Development of a novel self-locking mechanism for continuous propulsion inchworm in-pipe robot

In-pipe robots are usually used to carry many kinds of equipment to operate in the pipeline. In this article, a novel self-locking mechanism for continuous propulsion inchworm in-pipe robot is proposed. The constant power and continuous locomotion principle is obtained by upgrading the traditional pipeline robot. The structure of the inchworm in-pipe robot is designed including self-locking mechanism and telescopic mechanism. The operating principle of self-locking mechanism is analyzed for parameter design and performance evaluation. A new type of hydraulic cylinder series circuit is introduced, which realizes synchronous motion in the related mechanisms of pipe robot. And the dynamic characteristics of the hydraulic cylinders are analyzed and simulated to verify feasibility of the circuit. The prototype is developed to prove that the novel inchworm in-pipe robot can adapt to diameter of 140-180 mm pipe and has 550 N traction ability with the average speed of 0.11 m/s.