In-pipe robots have become popular, allowing for non-destructive testing, visual inspection, and cleaning. In-pipe inspection is crucial for maintaining pipeline integrity, but it is difficult for humans to access pipelines and perform checks. This article focuses on an in-pipe robot navigating various pipeline structures and diameters. It consists of a center module, a tracking module, and an active pantograph mechanism. The hardware components, such as the motorized gear train, screw, pantograph mechanism, springs, track module, and angular sensors, are discussed. Additionally, the control methods employed by the robot, including normal force control and posture control, are explained. Finally, the tracking algorithms used to estimate the robot’s position and direction within the pipeline are presented.