Design of a New In-Pipe Inspection Robot

Abstract Basically robots are designed in such way that they remove human intervention from labour intensive and hazardous work environment, sometimes they are also used to explore inaccessible work places which are generally impossible to access by humans. The inspection of pipe comes in same category because they carry toxic chemicals, fluids and most of the time has small internal diameter or bends which become inaccessible to human. The complex internal geometry and hazard content constraints of pipes demand robots for inspection of such pipes in order to check corrosion level of pipe, recovery of usable parts from pipe interior, sampling of sludge and scale formation on pipe internal surface etc. Several designs of In-pipe inspection robots (IPIR) have been proposed in the literature to solve the problems related with inspection of these complicated internal geometries. Designing of an in-pipe inspection robot (IPIR) is a difficult task and hence the designer must take care of the design issues like Mobility, Steer ability, Turning radius, Size and shape adaptability, Online adaptability, Flexibility, Stability, Autonomous operation and obstacle avoidance, Efficiency at uneven surface, Safe operation, Material selection, Type of task to be performed inside the pipe, Number of actuators, Operation in active pipe line, Retrieval of robot, User friendly navigation and control system, Range of operation, Quantitative analysis of defects inside the pipe. Based on above, this research work presents investigations into design issues pertaining to development of In-pipe inspection robotics and proposes a new model of an In-pipe inspection robot to overcome some critical design issues. This proposed model is a screw drive type wall press adaptable wheeled In-pipe inspection robot. It is able to move through vertical, horizontal pipes and it can easily pass through elbow of a pipe line. This model comprises of three modules- rotor, stator and control unit. The Rotor module has three wheels mounted on the outer periphery with a helix angle of 15°. Wheels of rotor follow the helical path on the internal surface of pipe line and move in the longitudinal direction inside the pipe. A geared DC motor of 200RPM is connected to rotor by a flexible sleeve coupling. Due to its flexibility motor can transmit torque to rotor even in case of minor misalignments and can easily be stopped at any point of journey inside the vertical or horizontal pipeline, thereby eliminating the need of braking system to achieve stability. Stator module is the housing of motor and it contains three spring loaded wheels on the outer periphery. Control Module of robot consist battery and wireless control unit. Spring loaded wheels of rotor and stator provide it shape adaptability and enhance friction between wheels and pipe interior.