Perspective and preconditions for the development and use of autonomous inspection robots in water mains

Asset management of distribution networks is currently based on generic knowledge and models of mains groups, supplemented by inspection data on a limited number of mains. Effective asset management requires data about the condition of mains, so that priority can be given to those mains with high failure probability and high failure impact. There are a variety of techniques to establish the condition of mains onsite, but these are not yet perfect nor universally applicable.

In this project we evaluate a system of autonomous inspection robots (AIRs), which remain permanently in the network and are equipped with various sensors which, among other things, determine the condition of the mains. The objective is to establish the extent to which the AIR system meets the needs of the water companies when it comes to achieving effective asset management.

Assessment of the value of autonomous inspection robots

On the basis of a survey, we determined the degree to which the autonomous robot system meets the development needs of water companies regarding techniques which, on the one hand, can establish the occurrence or progress of specific degradation mechanisms and, on the other hand, can satisfy further inspection needs, such as visual inspection, xyz determination and sampling. For purposes of comparison, the same analysis was applied to the alternative concepts. The characteristics required of such a robot system were then noted, a business case calculated, and the outline of a development process and a perspective for its future application sketched.

Perspectief en randvoorwaarden voor de ontwikkeling en toepassing van autonome inspectierobots in waterleidingen

Vision of a system of autonomous robots that can (A) freely move through the network; (B) be introduced and removed locally for maintenance work; (C) be powered at, and deliver data to, various points in the network; and (D) conduct relevant measurements wherever they are.

Considerable financial benefit

By avoiding premature mains replacement, cutting water loss and reducing failures, the use of the autonomous inspection robot offers water companies a considerable financial benefit: estimates point to annual savings of € 22.7 million for all of the Netherlands. Additional benefits include the possibility of monitoring work activities and system improvement. Taking into consideration the robots’ acquisition and operational costs, the power-supply and data processing system costs, alongside the non-quantifiable benefits, the outcome is a positive assessment of the business case.

It is recommended that the development of an autonomous robot system be conducted in an anticipated follow-up project. The use of autonomous inspection robots would enlarge the knowledge base for asset management decisions, and improve the quality of the elements that form the bases for these decisions. Furthermore, the general knowledge of the system would be enhanced. Interventions in the system would be better targeted and more accurate, and model calculations – upon which operational, tactical and strategic are based – would be more reliable.