某轿车转向回正性的仿真分析与改进
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摘要
近几年随着高速公路事业的发展和汽车速度的不断提高,汽车在行进中的转向路感受到了越来越多的关注,如果汽车的前轮没有转向回正力矩或者转向回正力矩过小,则它的直线行驶能力必将受到损害,只要一个微小的力就可使它转弯,驾驶员对转弯行驶速度和行驶性能也没有感觉,此外还存在驾驶员在转弯结束后不能及时回转转向盘使汽车偏离道路的危险。因为它关系着行驶中汽车的操纵感觉-“路感”,同时也影响着事故安全,所以对汽车转向回正性能的研究有很重要的意义。本文重点在于采用虚拟试验的方式改善汽车转向回正性能的过程。围绕着这个主题,本文主要做了以下几项研究工作:1.分别从整车参数、车轮定位参数、转向系、轮胎四个方面理论分析了其对转向回正性的影响;2.建立了较为准确的汽车转向系统动力学模型,并对整车模型进行了不同工况的试验验证;3.分别从转向系摩擦、阻尼、惯量、刚度、助力特性、车轮定位参数、轮胎等方面进行转向回正性能影响参数的灵敏度分析,并采用已有的客观指标及方法进行分析评价,得到提高转向回正性的有效改进措施;4.确定了对合作厂商有效的三套改进方案,并通过改变前后客观评价指标的变化验证了改进方案的正确性,同时验证了车辆的不足转向度,保证了车辆的操纵性。
In the driving processes, steering is a basic motion of the car. The driver changes the car's driving direction by controlling the steering wheel. Steering system is a necessary part in modern cars which consists of several transmission components and connects to the chassis, suspension and wheels. Toward the whole vehicle’s dynamics system,the steering system is the input part of the car’s turning motion and it’s characteristic has a direct influence to the automotive handling stability and driving security.
With the development of the freeway and the increasing of the vehicle’s speed, the turning road feel driving car gets more and more attentions.if the front wheels of a car’s don’t have steering returnability moments or steering returnability moments are too small, the ability of the car’s beeline running must be harmed, as long as a small force could make it turn,and the steering wheel must be turned back after running, it also returns its’beeline driving without returnability moments, and the driver doesn’t have the feeling of the turning speed and driving performance too, and there is still a danger the car deviating the road because the driver couldn’t turn steering wheel after finishing turning. Because it is concerned about the car’s handling sense-“road feel”especially in high-speed car, and it also affects the safety of the accident at the same time, hence, studying on the steering returnability in handling stabilities is a very important.
This thesis emphasizes the process of using virtual test method to improve the steering returnability of cars. Focusing on the topic, the following work is done. 1 The theoretical analysis about vehicle parameters affecting steering returnability
Here the software Matlab/Simulink was used to build a vehicle model of force input with two Degree of Freedom , through simulation analysis, we could acquire the effect of the whole vehicle parameters, which could help improvement analysis for structure-based vehicle dynamic model using ADAMS. we did the theoretical analysis about wheel alignment parameters, steering system and tires affecting steering returnability through examples,graphics or formulas, getted these factors which are caster angle, kingpin inclination angle, friction, damping, stiffness, inertia, assistance characteristic, and tire affecting steering returnability most. 2 Hydraulic power steering systems and vehicle modeling
In Adams/Car built a hydraulic power steering system dynamics model, modified the steering system template of the Adams/Car and added the hydraulic power steering system characteristics that we got from the experiments into the template. After that carried out some simulations, such as Pylon course slalom test, Steering wheel angle step input, Steering Returnability test and Steering efforts test procedure to validate the model. The results showed that the model we have built is correct.
3 The improvement and analysis for steering returnability performance
Have briefly introduced the objective evaluation indices and evaluation method of the steering returnability performances in national standards .Have analysed the effects of caster angle, kingpin inclination angle, friction, damping, stiffness, inertia, assistance characteristic, and tire to the whole vehicle steering returnability performances through the ADAMS dynamic model which we have built. The conclusions we had gotten were as following:
1) Reducing the friction of the steering system’s gemel could advance the vehicle’s steering returnability performance, meanwhile too small friction transferred would increase the impact of different road surfaces to steering wheel.
