Abstract
Energy efficiency is an important goal of robotic design, especially within the framework of Industry 4.0. In this paper, a methodology is proposed to reduce the energy consumption and is then demonstrated on a two-degree-of-freedom parallel robot (i.e. a Delta-2 robot) performing cyclic pick-and-place operations of a predefined trajectory. We define a mixed approach as a methodology that exploits two kinds of energy reducing systems: springs for storing elastic energy and capacitors for recovering braking energy. Using an optimization-based design methodology, two torsional springs with optimum stiffness values are coupled with energy-recuperating drive axles, leading to a reduction of motor torque required. Results show that this approach allows for a significant reduction in energy expenditure.