Abstract: Reliability is formulated in parallel machine energy-efficient schedluing problem, to consider the impact of machine condition on processing energy, and to reduce energy consumption effectively in production workshop. A mathematical programming model is developed with the objective to minimize both tardiness cost and energy cost. An ant colony algorithm is designed to solve the problem. A new heuristic factor is proposed to design the search process. And local search mechanisms are embedeed in the algorithm to improve the quality of the solution. The effectiveness and efficiency of the algorithm are verified by computational experiments. The impact of reliability dispersion and due date tightness on scheduling decisions are evaluated through sensitivity analyses, which provide useful support for real shop scheduling.

Key words: energy consumption; reliability; ant colony optimization (ACO); parallel machines; sheduling