Research On Aerodynamic Characteristics And Guidance Law Of Guided Mortar Based On Position Sensor

Higher requirements on the precision of projectiles have been put forward to meet the demand of modern warfare.Correspondingly,making improvements in the guidance of traditional projectiles has become the focus of research all over the world.In this thesis,the laser semi-active guided mortar projectile was taken as research object and the position sensor detector(PSD)was used as projectile detection unit.The aerodynamic characteristics,extraction method of LOS and the guidance law have been studied,and the relevant models and algorithms involved have been analyzed and verified.The validity of the numerical method was verified by the international standard AFF model.The simulation model of the mortar projectile was divided by overset dynamic grid technology.The flow field under subsonic of the guided projectile with canards was simulated.The principles of PSD was briefly introduced,and the laser semi-active detector model has been established.Importing the concept of LOS deviation angle,the mathematical transfer formulas between LOS angle and LOS deviation angle was derived through analyzing the relative position between the projectile and the target.The extraction model of LOS angel rate was established.Due to the strong non-linearity of the model,EKF and UKF estimation models were compared and analyzed.The result shows that the UKF model has higher precision in LOS angle and angle rate extraction.The relative motion model was established in the longitudinal plane,and two different guidance laws with angle constraint were designed combining with optimal control theory and sliding mode control theory.The performance between two guidance laws was compared and analyzed.Based on the simulation results,it can be seen that both the two guidance laws can meet the angle constraint requirements when attacking the target.However,the sliding mode guidance law require lower on the maneuverability of the projectile,and the LOS angle and angle rate can converge rapidly.