电动助力转向(electric power steering,EPS)系统是车辆常用的转向执行器,其失效将严重影响驾乘人员的安全。为提高EPS系统的安全性与可靠性,基于功能安全标准建立EPS系统安全冗余机制:基于ISO26262对EPS系统进行研究,通过相关项定义、...电动助力转向(electric power steering,EPS)系统是车辆常用的转向执行器,其失效将严重影响驾乘人员的安全。为提高EPS系统的安全性与可靠性,基于功能安全标准建立EPS系统安全冗余机制:基于ISO26262对EPS系统进行研究,通过相关项定义、危害分析与风险评估(HARA),得到系统的功能安全目标与需求,并对其进行分配;设计EPS系统架构、容错机制,以提高系统的安全性;最后,对所设计的安全冗余机制进行台架试验。结果表明,在单侧桥驱芯片故障、单侧电机位置传感器故障、双侧电机位置传感器故障等故障注入的情况下,系统能够实现预期响应,满足功能安全目标,验证了所设计安全冗余机制的有效性。展开更多
The tracking performance of motor current is an important factor that affects the assistance torque of electric power steering （EPS） system. Bad tracking performance will cause assistant torque delay, and make road ...The tracking performance of motor current is an important factor that affects the assistance torque of electric power steering （EPS） system. Bad tracking performance will cause assistant torque delay, and make road feeling bad, and is influenced by the input steering torque and system measuring noise. However the existing methods have some shortages on system＇s robust dynamic performance and robust stability. The mixed H2/H∞ strategy for recirculating ball-type EPS system in a pure electric bus is proposed, and vehicle dynamic model of the system is established. Due to the existence of system model uncertainty, disturbance signals, sensor noises and the demand of system dynamic performance, the indexes of robust performance and road feeling for drivers are defined as the appraisal control objectives. The H∞ method is introduced to design the H∞ controller, and the H2 method is applied to optimize the H∞ controller, thus the mixed H2/H∞ controller is designed. The response of EPS system to the motor current command with amplitude of 20 A, the road disturbance with amplitude of 500 N and the sensor random noise with the amplitude of 1 A is simulated. The simulation results show that the recirculating ball-type EPS system with the mixed H2/H∞ controller can attenuate the random noises and disturbances and track the boost curve well, so the mixed H2/H∞ controller can improve the system＇s robust performance and dynamic performance. For the purpose of verifying the performance of the designed control strategy, the motor current tracking performance ground tests are conducted with step response input of the steering wheel, double-lane steering test and lemniscate steering test, respectively. The tests show that the mixed H2/H∞ controller for the recirculating ball-type EPS system of pure electric bus is feasible. The designed controller can solve the robust performance and robust stability of the system, thus improve the tracking performance of the EPS system and provide satisfied road feeling for the drivers.展开更多
Pressure ripples in electric power steering （EPS） systems can be caused by the phase lag between the driver s steering torque and steer angle, the nonlinear frictions, and the disturbances from road and sensor noise...Pressure ripples in electric power steering （EPS） systems can be caused by the phase lag between the driver s steering torque and steer angle, the nonlinear frictions, and the disturbances from road and sensor noise especially during high-frequency maneuvers. This paper investigates the use of the robust fuzzy control method for actively reducing pressure ripples for EPS systems. Remarkable progress on steering maneuverability is achieved. The EPS dynamics is described with an eight-order nonlinear state-space model and approximated by a Takagi-Sugeno （T-S） fuzzy model with time-varying delays and external disturbances. A stabilization approach is then presented for nonlinear time-delay systems through fuzzy state feedback controller in parallel distributed compensation （PDC） structure. The closed-loop stability conditions of EPS system with the fuzzy controller are parameterized in terms of the linear matrix inequality （LMI） problem. Simulations and experiments using the proposed robust fuzzy controller and traditional PID controller have been carried out for EPS systems. Both the simulation and experiment results show that the proposed fuzzy controller can reduce the torque ripples and allow us to have a good steering feeling and stable driving.展开更多
