基于超磁致伸缩微应变与静压气浮复合工作机理的隔/减振方法

The traditional principle of vibration isolation based on low stiffness / zero stiffness would be failure and be damaged in the fierce impact and disturbing force of load. Active negative stiffness constructed by the giant magnetostrictive micro-strain and aerostatic supporting zero stiffness structure are composited according to the principle that vibration isolation system with high stiffness can resist impact and disturbing force, and zero stiffness can effectively isolate the ultra-low frequency vibration. A kind of method of vibration isolation based on the giant magnetostrictive micro-strain and aerostatic bearing composite mechanism is proposed. Relying on self-sensing mechanism of zero power driving method based on inverse magnetic effect of giant magnetostrictive materials, active negative stiffness control is achieved. The current closed loop control system is constructed, using performance of giant magnetostrictive materials with high frequence response, wide frequency band and high displacement sensitivity and self-sensing mechanism with high speed and high precision for measuring disturbing force in this method. When driving current tends to zero, the system total stiffness tends to infinity. So vibration isolation method based on this mechanism has ultra-low frequency (vertical, or horizontal natural frequency < 0.5Hz) and could effectively resist to strong impact (equivalent stiffness tends to infinity ).

针对传统基于低刚度/零刚度原理的隔振系统，在剧烈冲击和载荷直接作用力下会失效甚至被损坏的问题。利用隔振系统高刚度可以抵抗冲击和直接扰动，零刚度可有效隔离超低频振动的原理, 将超磁致伸缩微应变构建的主动负刚度和静压气浮支撑零刚度结构相复合，提出一种基于超磁致伸缩微应变与静压气浮复合工作机理的隔/减振原理和方法。使复合后的系统总刚度和阻尼可自适应控制（零刚度至无穷刚度范围）。依靠超磁致伸缩材料逆磁致效应自传感机理的零功率驱动方法实现超磁致伸缩主动负刚度控制，该驱方法利用超磁致伸缩材料在微应变下具有高频响、宽频带和高位移灵敏度的特性和低频微振动信号高速、高精度自传感工作机理，构建电流闭环控制系统。驱动电流趋于零时，系统总刚度可趋于无穷大。基于以上工作机理的隔振方法兼具超低固有频率（垂直、水平固有频率<0.5Hz）和抵抗强烈冲击（等效刚度趋于无穷大）的特性。

本项目主要围绕传统低刚度/零刚度原理的隔振系统在剧烈冲击和载荷直接作用力下会失效甚至被损坏的问题，提出了一种基于超磁致伸缩微应变与静压气浮复合工作机理的隔/减振原理和方法。课题解决的关键技术主要集中在以下方面：.1).具有大承载、低气膜扰动的静压气浮技术.依据雷诺方程构建静压气浮模型，引入小孔节流与复合节流方式，降低气膜扰动；重点研究静压气浮结构与超磁致伸缩微位移执行器电磁线圈结构复合方法，实现载荷重力完全由静压气浮支撑平衡，超磁致伸缩与静压气浮系统等效刚度连续可控。.2).基于零功率驱动控制的超磁致伸缩的无穷刚度工作机理.从超磁致伸缩微位移执行器的驱动控制原理和磁-机耦合机理入手，研究利用变应变（特别是微应变）实现隔振装臵系统刚度无穷大（k -> ∞）；在超磁致伸缩微应变工作模式下，具有频带宽和高灵敏度特性的超磁致伸缩微位移执行器电.流闭环驱动回路的模型建立与系统搭建。.3).扰动力信号的超低频自感知与提取技术.主要解决基于逆磁致效应对直接作用于隔振装臵上的扰动力的感知方法；以及自传感电流信号与驱动电流的分离提取技术研究。.4).超磁致伸缩微位移执行器可变电磁阻尼控制技术.主要解决超磁致伸缩微位移执行器的变阻尼控制方法和负刚度效应产生原理；通过自感知直接作用力实现高频响超精密运动控制；基于超磁致伸缩的变阻尼复合非线性控制策略，即在高频振动信号控制过程中，控制系统采用小阻尼比，超低频微振动信号控制中，采用大阻尼比的控制策略，最终实现快速无超调的主动隔振控制。