Design And Control Of The Pedestal For Multi-beam Antenna

With the development of radar antenna technology,the types of radar antennas are becoming more and more abundant,and the performance is also improving.Multi-beam antenna can cover a large area with high gain,and can adjust the beam shape according to the detection requirements,so that the spectrum resources are fully utilized,and thus it is widely used.In this thesis,the multi-beam antenna pedestal with the shape of the front surface as the cutting paraboloid is studied,and the design and control of the mechanism/structure is developed.Since the shape of the front surface is the cutting paraboloid,after comprehensive analysis of various feasible schemes,the scheme of using 6-UCU parallel mechanism as the antenna pedestal is determined,and the research on performance analysis,structure optimization,trajectory planning and pointing control experiment are carried out.The main work of the thesis is as follows: 1.Establishing the kinematic model and structural stiffness model of the 6-UCU antenna pedestal.Based on Newton's iterative method,the problem of forward kinemastic pose of the mechanism is solved.Combined with the actual application of the antenna system,the iterative result of the last time is used as the iterative initial pose of the next time in the iterative process of timing forward kinemastic solution,which improves the efficiency and reliability of the algorithm.In order to study the influence of structural parameter error on the pose error of the moving platform,the error transfer matrix between them is analyzed.Based on the virtual work theorem,the static stiffness matrix of the mechanism is derived,which lays a theoretical foundation for the structure optimization.2.Structure parameters optimization and workspace solution for multi-beam antenna pedestal are carried out.The improved artificial bee colony algorithm based on relative fitness is used to optimize the structural parameters of the antenna frame,and the optimization results are compared with the standard bee colony algorithm,which shows the superiority of the improved algorithm.A new method based on constraint classification is proposed.The golden partition search method is used to calculate the feasible domain of each type of constraint,and the workspace of the mechanism is obtained through intersection operation.For the frame mechanism that optimizes the obtained structural parameters,the flexible workspace and the reachable workspace shape and volume are solved.3.The trajectory planning and virtual motion simulation experiments were carried out.In the process of the antenna pointing,only the posture is required.Therefore,for the six-degree-of-freedom mechanism,the attitude angle matching position parameter is needed.Based on the principle of virtual branching,the correlation coefficient is determined by maximizing the attitude angle of the mechanism,and the relationship between attitude and position is obtained.In the trajectory planning,the acceleration and deceleration contour is designed with the maximum speed as the constraint,and the operation is simple,and the jerk curve has no impact continuously.In order to verify the effectiveness of trajectory planning and improve simulation efficiency,a special virtual simulation platform is built based on MATLAB.The solution of forward kinemastic,inverse kinemastic and trajectory planning algorithms are embedded,combined with the GUI to realize the virtual simulation of the antenna pedestal.4.Building the antenna frame and conducting antenna pointing control experiment.In order to reduce the structural parameter system error caused by processing,assembly and other factors,the contradiction equations are established by calibration,and the actual structural parameters are obtained by the least squares principle optimization.In order to verify the performance of the antenna pedestal,an accuracy experiment was carried out.The pose measured by the API laser tracker was used as the true value,and the pose displayed in the upper computer of the control system is compared to obtain the pose error of the antenna pedestal,and the error was analyzed.