【作者】 丁世稳；

【导师】 史文库；

【作者基本信息】 吉林大学 ， 车辆工程， 2009， 硕士

【摘要】 发动机是汽车的重要激振源,发动机悬置系统是指发动机与车身之间的弹性连接系统,其性能的好坏不仅影响乘坐舒适性,而且影响着车辆的使用寿命。如今传统的橡胶悬置和被动液压悬置已无法满足汽车多工况宽频带的隔振要求,主动悬置将会成为下一代发动机悬置系统。本文研究了各种主动悬置的性能和优缺点并选用了一种主动控制式电磁液压悬置,它是由传统的被动液压悬置和微型电磁作动器组成的,利用了液压悬置良好的低频减振性能和电磁作动器在高频振动下的主动隔振能力,从而在更宽频带内主动隔离发动机振动噪声向车内的传递,更好地解决了日益严重的发动机振动问题。作者首先运用MATLAB/Simulink软件建立了发动机—车身的二自由度仿真模型,采用LMS自适应前馈控制、最优控制、模糊控制和模糊PID控制方法进行了主动控制研究,仿真对比了它们在控制前后的隔振效果、鲁棒性、稳定性及对高频激励成分的隔振效果,分析了这四种控制方法的优缺点,得到模糊PID控制方法较其他控制方法而言是一种较优的主动悬置控制方法。然后作者建立了发动机隔振实验台的六自由度实验台力学模型和数学模型,并用计算机仿真实现了其隔振的最优控制和模糊PID控制。更多还原

【Abstract】 An ideal engine mount should have the following dynamic characteristics: (1) To bearing engine mass and output torque, it should have high static stiffness;(2)In order to attenuate large amplitude vibration induced by the starting、braking、accelerating、decelerating processes of vehicle, it should have large damping and high stiffness characteristic at low frequencies;(3)In order to reduce vibration transmittability, improve effect of noise attenuation, it should have the characteristic of small damping and low dynamic stiffness at high frequencies. At present, passive mounts were commonly adopted as engine mounts at home and abroad, small amount of semi-active mounts were used, these mounts can hardly meet the requirement of broad frequency band of engine vibration and noise reduction. In comparison with passive mounts and semi-active mounts, active mounts can reach ideal vibration isolating effect to some extent.Active vibration control technologies were applied to power assembly in this paper, the active control hydraulic mount with electromagnetic-actuator was used and by the way of impose energy on this mount to improve vibration isolating effect. This thesis carries on the comparatively deep research into LMS adaptive feedforward control theory、optimal control theory、fuzzy control theory、fuzzy-PID control theory, discussed the probability of these theories applied to active control mounts(ACM).Models of a 2-DOF ACM system and a 6-DOF ACM testing table were built up in MATLAB/Simulink, the control methods mentioned above were adopted in the simulation control and mutual contrast of the control effects was made, moreover, every kind of control method’s advantages and disadvantages were summarized. The main research contents are as follows:This paper introduces the ideal vibration isolating characteristics and presents research situations of active engine mounts, based on large amount of internal and external theses. The active vibration control technologies、classification、structure of ACM were introduced emphatically. The control principles、features、design methods of LMS adaptive feedforward control theory、optimal control theory、fuzzy control theory、fuzzy-PID control theory were researched. On account of each control theory contain different kinds of control methods, FX-LMS control arithmetic of adaptive feedforward control theory、linear quadratic optimal control method of optimal control theory、fuzzy control method and fuzzy-PID control method were introduced emphatically in this paper.Based on the analysis of hydraulic mount’s structure and operating principle,the mechanical model and mathematical model of hydraulic mount were established, then structure and operating principle of an active mount with its electromagnetic actuator driving hydraulic mount’s decoupling membrane directly were studied, on the base of which, the mechanical model and mathematical model of ACM were built up. Models of 2-DOF ACM system and 6-DOF ACM testing table were built up with the ACM, which lay a foundation for further simulation analysis.The simulation model of 2-DOF ACM system was established, then LMS adaptive feedforward control method、LQR control method、fuzzy control method、fuzzy-PID control method were adopted, the controllers were designed, simulation results were presented. After that, the author evaluate the advantages and disadvantages of control methods from these aspects: effect of vibration isolation with and without control、Robustness、stability、effect of vibration isolation when high frequency excitating components in existence, at last we got fuzzy-PID control method is a better control method for ACM comparing with other control methods.The comparative experiment model under active and passive control was built up in MATLAB/Simulink environment, the simulation control was done using LQR control method and fuzzy-PID control method, moreover, a comparative analysis of simulation results under LQR control and fuzzy-PID control was done. ?更多还原