Research On Electromagnetism Dynamic Vibration Absorber For Micro-vibration Suppression Of Space Optical Load

With the continuous development of C hina's aerospace industry,structural vibration caused by vibration sources and loads on spacecraft has become an important factor affecting the normal operation of delicate equipment.When these vibration source disturbances are transmitted to precise imaging devices such as space optical loads,the imaging quality of the camera becomes worse.Because these micro vibrations cannot be completely eliminated,the most effective measure is to reduce the vibration of these sensitive loads.In this paper,an electromagnetism dynamic vibration absorber is designed for practical engineering needs,which can be applied to space vibration absorption in space.The main contents of this paper are as follows:Firstly,the development of dynamic vibration absorber at home and abroad is introduced,especially its application in the field of aviation.Then,the theoretical basis of dynamic vibration absorber is discussed,including single degree of freedom,two degree of freedom vibration system theory,PQ fixed-point theory and electromagnetic damping calculation formula,and the corresponding resolving program is given.Secondly,the stiffness and damping parameters of the dynamic vibration absorber designed in this paper are determined according to the demand for the vibration suppression of the spatial optical load.On the basis of determining the parameters,the design of two key components of the dynamic vibration absorber is completed,including the design of the spring sheet and the design of the electromagnetic damper.The finite element mesh method is used to explore the main parameters that affect the stiffness of spring plate,such as thickness,material and structure.The electromagnetic damper is designed by non-contact,and the reliability of dynamic vibration absorber has been greatly improved.On the basis of completing the design of spring and electromagnetic damper,the overall structure design of absorber is perfected,and its overall structure is analyzed by finite element method.The finite element analysis proves that the structure of the absorber is reasonably designed,then the drawing,processing and adjusting of the principle prototype are completed.Thirdly,the experimental platform was built,and three experimental tests were carried out on the electromagnetism dynamic vibration absorber,which has been finished.One is the stiffness test of the spring sheet.The experimental results show that the error of the actual test results and the finite element analysis is only 0.624%.Then is the test of the fundamental frequency of the dynamic vibration absorber.Its results show that the design error of the fundamental frequency of the absorber is not more than 2.06%.Another is the experiment of vibration absorber's vibration reduction effect.Taking the equivalent model of the space optical load part as the object of vibration reduction,the influence of with and without the electromagnetic damper on the first two order frequency to the model is tested respectively.Experimental results show that according to the vibration of the equivalent cantile ver plate frequency is 29.88 Hz,the damping effect of vibration absorber with electromagnetic damping is less than without electromagnetic damping,but the vibration bandwidth expands 67.5%.The electromagnetic damping vibration absorber can suppress the resonance peak of the equivalent cantilever beam second order frequency72.94 Hz and the maximum inhibition is 37.3%.The above three tests show that the design of the absorber is feasible.The research method is effective and can be used for vibration suppression of space optical load.Finally,a mathematical model of active control for electromagnetism dynamic vibration absorber is built.Based on the Linear Q uadratic Regulator Control theory,a state feedback controller is constructed to achieve active control of dynamic vibration absorber.O n this basis,an active dynamic absorber Simulink simulation model is built.The simulation results show that the active vibration control of the absorber has better vibration suppression effect compared with the passive vibration absorber.