融合线控转向功能的汽车鲁棒滑模转向及横摆稳定性控制研究

Steer-by-Wire (SbW) system which is currently a hot and leading-edge topic in intelligent automotive steering research is an essential technology for realizing the vehicle high precision steering and yaw stability control. However, due to the complex nonlinear dynamical relationship of vehicles, researchers now are facing many challenges in theory and technology. This research is devoted to studying robust sliding mode-based steering and yaw stability control strategies based on the premise of unknown road conditions and vehicle dynamic parameters. Fast nonsingular terminal sliding mode and variable gain super-twisting sliding mode control algorithms will be designed, in order to overcome the shortcomings of existing steering control methods and improve the steering performance of the closed-loop system under the conditions of parameter uncertainties and road disturbances. Adaptive sliding mode control and sliding mode learning control algorithms will be proposed for the SbW equipped vehicle yaw stability control, with the aim of ensuring the closed-loop stability of yaw error dynamics with unknown vehicle lateral dynamic parameters. The developed control theories and methods will be validated on the SbW experimental platform and experimental car. This research will provide innovative idea and general strategy for the steering control and yaw stability control of SbW equipped vehicle, and also have an important reference for the application of sliding mode control theory to the vehicle SbW and yaw stability control systems.

线控转向系统是目前汽车智能转向研究的热点和前沿，是实现汽车高精度转向及横摆稳定性控制的关键技术。然而，由于车辆复杂的非线性动力学关系，在设计汽车转向及横摆稳定性控制过程中，研究人员面临着许多理论和技术上的挑战。本项目将致力于在路面条件和汽车动力学参数未知的前提下，研究基于鲁棒滑模控制的汽车转向及横摆稳定性控制策略。拟设计快速非奇异终端滑模及可变增益超螺旋滑模控制算法，克服现存转向控制算法的不足，改善闭环系统在参数摄动和路面干扰条件下的转向性能。拟设计用于整车横摆稳定性控制的自适应滑模和滑模学习控制算法，确保闭环横摆角速度误差动力学在横向动力学参数未知条件下的稳定性。控制理论和方法将在线控转向实验平台及实验样车上得到验证。本研究为线控转向汽车的转向控制和横摆稳定性控制问题提供新思路和通用策略，对滑模控制理论在汽车线控转向及稳定性控制系统中的应用具有重要借鉴意义。

本项目致力于线控转向系统动力学模型构建、汽车鲁棒滑模转向控制和横摆稳定性控制算法设计等方面的研究，从而可以借助滑模控制算法解决现存算法无法消除复杂路面条件和系统参数大范围变化对转向系统及车辆动力学系统影响的难题，提高转向精度及车辆稳定性。具体分为三个步骤开展设计。首先对线控转向系统与转向电机、齿轮齿条转向机构和转向前轮各部分之间的动力学关系，利用等效建模方法，将转向前轮看作是由齿轮齿条转向机构连接的转向电机负载，建立线控转向系统二阶等价数学模型，为后期算法设计设计奠定基础。其次提出鲁棒滑模和积分终端滑模控制算法，对系统参数精度要求低，减少使用外部传感器的同时，可实现复杂外界干扰和系统参数不确定性条件下的高精度控制和快速收敛；提出鲁棒自适应滑模、基于不确定观测器的连续快速非奇异终端滑模和基于不确定观测器的鲁棒自适应积分终端滑模控制算法，此类算法保证在系统参数不确定和扰动存在情况下，系统具有良好的暂态和稳态跟踪性能和抗干扰能力。最后，本项目所提出的控制理论和方法在线控转向实验平台及实验样车上得到验证，为线控汽车的转向及稳定性控制系统的应用提供了重要借鉴意义。