【作者】 郭军锋；

【导师】 陈丁跃；

【作者基本信息】 长安大学 ， 车辆工程， 2010， 硕士

【摘要】 悬架作为汽车中的重要组成部分,是一个较难达到完美要求的总成,因为悬架既要满足汽车的行驶平顺性要求,又要满足操纵稳定性的要求,而这两方面对悬架的要求是相互矛盾的。汽车主动悬架可以根据路面情况在车身与车轮之间及时主动调节产生所需的控制力。抑制车身的振动,使悬架处于最优减振状态,来达到改善车辆行驶平顺性与操纵稳定性的目的。车辆主动悬架设计的关键任务之一,就是要寻求一个能够为车辆提供良好性能的控制规律。许多学者提出了各种不同的控制理论,本文对这几种常见的控制算法进行了介绍并重点研究了最优控制器,PID控制,模糊控制,模糊PID控制四种控制策略。作为经典实用的控制方法,PID控制算法具有计算量小、实时性好、易于实现等特点,所以本课题也采用了PID控制作为基本的控制策略,并设计了PID控制器。最优控制的优点在于根据系统的状态变量并通过评价指标的最小化得到一个最优的综合性能指标,状态变量可以根据需要进行选择。选取不依赖于系统的精确数学模型,对参数变化不敏感,具有很强的鲁棒性,尤其适用于非线性、时变和滞后系统控制的模糊控制,而且模糊控制的算法是基于若干条模糊控制规则,算法非常简捷,进而对模糊控制器进行了设计。模糊控制和PID控制相结合的模糊PID控制能实现PID控制器参数的在线自调整,进一步完善PID控制器的性能。所以本课题将其两种控制策略结合,以消除其各自弊端的模糊PID控制器。本文通过建立1／4车辆模型,应用了四种控制理论对车辆主动悬架控制器的设计,并在Matlab/Simulink环境中建立系统模型并进行仿真。将仿真结果与被动悬架仿真结果进行对比分析。通过对比,全面分析在四种不同的控制策略下主动悬架的性能特点。仿真结果表明：四种方式下的主动悬架都能够减小车身加速度,悬架动挠度,车轮动载荷。这说明对于行驶平顺性和操纵稳定性的改善结果相当好。在这四种控制策略下模糊PID控制效果最好。更多还原

【Abstract】 Suspension as an important part of the car which is more difficult to achieve a required perfect assembly, it is not only to meet the requirements of comfortable, but also to meet the requirements of handling and stability, These requirements about the suspension are mutually contradictory. Vehicle active suspension is able to adjust or produce controlling force between wheel and vehicle body according to road conditions. So it can restrict vibration and improve the performance of suspension and achieve the purpose of improving ride comfort and handing stability simultaneously.One of the key tasks of the suspension design is to find a vehicle to provide good performance for the control law. Many scholars have put forth a variety of control theory. Optimal control, PID control, fuzzy control, and Fuzzy-PID control are studied in this paper. Because PID control algorithm as a classical and practical algorithm has some advantages such as little work of accounting, good real-time trait and easy achievement, PID control strategy has also been applied. Then, the PID controller has been designed. The advantages of The optimal control is according to the state variables of the system and through evaluation of the minimum, to get an optimum integrated control targets. State variables can be selected based on needed. Fuzzy logic has been selected because it is independence on the exact mathematical model of the system. Sensitivenessless to the variant and good robustness, besides, fuzzy logic is very fit to the model of non-linear, time-chageable and delay characteristics. The control algorithm of fuzzy logic base on several control rules and is simple. Then, the fuzzy logic controller has been designed. Fuzzy-PID control combined fuzzy logic and PID control is able to achieve the parameter’s self-adapative on-time status. It can furtherly improved the performance of the PID controller in order to adaptive to the changeable variant and changeable condition of the control model. Fuzzy-PID controller that combines the two strategies discussed above to eliminable the disadvantages of the singles has been designed. Establishment of quarter vehicle model and the application of four ways control theory, controllers of automobile active suspension are designed. The system model in Matlab/Simulink environment is built and used for simulation. Simulation results are compared with passive suspension.Simulation results show that all this four different forms of active suspension can remarkably deduce the vehicle body acceleration, dynamic flexibility suspension and dynamic load of tyre. That implies active suspension improves ride comfort and handing stability well. Among this four control strategies, the control effect of Fuzzy-PID control is the best.更多还原