2) Reducing the backpressure of hydraulic power steering system appropriately, reducing the cycle pressure of redirector and reducing oil pressure loss, could reduce fluid damping, which could advance the vehicle’s steering returnability performance. Meanwhile the fluid damping could reduce the system vibration energy and improve vehicle’s smoothness, hence, it should not be too small.
3) Allocating steering system’s the moment of inertia rationally, especially increasing the upper moment of inertia of redirector, could advance the vehicle’s steering returnability performance.
4) Increasing the torsional stiffness of steering system appropriately could advance the vehicle’s steering returnability performance, meanwhile too excessive torsional stiffness brought risk of excessive turn. Besides, increasing the stiffness between suspension and vehicle body could advance the returnability of suspension flexibility.
5) Adopting hydraulic electronic power steering system (HEPS) or electric power steering system (EPS) whose assistance characteristic are changed based on the vehicle speed could advance the vehicle’s steering returnability performance.
6) Increasing caster angle and caster moment arm, could advance the vehicle’s steering returnability performance, meanwhile consider steering ponderosity because of too big caster angle; Increasing kingpin inclination angle and scrub radius especially steering returnability in high speed could advance the vehicle’s steering returnability performance, but it is not too large, too large scrub radius could lead that the aligning torque longitudinal force generated are too sensitive which affects the beeline driving ability and make against the vehicle’s understeer.
7) Replacing the tire whose lateral stiffness is smaller could advance the vehicle’s steering returnability performance, meanwhile should assure vehicle’s handling stabilities performance.
4 Confirm and validate the improvement project
Considering the manufacturers’sample car and the upper methods about improving steering returnability, we confirm the project on caster angle, kingpin inclination angle, tire and returnability of suspension flexibility. Introduce the difference depression between left wheel and right wheel of understeer degree’s objecttive evaluation method in steady static circular test, and do the simulation analysis of steady static circular characteristic for our dynamic model. Separately validate the steering returnability and steady static circular characteristic of the three confirmed projects, the three improvement projects improve the steering returnability effectively through the contrast analysis, and understeer degree changes a little ,ensure the vehicle’s handling performance.
In the driving processes, steering is a basic motion of the car. The driver changes the car's driving direction by controlling the steering wheel. Steering system is a necessary part in modern cars which consists of several transmission components and connects to the chassis, suspension and wheels. Toward the whole vehicle’s dynamics system,the steering system is the input part of the car’s turning motion and it’s characteristic has a direct influence to the automotive handling stability and driving security.
With the development of the freeway and the increasing of the vehicle’s speed, the turning road feel driving car gets more and more attentions.if the front wheels of a car’s don’t have steering returnability moments or steering returnability moments are too small, the ability of the car’s beeline running must be harmed, as long as a small force could make it turn,and the steering wheel must be turned back after running, it also returns its’beeline driving without returnability moments, and the driver doesn’t have the feeling of the turning speed and driving performance too, and there is still a danger the car deviating the road because the driver couldn’t turn steering wheel after finishing turning. Because it is concerned about the car’s handling sense-“road feel”especially in high-speed car, and it also affects the safety of the accident at the same time, hence, studying on the steering returnability in handling stabilities is a very important.
