Robotic Systems for Sewer Inspection and Monitoring Tasks: Overview and Novel Concepts

The sewer system is an essential part of the public infrastructure. Many structures are in poor condition due to their age, so regular inspections and considerable maintenance work are required. Often occurring damages are cracks, holes, deformation of pipes, and displacement of joints. Currently, inspections are mainly carried out using manually controlled robotic systems. The assessment of the condition and detection of damage is performed by trained personnel based on camera images. This is a slow, tedious, and monotonous labor that automated processes should replace. Autonomous robotic platforms, high-resolution camera images, and laser scans generating a digital twin of the sewer system are intended to simplify proactive maintenance through regular damage monitoring and compensate for the shortage of skilled workers. This article examines which robotic systems and sensors are currently employed for commercial sewer inspection, what limitations they have on defect detection, and which advanced systems and sensors could be used to overcome these restrictions. Alongside other advanced systems, a new concept for a robotic system is presented to add intelligence and automation to the sewer inspection process using a camera ring, a laser scanner, and onboard high-power computation.