【作者】 张缓缓；

【导师】 王庆年；

【作者基本信息】 吉林大学 ， 车辆工程， 2009， 博士

【摘要】 在能源与环境的双重压力下,电驱动车辆已经成为当前汽车工业的发展趋势,电动轮驱动汽车更成为汽车领域的研究重点。本文分析了电动轮驱动车辆的关键技术,结合国内外的研究现状,将整车转矩协调控制作为研究的切入点和突破口,主要进行了以下研究:首先建立了电动轮驱动电动车仿真平台。该平台能够在驾驶员模型的转向角和油门踏板输入下,准确反映车辆运行的路径和姿态,并能进行路径跟踪。针对目前电机性能的现状,分析了电机输出转矩的稳态和动态误差对车辆直线行驶稳定性的影响,利用横摆角速度作为判据,实现对直线行驶过程中的驱动转矩进行协调控制,保证车辆直线行驶的稳定性。分析了车辆在转弯行驶过程中的能量消耗特点。在深入研究车辆的转弯行驶阻力之后,提出了车辆准中性转弯节能行驶模式。并以车辆滑移功率最小为优化目标,以车辆运动方程为约束条件,进行了车辆转矩协调控制,通过动态分配驱动转矩,改善汽车行驶过程中的能量分配,达到节省能量的目的。基于稳定性为目标的转矩协调控制系统。依据车辆横摆角速度的误差为判据,来估算车辆的行驶姿态。通过单轮或多轮控制使车辆的行驶姿态与路径达到最佳,并用BP神经网络方法实现了整车的驱动转矩差动分配。在制动力干涉之前结合驱动力控制,采取驱动转矩协调控制,减少制动力在主动安全控制中的参与范围,可以起到减少能量损耗的作用。最后以威乐三厢车为基础,建立电动轮驱动的理论研究与试验平台,利用dSPACE作为整车控制器,来验证所提的控制方法的正确性。本文提出的多目标的转矩协调控制系统可作为电动轮驱动领域研究的重要理论基础与参考,对掌握采用电动轮驱动的电动车的关键技术和形成自主开发能力具有重要的指导意义。更多还原

【Abstract】 Nowadays the Electric Vehicles (EV) is the effective way to keep a sustainable development model under the pressure of the protection of natural environment and the growing shortage of oil resource for automobile industry. The vehicle driven by in-wheel motor has attracted quite a few researchers and development for its key technology in variants electric vehicle than ever before. Recently the in-wheel motor driving vehicle has been widely studied and applied by local car makers because of advantage such as flexible layout, independent control and well vehicle dynamics performance. Now many OEM has designed their concept in in-wheel motor driving vehicle such as Tianjin FAW and lots of in-wheel motor products such as Siemens and TM4, but the key technology is still in the process of forward. This paper is focus on the ECU of Torque Coordinate Control System based on the project of HTRDP 863 program. After reviewed the current status of in-wheel motor driving vehicle technology, we present the principle of energy saving and Torque Coordinate Control System.The study field on the Torque Coordinate Control System is summarized. Compared with the conventional electric vehicle, original transmission and mechanical system are disappeared and DOF of driven wheels of the in-wheel driving vehicle increased which brings the new question, e.g. electric differential, which enlarge the space of Electric Control Integration Process. The target of the torque coordinate strategy is designed to solve these questions caused by in-wheel motor. It contains the single motor torque control/ torque coordinate between wheels and axles/multi motor control model to ensure the safety/stability/energy saving for in-wheel motor vehicle. Below is the main content.In this paper, a 9-DOFs dynamics model is described as a muti-body system for offline model system simulation and validation. The basic model components are briefly below: 5-DOFs vehicle body except for vertical direction motion and 4 DOFs of four wheels rotation motion. Tire model is extremely important to torque Coordinating system as it describes all the governing forces and torques between the vehicle and the road surface. The author used the Uni-tire model which created by academician Mr KH Guo, the motor model is the brushless DC type and the driver model can pre-drive the desire lateral acceleration through single point trace method. All the sub function models are built in the matlab/simulink envir. With the order of the steering angle and gas pedal from driver model, vehicle simulator can simulate vehicle trace and pose of different driving maneuver, and target trace following can be conduct on this simu-platform. The simulation result is validated via Cruise soft environment.Acc. to the current tech status of in-wheel motor in nation, the torque response uniformity performance is discussed in detail. The error of the torque response is divided into static/dynamic respectively. The vehicle Straight Line (SL) stability caused by the static/dynamic error is analyzed. The author creates an Active Compensation Control Strategy (ACCS) to control the error to the single motor. The simulation and testing results demonstrate the ACCS is validity. But this control method ignored the cost of getting control parameter. So from the view of vehicle control, the control strategy realize the SL stability control wheels using the Yaw Rate as a rules for vehicle with difference torque output on the driven is proposed. In additional, we discuss the SL stability cause by response fluctuate of driven in-wheel motor.Due the capability of energy loaded is lower than conventional vehicle, how to effective use energy on the electric vehicle platform is another key technology. After review the research result of energy saving strategy for in-wheel motor system, we put more research on steering condition. First, energy flow characteristic is analyzed for driven axle base on the resistance force. A creative method quasi-neutral steering is proposed for vehicle turning. This method is validate on the simulator by FWD and 4WD driven model, it also achieve a good result under constant speed and acceleration maneuver.The wheel slip ratio indicates how much power is waste between driven motor and tire. From the point of power transmitted, the slip is smaller the power loss is lower. In this part, we take optimized wheel slip as required target and vehicle motion equation as limit to conduct Torque Coordinating Control System and dynamics distribute the driven torque to get the energy saving through the power flow control.Through compared the active safety system of conventional vehicle and in-wheel motor drive vehicle, a new range is defined in term of ABS/TC/ESP system on new platform which property of driven torque can be control independent acc. to variants objective. This allows the Torque Coordinating Control System working and keeping vehicle at bigger stability rang before ESC system active. The Torque Coordinating Control System can manage the vehicle driving pose using error of yaw rate as reference variable. Also it can be achieved the driving torque differ distribution by BP neural network via the way of highly efficient signal driven wheel control or multi driven wheels coordinating control. In addition, it decreased the brake energy loss by compress the ranges of active safety intervene through the proposal Torque Coordinating Control System.Finally, the independent driven platform system for validation and strategy testing has built using the Weile Hatchback passenger car. For achieved high quality result, the Torque Coordinating Control System is validated within the virtual HIL environment including DSPACE controller, actuator of the driven motor and a real car. The compensation control strategy is validated on this platform. The performance is satisfactory because the Torque Coordinating Control System is based on the motor accurately, fast and precisely responding.The main contribution of this dissertation is that designed a Torque Coordinating Control System for in-wheel motor driving electric vehicle. The conclusion of this paper can be as a theory instruction of torque coordinating control field. It also has the positive significance to master the key technology and get the ability to develop independently for auto industry.更多还原