when the road surface is good,it can realize time-sharing full drive and has a good application prospect. However, because ofthe complexity of driving conditions of the
8、heavy vehicle and the uncertainty of driver soperation, the condition of one side wheel fall into the quagmire or steering often occur duringhydraulic auxiliary driving. At this time, the required speed and torque of the two hydraulicmotors of front wheels are different, and the output of the same s
9、peed and torque are bound tocause parasitic power such as tire wear, even dangerous conditions such as sideslip running. Therefore, the research of differential coordinated control based on two hydraulic motors of thefront axle is the key to improve the adaptability of hydraulic hub-motor drive syst
10、em under fulloperating conditions and improve its driving safety. In this paper, aiming at the problem ofdifferential coordinated control of hydraulic hub-motor heavy vehicle front axle, researchs on theworking condition adaptation layer based on the road adhesion coefficient identification, theimpl
11、ementation subsystem based on the throttle valve design and control, and the logic thresholddifferential control strategy based on the optimal slip rate are carried out. The main content ofthis dissertation includes the following elements: Firstly, according to the research objective of this paper,
12、a configuration scheme of ahub-motor hydraulic hybrid system capable of controlling two hydraulic motors independentlyon the front axle is proposed, and its differential working principle is analyzed. Modeling andanalysis of mechanical system and hydraulic system were carried out respectively accord
13、ing tothe system configuration scheme. Among them, the seven-degree-of-freedom vehicle model can 吉林大学硕士学位论文IVaccurately simulate the dynamic state of the vehicle under conditions such as steering andprovide the required vehicle kinematic parameters. Longitudinal slip characteristics and sideslipchar
14、acteristics of Dugoff tire model provides theoretical reference for the subsequent simulationanalysis research. Secondly, the realization of vehicle differential control strategy is inseparable from theperception of working condition information. Aiming at the study of working conditionadaptation la
15、yer of pavement adhesion coefficient identification, a pavement adhesion coefficientestimation algorithm based on extended Kalman filter is developed. A joint simulation platformis built based on TruckSim heavy vehicle model, working condition model and Simulinkestimation algorithm model. Then simul
16、ation verification is conducted on high-adhesion roadsurface, low-adhesion road surface, split road surface and docking road surface respectively. Theresult shows that the developed estimation algorithm can accurately identify pavementconditions within a reasonable error range and has good timelines
17、s. Thirdly, for the research on the execution subsystem of throttle valve design and control, theselection of the throttle and the determination of the basic structural parameters are based on theworking pressure of the hydraulic system and the basic parameters of the hydraulic motor. Thena throttle
18、 valve control model is constructed based on the AMESim software, by analyzing theinfluence factors of its cross-sectional area, the control rules for the relationship between theinput signal and the output flow are extracted. Finally based on the PID feedback control andfeedforward + feedback contr
19、ol method to check the response effect of the throttle valve, theresults show that the feedforward + feedback control method has a better control effect on thethrottle valve outlet flow. Finally, in order to study the logic threshold differential speed control strategy of optimalslip rate, the targe
20、t speed of each wheel under steering condition is firstly analyzed based onackerman steering model, which is used as the control input of hydraulic motor, and thedifferential coordinated control algorithm is developed based on the different optimal sliding raterange under different road conditions a
21、s the logical threshold. Secondly a joint simulationplatform based on the AMESim mechanical transmission system model, Simulink vehicle modeland differential control strategy model is built. At last, the simulation experiment is set up basedon the turning condition and the straight running condition
22、 including split road surface anddocking road surface. Through the analysis of vehicle speed following effect, wheel speedcontrol effect, slip rate control effect and vehicle trajectory effect, the accuracy and effectivenessof the differential coordinated control algorithm is proved. Key words: Heav
23、y vehicle, Hydraulic hub-motor drive system, Pavement adhesion coefficient,Differential coordinated control 目 录 摘 要 . I ABSTRACT . III 目 录 . I 幅较长,部分内容省略,具体全文见文末附件 第6章 全文总结与研究瞻望 6.1 全文总结 针对轮毂液驱重型车辆在转向工况和附着系数多变路面辅助行驶时,前桥左右车轮不能实现差速的问题,本文从工况适应层的路面附着系数估计、执行子系统和控制方式方法的设计,到基于最优滑动率的逻辑门限差速控制策略,系统地研究了轮毂液驱系统的
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