Abstract This study aims to address the problems of low efficiency and safety hazards of traditional manual methods in the maintenance of large and small diameter pipelines, as well as the shortcomings of existing robots, such as limited throughput capacity, single function mode, and dependence on manual labour. In this paper, a new multi-functional modular pipeline robot is designed for small pipelines with diameters ranging from 220 mm to 300 mm. The robot integrates cleaning, repair and detection functions and …