Research On The Kinematics And Precision Compensation Of An Antenna Pointing Mechanism

The antenna pointing mechanism is a device that can perform pointing adjustment and scanning.Based on the RRR mechanism,the antenna pointing mechanism of this paper is rotating through the rotating joints.The reflector can rotate around the focal point,so as to adjust the direction.This antenna pointing mechanism adjust to mechanical changing direction and mechanical scanning.In this paper,based on the three-axis rotating antenna pointing mechanism,we analyse its Kinematics,errors and compensation of accuracy.Aiming at the s three-axis rotating antenna pointing mechanism,first,we analyse the degree of freedom,then,we set up a mathematical model and solve the positive and negative solution of kinematics.In order to verify the correcyness and continuity of the positive and negative solutions,we do the analysis and simulationg.Then we analyzed the Jacobian and singularity of the pointing mechanism.Secondly,there are many kinds of error factors that affect the accuracy of the antenna pointing mechanism.For some basic errors,we analyse the qualitative or quantitative they carried to the focusing axis pointing,then the error solution method is carried out.Then,we analyzed the error properties of the focusing axis and set up a mathematical model according to the principle of pointing.Then,we realize the precision compensation of the antenna pointing mechanism through analyzing and soluting the positive and negative solutions.At the same time,actual direction rage of the antenna pointing mechanism under error are analyzed and carried out.Finally,gravity affects the accuracy of the pointing mechanism.Due to the influence of ground gravity when the antenna pointing mechanism is tested on the ground,we need to design a devices of gravity unloading to eliminate the influence of the gravity effect when we are expericing.The gravity unloading is divided into two parts,according to divide the module of the antenna pointing mechanism,analyzing the movement rules and organization of each.Without affecting the normal work of the directing organization and considering the feasibility and practicability,we design a device of gravity unloading.Then we use ADAMS to simulate the movement of the antenna pointing mechanism and the devices of gravity unloading,examing the effect of the unloading device.