| Deployable mechanisms in spacecraft generally have the characteristics of large space and low structural rigidity due to their functional requirements and structural characteristics.This character leads to that if small environmental changes,the structure will vibrate greatly.Such vibration will affect the stability and accuracy of the structure,and it will also cause premature fatigue damage to the structure.Clearance of joint exist widely in deployable mechanisms.This paper studies the influence of the rotating hinge clearance on the dynamic characteristics of the mechanisms.This paper takes the flexible and deployable mechanism with rotating hinge clearance as the research object,based on the dynamics of flexible multi-body system,uses the contact collision model to simulate the effect of the components at the rotation hinge clearance,and uses the virtual experimental modal analysis method(VEMAM)to analyze the the effect of rotating hinge clearance on the dynamic characteristics of flexible deployable mechanism.First of all,this paper analysis the the dynamic characteristics of the mechanism by using virtual experimental modal analysis method based on the dynamics response of a flexible multibody system(BEM-DFMS),considering the flexibility and nonlinearity.And in the multi-body dynamics software,the flexible and deployable mechanism model is established and the virtual experimental modal analysis is performed.The dynamic characteristics of the obtained flexible deployable mechanism are compared with the results obtained from the computational modal analysis in the finite element software to verify the validity and correctness of this method.Then,based on the virtual experimental modal analysis method of the dynamic response of the flexible multi-body system,the natural frequencies of the flexible deployable mechanism with ideal rotating hinge and the flexible deployable mechanism with rotating hinge clearance are compared,the effect of the rotating hinge clearance on the flexible deployable structure is analyzed.The results show that the existence of rotating hinge clearanc will reduce the natural frequency of the mechanism.Finally,based on the collision contact model of the rotating hinge clearance,the influence of each parameter of the rotating hinge clearance on the dynamic response of the extension mechanism is explored,and based on the dynamic response of the mechanism,the effects of the various parameters of the rotating hinge clearance on the dynamic response of the deployable mechanism are analyzed.It provides ideas and basis for controlling and optimizing the dynamic characteristics of the deployable mechanism by modifying the various parameters of the rotating hinge clearance. |
