Research On Active And Passive Composite Vibration Isolation Technology For Small Optical Systems

Optical Optical systems are currently widely used in aerospace,aviation,measurement and other fields.For precision optical systems,the micro-vibration of the instrument directly affects the measurement accuracy and performance of the system.Therefore,it is necessary to research and design the vibration isolation system for the optical system inside the precision instrument.Aiming at the current demand for vibration isolation of precision instruments and the problems of existing vibration isolation technology,this paper designs a positive and negative stiffness parallel passive vibration isolation system with adjustable stiffness,and subsequently adds an active vibration isolation system to further reduce the vibration peak of the system.Passive vibration isolation and active vibration isolation experimental platform,using experiments to verify the vibration isolation effect of passive vibration isolation and active vibration isolation.The main research contents of this paper are as follows:(1)Establish the force and stiffness model of the parallel vibration isolation system with positive and negative stiffness.Established passive vibration isolation and spring vibrator models based on different speed feedback methods,and calculated and analyzed its vibration transmission rate.According to the vibration transmission rate curve,the active vibration isolation system and the passive vibration isolation system were isolated at low,medium and high frequencies.The performance was compared.The comparison and selection of the load-based absolute speed feedback method also proved the feasibility of the positive and negative stiffness parallel vibration isolation system.(2)Established horizontal and vertical passive vibration isolation models.The vertical passive vibration isolation structure uses the buckling beam negative stiffness element in parallel with the spiral spring positive stiffness element,and horizontally uses the "beam-column effect" to achieve a low-rigidity structure;theoretical analysis and calculation of the stiffness in the two directions are carried out for the passive vibration isolation structure Simulations were carried out,and vertical and horizontal vibration isolation structures were designed.The theory realizes the parallel vibration isolator of positive and negative stiffness with adjustable horizontal and vertical stiffness.(3)An active vibration isolation system based on load absolute speed feedback is designed.After theoretical analysis of different feedback control methods,the load absolute speed feedback control method is designed to actively control the vibration isolation table,and the corresponding circuits of the signal detection module,signal acquisition module,signal processing module and feedback control module are designed to control the sensor signal.And the feedback loop is processed.An active vibration isolation system based on load absolute speed feedback is realized.(4)Based on the theory and simulation model,an active and passive composite vibration isolation platform was built.Experiments have proved that the vertical and horizontal natural frequencies of the active and passive vibration isolation system can reach 1.315 Hz and 0.875 Hz;the vertical resonance peak can reach below-10 dB,and the horizontal resonance peak can reach below 0 dB.