Design And Analysis Of A Cable-truss Truss-type Space Deployable Mechanism

With the constant advancement of aerospace technology,space expandable institutions have emerged thereupon.In the space missions,the expandable mechanism is mainly used for supporting solar sailboards and other tasks.As the demand of space exploration missions increases,the requirements of the reliability and rigidity of the mechanism increase therewith.Whether the organization can be smoothly deployed and whether it can maintain high rigidity after the deployment become the key to decide that whether the organization can work.This paper studies a new type of cable rod truss space expandable mechanism with high rigidity,high strength and large folding ratio.The cross-section unit is made of three regular triangles.The three sides of the triangle are replaced by cables,and the central trigeminal structure is used to pull and tension the cables.Then the overall structure of the mechanism is designed.Establishing the axial,tensile and flexural rigidity models of the mechanism,and analyzing the effects of the rods and cables in the mechanism on the rigidity of the mechanism.The force form of each node of the expandable mechanism with cable rod is given.At the same time,the finite element method ANSYS is employed to analyze the rigidity of the mechanism.Two models with cable and no cable are established to analyze the influence of cable on stiffness.Analyzing the kinematics and dynamics of the mechanism,and using the nodal method to derive the motion law of each point of the mechanism.The overall kinematics model of the mechanism are established,and the speed and acceleration are analyzed,and the model is verified by case simulation.For the mechanism deployment process,the ADAMS software is used to simulate the mechanism,and the variation time of the mechanism deployment time and the torsion spring angular velocity and angular acceleration in the mechanism are obtained.After unfolding,the mechanism can be regarded as a statically definite truss,which is subjected to modal analysis to analyze the natural frequency and vibration mode.Taking the structural quality and the first-order natural frequency as the objective function,the diameters of each member and cable are designed as variables,and a mathematical model for parameter optimization is established.Based on the BP model and genetic algorithm,the optimal solution of the mechanism is obtained,and the three-dimensional model of the mechanism is designed in detail.