【作者】 杨福广；

【导师】 李贻斌；

【作者基本信息】 山东大学 ， 控制理论与控制工程， 2010， 博士

【摘要】 全轮独立驱动独立转向(AWID/AWIS, All-wheels-independent-drive & steering vehicle)车辆是一种所有车轮均可独立驱动、独立转向的先进车辆。与传统车辆相比较,它具备更多、更灵活的转向驱动模式；每个车轮均可工作在最佳滑移率区间,能向车辆提供最优驱动力；通过车轮转向-驱动协调控制,可显著改善车辆的动力性、操纵性和安全性；AWID/AWIS车辆代表了未来高级车辆、军用车辆、无人驾驶车辆和大型高速高机动轮式移动机器人的发展方向。本论文结合在研的863项目,对AWID/AWIS车辆中最具有代表性的四轮独立驱动-独立转向(4WID/4WIS)电动车辆的防滑控制系统、动力学横摆稳定性控制以及与此密切相关的路面利用附着系数估计和路面识别问题进行了研究。论文的主要工作如下：1.论文首先建立了三个不同模型：四分之一车辆动力学模型、线性2自由度转向模型以及非线性的九自由度整车动力学模型,分别用于防滑系统设计、横摆稳定性控制系统的参考模型设计以及控制算法验证。2.把轮胎与地面之间的作用力作为系统的扩张状态,设计了二阶非线性扩张状态观测器。利用扩张状态观测器对轮胎与地面间的纵向力和轮速进行观测。在此基础上,计算出路面的当前利用附着系数,并根据已知的轮胎μ-s曲线信息,实时的对路面进行识别。避免了直接通过动力学方程计算而引入噪声和使用传感器测量路面特征带来的成本提高。驱动过程以及制动过程的仿真结果表明,本论文的方法在各种典型的路况以及突变的路况下均具有很强的鲁棒性和准确性。3.针对车辆防滑系统(包含驱动防滑系统和制动防抱死系统)的不确定性以及非线性特点,将自抗扰控制技术引入到车辆的防滑控制中。设计了跟踪目标滑移率的防滑控制系统,达到了制动防抱死和驱动防滑的目的。采用了遗传算法对控制器参数进行整定。各种工况下仿真结果表明：基于自抗扰技术的防滑系统对于外部扰动以及内部参数摄动均具有很强的鲁棒性。在路面识别的基础上,进一步的设计了对路面具有自适应功能的制动防抱死系统。该系统根据路面识别的结果实时的自动调整目标滑移率,达到了制动过程中充分利用地面附着力的目的。4.在高速转向的过程中,轮胎的侧偏角较大而进入侧偏特性的非线性区。利用线性2自由度模型设计的车辆横摆稳定性控制系统在轮胎的非线性区工作时将具有一定局限性。针对这一问题,基于4WID／4WIS动力学参数建立轮胎侧偏力与侧偏角之间非线性关系模型和4WID／4WIS车辆非线性2自由度模糊T-S模型,并进行了模型验证；采用模糊线性二次型最优控制设计了集成主动前轮转向、主动后轮转向、直接横摆力矩控制的车辆动力学横摆稳定性控制系统。仿真结果表明所建非线性模型的正确性和控制方法的鲁棒性。5.在无法获得4WID／4WIS车辆动力学参数的情况下,对侧偏角与横摆角速度之间的耦合性进行了分析,提出“当|β|比较小时以理想横摆角速度跟踪控制为主,当|β|比较大时以抑制质心侧偏角过大为主”的控制策略,利用模糊控制技术设计集成主动前轮转向、主动后轮转向和直接横摆力矩的横摆稳定性控制器,并利用九自由度车辆模型对上述控制方法有效性进行了仿真验证。6.简要介绍了样机的控制系统,通过实验验证了本文制动防滑控制方法以及集成的横摆稳定性模糊控制方法的有效性。本文成果也可以推广用于其它不同轮数的AWID/AWIS车辆动力学的控制,具有较好的普适性。更多还原

【Abstract】 AWID/AWIS is a kind of advanced vehicle of which all-wheels can be driven and steered independently. Compared with traditional vehicle, AWID/AWIS vehicle has more and flexible steering and driven style. For example, each wheel can be driven with optimization slip rate and provide optimization force, which can improve the maneuverability, dynamic performance and safety of vehicle by controlling the steering and driving coordinated. It is the development tendency of advanced vehicle, military vehicle, unmanned vehicle and wheel mobile robots with high speed in the future.Supported by the 863 projects, the 4WID/4WIS vehicle, which is the most typical vehicle of AWID/AWID, is studied in this paper. The research contents of this paper include:Anti-skid system, vehicle dynamic stability control system of 4WID/4WIS, and the method for estimation of utilization adhesion coefficient and road identification, which is strongly associated with Anti-skid and VDC.The main work of this paper is as follows:1. Firstly, three models were built, which were a quarter dynamic model of vehicle, linear dynamic model with two freedoms for steering, and nonlinear dynamic model with nine freedoms for the whole vehicle. They were used for Anti-skid system design, the reference model of yaw stability controller and control algorithm verification.2. By considering the force between the tire and road as an extended state of the system, a nonlinear second-order Extend State Observer was proposed. The longitudinal force was observed by ESO, so the utilization adhesion coefficient was estimated and the road was identified by curve of tire real time. This method avoided the noise caused by direct calculation, and cut back the cost of the sensor for measuring the road. Simulation of driving and braking indicated that this method is robust and accurate under typical road conditions and abrupt road changes.3. According to the uncertainty and nonlinearity of Anti-skid system (include Anti-lock Braking and Anti-Slip Reguration), Active Disturbance Rejection Control was introduced to design ABS and ASR system, whose target were to trace the anticipant slip ratio. Genetic algorithm was adapted for adjusting the parameters of ADRC controller. Simulation of some conditions indicated that ABS and ASR based on ADRC are robust to parameters perturbation and external disturbances. The ABS system which can be adaptive to road was designed based on foregoing works. It regulates anticipant slip rate during the braking process according to the result of road identification. And it takes full advantage of the forces between road and tire during braking process.4. During the process of steering with high speed, the side slip angle of tire is larger and in nonlinear cornering properties regional, the controller designed on linear model with two freedoms would has some limitation. To solve this problem, nonlinear cornering properties of tire model and nonlinear 4WID/4WIS vehicle model with two freedoms of vehicle were built based on parameters of 4WID/4WIS, the validation of these models were testified in succession. An Integrated yaw stability controller composed of Active Front Wheel Steering, Active Rear Wheel Steering and Direct Yaw moment Control were designed, Fuzzy Linear quadratic regulator was adopted in this controller. Simulation results indicated the validity of the nonlinear model and the robustness of control method.5. Sometimes parameters of 4WID/4WIS can not obtained. After analyzing the coupling relationship between vehicle side slip angle and yaw rate, a fuzzy yaw stability controller composed of AFS, ARS and DYC was designed based on the strategy ’when|β| is small, the main aim is to follow the anticipant yaw rate, and when|β| is big, the main aim is to reduce vehicle side slip angle’. Contrasting simulation results based on nine freedoms model indicated the validity and feasibility of this method.6. The configuration of the control system was introduced briefly. The validity of yaw stability control system and ABS control method proposed in this paper were proved by experiment.Achievements of this paper possess preferable applicability, and they can be popularized and applied on other AWID/AWIS vehicle with different number of wheels.更多还原