| Colloid thrusters,as one of the electric thrusters,can provide micro-newton level of thrust control accuracy,and the thrust can be adjustable,which has a wide application prospect in the field of attitude maintenance and orbit control of space science satellites and micro-nano satellite formation.The colloid propellant storage device,as the core part of the thruster,plays the role of storing and supplying propellant to the flow control device at the rear end,and has an important influence on the thrust control precision of the thruster.To sum up the current research on the storage device,some problems have been found,such as the inability to supply propellant at a constant pressure to the rear end,and the volume and weight are too large.To solve these problems,a colloid propellant storage and constant pressure supply device based on compliant mechanism is proposed.The details are as follows:(1)The overall structure design of the colloid medium storage device was completed.A storage and supply device based on compliant mechanism was designed,and the structure of each component and working principle of the device were described.By using the compliant mechanism as the supplying force source mechanism of the device,the problems of vibration,friction,large volume and weight caused by using the rigid force source mechanism were solved.The problem of sealing was solved by storing propellant with bellows assembly.The problem of unstable output pressure was solved by using the matching design of the rigidity of the supplying force source mechanism and the bellows assembly.(2)The optimization program of compliant beam was designed,and the optimal design of supplying force source mechanism was completed.In view of the compliant mechanism design and optimization process was very complicated,the planar compliant beam optimization program was designed.This program implemented the chain beam constraint model(CBCM)and generalized shooting method(GSM),which were suitable for the simple and complex planar compliant beam design.And it’s convenient for the user’s use with GUI interface;In order to make the displacement-load characteristics of the supplying force source mechanism match with the bellows assembly,the main size parameters of the mechanism were optimized by using the compliant beam optimization program.Finally,in order to verify the accuracy of the optimization results,the large deformation simulation analysis of the supplying mechanism was carried out by using ANSYS.The results showed that the error between the displacementload characteristics of the optimized supplying force source mechanism and the theoretical design value was less than 1%,which met the design requirements.(3)The principal prototype was made,and the performance test of the storage device was carried out.The displacement-load characteristics of the compliant force source mechanism were tested.The results showed that the mechanism had negative stiffness characteristics,but there was an error between the mechanism and the theoretical design value.After analysis,it was found that the error was caused by machining accuracy,material elastic modulus error and only considering the deformation of neutral axis.The output pressure of the storage device was tested,and the results showed that the constant pressure effect was good.There was a slight change in the pressure at the beginning and the end of the working area,and the fluctuation in the middle was kept within 0.081± 0.003 MPa.After analysis,this was caused by the output force error of the supplying force source mechanism and the change of the equivalent crosssectional area of the bellows,which could be improved for these factors in the future. |
