Optimization of Staggered Inspection Schedules for Protective Systems

This paper discusses inspection scheduling for protective systems of multiple components. Each component is periodically inspected and is not available to the system during inspection periods. Staggered inspection schedules can sometimes improve the minimum point-availability of the protective system over that of simultaneous inspection schedules. We construct a staggered inspection schedule by dividing components into subgroups; inspections of subgroups are staggered while components in the same subgroup are inspected simultaneously. A mixed-integer programming problem is formulated to optimize allocation of components into a specified number of subgroups. The method is helpful for systematically constructing a staggered inspection schedule. Multiobjective optimization is also discussed. A numerical example illustrates our method.