In this paper, the performance of a column-type electric power steering （EPS） system and vehicle has been studied and a detailed mathematical model for the system has been established. Based on the mathematic model ...In this paper, the performance of a column-type electric power steering （EPS） system and vehicle has been studied and a detailed mathematical model for the system has been established. Based on the mathematic model of the optimization design for steering feel, the parameters of the EPS system and vehicle on steering performance have been investigated. Moreover, the effects of the parameters on system stability have been analyzed and compared by the method of absolute sensitivity and the results are given in the end.展开更多
简单分析了电动助力转向(EPS)系统的结构与工作原理,介绍了EPS系统无刷直流电机(brushless DC motor,BLDC motor)的电路构成和控制方法。设计开发了采用单片机进行控制,车载蓄电池供电,用MOSFET构成的三相逆变器驱动的EPS控制系统的电...简单分析了电动助力转向(EPS)系统的结构与工作原理,介绍了EPS系统无刷直流电机(brushless DC motor,BLDC motor)的电路构成和控制方法。设计开发了采用单片机进行控制,车载蓄电池供电,用MOSFET构成的三相逆变器驱动的EPS控制系统的电控单元(ECU)。详细介绍了硬件电路和软件的设计,最终通过EPS台架实验,验证了所采用的PWM控制策略对EPS系统助力转向过程的有效控制。该系统实现简单,具有较强的实用性和经济性。展开更多
行车安全与驾驶员、车辆、道路等密切相关,而不同驾驶员个体之间的特性差异很大。文章将驾驶员分为A(熟练)、B(一般)、C(生手)3类,给定的行驶路径作为驾驶员模型的输入,转向盘转矩作为模型的输出;将A类驾驶员的输出转向盘转矩作为期望值...行车安全与驾驶员、车辆、道路等密切相关,而不同驾驶员个体之间的特性差异很大。文章将驾驶员分为A(熟练)、B(一般)、C(生手)3类,给定的行驶路径作为驾驶员模型的输入,转向盘转矩作为模型的输出;将A类驾驶员的输出转向盘转矩作为期望值,考虑不熟练驾驶员因对侧向力感知缺乏而导致的误操作转矩的影响,提出了一种跟踪期望驾驶特性的汽车电动助力转向系统(electric power steering,EPS)控制策略,建立了能够表征驾驶特性(熟练程度等)并考虑误操作转矩的驾驶员模型,与车辆组成人-车闭环系统。仿真结果表明,采用跟踪期望驾驶特性的汽车EPS控制策略,改善了汽车的操纵稳定性,减轻了驾驶员的转向负担,从而验证了该控制策略的有效性。展开更多
文摘电动助力转向(electric power steering,EPS)系统是车辆常用的转向执行器,其失效将严重影响驾乘人员的安全。为提高EPS系统的安全性与可靠性,基于功能安全标准建立EPS系统安全冗余机制:基于ISO26262对EPS系统进行研究,通过相关项定义、危害分析与风险评估(HARA),得到系统的功能安全目标与需求,并对其进行分配;设计EPS系统架构、容错机制,以提高系统的安全性;最后,对所设计的安全冗余机制进行台架试验。结果表明,在单侧桥驱芯片故障、单侧电机位置传感器故障、双侧电机位置传感器故障等故障注入的情况下,系统能够实现预期响应,满足功能安全目标,验证了所设计安全冗余机制的有效性。
基金supported by National Natural Science Foundation of China (Grant No. 51005115, No. 51005248)Science Fund of State Key Laboratory of Automotive Safety and Energy of China (Grant No. KF11201)
文摘The tracking performance of motor current is an important factor that affects the assistance torque of electric power steering （EPS） system. Bad tracking performance will cause assistant torque delay, and make road feeling bad, and is influenced by the input steering torque and system measuring noise. However the existing methods have some shortages on system＇s robust dynamic performance and robust stability. The mixed H2/H∞ strategy for recirculating ball-type EPS system in a pure electric bus is proposed, and vehicle dynamic model of the system is established. Due to the existence of system model uncertainty, disturbance signals, sensor noises and the demand of system dynamic performance, the indexes of robust performance and road feeling for drivers are defined as the appraisal control objectives. The H∞ method is introduced to design the H∞ controller, and the H2 method is applied to optimize the H∞ controller, thus the mixed H2/H∞ controller is designed. The response of EPS system to the motor current command with amplitude of 20 A, the road disturbance with amplitude of 500 N and the sensor random noise with the amplitude of 1 A is simulated. The simulation results show that the recirculating ball-type EPS system with the mixed H2/H∞ controller can attenuate the random noises and disturbances and track the boost curve well, so the mixed H2/H∞ controller can improve the system＇s robust performance and dynamic performance. For the purpose of verifying the performance of the designed control strategy, the motor current tracking performance ground tests are conducted with step response input of the steering wheel, double-lane steering test and lemniscate steering test, respectively. The tests show that the mixed H2/H∞ controller for the recirculating ball-type EPS system of pure electric bus is feasible. The designed controller can solve the robust performance and robust stability of the system, thus improve the tracking performance of the EPS system and provide satisfied road feeling for the drivers.
