| With the popularization of the application of vehicle-borne instruments and equipment,the research on the vibration isolation system of vehicle-borne instruments and equipment becomes more and more important.Considering the influence of the driving environment and vibration frequency of vehicle-borne precision instruments.Based on the parallel principle of positive and negative stiffness springs,a quasi-zero stiffness vehicle-borne vibration isolation system with small space occupation,convenient installation and adjustable limit is designed in this dissertation.Through theoretical calculation,simulation analysis and test verification,the excellent performance of the vibration isolation system is verified.The vertical spring is connected in parallel with two symmetrical negative stiffness structures,In the derivation,the machining error coefficient is introduced,and the influence of the machining error coefficient on the quasi-zero stiffness of the system is analyzed.Used the average method to get the dynamic response of the system under the harmonic displacement excitation of the vehicle body,and analyzed the influence of the system parameters and the excitation amplitude on the displacement transfer rate.On this basis,a quasi-zero stiffness vibration isolation system is designed and manufactured,and the amplitude-frequency response of displacement transfer rate under different excitation amplitude and frequency is measured,and compared with the theoretical results to verify the correctness of the theoretical analysis.Then,the MR damper is installed in the quasi-zero stiffness isolation system,and the semi-active switch control strategy is used to control the isolation system.Through the co-simulation of Trucksim/Simulink,the isolation effect under different conditions and different speeds is analyzed.and compared with the quasi-zero stiffness vibration isolation system without control.Finally,based on the Lab View software and PXI embedded system,the semi-active vehicle-borne quasi-zero stiffness vibration isolation system is tested and studied,and compared with the simulation results.and the vibration isolation performance of the designedsemi-active vehicle-borne QZS vibration isolation system is comprehensively verified by the test and simulation results.Research shows:(1)The experimental results of the designed vibration isolation system are in good agreement with the theoretical results,which verifies the correctness of the model and theoretical derivation.(2)The initial isolation frequency of the quasi-zero stiffness vibration isolation system is about 1.4 Hz,which is better than the initial isolation frequency of the linear system at 2.9 Hz,significantly reduces the natural frequency of the system and can achieve low-frequency isolation.(3)The QZS isolation system has good stability under the condition of simple harmonic excitation road and B-level random excitation Road,the isolation efficiency reaches 70% ～ 80%,the isolation characteristics are good,and the isolation characteristics are general under the condition of C-level random road.(4)Under different working conditions,the stability and buffering performance of semi-active quasi-zero stiffness vibration isolation system are better than that of uncontrol quasi-zero stiffness vibration isolation system.The vibration isolation efficiency has been improved by 25.9%,41.3%,and 52.6%,and the effect of low-frequency vibration isolation is obvious.The model,theoretical simulation and experimental results can provide theoretical guidance and engineering reference for the design of vehicle-borne vibration isolator. |