This thesis emphasizes the process of using virtual test method to improve the steering returnability of cars. Focusing on the topic, the following work is done. 1 The theoretical analysis about vehicle parameters affecting steering returnability
Here the software Matlab/Simulink was used to build a vehicle model of force input with two Degree of Freedom , through simulation analysis, we could acquire the effect of the whole vehicle parameters, which could help improvement analysis for structure-based vehicle dynamic model using ADAMS. we did the theoretical analysis about wheel alignment parameters, steering system and tires affecting steering returnability through examples,graphics or formulas, getted these factors which are caster angle, kingpin inclination angle, friction, damping, stiffness, inertia, assistance characteristic, and tire affecting steering returnability most. 2 Hydraulic power steering systems and vehicle modeling
In Adams/Car built a hydraulic power steering system dynamics model, modified the steering system template of the Adams/Car and added the hydraulic power steering system characteristics that we got from the experiments into the template. After that carried out some simulations, such as Pylon course slalom test, Steering wheel angle step input, Steering Returnability test and Steering efforts test procedure to validate the model. The results showed that the model we have built is correct.
3 The improvement and analysis for steering returnability performance
Have briefly introduced the objective evaluation indices and evaluation method of the steering returnability performances in national standards .Have analysed the effects of caster angle, kingpin inclination angle, friction, damping, stiffness, inertia, assistance characteristic, and tire to the whole vehicle steering returnability performances through the ADAMS dynamic model which we have built. The conclusions we had gotten were as following:
1) Reducing the friction of the steering system’s gemel could advance the vehicle’s steering returnability performance, meanwhile too small friction transferred would increase the impact of different road surfaces to steering wheel.
2) Reducing the backpressure of hydraulic power steering system appropriately, reducing the cycle pressure of redirector and reducing oil pressure loss, could reduce fluid damping, which could advance the vehicle’s steering returnability performance. Meanwhile the fluid damping could reduce the system vibration energy and improve vehicle’s smoothness, hence, it should not be too small.
3) Allocating steering system’s the moment of inertia rationally, especially increasing the upper moment of inertia of redirector, could advance the vehicle’s steering returnability performance.
4) Increasing the torsional stiffness of steering system appropriately could advance the vehicle’s steering returnability performance, meanwhile too excessive torsional stiffness brought risk of excessive turn. Besides, increasing the stiffness between suspension and vehicle body could advance the returnability of suspension flexibility.
5) Adopting hydraulic electronic power steering system (HEPS) or electric power steering system (EPS) whose assistance characteristic are changed based on the vehicle speed could advance the vehicle’s steering returnability performance.
6) Increasing caster angle and caster moment arm, could advance the vehicle’s steering returnability performance, meanwhile consider steering ponderosity because of too big caster angle; Increasing kingpin inclination angle and scrub radius especially steering returnability in high speed could advance the vehicle’s steering returnability performance, but it is not too large, too large scrub radius could lead that the aligning torque longitudinal force generated are too sensitive which affects the beeline driving ability and make against the vehicle’s understeer.
7) Replacing the tire whose lateral stiffness is smaller could advance the vehicle’s steering returnability performance, meanwhile should assure vehicle’s handling stabilities performance.
4 Confirm and validate the improvement project
Considering the manufacturers’sample car and the upper methods about improving steering returnability, we confirm the project on caster angle, kingpin inclination angle, tire and returnability of suspension flexibility. Introduce the difference depression between left wheel and right wheel of understeer degree’s objecttive evaluation method in steady static circular test, and do the simulation analysis of steady static circular characteristic for our dynamic model. Separately validate the steering returnability and steady static circular characteristic of the three confirmed projects, the three improvement projects improve the steering returnability effectively through the contrast analysis, and understeer degree changes a little ,ensure the vehicle’s handling performance.
引文
[1] 郭孔辉,汽车操纵动力学,吉林科学技术出版社,1991
[2] 余志生,汽车理论(第 4 版),机械工业出版社,2007
[3] 汽车操纵稳定性试验报告,国家汽车质量监督检验中心(襄樊),2007
[4] 汽车百科全书编篡委员会,汽车百科全书(上册),机械工业出版社,1992
[5] 杨启梁,汽车转向回正性能仿真分析,装配制造技术,2006/5
[6] Hiroshi YAMAKAWA Youichi SAKAI Yoshimichi YAMAMOTO,An Application of Full Vehicle ADAMS Modeling with Detailed Force Elements:Collaborative activity among Design, Experiment & CAE in the field of vehicle dynamics,Vehicle Evaluation and Test Dept.
