The Research Of The Automatic Magnetic Flux Leakage Inspector For Tank Floors

Storage tanks are special equipments which play a very important role in storingliquid ingredients and intermediate products for oil stocks, port and petrochemicalenterprises, and infrastructures in petroleum, chemical industry, fire fighting,transportation, metallurgy, national defense and other industries, etc. The safe and stableoperation of storage tanks is directly related to the national economy and people’s livessafety, which play in important role in petrochemical production and people’s life.Although remarkable achievements has been made and a series of related products hasbeen developed around the tank bottom detection at home and abroad, most of thesedetection equipment need the inspectors enter the storage tanks. In order to overcomesuch disadvantages such as the low-level automation, high labor intensity and lowefficiency for the current tank floor testing system, an automatic MFL inspector for tankfloors is developed, which realize the combination of the magnetic flux leakagetechnology and robot technology, improve the detection efficiency of tank bottom plateand reduces the detection of the inspectors’ labor intensity, has wide prospects andimportant significance.Firstly, according to the tank bottom plate testing environment, this paper analyzesthe functions which the inspect equipment need to achieve. Three wheels institution isselected as the travel mechanism of the detection equipment which adopts doubledifferential drive. The appropriate drive device, transmission device, positioning deviceand marking device are chosen. The dynamitic model of the inspect equipment has beenset up. Through in-depth analysis of the existing guidance technology, the laserguidance has been chosen.Secondly, the hardware circuit of the control system has developed. Through theanalysis of the overall structure of the hardware circuit, the main controller module,power supply module, motor drive module, the speed detection module, the directiondetection module, data processing module and so on main components of the hardwareselection and circuit design has been given. According to the positioning technology, theinspect equipment can plan path. Motion control and magnetic flux leakage testing arethe primary problem of the inspect equipment to solve, and the key factors to realize thefunctions of the inspect equipment. On the basis of completion of the hardware circuitdesign, the software program of control system has been designed. The motion controlalgorithm of the inspect equipment is studied, which discusses the speed control anddirection control, and analyzes the application of PID control in motion control andPWM motor control principle.Finally, through the study on the experiment of testing equipment including thepath tracking effect, the effect of motion control and the testing of MFL signalprocessing ability, verify the hardware of control system and the validity and reliabilityof motion control algorithm. The inspect equipment realize drive automatically which can detect and judge defect and mark timely on the defect location. So the purpose ofdetect independently has achieved.