Optimal Design of Stiffness of Torsion Spring Hinge Considering the Deployment Performance of Large Scale SAR Antenna

전개성능을 고려한 대형 전개형 SAR 안테나의 회전스프링 힌지의 강성 최적설계

Abstract

This paper describes the stiffness optimization of the torsion spring hinge of the large SAR antenna considering the deployment performance. A large SAR antenna is folded in a launch environment and then unfolded when performing a mission in orbit. Under these conditions, it is very important to find the proper stiffness of the torsion spring hinge so that the antenna panels can be deployed with minimal impact in a given time. If the torsion spring stiffness is high, a large impact load at the time of full deployment damages the structure. If it is weak, it cannot guarantee full deployment due to the deployment resistance. A multi-body dynamics analysis model was developed to solve this problem using RecurDyn and the development performance were predicted in terms of: development time, latching force, and torque margin through deployment analysis. In order to find the optimum torsion spring stiffness, the deployment performance was approximated by the response surface method (RSM) and the optimal design was performed to derive the appropriate stiffness value of the rotating springs.

본 연구에서는 전개성능을 고려한 대형 전개형 SAR 안테나의 회전스프링 힌지의 강성 최적설계에 대해 기술한다. 대형 전개형 SAR 안테나는 발사환경에서는 접혀 있다가 궤도에서 임무를 수행할 때 펼치게 된다. 이러한 조건에서 여러 장으로 구성된 안테나 패널을 주어진 시간 내에 최소의 충격으로 전개할 수 있도록 회전스프링 힌지의 적절한 강성을 찾는 것은 매우 중요하다. 회전스프링 강성이 강하면 완전 전개시점에서 발생하는 큰 충격하중이 구조체에 손상을 주며, 약하면 전개 저항으로 인해 완전전개를 보장할 수 없기 때문이다. 이러한 문제를 해결하기 위해서 RecurDyn을 이용한 다물체동역학 해석모델을 생성하였으며 전개해석을 통해 전개성능(전개시간 전개충격하중)을 도출하였다 최적의 회전스프링 강성을 찾기 위해 이에 따른 전개성능을 반응표면법을 통해 근사화 시켰으며 최적설계를 수행하여 적절한 회전스프링의 강성 값을 도출하였다.

Fig. 1 Deployed configuration of SAR antenna

Fig. 2 Stowed configuration of SAR antenna

Fig. 3 SAR antenna analysis model

Fig. 4 Latching mechanism of 90° torsion spring hinge

Fig. 5 Latching mechanism of 180° torsion spring hinge

Fig. 6 Overconstrained mechanism

Fig. 7 Underconstrained mechanism

Fig. 8 Multi-body dynamics modeling of SAR antenna for deployment analysis

Fig. 9 Flowchart of response surface method

Fig. 10 Central composite design for two design variables

Fig. 11 Normalized response surface of deployment performances

Fig. 12 Comparison of analysis result of 90° hinge before/after optimization

Fig. 13 Comparison of analysis result of 180° hinge before/after optimization

Fig. 14 Comparison of latching force of 90° hinge before/after optimization

Fig. 15 Comparison of latching force of 180° hinge before/after optimization

Fig. 16 Comparison of deployment configuration of SAR antenna before/after optimization

Table 1 Mass properties of SAR antenna panel

Table 2 Number of constraints and active DOFs of various types of joints

Table 3 Level of design variables

Table 4 Central composite design table

Table 5 Torsion spring hinge stiffness result of before/after optimization