[7] Hans B.Pacejka,Tire and Vehicle Dynamics,Professor Emeritus Delft University of Technology Consultant TNO Automotive Delft The Netherlands
[8] Prof.Dr.Georg Rill,Vehicle Dynamics, Fachhochschule Regensburg University of Applied Sciences, Oktober 2007
[9] 吕威,轿车交流电机 EPS 控制研究与试验台测控系统开发,吉林大学硕士学位论文,2007/4
[10] 宗长富、郭孔辉,汽车操纵稳定性的主观评价,汽车工程,2000/5
[11] 宗长富、郭孔辉,汽车操纵稳定性的客观定量评价指标,吉林工业大学自然科学学报,2000/1
[12] 陈振日,对汽车操纵稳定性现行评价指标的分析与建议,汽车技术,2006/9
[13] 柯愈治,汽车操纵稳定性能的评价方法,专用汽车,1996/3
[14] D.A.Crolla,D.C.Chen,J.P.Whitehead,C.J.Alstead,Vehicle handling assessment using a combined subjective-objective approach,SAE Technical Paper,980226.
[15] 陆佑方,柔性多体系统动力学,高等教育出版社,1989
[16] Kenneth.D.Norman, Objective Evaluation of On-Center Handling Perfor -mance, SAE 840069
[17] Gary P. Bertollini, General Motors Corp. Robert M. Hogan, Raytheon Systems Co, Applying Driving Simulation to Quantify Steering Effort Preference as a Function of Vehicle Speed. SAE 1999-01-0394
[18] 刘维信,汽车设计,清华大学出版社,2001
[19] Evans R. D., Properties of tires affection riding, steering and handing . Tans, SAE,Vol.36, No.2 February 1935
[20] 俞凡、林逸,汽车系统动力学,机械工业出版社
[21] 耶尔森.赖姆帕尔,张洪欣 余卓平译,汽车底盘基础,北京:科学普及出版社,1992/9
[22] 安部正人著,陈幸波译,汽车的运动与操纵,机械工业出版社,1998
[23] Saied Taheri , Reza Kazemi and M. Tabatabai , Analysis and Optimization of Vehicle Steering System, SAE 981113
[24] M. Kamel Salaani, Modeling and Implementation of Steering System Feedback for the National Advanced Driving Simulator , SAE 2002-01-1573
[25] I. Camuffo and G.Caviasso, Simulation Tools and Evaluation Criteria for Steering Wheel Feel Improvement of an Electric Power Steering System, SAE 2002-01- 1593
[26] Zbigniew Lozia, Vehicle Dynamic and Motion Simulation Versus Experiment, SAE 980220
[27] 尹军明、彭华东,解析汽车转向回正性能,重庆重汽科技,2006/2
[28] Thomas D.Gillespie 著、赵六奇 金达锋译,车辆动力学基础,清华大学出版社,2006/12
[29] 丁海涛,轮胎附着极限下汽车稳定性控制的仿真研究,吉林大学博士学位论文,2003/6
[30] 李宁,复杂工况下轮胎侧偏特性仿真模型的修正,吉林大学硕士学位论文,2007/4
[31] 范成建、熊光明、周明飞,虚拟样机软件—MSC.ADAMS 应用与提高,机械工业出版社,2006
[32] 吴浩, 电动助力转向系统建模及其助力特性的研究, 吉林大学硕士学位论文, 2003/2
[33] 李莉, C926 悬架 K&C 特性建模与仿真分析报告, 2006/4, 吉林大学汽车动态模拟国家重点实验室
[34] 隋震宇,Stantana 轿车前悬架弹性运动学特性 ADAMS 建模与仿真,吉林大学硕士学位论文,2002/6
