| Loitering missile is favored by many countries because of its integration of reconnaissance,strike,damage assessment and other functions.Seeker is an important part of missile precision strike.Its type and accuracy determine the missile’s guidance effect and strike accuracy.The roll-pitch seeker has the advantages of small size,light weight,large off-axis angle and large field of view,making it an ideal choice for today’s precision guided weapon.The roll-pitch seeker has the two-frame structure of the roll-out frame and the pitch-inner frame,in order to achieve accurate guidance,the seeker servo control system is required to have good robustness and precise tracking performance.Therefore,the roll-pitch seeker is taken as the research object and the loitering missile is taken as the seeker carrier in this paper.The research is carried out from several aspects such as mathematical model establishment,control system parameter design,interference compensation and terminal guidance line information extraction.Firstly,according to the working characteristics of the roll-pitch seeker,the structure and working principle of the seeker are expounded,and the coordinate system of the seeker and the missile is established.On this basis,kinematics analysis is carried out.The seeker dynamics model and servo motor model are established,which lays a theoretical foundation for the follow-up research.Secondly,for the motion characteristics of the roll-pitch seeker,the servo control system is designed.Through the double-loop control form of speed-position loop,the control parameters are designed by PID parameter tuning method.The design variables are damping ratio,rising time and steady-state error.It is analyzed by time domain and frequency domain to meet the performance index of the control system.The robustness of the control system is analyzed by introducing friction disturbance.The results show that when the disturbance is small,the designed control system has a certain inhibitory effect on it.Thirdly,Aiming at the problem that the friction torque affects the servo control performance,a control method based on disturbance observer compensation is studied.The instability of seeker servo system caused by missile angular velocity coupling is modeled and analyzed.The disturbance observer is designed to suppress the friction disturbance.The design results show that the method effectively improves the robustness and stability of the control system,and enhances the anti-interference ability of the seeker.Finally,because of the special structure of the roll-pitch seeker,it can not directly provide the angular rate information required by the guidance law.For this reason,the line-of-sight angular rate extraction algorithm is derived.The simulation results show that the algorithm is correct and effective.Through the seeker flying test,the adaptability of the extraction algorithm in engineering application is further explained,and the error sources in the line-of-sight angular rate information are analyzed and filtered.The research results and ideas of this paper will provide some reference for the research and analysis of the roll-pitch seeker. |
