轿车防抱死制动系统的压力估算算法研究
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摘要
作为汽车主动安全控制系统中最常见的一种,防抱死制动系统对提高行驶安全性具有十分重要的作用。而液压调节单元作为轿车防抱死制动系统的主要执行机构,其工作性能直接影响整个系统的控制效果。尽管液压调节单元的形式多种多样,但宗旨都是对制动系统的压力进行调节。对于轿车防抱死制动系统,如果能够精确获得车轮上当前的制动压力,就可以实现对制动压力进一步精确控制。采用压力传感器可以很好地实现这一目标,但是为了降低整个系统的制造成本,往往不用压力传感器来测量车轮上的制动压力,这就需要通过控制算法对压力进行估算从而保证制动压力调节的实时性和精确性。然而,国内对于这一方面的研究还处于起步阶段,开展液压制动系统压力预估的研究具有一定现实意义和应用价值。
本文在吸收国内外防抱死制动系统压力控制研究成果的基础上,结合软件仿真深入研究了液压调节单元工作特点和控制方式,提出了轿车防抱死制动系统压力估算算法。通过在MATLAB/Simulink环境下进行建模与仿真,验证了所提出算法的可行性和有效性。
As one kind of active driver assistance systems, Anti-lock Braking System plays an important part in maintaining vehicle stability and shortening brake distance. Almost all new cars are offered today with ABS. To some extend, this technology has come to perfection abroad, while the domestic research is only in its infancy. The core technology of ABS involves developments of ECU, control strategies, HCU, sensors, and evaluations for brake system-matching. As the actuator of the system, HCU directly affects the performance.
ABS is used to control the force applied on the tires in an effort to optimize vehicle performance. Because the force applied on the tires is so critical to ABS, it obviously would be an advantage to know the force directly. Unfortunately, there is currently not an easy and cost-effective way to measure the force. As a secondary solution, the brake pressure could be achieved using pressure sensors whose measurements are can be used by ABS strategy; however, this approach also involves an increase in manufacturing cost of the device. The brake pressure can be estimated by the characteristics of the hydraulic modulator, which is used to perform the ABS brake pressure regulation. This paper presents a brake pressure estimation algorithm for anti-lock braking system which gives accurate and real-time pressure estimation. This paper is carried out as follows:
Above all, theoretical analysis to the hydraulic control unit is carried out. The performances of high speed digital valves, including operating feature, dynamic performance and static performance, are studied firstly. On the basis of theoretical analysis to high speed digital valves, the model of hydraulic control unit for ABS is developed using AMESim. Through the simulation, several results are achieved, including the varieties of pressure, flow rate and volume of wheel cylinder. So are the variety of characteristic parameters of the accumulator, the pump, especially control valves. These results reflect dynamic characteristics of the system well.
Secondly, based on the data accumulated a reduced mathematics model of the Anti-lock Braking System is developed, which consists of a brake pedal, a master cylinder, a vacuum booster, a hydraulic control unit, lines and brakes, etc. This model explicitly describes the nonlinear capacitance of the brake system. Furthermore, the model allows for brake pressure variations between wheels. The final aspect of the model, therefore, involves relating the wheel pressure to the displaced fluid volume. Finally, a concept of the hydraulic model and inversed hydraulic model is presented, which is the theoretical principle of brake pressure estimating and controlling.
Thirdly, two methods of estimating the brake pressure is present on the principle of hydraulic drive and the characteristics of ABS in this paper. One approach relies on the empirical model. This kind of estimation algorithm derived from numerous of vehicle tests to determine the functions of brake pressure under kinds of work condition, which is not available under current stage. Another approach is to develop a model-based brake pressure estimation strategy. The model-based brake pressure estimation strategy is developed in terms of relating the wheel pressure to the displaced fluid volume.
Finally, simulated studies of an anti-lock braking system are undertaken using Matlab/Simulink. The simulation is carried out step by step. The model of the anti-lock braking system is built to estimate the brake pressure and a simulation is performed. Then the modulation of the pressure is simulated using Stateflow. The simulation results show that the algorithm gives accurate pressure estimation.
本文在吸收国内外防抱死制动系统压力控制研究成果的基础上,结合软件仿真深入研究了液压调节单元工作特点和控制方式,提出了轿车防抱死制动系统压力估算算法。通过在MATLAB/Simulink环境下进行建模与仿真,验证了所提出算法的可行性和有效性。
As one kind of active driver assistance systems, Anti-lock Braking System plays an important part in maintaining vehicle stability and shortening brake distance. Almost all new cars are offered today with ABS. To some extend, this technology has come to perfection abroad, while the domestic research is only in its infancy. The core technology of ABS involves developments of ECU, control strategies, HCU, sensors, and evaluations for brake system-matching. As the actuator of the system, HCU directly affects the performance.
