Research on spatial positioning of online inspection robots for vertical storage tanks

Purpose: This paper aims to introduce a new acoustic positioning method to solve the problem of space positioning for online inspection robots within the storage tank. Design/methodology/approach: The proposed positioning system comprises two acoustic signal emitters and two receivers. Emitters are brought by the robot into the storage tank. Receivers are mounted on the external edge of the storage tank floor. The spatial coordinate values and motion directions of the robot in the storage tank are calculated by using the proposed acoustic positioning algorithm. Findings: The experiment results and positioning error analysis indicate that the method can obtain the data of robotic space coordinates and motion orientation, while the positioning error of the method can be less than 20 cm. The accuracy reaches the positioning technology level of other tank online inspection robots. Originality/value: This method not only expands the positioning of the inspection robots from 2D plane to 3D space but also significantly reduces the number of positioning sensors carried by a robot and improves the safety of a robot in the tank.