On The Novel Solution Of The Antenna Pedestal Based On Lifting Mechanism

As the supporting device of the radar antenna and the plant of the servo system,the pedestal is the key guarantee for the realization of antenna's electrical performance.With the improvement of radar performance and the increase of antenna aperture,the design requirements of the antenna pedestal become more stringent.In view of the difficulty to meet the weight requirement in the design process of the large shipborne radar,an innovative solution of the antenna pedestal based on lifting mechanism was proposed,which adopted a two-DOF planar five-bar mechanism and a gear bearing as the pitch drive and the azimuth drive respectively.The kinematics,optimization design,structural performance,dynamics and motion trajectory planning were carried out,which were validated by the simulation based on the software.The main work can be described as follows.(1)The structural function,working principle,operating environment and accuracy requirements of the novel antenna pedestal were described firstly,and the loads under different working conditions were calculated.According to the geometric relationship of the mechanism,the kinematics and forces of the pedestal were analyzed.The configuration optimization model of the pedestal was established,which considered the driving force of the hydraulic cylinder.The artificial bee colony algorithm was employed to solve the optimization problem.Under the conditions of satisfying the ratio of ultimate length of hydraulic cylinder,the positions of the hinges and the transmission angle,the design parameters of the pedestal with better kinematic performance were obtained.(2)The finite element analysis of the antenna pedestal under typical working conditions was carried out to evaluate its static and dynamic performance.Based on the topology optimization design technology,the structural topology optimization of the key supporting parts was completed,which effectively reduces the weight of the antenna pedestal.Then the optimized pedestal was compared with the original pedestal from the aspects of maximum deformation,maximum stress,axis error and natural frequency,it was proved that the performance of the optimized pedestal met the requirements.(3)The dynamic model of the antenna pedestal was established by using the Lagrange equations.Then the different motion trajectorys of the antenna pedestal in joint space were presented by polynomial law,which can minimize the driving power of crank,hydraulic cylinder and both of them respectively.The simulation of the antenna pedestal was carried out using the multi-body dynamics analysis software,which verified the correctness of the dynamic model and the effectiveness of the planned trajectory.