Research On Passive Control Technology Of Satellite Micro Vibration Equipment

The problem of micro-vibration is widespread in various spacecraft.For highprecision spacecraft,micro-vibration will seriously affect the pointing and attitude stability of the payload.Therefore,vibration control must be used to reduce the impact of micro-vibration and ensure the normal operation of the spacecraft.Pumps and payloads are common equipment on spacecraft,and their micro-vibration control can improve the working accuracy of the payload.This paper gives the general steps of passive control of pumps and payloads,namely establishing vibration isolation targets,analyzing input characteristics,proposing vibration isolation configurations,theoretical modeling analysis,parameter optimization design,connection structure design,simulation and test verification,etc.This paper provides a reference for the general passive control design.For the active vibration reduction of the pump,the goal is to reduce the vibration input of the pump to the satellite body.By analyzing the input characteristics of the pump,it is found that the excitation frequency of the pump is mainly 133 HZ and its frequency multiplication.According to the law of the transmission rate of passive vibration isolation,as long as the overall natural frequency of the vibration isolation system is controlled below a certain value,the vibration isolation effect can be achieved.And the lower the natural frequency,the better the vibration isolation effect.Based on the shape and quality of the pump,this paper proposes the configuration of a three-leg symmetric vibration isolation platform,and then conducts theoretical modeling and analysis on this configuration to obtain the relationship between the system’s natural frequency and structural parameters.In order to improve the vibration isolation efficiency,the sixthorder frequency of the system needs to be as low as possible.At the same time,the lower the natural frequency,the lower the structural rigidity.The structural parameters exist in a reasonable range in combination with the actual situation.The structural parameters are determined by comprehensively considering the above factors.A single isolator is designed according to the structural parameters.In this paper,the form of a cylindrical coil spring is used.In order to design a spring that meets the requirements,the relationship between the axial stiffness,the ratio of the diameter to the axis and the spring parameters is given.The design of the connection structure is as light and high strength as possible.In order to reduce the impact of the vibration isolation platform on the quality and inertia of the vibration isolation object,the method of digging holes is adopted.For the designed vibration isolation system,simulation verification and test verification are also needed.Simulation verification not only accelerates product iteration,but also reduces test costs.The first is the gap between the frequency of the simulation system and the theoretical design frequency to verify the rationality of the theoretical design,and then the dynamic response is solved by modal analysis to directly verify the vibration isolation effect of the system.The test verification more accurately illustrates the vibration isolation effect of the system.The test found that the designed vibration isolation system has a good vibration isolation effect.For the vibration isolation of the payload,the goal is to reduce the vibration input of the satellite body to the payload.Through the analysis of the input characteristics of the payload,it is found that the vibration input frequency of the satellite body to the payload is widely distributed,from a few hertz to a few hundred hertz.According to the principle of passive vibration isolation,the natural frequency of the entire system needs to be controlled at a few hertz.The mass of the object is large(460kg),and the system rigidity must be very small.Based on the shape and quality of the optical payload,the six-leg vibration isolation platform configuration is proposed.Then the relationship between the natural frequency of the system and the structural parameters is obtained through theoretical modeling and analysis.According to this relationship,it is found that there are reasonable parameters that decouple the six degrees of freedom.Optimize and determine the remaining structural parameters.The design of the eddy current damper is based on the structural parameters.The relationship between the damping coefficient of the eddy current damper and the structural parameters is obtained through theoretical analysis,and then the eddy current damper that meets the requirements is obtained through simulation iteration.The spring leaf is designed according to the stiffness parameter and fixed in the eddy current damper.Regarding the design of the connection structure,flexible hinges are very important.Flexible hinges have a greater impact on the natural frequency of the system.If the rigidity is too small,the bearing capacity is insufficient,and if the rigidity is too large,the system frequency rises and the vibration isolation effect is reduced.It is necessary to consider the impact of both.Finally,simulation verification and test verification are conducted for the designed vibration isolation system.The gap between the frequency of the simulation system and the theoretical design frequency shows the rationality of the theoretical design.Because the eddy current damper has a significant impact on the performance of the entire system,a separate test test was conducted for the eddy current damper to verify the gap between the eddy current damper’s damping and stiffness and the theoretical design.The results and the theoretical design are in good agreement.Finally,the vibration isolation performance of the entire system was tested in a simulated environment,and a good vibration isolation effect was achieved.