Applied energy optimization of multi-robot systems through motion parameter tuning

In this paper, an optimization method for energy reduction of robot stations is presented, including an evaluation on an industrial robot station. The problem is formulated as a convex mixed integer nonlinear optimization problem, where the objective is to reduce the energy use by finding the optimal execution time and execution order of the robot motions. A simulation model of the station is used to find simplified energy models of the robot motions, that is used to solve the optimization problem. The optimal execution times of the robot motions are realized by tuning parameters in the robot control system. Different types of parameter settings are tested, such as reduced acceleration and velocity. The optimal parameter settings are then implemented in robot code in a real four robot welding station. The result shows a 12% reduction in energy use, without extending the cycle time of the station. A validation of the energy models used to solve the optimization problem is also made, by comparing them with real energy measurements. (C) 2021 CIRP.