Scheduling of maintenance work: A constraint-based approach

The growing demand for IT tools for maintenance management in the workplace has led to the development of a wide range of software, both of a general nature and designed for specific purposes. The need for such tools becomes more evident as the number of machines and installations grows, since their maintenance, particularly preventative maintenance, must be planned and scheduled. Planning a maintenance schedule implies knowing the tasks to be carried out, their periodicity and all the details necessary for these tasks to be accomplished. Then, bearing in mind the daily (or weekly) work orders, it will be necessary to program the exact order in which the various maintenance tasks must be carried out. This will involve coordinating a large number of temporal constraints, which can only be described as a ''headache'' for maintenance engineers. Within the framework of Knowledge Engineering, we present an application based on Constraints Satisfaction Problems (CSP) techniques, such as Forward checking, whereby, from a set of initial proposals, constraints are propagated until increasing better solutions are incrementally found. In this case, the G2 tool from Gensym was successfully applied to planning the weekly maintenance tasks of a municipal service charged with distributing and controlling drinking water supplies to a city, the main characteristic being the wide geographical dispersion of the installations and the limited personal and operative resources available.