ABS is used to control the force applied on the tires in an effort to optimize vehicle performance. Because the force applied on the tires is so critical to ABS, it obviously would be an advantage to know the force directly. Unfortunately, there is currently not an easy and cost-effective way to measure the force. As a secondary solution, the brake pressure could be achieved using pressure sensors whose measurements are can be used by ABS strategy; however, this approach also involves an increase in manufacturing cost of the device. The brake pressure can be estimated by the characteristics of the hydraulic modulator, which is used to perform the ABS brake pressure regulation. This paper presents a brake pressure estimation algorithm for anti-lock braking system which gives accurate and real-time pressure estimation. This paper is carried out as follows:
Above all, theoretical analysis to the hydraulic control unit is carried out. The performances of high speed digital valves, including operating feature, dynamic performance and static performance, are studied firstly. On the basis of theoretical analysis to high speed digital valves, the model of hydraulic control unit for ABS is developed using AMESim. Through the simulation, several results are achieved, including the varieties of pressure, flow rate and volume of wheel cylinder. So are the variety of characteristic parameters of the accumulator, the pump, especially control valves. These results reflect dynamic characteristics of the system well.
Secondly, based on the data accumulated a reduced mathematics model of the Anti-lock Braking System is developed, which consists of a brake pedal, a master cylinder, a vacuum booster, a hydraulic control unit, lines and brakes, etc. This model explicitly describes the nonlinear capacitance of the brake system. Furthermore, the model allows for brake pressure variations between wheels. The final aspect of the model, therefore, involves relating the wheel pressure to the displaced fluid volume. Finally, a concept of the hydraulic model and inversed hydraulic model is presented, which is the theoretical principle of brake pressure estimating and controlling.
Thirdly, two methods of estimating the brake pressure is present on the principle of hydraulic drive and the characteristics of ABS in this paper. One approach relies on the empirical model. This kind of estimation algorithm derived from numerous of vehicle tests to determine the functions of brake pressure under kinds of work condition, which is not available under current stage. Another approach is to develop a model-based brake pressure estimation strategy. The model-based brake pressure estimation strategy is developed in terms of relating the wheel pressure to the displaced fluid volume.
Finally, simulated studies of an anti-lock braking system are undertaken using Matlab/Simulink. The simulation is carried out step by step. The model of the anti-lock braking system is built to estimate the brake pressure and a simulation is performed. Then the modulation of the pressure is simulated using Stateflow. The simulation results show that the algorithm gives accurate pressure estimation.
引文
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[21]齐志权,刘昭度,马岳峰,崔海峰. Jetta GTX轿车MK20_I型ABS液压系统数学模型[J].液压与气动.2005(1):42-44.
[22]张彪,刘昭度,崔海峰,李志远.基于PWM控制的轮缸压力精细调节试验[J].农业机械学报.2007(7):58-61.
[23]李志远,刘昭度,崔海峰,王仁广.汽车ABS制动轮缸压力变化速率模型试验[J].农业机械学报.2007(9):6-9.
[24]丁能根,潘为民,方裕固.ABS压力响应测试和压力的精细调节[J].机械工程学报.2004(6):188-190.
[25]李亮,宋健,韩宗奇,孔磊.用于电子稳定程序(ESP)在线控制的液压模型和反模型[J].机械工程学报.2008(2):139-144.
[26]程军.车轮最佳滑移率控制的研究[J].试验与研究.2000(1):36-39.
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[30]朱旬,金海东.轿车制动主缸结构浅析.[J].设计与计算.1999(2):27-29.
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[32]欧阳.乘用车ABS/TCS/ESP HCU的仿真与特性研究[D].长春:吉林大学汽车工程学院,2007.
[33]张永生.商用车轮速与轮角加速度信号采集与处理技术研究[D].长春:吉林大学汽车工程学院,2007.
[34]陈箭.ABS&TCS控制系统的控制算法研究与仿真分析[D].长春:吉林大学汽车工程学院,2005.
[35]徐镝.轻型汽车ESP神经网络控制及压力估算算法研究[D].长春:吉林大学汽车工程学院,2006.
[36]熊泽伟.ABS液压单元HCU的性能研究及测试设备的开发[D].重庆:重庆大学机械工程学院,2004.
[37]赵健.四轮驱动汽车TCS制动压力调节装置及附着系数分离路面控制方法的研究[D].长春:吉林大学汽车工程学院,2003.
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[2]殷程良.车辆防抱死制动系统(ABS)实用化技术控制逻辑与实车试验研究[D].上海:上海交通大学,2002.5.
[3] 2006-2007年中国汽车电子市场研究年度报告. http://www.52bus.com/bus_hy/2007/1116/article_265.html
[4]杨絮.从创新到标配——博世ABS安全制动30年[J].世界汽车.2008(11):40-41.
[5]陈祯福.汽车底盘控制技术的现状和发展趋势[J].汽车工程.2006(2):105-113.
[6] Anton T. van Zanten. Evolution of Electronic Control Systems for Improving the Vehicle Dynamic Behavior. AVEC'2002, 2002.
