Abstract: Aiming at flexible job shop low carbon scheduling problem (FJSP) with sequence-dependent setup times, a new imperialist competitive algorithm (ICA) is proposed to optimize fully makespan and total tardiness as key objectives and continuously improve total energy consumption as non-key one. In ICA, a new assimilation is implemented by making each solution have more than one learning object and differing some best solutions from other colonies and a new imperialist competition is done by the new definition of normalized total cost and the inclusion of global search of imperialist. A number of experiments are conducted to analyze the relation between the deterioration degree of total energy consumption and improvement degree of key objectives. Experimental results also demonstrate the strong advantages on solving the considered FJSP.

Key words: flexible job shop low carbon scheduling, imperialist competitive algorithm, setup times, key objectives