Design and analysis of a pipe robot based on metamorphic mechanism

Addressing the challenges of limited passability and adaptability encountered by existing pipe robots in navigating through tee and four-way junction pipes, This article designs a pipe robot based on the principle of metamorphism. This robot is designed with a variable number of linkages, constituting the core of its system structure. Through this innovative approach, it achieves movement in diverse types of pipelines by altering its own structural configuration. Kinematic analysis is conducted using both the Denavit-Hartenberg (D-H) method and screw theory, providing expressions for the forward kinematics in terms of the robot’s positional and attitudinal states, as well as geometric solutions for the inverse kinematics. Simulations conducted in MATLAB and ADAMS software demonstrate consistent postural changes of the robot, validating its design and capabilities. Prototype experiments in a 500 mm diameter pipeline further confirm the robot’s structural design rationality and its ability to navigate through tee and four-way junction pipes by altering its posture. The results indicate that this pipe robot effectively navigates through straight, vertical tee, and horizontal four-way junction pipes, offering a viable solution for efficiently maneuvering through complex pipeline junctions.