[7]程军.汽车防抱死制动系统的理论与实践[M].北京:北京理工大学出版社,1999.9.
[8]司利增.汽车防滑控制技术——ABS与ASR[M].北京:人民交通出版社,1997.7
[9]张也影.流体力学(第2版)[M].北京:高等教育出版社,1999.
[10]张志涌等.精通MATLAB 6.5版[M].北京:北京航空航天大学出版社,2003.3.
[11]张亮,郭仕剑,王宝顺,贺兴华等.MATLAB 7.x系统建模与仿真[M].北京:人民邮电出版社,2006.11.
[12]薛定宇,陈阳泉.基于MATLAB/Simulink的系统仿真技术与应用[M].北京:清华大学出版社,2002.4.
[13]付永领,祁晓野.AMESIM系统建模和仿真——从入门到精通[M].北京:北京航空航天大学出版社,2006.6.
[14]余志生.汽车理论(第4版)[M].北京:机械工业出版社,2006.5.
[15]喻凡,林逸.汽车系统动力学[M].北京:机械工业出版社,2005.7.
[16]李成功,和彦森.液压系统建模与住真分析[M].北京:航天工业出版社,2008.9.
[17]张利平.液压控制系统及设计[M].北京:化学工业出版社2006.6.
[18]刘金琨.先进PID控制MATLAB仿真(第2版)[M].北京:电子机械工业出版社,2004.9.
[19]于良耀,王会义,宋健,祁雪乐,孔磊.汽车防抱制动系统中液压系统性能评价与试验[J].机械工程学报.2007(9):40-46.
[20]吴诰珪,刘绍辉.汽车ABS制动轮缸压力函数的试验研究[J].机床与液压.2001(3):25-26.
[21]齐志权,刘昭度,马岳峰,崔海峰. Jetta GTX轿车MK20_I型ABS液压系统数学模型[J].液压与气动.2005(1):42-44.
[22]张彪,刘昭度,崔海峰,李志远.基于PWM控制的轮缸压力精细调节试验[J].农业机械学报.2007(7):58-61.
[23]李志远,刘昭度,崔海峰,王仁广.汽车ABS制动轮缸压力变化速率模型试验[J].农业机械学报.2007(9):6-9.
[24]丁能根,潘为民,方裕固.ABS压力响应测试和压力的精细调节[J].机械工程学报.2004(6):188-190.
[25]李亮,宋健,韩宗奇,孔磊.用于电子稳定程序(ESP)在线控制的液压模型和反模型[J].机械工程学报.2008(2):139-144.
[26]程军.车轮最佳滑移率控制的研究[J].试验与研究.2000(1):36-39.
[27]李君,喻凡,张建武,冯金芝.车辆转向制动防抱死系统仿真研究[J].系统仿真学报.2001(6):789-793.
[28]陈宝江,杨树兴,曹泛.PWM高速开关阀特性分析[J].北京理工大学学报.1993(3):354-360.
[29]窦一兵.蓄能器在汽车液压系统中的应用[J].液压气动与密封.1995(4):29-32.
[30]朱旬,金海东.轿车制动主缸结构浅析.[J].设计与计算.1999(2):27-29.
[31]张威.Stateflow辑系统建模[M].西安:西安电子科技大学出版社,2007.10.
[32]欧阳.乘用车ABS/TCS/ESP HCU的仿真与特性研究[D].长春:吉林大学汽车工程学院,2007.
[33]张永生.商用车轮速与轮角加速度信号采集与处理技术研究[D].长春:吉林大学汽车工程学院,2007.
[34]陈箭.ABS&TCS控制系统的控制算法研究与仿真分析[D].长春:吉林大学汽车工程学院,2005.
[35]徐镝.轻型汽车ESP神经网络控制及压力估算算法研究[D].长春:吉林大学汽车工程学院,2006.
[36]熊泽伟.ABS液压单元HCU的性能研究及测试设备的开发[D].重庆:重庆大学机械工程学院,2004.
[37]赵健.四轮驱动汽车TCS制动压力调节装置及附着系数分离路面控制方法的研究[D].长春:吉林大学汽车工程学院,2003.
[38]吕济明.汽车TCS系统建模及控制逻辑研究[D].长春:吉林大学汽车工程学院,2005.
[39]汪继斌.汽车ABS液压调节器建模与分析[D].长春:吉林大学汽车工程学院,2007.
[40]谢敏松.汽车ESP液压系统动态特性研究[D].重庆:重庆大学机械工程学院,2007.
[41] Vinod Nanda, Velliyiur Subbarao. Computer Modeling and Simulation of Hydraulic Systems, SAE International Off-Highway and Powerplant Congress and Exposition [C]. United States: Milwaukee, Wisconsin, 1998.
[42] http://www.amesim.com.cn/about.asp?D_ID=5
[43]黄维纲,王旭永,王显正,钟廷修.高速电磁开关阀开关特性的机理研究[J].上海交通大学学报.1998(32):38-41.
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