【作者】 杨小卫；

【导师】 周孔亢；

【作者基本信息】 江苏大学 ， 车辆工程， 2007， 博士

【摘要】 可调阻尼减振器是影响车辆半主动悬架振动控制效果的重要部件之一,目前相关的研究正日益得到重视。磁流变减振器可以在外加磁场作用下实现阻尼力的无级可调,能够根据系统的振动特性产生最佳阻尼力,实现悬架振动的半主动控制,而且在零磁场下相当于传统的被动液压阻尼器,具有较强的可靠性,在车辆工程界正受到广泛重视。车辆半主动悬架较被动悬架提高了乘坐舒适性和操纵稳定性,同时又比主动悬架有良好的性价比,耗能小,而基于磁流变减振器的车辆半主动悬架可以进一步提升悬架性能,成为近年来车辆工程研究的热点方向之一。本文简述了磁流变技术及磁流变减振器的发展过程和研究现状,探讨了车辆半主动悬架技术的发展趋势。结合当前磁流变减振器研究中的关键问题,对磁流变减振器的磁路设计从理论和有限元分析的角度进行了深入的探讨。建立了采用Fuzzy-PID控制理论的半主动悬架振动模型,对采用磁流变阻尼可调减振器的车辆半主动悬架控制理论进行研究。探讨了磁流变液的流变机理和磁流变减振器的工作原理,对磁流变减振器中产生和改变磁场的关键部位之一——磁路的设计原理进行分析,为磁流变减振器的磁路设计提供理论基础。利用有限元法对磁流变减振器的电磁场进行数值模拟,研究磁场在减振器磁路内部的分布。对磁场中各励磁材料结构尺寸,材料特性等因素对减振器磁路及整体性能的影响进行了研究,分析具体的影响规律。研究不同磁路级数时,磁路结构参数对磁路性能的影响和磁路性能的差异。台架实验研究了磁流变减振器的外特性,结果表明磁流变减振器阻尼力存在可控特性和迟滞性。分析了磁流变减振器可控阻尼力与控制电流之间的关系,根据实验数据拟合了库仑阻尼力—电流的关系曲线,为磁流变减振器控制模型的建立和半主动悬架系统控制提供了理论支持。在模糊控制和PID控制的基础上建立了Fuzzy—PID开关切换控制策略,并采用工程整定法确定PID参数。基于2自由度1/4车辆模型,对MR半主动悬架进行控制仿真,结果表明采用Fuzzy—PID控制时,簧载质量加速度、悬架动挠度较Fuzzy控制时都有所减少小,收到较好的减振效果,悬架平顺性得到进一步改善。综合悬架性能要求,和Fuzzy控制策略比较,Fuzzy—PID开关切换控制的控制效果相对更好,适用于车辆悬架复杂非线性系统的建模与控制。进行控制系统软、硬件的选用与开发,编写了基于Fuzzy—PID开关切换控制策略的半主动悬架控制程序,采用单片机开发了半主动悬架Fuzzy—PID控制器。基于该控制器进行了台架实验,结果表明:磁流变半主动悬架同被动悬架相比,簧载质量加速度有较大改善,尤其簧载质量在低频共振点附近有明显改善。实验验证了所提出的控制方法和控制系统的正确性、可行性,设计的Fuzzy—PID控制系统可以较好地抑制车身振动。更多还原

【Abstract】 Adjustable damper is the main part that has great effect on the vibration control of simi-active suspension, correlative research are getting increasingly recognition. Depend on the magnetic field, MR damper can adjust the damp and bring best damp force which can make the semi-active suspension control come ture and has strong reliability. Compared with passive suspension, the vehicle semi-active suspension improves both riding comfort and vehicle maneuverability. The semi-active suspension with MR damper has arosed great attention in recent years.Research status and development course about MR Fluid and MR dampers are introduced in this paper.The development trend of vehicle semi-active suspension are summarized. According to key questions of the MR damper, magnetic circuit design of MR damper has been discussed. Semi-active suspension vebrition model has been established with Fuzzy-PID control theory. The control theory of vehicle semi-active suspension with MR damper has been researched.Working principle of MR fluid and MR damper has been discussed, magnetic circuit design principle has been analysised. Foundational design theory of MR damper’s magnetic circuit was given in the paper. MR damper’s electromagnetism field was simulated with Finite Element Analysis way and field distributing were researched. The influce deal to the MR damper’s magnetic circuit of structure size and characteristic of excitation materal in the field were studied.The fluence dealed by magnetic circuit structure parameter has been reseached with different magnetic circuit classes.Experiment has been done to test the damp characteristics of MR Damper. Result shows the controllable character and delay character of the MR Damper. Relationship between coulomb damper force and current were analysed . Curves about coulomb damper force and current were drafted based on the test data which give theory sustain to the control system of semi-active suspension and control model of MR damper.Fuzzy-PID switch control strategy was established basd on fuzzy control and PID control. Based on 2 DOF 1/4 car model,the control simulation of MR simi active suspension has been down, results show that spring mass acceleration and suspension dynamic load reduced while Fuzzy-PID switch control was used to compare with Fuzzy control strategy, the riding comfort got improved. The control effect of Fuzzy-PID switch control is furthermore well.Hardware and software of control system has been developed. Fuzzy-PID control progam of magnetorheological semi-active suspension has been written and Fuzzy-PID controller has been empoldered based on SCM.Experiment has been done with controller. Results show that suspension with controller can minish spring mass acceleration compared with suspension without control, especially at low frenquence. Experiment data validated that the trait of Fuzzy-PID switch control was correct and feasible, the control system can good restrain the vibration of vehicle.更多还原