Research On Key Technology Of Strapdown Laser Semi-active Guided Mortar Control System

In order to correct the trajectory of double-spin projectile accurately,a steering gear control system with a permanent magnet synchronous motor(PMSM)as the actuator has been designed.Based on the characteristics of low rotation speed,small volume and high overload of the gun platform,the working principle and driving method of the permanent magnet synchronous motor were analyzed,and the structure of the steering gear was optimized to save space and cost.In order to improve the precision and robustness of the control system,the control performance of the motor under different driving modes was evaluated.The decoupling control of flux and torque generated by the stator of the permanent magnet synchronous motor was realized through space vector pulse-width modulation,and the torque pulsation of the motor under low rotation speed has been effectively reduced.The correction principle and function requirements of steering gear were analyzed,and the position,speed and current three-closed-loop control system of steering gear under the inertial system was established by the combination of the classical PID control theory.In order to improve the update speed and accuracy of feedback information of the steering gear control system,a simple magnetic encoder was designed by making full use of motor structure,which can quickly and accurately reflect the rolling information of rudder wing relative to missile body.The roll information of the projectile was obtained by the use of geomagnetic sensor and GPS,and the calculating model of the projectile roller under the inertial system was established.Combined with the output information of the magnetic encoder,the roll information of the rudder wing under the inertial system could be calculated in real time so as to realize the roll control of the steering gear.Matlab/Simulink software was used to model and simulate the three-closed-loop vector control system of the double-spin steering gear.The simulation results show that the control system has rapid response,smooth movement,low torque ripple,good dynamic and static performance.In order to evaluate the actual control performance of the steering gear control system,the hardware design of the main control circuit,signal detection circuit and drive circuit with ARM processor as the core was completed,and the functions of data communication and storage,signal acquisition and capture,control algorithm operation and control signal output of the control system were realized through Keil software.At last,the rolling control experimental of the steering gear was carried out through the ground semi-physical simulation platform.The experimental results show that the position response time of steering gear control system is less than 0.5s,the position error is less than2~?,and the rotational speed error is less than 4r/min,which has good control accuracy and stability and can meet the needs of practical engineering.