Research On The Inspection Method Of Thread Inside The Bullet Based On Laser Profile Scanning

The internal thread of the muzzle of the shell is an important structure connected with the fuze.The quality of the internal thread processing directly affects the assembly accuracy and connection strength between the shell and the fuze,which in turn affects other properties such as the flight stability,firing strength and dispersion density of the shell.In the actual industrial inspection,due to the small size of the threads in the mouth of the shell,it is difficult to detect them,so most of the enterprises adopt the contact inspection with manual gauges.In order to solve the above mentioned problems,this paper designs a thread inspection system based on laser profile scanning inside the bullet.The main tasks accomplished in this thesis are described as follows.(1)Hardware and software design of the inspection system.According to the required functions of the thread inspection system inside the bullet,the design of the overall scheme of the inspection system is proposed,and the 2D laser sensor data acquisition and motion control modules are given to draw up the design scheme.For the software system,the requirements of the inspection system software are analyzed and a design plan is given,and the design steps and processing of the software interface are explained in detail.(2)Extraction and calculation of internal thread feature parameters.The data processing of the internal thread profile data was carried out,and the exact values of the five main thread parameters,namely the basic major diameter,medium diameter,minor diameter,pitch and thread angle of the internal thread,were calculated by fitting the algorithm according to the definition of the thread,and the calculation process was given.(3)Error analysis of the inspection system.The sources of errors in the inspection system are analyzed,and a mathematical model is established for each error in the inspection system,which is experimentally calibrated and solved to reduce the impact of errors on the measurement results of the inspection system.(4)Implementation and application of the detection system.Complete the system algorithm design and application software preparation,debugging of the detection system.Repeatability and stability experiments were conducted to verify the actual use of the detection system.