【作者】 孟令雷；

【导师】 王永；

【作者基本信息】 中国科学技术大学 ， 控制科学与工程， 2009， 硕士

【摘要】 舰船的减振问题很久以前就引起了人们的重视。被动隔振是舰船上常用的减振方法,但其低频隔振效果不甚理想,而主动隔振能够克服被动隔振的这一缺陷,近年来得到越来越多的研究。本文以自行设计的磁悬浮隔振器为基础进行了主动隔振的实验研究。目标是在不降低磁悬浮隔振器高频减振效果的基础上,提高其低频减振效果。力传递率、插入损失和振级落差是三种常用的被动隔振评价方法,针对设计的磁悬浮隔振器,在给出了三种评价方法的表达式的基础上,对其被动隔振特性进行了仿真和实验研究。结果验证了磁悬浮隔振器低频隔振效果不理想的结论,需要在磁悬浮隔振系统中引入振动主动控制。设计的磁悬浮隔振器的电磁作动器是非线性的,它利用上下两块电磁铁吸引衔铁产生电磁力,通过控制通入电磁铁的电流控制磁场的强弱,进而控制电磁力的大小。利用MTS809电液伺服系统测量该电磁作动器通入不同电流时在不同气隙下输出电磁力的大小,采用最小二乘法得到了电磁作动器通入电磁铁线圈的电流与电磁力在不同气隙下的函数关系。在比较了线性功率放大器和PWM功率放大器之后,选择PWM功率放大器作为控制信号的功率放大环节。在将电磁作动器之外的环节视为线性环节的基础上,应用线性控制器设计方法,得到需要的控制量——电磁力后,求解上述函数关系得到真正的控制量——电磁铁线圈电流。最优控制实验效果表明了这种处理方法是可行的。另外为了实现振动主动控制实验利用VC++程序设计语言编写了软件程序。给出了两种提取参考信号的方法,分别进行了实验研究并分析了各自存在的缺陷。在对基础加速度信号进行滤波的基础上,采用滤波x最小均方(滤波x-LMS)算法进行了磁悬浮隔振器振动主动控制实验研究。实验结果表明,7.0-15.0Hz频段内,在被动隔振的基础上主动隔振取得了8dB以上的减振效果,达到了磁悬浮隔振器设计的指标要求。更多还原

【Abstract】 Issue of the ship’s vibration reduction has attracted people’s attention for a long time. Passive vibration isolation technique has been traditionally used to reduce the ship’s vibration. But its isolation performance in low frequency is not good enough. Active vibration isolation can overcome the inherent defect of passive vibration isolation in low frequency band, and has been deeply researched recently.This paper is dedicated to experiment study of self-designed Electromagnetic Suspension Vibration Isolator (ESVI)’s active control. It aims at improving the ESVI’s vibration reduction performance in low frequency and not reducing it performance in high frequency.Force Transmissibility, Insertion Loss and Vibration Level Difference are three most popular methods to evaluate passive vibration isolation. For this ESVI, after giving the expressions of the three methods, its passive vibration isolation characteristic is studied by simulation and experiment. Result shows that it is true the passive vibration isolation performance of the ESVI in low-frequency is not good and active vibration isolation is needed.The designed ESVI’s electromagnetic actuator which through upper and lower electromagnets attracting armature induces electromagnetic force is nonlinear. By controlling current in electromagnet coil strength of magnetic field can be controlled and then magnetic force can be controlled. MTS809 electro-fluid servo system is used to measure force the electromagnetic actuator induces, when it is passed different current under different gap, and then least squares method is used to get the functional relationship between them. After comparing Linear Power Amplifier with PWM Power Amplifier, PWM Power Amplifier is selected as control signal’s power amplifier part. After considering that the other parts of the ESVI is linear, linear controller designing method can be used to get control variable which the electromagnetic actuator needs induce, and then through solving the functional relationship, the real control variable– current in the electromagnet coil can be got. Experimental result of optimal control shows that this controller design method is viable. Besides, software for active vibration isolation experiment has been programmed using VC++ programming language.Two ways to deal with the problem of reference signal extraction is given. And experiment study has been given for each of them, and their defects are also analyzed independently. After filtering the base’s acceleration signal, Filtered-x Least Mean Square (Filtered-x LMS) algorithm is used in the ESVI’s active vibration control. Experiment result shows that the active vibration isolation efficiency upon passive vibration isolation is more than 8dB, which meets the technical requirements of the ESVI.更多还原