[35] 刘青,郭孔辉,非稳态轮胎侧偏特性仿真的数值算法,清华大学学报,1999 年,39 卷
[36] 叶耿,杨家军,刘照,肖大友,汽车电动式转向系统转向路感研究,华中科技大学学报,2002/2
[37] 国家标准,操纵稳定性试验方法_稳态回转试验,GB T 6323.6-1994
[38] 国家标准,操纵稳定性试验方法_转向回正性能试验,GB T 6323.4-1994
[39] 国家标准,操纵稳定性试验方法_转向轻便性试验,GB T 6323.5-1994
[40] 郭文鑫,轿车转向系样件助力特性试验报告,2006/7,吉林大学汽车动态模拟国家重点实验室
[41] 郭文鑫,轿车整车转向系干摩擦特性试验报告,2006/3,吉林大学汽车动态模拟国家重点实验室
[42] Sanjay Singh, Design of Front Wheel Active Steering for Improved Vehicle Handling and Stability, SAE 2000-01-1619
[43] 郭文鑫,轿车液压助力转向系统试验研究与中心区操纵性分析,吉林大学硕士学位论文,2007/6
[44] 田阳,汽车底盘操纵性虚拟试验评价与改进,吉林大学硕士学位论文,2007/6
[45] 李莉,基于 ADAMS/Car 的某轿车平顺性仿真分析与改进,吉林大学硕士学位论文,2007/6
[46] 王蠡,汽车悬架 K&C 特性的试验研究与性能分析,吉林大学硕士学位论文,2007/6
[47] 魏丽丽,提高操纵稳定性的汽车前轮电子转向系统控制方法研究,吉林大学硕士学位论文,2006/6
[48] 郭猛,汽车前轮定位参数分析与优化设计,吉林大学硕士学位论文,2006/6
[49] 魏道高,汽车前轮定位参数研究与展望,合肥工业大学学报,2004/12
[50] 陈丽,基于 ADAMS 的汽车电动助力转向系统仿真分析,华中科技大学硕士学位论文,2005/6
[51] 耿谦,基于虚拟样机的 EPS 助力特性对汽车操纵稳定性影响研究,浙江大学硕士学位论文,2006/5
[52] J.W.Post and E.H.Procedure for the Characterization of Friction in Automobile Power Steering Systems, SAE 960933
[53] Yasuo Shimizu and Toshitake Kawai, Developme nt of Electric Power Steering, SAE 91001
[54] 王忠仪 于翔,现代汽车转向轮定位的变化趋势,世界汽车,1997/6
[2] 余志生,汽车理论(第 4 版),机械工业出版社,2007
[3] 汽车操纵稳定性试验报告,国家汽车质量监督检验中心(襄樊),2007
[4] 汽车百科全书编篡委员会,汽车百科全书(上册),机械工业出版社,1992
[5] 杨启梁,汽车转向回正性能仿真分析,装配制造技术,2006/5
[6] Hiroshi YAMAKAWA Youichi SAKAI Yoshimichi YAMAMOTO,An Application of Full Vehicle ADAMS Modeling with Detailed Force Elements:Collaborative activity among Design, Experiment & CAE in the field of vehicle dynamics,Vehicle Evaluation and Test Dept.
[7] Hans B.Pacejka,Tire and Vehicle Dynamics,Professor Emeritus Delft University of Technology Consultant TNO Automotive Delft The Netherlands
[8] Prof.Dr.Georg Rill,Vehicle Dynamics, Fachhochschule Regensburg University of Applied Sciences, Oktober 2007
[9] 吕威,轿车交流电机 EPS 控制研究与试验台测控系统开发,吉林大学硕士学位论文,2007/4
[10] 宗长富、郭孔辉,汽车操纵稳定性的主观评价,汽车工程,2000/5
[11] 宗长富、郭孔辉,汽车操纵稳定性的客观定量评价指标,吉林工业大学自然科学学报,2000/1
[12] 陈振日,对汽车操纵稳定性现行评价指标的分析与建议,汽车技术,2006/9
[13] 柯愈治,汽车操纵稳定性能的评价方法,专用汽车,1996/3
[14] D.A.Crolla,D.C.Chen,J.P.Whitehead,C.J.Alstead,Vehicle handling assessment using a combined subjective-objective approach,SAE Technical Paper,980226.
