EXTREME VALUE ANALYSIS OF IN-SERVICE ROBOTIC STORAGE TANK FLOOR INSPECTION

Robotic technology is the most advanced quantitative in-service inspection technology for storage tank floor in the word, which can densely scan the tank floor and get thickness of tank floor without opening and cleaning the tank. Compared with the traditional sampling inspection with ultrasonic thickness gauge after opening the tank, in-service robotic inspection is more reliable and efficient. However in some situation robot can't fully scan the tank floor due to the restriction of the internal structure of tank. Here the extreme value analysis (EVA) method is applied to the data process of robotic tank floor inspection to improve its reliability, and to make this technology adapt to the situation where there are some obstacles and unreached zones on the tank floor. The procedure of EVA is introduced in detail and an example based on field inspection data is demonstrated to verify the benefits of this method.