Specifying and Synthesizing Energy-Efficient Production System Controllers that Exploit Braking Energy Recuperation

Abstract

Reducing the energy consumption is a major concern in industrial production systems. One approach is recuperating the braking energy of robot axes. Ideally, their acceleration and deceleration phases should be synchronized so that the braking energy of one axis can be reused directly to accelerate another. This requires a detailed alignment of the axes' trajectories, but also a careful design of the overall discrete control. Finding an optimal control strategy manually, however, is difficult, as also many functional and safety requirements must be considered. We therefore propose an automated methodology that consists of three parts: (1) A scenario-based language to flexibly specify the discrete production system behavior, (2) an automated procedure to synthesize optimal control strategies from such specifications, including PLC code generation, and (3) a procedure for the detailed trajectory optimization. We describe the methodology, focusing on parts (1) and (2) in this paper, and present tool support and evaluation results.

Trajectory Optimization Methods for Robotic Cells Considering Energy Efficiency and Collisions

“…In this paper the second part of a novel engineering methodology for the development of energy-efficient production system controllers is presented. The functional principle and results of the first optimization level (SCO) have already been published in [12]. This publication presents the underlying optimization strategy (DTO) together with a collisions detection.…”

“…Since the model is often invoked within the optimization, one of the main requirements, besides the accuracy, is a short computing time. The complete model was already presented in [12] but it will be described roughly for the sake of completeness. The general structure of the energy flow is shown in Fig.…”

“…An automated methodology to exploit braking energy recuperation though scheduling and slowing down trajectories was proposed in [12]. The proposed methodology accomplishes this in two levels.…”

“…For example, the braking phase of one axis can be shifted, stretched, or compressed to match the energy demand for ac-celerating another axis. In this paper, we focus on the DTO, a method for the overlying SCO was already published in [12].…”

Simulation-Based Efficiency Comparison of Different Mains Configurations for DC Grid Branches for Supplying Production Plants Based on a Rule-Compliant Design

“…With a DC network, the structure is reduced to an inverter, whereby the entire lossy rectification and the associated material costs are eliminated. This extended DC intermediate circuit with storage and consumers opens up the possibility of energy utilization of electrical braking energy, which is often only dissipated specifically in the form of heat via braking resistors [2][3][4][5]. In the industrial context, the introduction of DC grids can save around 10 to 12% of the total electrical energy per year [6].…”