Multi-objective Optimization Design Of Atomic Force Microscope Vibration Isolation System Based On Nsga-Ⅱ

With the increasing development of science and technology,the demand for the detection resolution and sensitivity of precision measuring instruments in aerospace,vehicle engineering,geological exploration and other applications has increased,but the detection resolution of precision instruments does not rely on its own accuracy level,and is closely related to the strict vibration isolation measures it receives.Therefore,in order to ensure the stability of the measurement environment of the precision instrument and improve the measurement accuracy,it is of great significance to study the vibration isolation system.Vibration isolation has been proven in theory and practice to be one of the most effective means to improve the stability of the device measurement environment,and the fast non-dominant sorting genetic algorithm with elite strategy has also been identified by the academic community as one of the important methods for searching for the optimal combination of multiple unknown variables.At present,the combination of the above two kinds of research and the design of vibration isolation systems for precision instruments are still few,and the main purpose of this paper is to design a high-performance vibration isolation system for atomic force microscopy by combining the optimization and verification results of parameters.The main research work in this paper is as follows:First of all,the paper mainly expounds the basic principles of atomic force microscopy,analyzes its working principle and working mode,and experimentally verifies one of the methods of using electrostatic power to drive cantilever vibration.The spectrogram shows that there are two peaks at the resonance frequencyf₀ and1/2 f₀ under this method,and the vibration amplitude of the two cantilevers has a corresponding relationship with the AC voltage and the DC voltage.In addition,the principle of the two-stage spring suspension vibration isolation system was combined to determine the important design conditions for the design of the atomic force microscope vibration isolation system.Secondly,according to the internal and external vibration of the instrument,the vibration noise is traced,and a mathematical model of vibration isolation of atomic force microscope is established based on the vibration isolation principle,and the optimization ideas are analyzed and sorted out to prepare for multi-objective optimization,and the design requirements of vibration isolation are transformed into optimization problems with multiple sets of minimized objective functions.Combined with the conditions of the design of the vibration isolation system,the parameters associated with the mathematical model,the physical size and other factors,a multi-objective optimization design method of the two-stage spring suspension vibration isolation system is proposed.NSGA-II algorithm is implemented in python language to obtain multiple sets of non-dominant solution sets,and the restrictions such as vibration isolation ideas of the vibration isolation system are selected as the optimal scheme for higher-level qualitative conditions.In this paper,1.58 is determined as the spring constant ratio,and the spring constants of 96N/m and 150N/m are selected according to the physical size and constraints of the atomic force microscope.Finally,the vibration isolation system was built with parameters and the vibration isolation performance test was carried out,which realized the vibration isolation of external and internal low/high frequency vertical noise,and the original vibration amplitudes of 23nm and 69nm at15Hz and 40Hz in the low band were reduced to 0.017nm and 0.025nm;the vibration amplitudes of 4.3nm and 4.6nm at the original 1.0KHz and 1.27KHz in the high frequency band were reduced to 0.013 nm at 1.165KHz.In this paper,the structural design and parameter optimization of the atomic force microscope vibration isolation system are carried out,and a set of vibration isolation system is designed and built,which has practical application value and lays the foundation for the development of high-resolution atomic force microscopy.In addition,this study has certain reference value for the optimization and design of vibration damping devices in other two-stage vibration isolation forms.