Research On Technologies Of Multi-point Active And Passive Intergrated Vibration Isolation Of Sensitive Equipment Of The Air Vehicle

Near space is a field that many countries are scrambling to enter. The vehicle innear space has become a hot topic of present study and has an important militarysignificance. When the vehicle in the implementation of the complex task, to meetingthe working accuracy of precision instruments just as navigation, guidance and so on, topreventing vibration caused by the friction of the air flow from the outside, simplepassive vibration isolation and active vibration isolation cannot meet the requirements,so this paper proposes a piezoelectric-rubber combination vibration isolator, usesmulti-point support, achieves active and passive integrated vibration isolation ofmulti-degree of freedom.This paper derives the piezoelectric stack output power and output displacementbased on the piezoelectric equation, designs the piezoelectric stack actuator and therubber part, and proposes an active and passive integrated isolator that piezoelectricmaterial is for the active part and the rubber is for the passive part.It establishes the dynamics model of vibration isolation system, derives its transferfunction, discusses the influence of various parameters on the vibration transmissibility.Then it designs the controller, which takes feedforward and feedback composite controland makes the system have a better isolation effect at low-frequency phase, near theresonant frequency and high-frequency phase when it takes absolute displacement of thebasis for feedforward amount and the absolute velocity of the sensitive equipment forfeedback amount.The isolator is applied to the cubic Stewart platform to achieve a six degree offreedom vibration isolation. For the designed vibration isolation platform, it usesSimulink to make the simulation, and then has verified its isolation effect at the case ofthe sinusoidal excitation signal and random excitation signal of the basis.Based on the design of single-isolator, this paper designs a four-point supportdouble-layer integrated active and passive vibration isolation platform, establishes thedynamics model of vibration isolation system, applies an improved Linear QuadraticRegulator (LQR) optimal control to the double-layer vibration isolation system and hasthe numerical simulation analysis based on Simulink. The results show that thevibration isolator can effectively isolate from the displacement excitation of the basis,prove the study of the isolation method in theory is effective and feasible, thus laid thefoundation for further experimental studies.