基于车轮转矩的四轮转向模糊控制策略研究

发布时间：2018-05-04 00:23

本文选题：四轮转向 + Carsim模型　；参考：《北京理工大学》2016年硕士论文

【摘要】：四轮转向技术以提高汽车的运动特性为目的,是现代汽车控制技术之一,其主要作用在通过对后轮转角的控制,提高汽车低速工况下的转向灵活性,高速工况下的操纵稳定性,提高了对开路面时的制动性。本文以常见的商务车作为研究对象,在分析了汽车转向原理特性的基础上,对研究车轮转矩对侧偏力以及轮胎侧偏角的影响,进而通过探讨车轮转角的模糊控制策略,改善汽车操纵稳定性的方法。主要内容包括:(1)本文对建立动力学模型的方法进行了介绍并研究。利用牛顿矢量力学体系的动量、动量矩定理及牛顿第二定律在Matlab/Simulink里建立了考虑了车轮转矩输入和轮胎非线性的八自由度模型。将建立好的模型与通过虚拟样机软件Carsim建立的整车动力学模型进行对比,验证了利用牛顿矢量力学体系建立的动力学模型的正确性。(2)分析了汽车失去稳定性的原因,并研究了轮胎纵向力与侧偏力之间的关系。对前轮驱动非线性八自由度汽车模型进行仿真,并与无车轮转矩的整车模型进行对比,分析车轮转矩对汽车操纵稳定性的影响。并在驱动、转向联合工况下,对汽车的转向性能进行了研究。(3)分析二自由度四轮转向动力学模型,并以此为基础,分析了四轮转向的转向特性。研究了模糊控制的控制策略。利用Matlab为模糊控制器搭建了控制四轮转向的模糊控制算法,并与其他的控制方法进行对比。最后,得出前馈模糊联合控制器的控制策略在提高汽车安全性及稳定性上的效果最优的结论。
[Abstract]:The four-wheel steering technology is one of the modern vehicle control technologies, which aims to improve the motion characteristics of the vehicle. Its main role is to improve the steering flexibility at low speed and the handling stability at high speed through the control of the rear wheel rotation angle. The braking performance of the off-road is improved. On the basis of analyzing the characteristics of automobile steering principle, this paper studies the influence of wheel torque on the side deflection force and tire side deflection angle, and then discusses the fuzzy control strategy of wheel rotation angle. A method for improving the handling stability of a car. The main contents include: (1) this paper introduces and studies the method of establishing dynamic model. Using the momentum, moment of momentum theorem and Newton's second law of Newtonian vector mechanics system, an eight-degree of freedom model considering wheel torque input and tire nonlinearity is established in Matlab/Simulink. By comparing the established model with the whole vehicle dynamics model established by virtual prototyping software Carsim, the correctness of the dynamic model established by Newton vector mechanics system is verified. (2) the reason of vehicle losing stability is analyzed. The relationship between tire longitudinal force and lateral deflection force is also studied. The nonlinear eight degree-of-freedom vehicle model of front wheel drive is simulated and compared with the model without wheel torque to analyze the influence of wheel torque on vehicle handling stability. Under the combined driving and steering conditions, the steering performance of the vehicle is studied. (3) the dynamic model of two-degree-of-freedom four-wheel steering is analyzed, and the steering characteristics of the four-wheel steering are analyzed on the basis of this model. The control strategy of fuzzy control is studied. A fuzzy control algorithm for four wheel steering is constructed by using Matlab for fuzzy controller and compared with other control methods. Finally, the conclusion that the control strategy of the feedforward fuzzy joint controller is optimal in improving the safety and stability of the vehicle is obtained.
【学位授予单位】：北京理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U463.4

【相似文献】