Research On The Measurement Method Of Outfield Projectile Movement Attitude Based On High-speed Imaging Technology

Studying the motion attitude of the muzzle projectile is of great significance for controlling and improving firing accuracy of the artillery.Aiming at the measurement demand of large-caliber projectile attitude,the research on the attitude measurement method of large-caliber projectile based on high-speed imaging technology is carried out.The measurement principle and working process of the current shadow camera station,the motion characteristics of large-diameter projectiles and environmental characteristics were analyzed in detail.On this basis,the main points and difficulties of the measurement system design were expounded.Based on the high-precision measurement requirements of pitch angle and yaw angle,the camera station adopts the “horizontal-vertical” orthogonal layout of the camera optical axis to reduce the conversion error between the image coordinate system and the camera coordinate system.The camera and lens parameters were calculated and analyzed,including camera resolution and lens focal length,and the dust-proof design and the stray light suppression design of the imaging components were carried out.The measurement system calibration method based on laser reflection alignment was employed.The collimated light source module and double square nets position-attitude detection module were designed.Due to the fact that the camera field of double square nets' s mesh area could not be occluded and the measurement system's measuring line was high and adjustable,the six-axis parallel robot with large visible area was selected,and the movable adjustment table and two different heights of double square nets bases were designed.The static simulation of the movable adjustment table,by using FEM,showed that the height adjustable range of the movable adjustment table was up to 80 mm under the condition of wind load of 75 Pa and vertical load of 1000 N.Aiming at the lack of moving tracks in the field environment,the docking station handling module was designed.Aiming at the low contrast and shock wave noise of shadow images,the segmented gamma transform was used to enhance the shadow image.A tip extraction method based on the intersection of the central axis and the edge was selected.A method of the projectile tail feature extraction based on ellipse fitting was proposed and simulated.The simulation results showed that the extraction accuracy of the tail center point of the projectile was 0.44 piexl.The measurement error of the measurement system was analyzed,and the large-caliber projectile attitude measurement system was built,and the accuracy verification experiment was carried out.The experiment showed that the attitude measurement accuracy was better than 1?,which meet the task requirements.The attitude measurement experiment of the 155 mm projectile was carried out,and the pitch and yaw angle of the projectile were obtained.The accuracy verification experiments and 155 mm projectile attitude measurement experiments show that the proposed measurement method is effective and the designed measurement system is feasible.