A "capacitor" bridge builder based safe path planner for difficult regions identification in changing environments

Finding paths in difficult regions of C-space, such as narrow passages and configuration obstacle boundaries, is a rather challenging problem for path planning in changing environments. When obstacles move in W-space, these regions in C-space will change their edge points from free to collision or on the contrary, for which a “Capacitor” Bridge Builder (CBB) is proposed in this paper to identify their changing characteristics. Specifically, a “Capacitor” bridge is built between positive and negative toggled points in C-Space, which looks like capacitors stuck between narrow passages or boundary regions. Through CBB, the back boundary of an obstacle, which is less likely to be occupied immediately, is marked as a temporary safe region. Furthermore, a Half Bridge Strategy (HBS) is novelly proposed to boost samples inside these regions. Eventually, highly safe paths are revealed by predicting moving directions of obstacles, then replanning times and total planning times will be decreased significantly. Effectiveness of the proposed method has been verified by experiments with two manipulators in difficult changing environments.