【作者】 陈光；

【导师】 韩振南；

【作者基本信息】 太原理工大学 ， 车辆工程， 2011， 硕士

【摘要】 四轮转向技术做为当代汽车发展的一个重要方向,通过对汽车的前轮转向和后轮转向同时控制来改善汽车的转向特性,四轮转向车辆的操纵稳定性得到了很大的提高。本文以四轮转向车俩的模型建立和控制策略为研究对象,讨论了四轮转向技术在操纵稳定性方面的特性。本论文的主要研究内容如下：因为轮胎的非线性对车辆的操纵稳定性有很大影响,由于在Simul ink中轮胎模型建模非常困难,所以本文通过利用多体动力学仿真软件ADAMS建立基于虚拟样机技术的整车模型,然后在MATLAB/Simulink环境下建立四轮转向神经网络的控制模型,并将虚拟样机模型与神经网络控制模型相结合,利用模糊理论对质心侧偏角进行控制,从而构成研究四轮转向车辆的联合仿真模型。建立的程序如下：首先,建立四轮转向车辆的控制系统模型,运用神经网络算法训练得到四轮转向车辆后轮控制器,实现车辆转向行驶时按照一定的控制方法对后轮转角大小的控制。其次,利用模糊控制理论对整车的质心侧偏角进行PID控制,使车辆系统的操纵稳定性得到控制,并且车辆具有较好的适应性。再次,在ADAMS软件中ADAMS/Vi ew环境下建立整车动力学模型,动力学模型包括汽车的车身、轮胎模型、悬架系统、路面模型及转向执行机构。之后,输入一定的前轮转向角和一定的车速,利用不同的四轮转向控制方法,对机械系统和控制系统进行联合仿真并比较分析,从而得出质心侧偏角、横摆角速度在不同的控制算法下的效果图,比较得到联合仿真控制策略的有效性和可靠性。最后,通过参数的变化分析得到整车质量、质心位置对操纵稳定性的影响,得出控制系统有比较好的稳定性和适应性。综上所述,通过仿真结果可以看出联合仿真比前轮转向、四轮转向比例控制、四轮转向反馈控制、以及横摆角速度控制有较好的操纵稳定性,可以为四轮转向车辆的理论研究提供一些思路。更多还原

【Abstract】 Four-wheel steering technology as a contemporary automobile development, through an important direction of car front wheel steering wheel steering control and at the same time to improve cars, and the vehicle steering control stability of had been improved. Based on the model with four-wheel steering and control strategies for research object, discussed the four-wheel steering in handling stability superiority.The main contents this thesis can be summarized as follows: Because of the nonlinear tire of vehicle has a great influence in handling stability, but it is difficult to model in Simulink,, therefore this paper by using dynamics simulation software ADAMS establishes vehicle model based on virtual prototype technology, then establish four-wheel steering model by neural network in MATLAB/Simulink, and unite virtual prototyping model with neural network model, and by using fuzzy theory control the sideslip angle. so the model of four-wheel steering united can be made. Program is as follows;Firstly, four-wheel steering control system model can be established, and through the neural network training rear controller of four wheel steering vehicle can be got, and then realize vehicle steering according to certain control method to rear steering.Secondly, by using fuzzy theory control the sideslip angle with PID, and make the handling stability of vehicle system controlled, and vehicle has better adaptability.Again, establish the vehicle dynamic model in ADAMS/View, which include body, tire model, suspension system, road model and steering。 After that, using different four-wheel steering control method, analysis the mechanical system united with control system under the input of certain front wheel steering angle and certain speed and compare with them, thus draws sideslip angle and yaw velocity, gets the validity and reliability compared with the united simulation control strategyFinally, through changing the parameters can obtained the influence which vehicle quality and the position of centroid made, the result show control system has a good stability and adaptability.To sum up, through the simulation results that co-simulation has good control stability than front wheel steering, proportional control four-wheel steering, feedback control four-wheel steering, and yaw velocity control for four-wheel steering vehicles, which can provide theoretical studies of some ideas.更多还原