Multibody Dynamics Of The Large-scale Coilable Mast And Solar Array

The deployment mast is the main load-bearing parts of the solar array, whether itdeploys solar array from folded state to the expanded state is directly related to theenergy supply of the spacecraft and success of mission. Large scale spacecraft such asthe space station often use flexible principles to design mast supporting large scale solararray, the typical sample includes coilable mast, FAST mast. This paper establishesflexible multi-body dynamic model of large coil mast and multi-rigidbody model of thebattery array. The reliability of the entire system during deployment, parametersensitivity and the flexible member strain are studied. The works includes:The dynamic model of coilable mast and solar array are established based on themulti-body dynamic solver Thudynamics, the parameter sensitivity that influence thereliability of coilable mast deployment is revealed. By simplifying the factual physicalrealistic, using Timoshenko beam element, rigid model, constraints, contacts andunidirectional spring force, batten, longeron, canister, diagonal are established. Coilablemast established allows arbitrarily large displacements occurred in three-dimensionalspace, large rotation and small strain deformation. The model of solar array on bothsides is established by using the function analog guy wires. Morever, battery array’sparameter sensitivity is found which cause the asymmetry during movement.Two sensitive parameters drive ratio and bay length are revealed which decide thereliability of deployment, so four solutions: adjusting the transmission ratio, increasingthe height cylinder canister height, adding guide groove, shortening the bay areproposed against the failure of coilable mast deployment, which make the mast deployand coil smoothly.The key of successful expansion and coil of coilable mast is theconnector enter into the guide. By simulating the model the section of longeron andbatten are changed, the principle of coilable mast coil and deployment is more clear: thecoil and deployment of coilable mast achieve by the batten’s buckling instability, theration of longeron and batten’s section should keep at appropriate range, if not, thedeployment and coil will fail.The law of drive torque when base is constrained and base free, axial force act onthe base, the relationship of drive velocity with drive torque are revealed: the key factor affecting axial force is transition arcs, drive torque is decided by the elasticitydeformation of mast in canister, the drive torque when base is constrained is greater thanfree. Then, tensile and shear strain of longeron and batten are extracted for reliabilityanalysis, the dangerous areas of longeron and batten are pointed out, which shows thatthe longeron and batten should be made of material own big proportion limit to meetlarge deformation and strain of coilable mast during movement, such as fiberglass. Thetense of diagonals are extracted which reveal the batten’s buckling.The integral simulation of coilable mast and solar array is completed. By studyingthe asymmetry of solar array indicates that torsion vibration of coilable mast tip is thesource, but the asymmetry can be reduced by adding stiffness and damp of connectorsbetween battery panels. The overload acceleration of transmission and rotation arecomputed and difference of acceleration is analyzed.