Dynamic Analysis And Design Of Parallel And Hybrid Antenna Supporting Mechanism

Antenna is an important equipment for data information interaction in the fields of space exploration,navigation early warning and military investigation.The parallel antenna supporting mechanism has the characteristics of large structural stiffness,strong bearing capacity and small cumulative error.It can drive the reflector to realize continuous rotation,thus effectively avoiding the blind area of detection,which helps to improve the stability and pointing accuracy of the antenna system.In this paper,the key technologies and basic problems of the parallel antenna supporting mechanism are studied according to the requirements of the aerospace field for the trajectory tracking of the antenna supporting mechanism.The purpose is to explore the design and application of the parallel antenna supporting mechanism from the aspects of configuration analysis,kinematics and dynamics,and structural design.The main research contents are as follows.In this paper,the basic principle and application of screw theory are systematically expounded,the important operations of vector cross multiplication are summarized,the coordinate transformation and differential transformation expressions of velocity screw and force screw are derived,the relationship between rigid body angular velocity,velocity screw,pose matrix and Lie group,Lie algebra is revealed,and the expression of space acceleration and force balance equation of rigid body is explained,which lay the foundation for the theoretical basis research of this paper.Taking the 6 degree of freedom(DOF)parallel antenna supporting mechanism with strong bearing capacity as the research object,the motion pose simulation of the 6-DOF parallel antenna supporting mechanism is carried out,and the constraint matrix and its differential expression of the parallel antenna supporting mechanism are derived.The dynamic analysis of the parallel antenna supporting mechanism is carried out with the help of screw theory and rigid force balance equation,and the parallel antenna supporting mechanism is analyzed with the help of simulation software considering the branch stiffness,the vibration characteristics of the parallel antenna supporting mechanism are analyzed.The calculation accuracy of the dynamic model based on the screw theory is studied through comparative analysis.The 2UPS-PU 3-DOF parallel mechanism is applied as a parallel antenna supporting mechanism.The DOF properties of the 2UPS-PU parallel antenna supporting mechanism are analyzed.The pitching,azimuth and stowing motion capabilities of the 2UPS-PU parallel antenna supporting mechanism are studied.The kinematics analysis of the2UPS-PU parallel antenna supporting mechanism is carried out,and the kinematic model of the 2UPS-PU parallel antenna supporting mechanism is established based on the constraint matrix.The workspace of the 2UPS-PU parallel antenna supporting mechanism is analyzed,and the kinematics and dynamics theoretical model of the 2UPS-PU parallel antenna supporting mechanism is verified by simulation combined with the motion trajectory of the 2UPS-PU parallel antenna supporting mechanism.The 3-RSR 3-DOF parallel mechanism is applied as a parallel antenna supporting mechanism.The constraint matrix and its differential form of the 3-RSR parallel antenna supporting mechanism are derived.The expressions of velocity screw and spatial acceleration of each member are derived.Based on the screw theory and force balance relationship,the dynamic model of the 3-RSR parallel antenna supporting mechanism considering wind load is established.The dynamic model considering wind load is simulated.Considering the polarization rotation requirement of antenna reflector,a3-R(RRR)R+R hybrid antenna supporting mechanism suitable for non-circular polarization antenna is constructed based on the prototype of 3-RSR parallel antenna supporting mechanism.The DOF property of the hybrid antenna supporting mechanism is analyzed based on the screw theory,and the motion and envelope space of the hybrid antenna supporting mechanism are analyzed.The static analysis of the mechanism is carried out,and the deformation of the typical posture of the mechanism is studied by means of the finite element software.The kinematics and dynamics analysis of the3-R(RRR)R+R hybrid antenna supporting mechanism are carried out by using the screw theory.The structure design of the hybrid antenna supporting mechanism is carried out and the prototype is developed.The key components of the experimental prototype of the parallel antenna supporting mechanism are designed,the electrical system and software system are designed and selected,the controller and driver main circuit of the system are designed,and the human-computer interaction interface of the control system of the parallel antenna supporting mechanism is developed.Based on the experimental sample machine,the motion characteristics of the parallel antenna supporting mechanism are tested,and the parallel antenna supporting mechanism is analyzed,the motion performance and trajectory tracking accuracy are verified.