Research On Vibration Characteristics Of Electro-hydraulic 3-UPS/S Ship Parallel Stabilized Platform

As a typical attitude compensation mechanism,the ship parallel stabilization platform has a wide application prospect in the fields of marine rescue and marine scientific research.When the electro-hydraulic drive is adopted,the load-carrying capacity and response speed of the mechanism can be significantly increased.However,the fluctuation of fluid parameters and the coupling with mechanical components make the vibration mode and dynamic response of the mechanism more complicated.When the external excitation frequency is close to the natural frequency of the mechanism,it is easy to cause resonance,which can affect the dynamic performance of the mechanism,and may cause damage to the mechanism in severe cases.Therefore,the analysis of vibration characteristics has certain reference value for further improving the dynamic performance of mechanisms.Taking the electro-hydraulic 3-UPS/S ship parallel stabilized platform as the research object,the vibration characteristics of the platform are analyzed.The main research contents are as follows:Wave disturbance and kinematics analysis of electro-hydraulic 3-UPS/S platform.Aiming at the random sea wave disturbance under level 6 sea conditions,simulation on mechanism tracking ship motion is conducted,and the velocity Jacobian matrix of each component of electro-hydraulic 3-UPS/S platform is obtained by performing the kinematics analysis.Analysis of free vibration of electro-hydraulic 3-UPS/S platform.The dynamic equation of the mechanism is established by using the virtual work principle,and the vibration modes of the mechanism and the variation of the natural frequency in the actual working condition and the initial workspace are analyzed.Forced vibration analysis of electro-hydraulic 3-UPS/S platform.Considering fluid viscous damping and external excitation,the forced vibration equation of the mechanism is established,and the response characteristics and the amplitude variation of the forced vibration in the initial workspace are analyzed.Parameter vibration analysis of electro-hydraulic 3-UPS/S platform.Based on establishing parametric vibration equation of mechanism,the analytical solutions of the primary resonance and the combined resonance responses of the mechanism are determined by using the multi-scale method.The response characteristics of the primary resonance and combined resonance of the mechanism is analyzed.Besides,the variation characteristics of the primary resonance and combined resonance amplitudes in the initial workspace is analyzed.Mode test of the prototype of electro-hydraulic 3-UPS/S platform.The modal test is carried out by using the pulse excitation method,and the maximum error between the theoretical and experimental values of the natural frequency of the prototype is 4.66%,which can verify the correctness of the dynamic model.