| Modern small satellites feature small volume,light weight,short cycle and fast response,which represent an important developing trend of space technology.Recently,this field has developed rapidly and will have a wide developing prospect.However,with the increase of the number of small satellites and the increasing time of orbit running,requirements for the on-orbit servicing for small satellite are becoming more and more obvious.Due to the particularity of the structure of micro satellites,the traditional reusable latch mechanism is not suitable for the small satellites,so it is necessary to carry out the research on the reusable latch mechanism.This article mainly studies the reusable latch mechanism which can achieve low impact,linkage and bear some wear deformation with high fault tolerance.The research work,from an overall layout optimization point of view and according to the requirement of locking force index,has carried out a reusable latch mechanism optimization for small satellites.The main work includes the following aspects:(1)Contrary to the reusable latch mechanism requirements,this paper developed a set of the bar bending deformation generates locking force,which can achieve self-locking when it is located at the highest locking force point.By analyzing the kinematics and dynamics characteristics of the mechanism,the mathematical model of the mechanism is established.Regarding the minimum required motor driving force as the objective function,the design variables and constraints are determined according to the design requirements of the mechanism and the characteristic of the optimization object,and established the mathematical model of the mechanism.(2)Aiming at the problem that the parameters of the locking mechanism are optimized and the solution is complex,proposed a step by step optimization method based on variable decoupling.By decoupling the variables,the optimization strategy is to decompose this problem into several sub-problems,which are independent of each other and can gradually obtain the optimization scheme.This research has greatly reduced the complexity.(3)In view of the above decoupling mechanism layout optimization problem,making analysis of the objective function in the optimization space distribution based on the test design,and ensuring the potential optimal region of design variables.It is consistent with reasonable interval in the second chapter,which is carried out by the theoretical analysis and engineering experience.And it has proved the rationality of the interval.Then,genetic algorithm is used to solve the optimization problem in this region.This work greatly reduces the search range and improves the optimization efficiency,from which the optimization of distribution mechanism is obtained.(4)According to the mechanical properties mechanism based on mathematical model in the process mentioned above,due to the simplification and approximation lead to deviation from the actual model,we uses ADAMS software to establish dynamic model of repeatable locking mechanism,making analysis of dynamic characteristics of mechanism with high precision.Due to the existence of flexible bars in the mechanism,the parametric modeling can not be realized in ADAMS,we carry out an approximate equivalent model of rigid body and realize parametric modeling,and its effectiveness is verified.Based on the parameters of the rigid body modeling,we use ADAMS and ISIGHT to achieve the optimization of the parameters of the model.Several representative optimal layout schemes are obtained,and the simulation results are verified by the high accuracy model of the flexible rod.The optimal scheme of the mechanism is obtained.(5)By comparing the two optimization results based on ADAMS and MATLAB,the final optimization layout is proved.The maximum motor driving force and corresponding parameter index are calculated according to the design requirements.Taking the wear of mechanism into account,the analysis of the locking force changes is made to verify the reliability of the design mechanism.(6)Analyzing the uncertainty in the mechanism and establishing the uncertainty model of the mechanism.Using Monte Carlo simulation method to obtain the failure probability of the mechanism.By analyzing to find out the key factors of reliability and proposing an effective method to enhance reliability of the mechanism.This paper proposes a set of oriented micro satellites can be used repeatedly,with low impact,linkage,and can bear some wear deformation of the locking releasing mechanism design scheme.The layout and parameters are optimized to meet the design index,which reaches the required locking force for the driving force.This research on microsatellite repeatable locking mechanism provides a feasible solution for the on-orbit locking and release of microsatellites in the future,which has great significance for the development of microsatellites. |
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