汽车横摆与侧倾稳定性集成控制研究

发布时间：2018-02-28 08:10

本文关键词： 横摆稳定性侧倾稳定性相平面切换控制集成控制　出处：《吉林大学》2016年硕士论文　论文类型：学位论文

【摘要】：近年来,日益复杂的交通环境导致了交通事故的频繁发生,其中车辆的侧翻和侧滑事故已经成为人类生命和财产安全的主要威胁。考虑二者具有强烈的耦合性,本文以前轮转角和轮胎制动力为控制变量,对车辆的横摆和侧倾运动进行控制。首先针对车辆横摆运动的稳定性能需求,利用李雅普诺夫第二稳定性判定方法对参考的横摆角速度进行了规划,确定了不同车速和摩擦系数下质心侧偏角相轨迹稳定边界的三维map。此外为了满足车辆侧倾运动的稳定性能需求,采用侧向载荷转移率和侧倾预警时间作为车辆动态侧翻指标。然后在车辆横摆和侧倾稳定性同时满足的控制需求下,采用模型预测控制策略,选取附加前轮转角和四个轮胎的制动力为优化变量,通过选择不同的目标函数和约束条件,设计了车辆横摆与侧倾切换控制系统,系统包含了四种控制模式,即单纯横摆控制模式、单纯侧倾控制模式、无控制模式以及横摆和侧倾综合控制模式。根据当前车辆测量系统反馈回来的状态信息和车辆系统的参考状态,判断出相应的控制模式,优化出最优的控制变量,并分别将其中的附加前轮转角作用于转向执行机构,将各轮胎制动力通过线性变换转换为相对应的轮缸制动压力作用于制动执行机构。为了验证所设计的切换控制系统的效果,选择红旗HQ430车辆动力学模型作为被控对象,在给定的工况下进行了离线仿真实验。仿真结果证明,切换控制器虽然能够保证车辆的横摆和侧倾稳定性,但在极限工况下,车辆系统状态会随着控制模式的频繁切换而抖动,这不仅会加剧执行机构的磨损,也会会影响驾乘人员的乘坐舒适性。为了避免由于控制模式的切换而导致系统抖动的问题,本文采用模型预测控制的方法设计了一种车辆稳定性集成控制系统。在综合考虑车辆稳定性能和安全性能约束的基础上,将横摆稳定性需求和侧倾稳定性需求统一在目标函数中,为了满足不同工况下车辆对横摆稳定性和侧倾稳定性的要求,选择模糊控制策略对目标函数中的权重系数进行实时调整。通过求解上述非线性优化问题,得出最优控制变量-附加前轮转角和各轮胎的制动力,并作用于车辆系统。通过极限工况实验、高附着双移线实验以及鱼钩实验等离线仿真验证集成控制器的有效性,并与切换控制器的控制效果进行了对比,仿真结果表明,在两种控制系统作用下,车辆均能保证横摆和侧倾稳定性,并且集成控制系统可有效避免控制策略切换带来的车辆系统振荡问题,其控制具有一定的平顺性。
[Abstract]:In recent years, the increasingly complex traffic environment has led to the frequent occurrence of traffic accidents, in which the rollover and sideslip accidents have become the main threat to the safety of human life and property. In this paper, the front wheel angle and tire braking force are used as control variables to control the roll and roll motion of the vehicle. Using Lyapunov's second stability determination method, the yaw velocity of reference is planned. Three dimensional maps of stable boundary of phase trajectory of lateral deflection angle of mass center under different speed and friction coefficient are determined. In addition, in order to meet the requirements of the stable performance of vehicle roll motion, The roll load transfer rate and the roll warning time are used as the dynamic roll index of the vehicle, and then the model predictive control strategy is adopted to meet the control requirements of both the pendulum and the roll stability of the vehicle. Selecting the braking force of the additional front wheel angle and four tires as the optimization variables, the vehicle swinging and roll switching control system is designed by selecting different objective functions and constraints. The system includes four control modes. That is, simple pendulum control mode, simple roll control mode, no control mode and integrated control mode of pendulum and roll. According to the state information feedback from the current vehicle measurement system and the reference state of the vehicle system, The corresponding control mode is judged, the optimal control variable is optimized, and the additional front wheel rotation angle is respectively applied to the steering actuator. In order to verify the effect of the designed switching control system, the Red Flag HQ430 vehicle dynamic model is selected as the controlled object. An off-line simulation experiment is carried out under a given working condition. The simulation results show that the switching controller can guarantee the stability of the vehicle roll and roll, but under the limit condition, the state of the vehicle system will jitter with the frequent switching of the control mode. This will not only aggravate the wear and tear of the actuator, but also affect the ride comfort of the driver. In order to avoid the problem of system jitter caused by the switching of the control mode, In this paper, a vehicle stability integrated control system is designed with the method of model predictive control. The requirements of pendulum stability and roll stability are unified in the objective function, in order to meet the requirements of the vehicle under different working conditions for the stability of the pendulum and the roll stability. The fuzzy control strategy is chosen to adjust the weight coefficient in the objective function in real time. By solving the above nonlinear optimization problem, the optimal control variable, the additional front wheel angle and the braking force of each tire, is obtained. The effectiveness of the integrated controller is verified by off-line simulation, such as limit condition experiment, high attachment double moving line experiment and fishhook experiment. The control effect of the integrated controller is compared with that of the switching controller. The simulation results show that the proposed controller is effective. Under the action of the two control systems, the vehicle can ensure the yaw and roll stability, and the integrated control system can effectively avoid the vehicle system oscillation caused by the switching of control strategy, and its control has a certain degree of ride comfort.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U461.6

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