Modeling and optimization of implementation aspects in industrial robot coordination

D. Spensieri, E. Åblad, R. Bohlin, J.S. Carlson, R. Söderberg. Robotics and Computer-Integrated Manufacturing 69, 102097. June 2021.


Cycle time for an assembly line in the automotive industry is a crucial requirement for the overall production rate and business achievements. In a multi-robot station, besides workload distribution, operations sequencing, and robot motions, an important issue is robot coordination. A key aspect, so far neglected, is the robot motion delay due to the implementation of robot coordination scheduling: our first contribution is to model these delays into a mathematical formulation in order to minimize their contribution to the overall cycle time. Two different setup scenarios, based on typical hardware setups, are modeled and optimized. The major contribution is an efficient heuristic algorithm to optimize our suggested model, which provides near optimal solutions in fraction of the time required by a general optimization package. We have also integrated such algorithm in a CAM software for robot offline simulation to be able to run industrial scenarios with real CAD models from the automotive industry. The results show that it is possible to reduce the delays due to the synchronization points and consequently cycle time, while still maintaining the pre-computed nominal time scheduling for robot coordination.

Photo credits: Nic McPhee