Energy Efficient Use of Multirobot Production Lines in the Automotive Industry: Detailed System Modeling and Optimization

Abstract

This paper quantitatively reports about potential energy savings on robotic assembly lines for the automotive industry. At first, a detailed system model is described, which improves previously published results by explicitly considering both manipulator and electrical drive dynamics. The model closely captures experimental data in terms of actuation torques and servodrive voltages, which are directly used to derive the plant input power. Two practical methods are then evaluated for reducing the overall energy consumption. The methods rely on: 1) implementation of energy-optimal trajectories obtained by means of time scaling, concerning the robots' motion from the last process point to the home positions and 2) reduction of energy consumption by releasing the actuator brakes earlier when the robots are kept stationary. Simulation results, based on the production timing characteristics measured at a real plant, clearly shows that the system energy consumption can be effectively reduced without negative effects on the production rate

Industrial robot trajectory optimization- a review

“…This type of optimization, developed in recent times in industrial applications, due to the need to reduce the energy consumption, is found in several studies: T. Mashimo, T. Urakubo and T. Kanade [34]; D. Meike, M. Pellicciari and G. Berselli [35]; O. Wigstrom, B. Lennartson, A. Vergnano and C. Breitholtz [36]; J. Gregory, A. Olivares and E. Staffetti [37]". In these studies are used different algorithms or methods for trajectory planning, including modeling and simulation.…”

A Review on Energy-Saving Optimization Methods for Robotic and Automatic Systems

“…The first step of the general workflow of the software approach is the definition of a suitable system model: this is exploited to perform simulations and the analysis of different strategies, through the evaluation of the energy consumption and the dynamic behavior of the mechatronic system [37]. In literature, different approaches are used to build the model; it can be defined through a mathematical formulation and by considering only the main important factors (i.e., basic mathematical model) , or it is possible to also take into account secondary terms that increase the results' precision but on the other hand need more computational efforts (i.e., extended mathematical model) [71][72][73][74][75][76][77]. The availability of software simulation tools allows thus the simple implementation of complex extended models [78][79][80][81] that can describe several physical domains [37,[82][83][84][85].…”

“…Operations scheduling is a further approach related to the motion planning modification that can be found in literature, which saves energy by reducing the energy consumption of a single robotic system or a robotic cell [61][62][63][64][65][66][67][76][77][78]88,89,91,92]. In a robotic cell, a robot works synchronously with other robots or mechatronic systems, and the whole work has to be balanced in order to avoid queues.…”

“…Thus, a robot waits for the completion of the previous robotic operation before executing its task in order to avoid collisions. The scheduling approach focuses on the optimization of the robot cell operations as a whole, and two main methods can be found: time scaling [61][62][63][64][65][76][77][78] and sequence scheduling [66,67,88,89,91].…”

“…In [76,77], this approach is applied to optimize the motion of an anthropomorphic robotic cell (electro-mechanical model is needed) from the end of a process to the home position, in order not to affect the overall industrial process. Moreover, the activation of a mechanical brake during the robot idle state (also in short-time idle state) is considered to reduce the energy consumption.…”