Energy conscious scheduling of a material handling robot in a manufacturing cell

In cyclic scheduling of material handling robots in manufacturing cells, a common approach is to minimize the cycle time objective, which is a measure of the throughput of the cell. In a typical robot move cycle, robot move times constitute a significant portion of the cycle time. During handling operations, robots consume significant amount of energy, which is determined by their speed, load and the distance they travel. In this paper, we propose considering robot speed decisions along with robot move sequencing decisions in a robotic cell scheduling problem. We study the trade-off between the cycle time and the energy consumption of a robot in a robotic cell which produces identical parts. In this cell, the robot loads and unloads the machines. Each machine performs a different operation on a part and the robot moves linearly along a track. We provide models to find efficient solutions for cycle time and robot energy consumption objectives in an m-machine robotic cell. In a case study for two machine robotic cell, we show that robot speed control can lead to significant savings in energy consumption.