Automatic generation of motion sequence in programmable logical control

We discuss how to automatically generate the motion sequence of actuators including parallel path divergence in the programmable logical control (PLC). Since the sequential path in PLC can be expressed by a state flow the goal of our research is to find an optimal shortest path from the initial state to the final state. In order to solve this problem, we propose a new search strategy which consists of two search stages. In the first stage, real-time A* (RTA*) algorithm is used to find a suboptimal sequential path from the initial state to the final state. Based on the suboptimal solution found by RTA*, the second stage try to pick up some underlying parallel path divergences in the suboptimal sequential path obtained in the first stage. From simulation results, we verified that our proposed method could search a suboptimal motion sequence including parallel path divergence with less computational amount.