Deployment Dynamics And Control Of A Solar Array System With Mast

Solar array system is an important functional component of the spacecraft.It provides required electric power for the spacecraft in on-orbit working.Therefore,Successful deployment of the solar array system is of great importance for the spacecraft system.Along with the advance of aerospace science and technology,space stations,large space telescopes and space solar power stations and other large spacecrafts have been designed and built,so more and more solar array systems with deployable masts are applied to the spacecraft.The structure of the solar array system with deployable mast is complex with lots of components;the stiffness is much lower and the scale is much larger than the traditional solar arrays.All these features have improved the quality of the solar array system with deployable mast.However,complexities in experiment and simulation arise too because of these features.Calculation amount of modeling and simulation is significantly raised.What’s more,there are many other problems during the deployment,such as topology changes,contact and impact,joint clearance,friction and controller design.There are big challenges in the front of establishing a reasonable model and simulation.The research was funded by the National Natural Science Foundation of China(11272202,11132001)and the Natural Science Foundation of Shanghai(16ZR1436200).This dissertation studies deployment dynamics and control problems using a solar array system with deployable mast as research object.Some achievements are obtained both in theory and application and a few highlights are as follows:(1)Dynamic model of the solar array system with deployable mast is established by the Jourdain velocity variation principle and a method for dynamics with topology changes is introduced.The deployment of the system is simulated.Simulation results indicate that the proposed model is effective to describe the deployment dynamics of the system.The effects of guy-wire,tension control mechanism and joint damper on the system performance are studied based on the modeling method.(2)Considering the characteristics of multiple joint clearances,theoretical derivation processes of contact detection and contact force calculation are given.A three-dimensional revolute joint model with clearance is established.The effects of clearance on components of the system are discussed.Simulation results show that clearance will affect the deployable units,the container and the flexible sub-panels.(3)Dynamics modeling of the system with clearance and friction is studied.Some existing friction models are introduced and analyzed.The method to calculate the friction force is given.Simulation of the solar array system with deployable mast is carried out considering joint friction.The effect of friction is investigated by comparison of the simulation result.(4)Considering the large scale and low stiffness of the solar array system with deployable mast,dynamic model of a floating spacecraft with deployable mast and solar arrays is established.A new controller with disturbance estimation is designed based on the traditional PD controller and the stability of the controller is proved.Simulation is performed and the effect of the deployment on the spacecraft main-body is discussed.Simulation results show that the proposed controller could achieve better control effect than the traditional PD controller.(5)Based on the Object-oriented technology of C++ language,a multibody dynamics simulation program is developed used for the solar array system with deployable mast.The program is universal and extensible.Basic features and simple operations of the Object-oriented technology of C++ language are introduced by some examples firstly.And then simulation flow and other details of the program are given.Finally,the universality and validity are proved by comparison of several numerical cases.