Dynamic Trajectory Planning Path-Velocity Decomposition and Adjacent Paths

Abstract

his paper addresses Dyna1nic Trajectory Planning , which is defined as Motion Planning for a robot A moving in a dynan1ic workspace W , i.e. with moving obstacles. Besides A is subject. both to kinematic constraints and dynamic constraints. We consider the case of a car-like robot. A with bounded velocity and acceleration, moving in a dynamic workspace vV = IR. 2 . Our approach is an ex t.ension to the Path- Ye lo c it.y Decomposit.ion [!~ ant. and Zucker, 1986) . We introduce the concept of adjacent paths and we use it within a novel planning schema which operates in two complementary stages: (a) Path s Plnnning and (b) Trajectory Planning. In Paths Planning, a set. of adjacent paths, one of which leading A to it.s goal, are computed. These paths are co llision-fr ee with the stationary obstacles and respect. A 's kinematic constraints. In Trajectory Planning, knowing that. A is able t.o shift. from one p<tt.h t.o an adjacent on e freely. we determine the motion of A along and between these paths so as t.o avoid the movin g obst.a.cles while respecting A 's dynamic constraints.