Pipelines play an important role in delivering fluids such as drinking water, effluent water, oils, and gas. A lot oftroubles caused by piping networks aging, corrosion, cracks, and mechanical damages are possible which leads to aloss of the transported medium and can also affect the environment. Hence continuous inspection, maintenance, andcleaning are strongly demanded.
Application of robots seems to be the most feasible solutions. Robots are designedto reduce human factor and also to act in the inaccessible environment. Robots can be remotely controlled to carryout most of the inspection and even sometimes maintenance operations 1-3.Most of the previous research work have employed conventional robots such as electric motors, pneumaticactuator etc. Kurata et al. 1 developed a prototype inspired by the motion of spirochetes, driven by motors andpulleys. It does not damage the inner wall since it does not drag its body but may get jammed in the pipe ifmechanism doesn’t work properly. Osuka et al.
2 developed a pipe inspection robot, SPRING that can pass freelythrough gas pipes. Experimental results revealed a problem that the robot stops after rapid deceleration whenapproaching a valve in the piping segment. Kim et al. 3 proposed an active pipe inspection robot with the wallpressingforce adjustment using DC motor. It consists of a driving module having three pantograph-type linksspaced at 120° with three caterpillar track wheels and a control module comprising of microcontroller, motor driverand sensor interface.
It has the disadvantage of slipping. Also, high friction may damage the inner surface of thepipe. Yoon et al. 4 developed a prototype of pipe inspection robot actuated by using compressed air. Thisprototype can operate both on a plane and in liquid but difficult in bending pipes.
Fjerdingen et al. 5 proposed arobot with articulated transport mechanism consisting of series of identical modules interconnected by two rotationaljoints on both sides of the modules. Wheels at each module give forward and backward propulsion.
It is energyefficient with the disadvantage of wheel getting stuck if there is a hole in the pipe. Suzomori et. al 6 havedeveloped a micro pipe inspection robot for 1 inch pipelines that offers good mobility and has functionality suitablefor practical use. The prototype carries a camera which provides resolution for micro cracks in internal surface ofpipe and has a dual-hand system with six degree of freedom for manipulating and recovering small objects.