【作者】 刘峰；

【导师】 李殿起；

【作者基本信息】 沈阳工业大学 ， 机械， 2025， 硕士

【摘要】 线控转向系统通过取消方向盘与转向轮间的刚性连接,可以实现转向过程中力传递特性和角传递特性的独立设计,从而显著提升“人-车-路”闭环系统的操纵稳定性、驾驶舒适性以及主动安全性。基于以上内容,本文在分析国内外研究现状的基础上,以Car Sim中的B级车为研究对象,对路感模拟与理想传动比进行了研究,主要工作内容如下:首先,分析线控转向系统的组成与工作原理。基于降解建模方法,构建了包含方向盘模块、路感电机、转向执行机构的动力学模型,并采用Matlab/Simulink与Car Sim软件相结合的方式,对线控转向系统的动态特性进行研究。通过角阶跃、双移线及双纽线工况测试,验证了模型的动态响应精度,其横摆角速度峰值误差小于2.5%,侧向加速度稳态偏差为0.05g,为后续控制算法的设计与验证提供了可靠的仿真环境。其次,进行路感模拟算法的研究。提出一种以驾驶员偏好为基础的方向盘力矩计算模型。综合考虑方向盘转角、车速及侧向加速度的动态耦合关系,并引入摩擦补偿、阻尼调节及限位控制等多维度补偿机制。通过标准测试工况的仿真表明,本文提出的路感算法在低速时转向力矩波动较小,高速工况下反馈力矩清晰度提升15%。再次,在保证车辆横摆角速度增益不变的基础上,对理想传动比进行了研究。结合模拟退火算法对增益参数进行全局优化,并在高速区间引入模糊控制策略,实现传动比的自适应调节。仿真结果表明,优化后的传动比在双移线工况下跟踪误差降低23%,高速稳定性提升20%,横摆角速度超调量减少5%。最后,为了确保路感电机能够快速有效地实现路感仿真和方向盘的回正,本文着重研究了汽车转向和回正两个环节的控制策略。考虑到车辆在行驶过程中容易受到外界干扰,提出了一种PID控制方法对转向过程中的路感模拟进行控制。仿真结果显示,本文所提出的控制策略,可在较短时间内完成路感模拟,跟踪精度达98.5%以上。针对回正过程的非线性特性,应用反步法来对汽车回正过程进行控制,并将其与常规PID控制相比较。模拟实验表明,该控制策略可以有效地避免在低速状态下的回正不足和在高速状态下的回正超调问题。更多还原

【Abstract】 By eliminating the rigid connection between the steering wheel and the steering wheel,the steering-by-wire system realizes the independent design of the force transmission characteristics and angle transmission characteristics in the steering process,thus significantly improving the handling stability,driving comfort and active safety of the closed-loop system of“human-vehicle-road”.Based on the above,this thesis analyzes the current research situation at home and abroad and takes the B-class car in Car Sim as the research object to study the road sensing simulation and ideal transmission ratio,and the main contents are as follows:Firstly,we study the composition and working principle of the steering-by-wire system.Based on the degradation modeling method,a dynamics model containing the steering wheel module,road-sensing motor,and steering actuator is constructed,and the dynamic characteristics of the steering-by-wire system are studied by combining Matlab/Simulink and Car Sim software.The dynamic response accuracy of the model is verified through the angular step,double-shift line and double-newline condition tests,and the peak error of its transverse angular velocity is less than 2.5%,and the steady-state deviation of lateral acceleration is 0.05g,which provides a reliable simulation environment for the design and verification of the subsequent control algorithms.Secondly,the research of road sensing simulation algorithms is carried out.A steering wheel moment calculation model based on driver preference is proposed.The dynamic coupling relationship among steering wheel angle,vehicle speed and lateral acceleration is comprehensively considered,and multi-dimensional compensation mechanisms such as friction compensation,damping adjustment and limit control are introduced.Simulation-based on standard test conditions shows that the road sensing algorithm proposed in this thesis has less fluctuation of steering torque at low speeds,and the clarity of feedback torque is improved by15%at high speeds.Once again,on the basis of ensuring the constant gain of vehicle yaw rate,the ideal transmission ratio was studied.Combined with the simulated annealing algorithm to globally optimize the gain parameters,and introduce a fuzzy control strategy in the high-speed interval to realize the adaptive adjustment of the transmission ratio.The simulation results show that the optimized transmission ratio reduces the tracking error by 23%under the double-shift line condition,improves the high-speed stability by 20%,and reduces the overshoot of the transverse angular velocity by 5%.Finally,to ensure that the road-sensing motor can quickly and effectively realize the road-sensing simulation and steering wheel correction,this thesis focuses on the control strategy of the two links of vehicle steering and correction.Considering that the vehicle is easy to be disturbed by the outside world in the process of traveling,as well as the changes of the internal parameters of the vehicle.A PID control method is proposed to control the road sense simulation in the steering process.The simulation results show that the control strategy proposed in this thesis can complete the road-sense simulation in a shorter time,and the tracking accuracy reaches more than98.5%.Aiming at the nonlinear characteristics of the steering back process,the backstepping method is proposed to control the car steering back process,and it is compared with the conventional PID control.Simulation experiments show that the control strategy can effectively avoid under correction at low speeds and overcorrection at high speeds.更多还原