ABSTRACT

In the first two examples, the moving obstacles cre­ ate narrow passages through which the robot must pass to reach the goal. Yet planning time remains much under 1 second. The fact that the planner never failed in 100 runs indicates its reliability. The configuration x time space for Example (b) is shown in Figure 8. The robot maps to a point (x ,y ,t), and the obstacles to cylinders. The velocity and accelera­ tion constraints force any solution trajectory to pass through a small gap between cylinders. Example (c) is much simpler. There are two stationary obstacles ob­ structing the middle of the workspace and three mov­ ing obstacles. Planning time is well below 0.01 second, with an average of 0.002 second. The number of mile­ stones is also small, confirming the result of Theorem 5 that in the absence of narrow passages, KDP is very efficient. As in the experiments on nonholonomic ro­ bot carts, the running time distribution of the planner tends to have a long and thin tail.