Heuristics for minimizing total tardiness based on learning curves and ergonomic aspects

Abstract

Industrial environments that rely on Mass Customization are characterized by a high variety of product models and reduced lot sizes, demanding prompt adaptation of resources to a new product model. These scenarios make it hard to schedule tasks that require manual procedures with different levels of complexity and repetitiveness. This article integrates learning curves, scheduling heuristics and tasks ergonomic aspects aimed at sequencing tasks in teams of workers. For that matter, we propose the ATCE rule (Apparent Tardiness Cost with Ergonomics Factors), which simultaneously reduces the total weighted tardiness and the allocation of tasks with similar complexities to the same team (measured by percentage of saturation). When applied to two assembly lines in the footwear industry, the ATCE presented satisfactory performance in ergonomics terms by reducing the percentage of saturation compared to the results yielded by the ATC rule (Apparent Tardiness Cost). In addition, the objective function slightly increased in both cases.