基金supported Foundation of National Development and Reform Commission of China (No. 2040)
文摘Pressure ripples in electric power steering （EPS） systems can be caused by the phase lag between the driver s steering torque and steer angle, the nonlinear frictions, and the disturbances from road and sensor noise especially during high-frequency maneuvers. This paper investigates the use of the robust fuzzy control method for actively reducing pressure ripples for EPS systems. Remarkable progress on steering maneuverability is achieved. The EPS dynamics is described with an eight-order nonlinear state-space model and approximated by a Takagi-Sugeno （T-S） fuzzy model with time-varying delays and external disturbances. A stabilization approach is then presented for nonlinear time-delay systems through fuzzy state feedback controller in parallel distributed compensation （PDC） structure. The closed-loop stability conditions of EPS system with the fuzzy controller are parameterized in terms of the linear matrix inequality （LMI） problem. Simulations and experiments using the proposed robust fuzzy controller and traditional PID controller have been carried out for EPS systems. Both the simulation and experiment results show that the proposed fuzzy controller can reduce the torque ripples and allow us to have a good steering feeling and stable driving.
基金Project supported by the National Natural Science Foundation of China (Grant No.60674067)the Scientific and Techno-logical Foundation of Hubei Province (Grant No.2006AA101B13)
文摘In this paper, the performance of a column-type electric power steering （EPS） system and vehicle has been studied and a detailed mathematical model for the system has been established. Based on the mathematic model of the optimization design for steering feel, the parameters of the EPS system and vehicle on steering performance have been investigated. Moreover, the effects of the parameters on system stability have been analyzed and compared by the method of absolute sensitivity and the results are given in the end.
文摘简单分析了电动助力转向(EPS)系统的结构与工作原理,介绍了EPS系统无刷直流电机(brushless DC motor,BLDC motor)的电路构成和控制方法。设计开发了采用单片机进行控制,车载蓄电池供电,用MOSFET构成的三相逆变器驱动的EPS控制系统的电控单元(ECU)。详细介绍了硬件电路和软件的设计,最终通过EPS台架实验,验证了所采用的PWM控制策略对EPS系统助力转向过程的有效控制。该系统实现简单,具有较强的实用性和经济性。
文摘行车安全与驾驶员、车辆、道路等密切相关,而不同驾驶员个体之间的特性差异很大。文章将驾驶员分为A(熟练)、B(一般)、C(生手)3类,给定的行驶路径作为驾驶员模型的输入,转向盘转矩作为模型的输出;将A类驾驶员的输出转向盘转矩作为期望值,考虑不熟练驾驶员因对侧向力感知缺乏而导致的误操作转矩的影响,提出了一种跟踪期望驾驶特性的汽车电动助力转向系统(electric power steering,EPS)控制策略,建立了能够表征驾驶特性(熟练程度等)并考虑误操作转矩的驾驶员模型,与车辆组成人-车闭环系统。仿真结果表明,采用跟踪期望驾驶特性的汽车EPS控制策略,改善了汽车的操纵稳定性,减轻了驾驶员的转向负担,从而验证了该控制策略的有效性。
