商用车电液复合转向系统的车道保持策略

Lane-keeping Assistance Strategy for Integrated Electric-hydraulic Steering System of Commercial Vehicles

为了提高商用车的行驶安全性,避免因驾驶人的分心驾驶出现车辆偏离车道的问题,提出一种基于电液复合转向系统的商用车车道保持策略;在建立电液复合转向系统模型、二自由度车辆模型、预瞄驾驶人模型的基础上,设计基于驾驶人在环的MPC和ADRC串级的车道保持控制策略。首先,采用MPC算法将车辆横向位置控制的最优问题转化为二次规划求得目标前轮转角;然后,考虑电液复合转向系统的不确定和干扰问题,利用ADRC算法对目标转向盘转角和实际驾驶人的转向盘转角差值以转矩信号的形式进行补偿。同时研究车道保持系统对驾驶人的干预问题,引入干预系数的概念,采用模糊控制的方法,将驾驶人手力和车辆的运动状态作为输入变量,干预系数作为输出变量,保证整车行驶安全性的前提下减小车道保持辅助系统对驾驶人的干预。最后,通过MATLAB/Simulink仿真和硬件在环试验对所设计的控制策略进行验证。研究结果表明:所设计的基于商用车电液复合转向系统的车道保持策略能够及时地纠正因驾驶人的分心驾驶而导致车辆偏离所在行驶车道的行为,特别是在弯道处出现驾驶人转向不足或过度转向的情况时,能够将车辆维持在车道线之内,保证车辆的行驶安全性,同时由于干预系数的设计,使得驾驶人也有良好的人机交互体验感。

To improve the driving safety of commercial vehicles and avoid lane deviations owing to distracted driving,a lane-keeping assistance strategy for commercial vehicles based on an integrated electric-hydraulic steering system(IEHS)was proposed.Using this model,a two-degree-of-freedom vehicle and preview-driver model,a lane-keeping assistance control strategy based on driver-in-loop MPC and ADRC cascade was designed.First,the MPC algorithm was used to transform the optimal control of vehicle lateral position into a quadratic programming problem and obtain the target front-wheel angle.Then,considering the uncertainty and interference of the IEHS,the ADRC algorithm was used to compensate for the difference between the target steering-wheel angle and the actual steering-wheel angle in the form of a torque signal.Moreover,the intervention of a lane-keeping assistance system was studied,the concept of intervention coefficient was introduced,a fuzzy control method was adopted,the driver’s hand force and vehicle motion state were used as input variables,and the intervention coefficient was used as the output variable to reduce the intervention of the lane-keeping auxiliary system on the premise of ensuring vehicle driving safety.Finally,the proposed control strategy was verified using MATLAB/Simulink simulations and hardware-in-the-loop tests.The results demonstrate that it can timely correct line deviations caused by distracted driving,particularly when the driver understeers or oversteers at corners,and can keep the vehicle in its travel lane,ensuring driving safety.Furthermore,the intervention coefficient is useful for positive human-machine interaction.