Energy expenditure and makespan multi-objective optimization for cobots systems design

Abstract

Nowadays, we are living a transitional period from Industry 4.0, with its principles of high productivity and high flexibility of modern production systems due to the mass customization, to Industry 5.0, that aims to realize a more human-centered design of the workplace in order to improve the operators’ wellness. For this purpose, new technologies such as collaborative robots are always more integrated since they are able to guarantee, at the same time, productivity and flexibility but they can also perform the more burdensome tasks, leaving to the operators the more challenging ones. However, since these systems are thought to work directly with human operators, it is fundamental to consider the human-robot collaboration, in order to correctly assign the tasks to the resources. This is the cornerstone of Industry 5.0, that points toward the realization of human-centered systems.For this purpose, the here presented paper proposed a bi-objective optimization for task allocation, aiming at minimizing both the time required to assemble the parts, including so the makespan minimization as objective function, and the energy required by the operator during the work. Multi-objective optimization has already been extensively studied, however, there is still no research concerning this for collaborative systems. Hence, the objective functions are described, followed by the problem statement with the constraints included. Moreover, characteristics indexes are analyzed to evaluate the performance of the method.A case study is finally reported to demonstrate the practical implication of the research, proposing a different set of optimal solutions, which may be selected according to specific needs.