Study On Vision Assisted Robot System For Magnetic Field Distribution Measurement

The electromagnetic focusing system of multi-beam klystron is a key part ofradar system, as well as its magnetic field distribution characteristics have animportant effect on the performance of radar. Because of the difficulty of detectionand location for deep hole, the measurement of magnetic field for electromagneticfocusing system is a difficult problem which has restricted the research anddevelopment of klystron for a long time.This paper is supported by the sub-project, the magnetic field measuring systemwith vision positioning, of the national high technology research and developmentprogram ("863"Program) of China named L-Band and multi-beam continuous wavebroadband klystron (ID: 2002AA872020). Aiming at the key technologies andtheories of probe precise positioning and intelligent measurement, as well as thedevelopment of the measurement equipment, the robot system for magnetic fielddistribution measuring of deep hole based on visual guiding and locating is studied.The main works of this paper are as follows:1. The structure, properties and measuring methods of electromagnetic focusingsystem of the L-Band and multi-beam continuous wave broadband klystronare analyzed. Combined with the requirements of measurement, the generalscheme of robot system for magnetic field measuring is given, which issuitable for electromagnetic focusing system. The research works of therobot's sub-system are also carried out.2. To guarantee the data reliability and safety of equipment, the probe must beadjusted to be perpendicular to the upper surface of the electromagneticfocusing system before measuring the magnetic field. The photogrammetrytheory based on P4P model is studied deeply. A pose measurement andadjustment method based on P4P model is proposed. The auto-focusingalgorithm, image denoise algorithm and corner extraction algorithm are alsodiscussed. The experiments show that this method can achieve higherprecision, and is easy to use.3. According to the precision positioning problem of hole center after theadjustment of probe, the distortion characteristic of circle array with camera model of one order radial distortion is analyzed thoroughly, and then a newapproach for solving the camera distortion parameters and positioning thehole center based on circle array is proposed, which improves the accuracyand speed of positioning for electromagnetic focusing system effectively.4. Due to the traditional magnetic measuring method with equal interval can notmeet the requirements of detection efficiency and details at the same time,the dynamic adjustment method of measurement intervals during the processof magnetic measuring is studied thoroughly. According to the control modelof magnetic measurement, a new measurement method based on greyprediction and fuzzy logic model is proposed, which can adjust themeasurement intervals dynamically by the change trend of magnetic field.And this method can achieve better measurement control effects inapplication.5. According to the theory of machine vision and robot system, the visionassisted robot system for magnetic field measuring is developed, which canmeet the measurement requirements of multi-beam electromagnetic focusingsystem such as precision, reliability, intelligence and efficiency. And thismeasurement system has been put into use in institute of electronics, ChineseAcademy of Sciences successfully.