[15] 陆佑方,柔性多体系统动力学,高等教育出版社,1989
[16] Kenneth.D.Norman, Objective Evaluation of On-Center Handling Perfor -mance, SAE 840069
[17] Gary P. Bertollini, General Motors Corp. Robert M. Hogan, Raytheon Systems Co, Applying Driving Simulation to Quantify Steering Effort Preference as a Function of Vehicle Speed. SAE 1999-01-0394
[18] 刘维信,汽车设计,清华大学出版社,2001
[19] Evans R. D., Properties of tires affection riding, steering and handing . Tans, SAE,Vol.36, No.2 February 1935
[20] 俞凡、林逸,汽车系统动力学,机械工业出版社
[21] 耶尔森.赖姆帕尔,张洪欣 余卓平译,汽车底盘基础,北京:科学普及出版社,1992/9
[22] 安部正人著,陈幸波译,汽车的运动与操纵,机械工业出版社,1998
[23] Saied Taheri , Reza Kazemi and M. Tabatabai , Analysis and Optimization of Vehicle Steering System, SAE 981113
[24] M. Kamel Salaani, Modeling and Implementation of Steering System Feedback for the National Advanced Driving Simulator , SAE 2002-01-1573
[25] I. Camuffo and G.Caviasso, Simulation Tools and Evaluation Criteria for Steering Wheel Feel Improvement of an Electric Power Steering System, SAE 2002-01- 1593
[26] Zbigniew Lozia, Vehicle Dynamic and Motion Simulation Versus Experiment, SAE 980220
[27] 尹军明、彭华东,解析汽车转向回正性能,重庆重汽科技,2006/2
[28] Thomas D.Gillespie 著、赵六奇 金达锋译,车辆动力学基础,清华大学出版社,2006/12
[29] 丁海涛,轮胎附着极限下汽车稳定性控制的仿真研究,吉林大学博士学位论文,2003/6
[30] 李宁,复杂工况下轮胎侧偏特性仿真模型的修正,吉林大学硕士学位论文,2007/4
[31] 范成建、熊光明、周明飞,虚拟样机软件—MSC.ADAMS 应用与提高,机械工业出版社,2006
[32] 吴浩, 电动助力转向系统建模及其助力特性的研究, 吉林大学硕士学位论文, 2003/2
[33] 李莉, C926 悬架 K&C 特性建模与仿真分析报告, 2006/4, 吉林大学汽车动态模拟国家重点实验室
[34] 隋震宇,Stantana 轿车前悬架弹性运动学特性 ADAMS 建模与仿真,吉林大学硕士学位论文,2002/6
[35] 刘青,郭孔辉,非稳态轮胎侧偏特性仿真的数值算法,清华大学学报,1999 年,39 卷
[36] 叶耿,杨家军,刘照,肖大友,汽车电动式转向系统转向路感研究,华中科技大学学报,2002/2
[37] 国家标准,操纵稳定性试验方法_稳态回转试验,GB T 6323.6-1994
[38] 国家标准,操纵稳定性试验方法_转向回正性能试验,GB T 6323.4-1994
[39] 国家标准,操纵稳定性试验方法_转向轻便性试验,GB T 6323.5-1994
[40] 郭文鑫,轿车转向系样件助力特性试验报告,2006/7,吉林大学汽车动态模拟国家重点实验室
[41] 郭文鑫,轿车整车转向系干摩擦特性试验报告,2006/3,吉林大学汽车动态模拟国家重点实验室
[42] Sanjay Singh, Design of Front Wheel Active Steering for Improved Vehicle Handling and Stability, SAE 2000-01-1619
[43] 郭文鑫,轿车液压助力转向系统试验研究与中心区操纵性分析,吉林大学硕士学位论文,2007/6
[44] 田阳,汽车底盘操纵性虚拟试验评价与改进,吉林大学硕士学位论文,2007/6
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