Simulation Of Air Floating And Balloon Microgravity Deployment Of Space Deployable Manipulator

In the process of on orbit deployment of deployable mechanism,the factors of deployable mechanism,such as flexibility and clearance,and microgravity environment seriously affect the deployment characteristics.It is necessary to verify the effectiveness of on orbit deployment of deployable mechanism through ground microgravity test.However,the ground test will introduce additional factors,including balloon air resistance,air foot additional tooling quality and air foot friction resistance.These factors will also affect the deployment characteristics of the deployment mechanism.At the same time,due to the design complexity and longtime of ground test,microgravity simulation and ground test are considered to verify each other.In this paper,the rigid flexible coupling model of umbrella SAR Antenna and solar panel is taken as the research object.Based on the dynamic analysis results of Adams,the influence of deployment mechanism factors and additional factors on the dynamic characteristics of deployment mechanism is fully studied.The applicability of microgravity simulation scheme is further judged and the detailed design scheme is determined.It mainly includes:Firstly,the bearing mechanism of balloon method,air flotation method and the modeling method of gap dynamics model are described.Based on Archimedes’ principle and related hydrodynamic equations,the bearing mechanism of balloon method and air flotation method is described respectively;Through the impact contact collision model and the modified Coulomb model,the contact collision force and the tangential friction force at the gap are solved respectively,which lays the foundation for the subsequent analysis of the influence of the deployment mechanism factors on the deployment characteristics.Secondly,based on the rigid flexible coupling model,the influence of deployment mechanism factors on deployment characteristics is studied.The effects of clearance and flexibility on deployment characteristics are analyzed by dynamic simulation: the peak value of locking torque decreases and the vibration frequency increases due to rigid flexible coupling;The contact and collision characteristics of the clearance lead to a certain degree of vibration in the initial stage of deployment,and a severe contact and collision phenomenon occurs in the stage of deployment and locking,and the impact force presents a trend of attenuation of harmonic oscillation;The coupling effect of flexibility and clearance further aggravates the vibration of the deployable mechanism.Thirdly,the influence of additional factors of microgravity simulation scheme on dynamic expansion characteristics is studied to judge the applicability of microgravity simulation scheme.By analyzing the influence of additional factors on deployment time,further quantitative analysis of the influence of additional factors on deployment accuracy is carried out: for balloon method,the larger the deployment speed is,the larger the deployment error is;For the air flotation method,the larger the mass of the additional tooling of the air foot is,the larger the deployment error is,while the impact of the friction resistance of the air foot on the deployment accuracy is relatively small.According to the structural and kinematic characteristics of the deployment structure and the advantages and disadvantages of the microgravity simulation method,the corresponding microgravity simulation scheme is matched for the deployment mechanism,and the applicability of the microgravity simulation scheme is further judged based on the critical deployment speed of the balloon method and the critical additional tooling mass of the air flotation method.Finally,the design scheme of microgravity simulation is determined.On the premise that the microgravity simulation scheme is applicable,based on the bearing mechanism of balloon method and air flotation method,the design scheme of balloon method and air flotation method microgravity simulation is determined according to the gravity of space deployment mechanism,that is,the size of balloon,the type of air foot and the size of air supply pressure.