Seminar on “A Robotic Inspection System Large Bore Sewer System”

The Singapore used water transport infrastructure comprises of trunk sewer, link sewer network and the Deep Tunnel Sewerage System (DTSS). Environmental conditions and activities, in and outside the tunnels, can lead to deterioration and damage to tunnel assets. Inspection is an essential aspect of infrastructure maintenance. The use of robots to inspect such underground spaces, as well as to enhance inspection and maintenance capabilities is being explored by a team of researchers from Nanyang Technological University, in collaboration with PUB. This approach promises enhance productivity and reduces the risk to humans from prolonged incursions into a hazardous environment.

Deploying robots into the sewer systems is not a trivial problem. Frequently, structural obstructions in the tunnel restrict access. The depth of service tunnels can be up to 50 m with distances between adjacent accesses points up to 500m and, occasionally, up to 2km. Keeping the robots supplied with power is critical and with conflicting operational advantages.

A robotic system has been designed and a prototype built. An inspection array, mounted on the robotic platform with three HD cameras and four LED spotlights, is capable of capturing a near 270 degree of the tunnel’s interior surface above water. Deployment trials were done collaboration with PUB as well as a local contractor. Post processing of video data allows a stitching of images from the three HD cameras to form a large flat map of the tunnel surface. This permits the inspection processes to be automated for defect identification and location.

This research is supported by the Singapore National Research Foundation under its Environment & Water Research Programme and by PUB, Singapore’s National Water Agency.