Snakes. Why’d it have to be snakes? Because it turns out those long thin bodies make snakes nature’s perfect model for robotic pipe welders. LaserPipe, a collaborative project led by OC Robotics and TWI, recently developed and demonstrated a unique, snake-like robotic welder capable of navigating narrow, twisting pipes that slow normal joining methods to a crawl.
Pipe-welding is usually an expensive and time consuming job requiring welders to accept a cramped workspace and potentially dangerous conditions. Standard practice for joining pipe segments involve a welder either joining those segments by hand, or using large orbital welding machines that circle a pipe from the outside. Both of these process are efficient enough when working with straight pipes, but things get much more complicated when you’re dealing with the spaghetti-like junction of an oil refinery or a reactor container.
By combining a OC Robotics’ Series II X125 robotic arm with a specially fitted laser-welding head, LaserPipe has created the perfect welding tool for navigating these twists and turns. The robotic snake is controlled by a human operator who actually directs the head of the the robot through the pipe. The head is equipped with HD cameras and remote location sensors to help the operator navigate the cramped space.
The eerie undulation of the machine’s snake like body is also part of what helps set the device apart from other “pipe-running” welding robots. The operator only steers the robot’s head. The long body, which houses the fiber optic cable used to power the laser, moves rhythmically behind as it intelligently avoids as much of the pipe as possible along the way.
A collar needs to be fitted around the joint to keep the 5kW laser from scattering beyond the pipe, but as the whole welding system weighs under 11lbs, it remains easier than affixing a large orbital welder to the pipe. The snake can fit into any weld-standard pipe, rotates 360 degrees, has 22 degrees of freedom and has a sheath to protect the arm from splatter and abrasions. To help the operator weld with precision, the laser head cameras are paired with a laser alignment system that maps out the exact path for the welding laser.
When the welding operation is done, the snake remembers the path it was guided down and retreats along an identical exit path, adding to the method’s efficiency. The technology developed through the year-long LaserPipe project was funded by Innovate UK in an effort to improve the technology available for repairing and replacing pipes used in the nuclear industry. The robotic snake welder has a bright future in aerospace, construction, defense, and oil & gas industries as well.
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