On-line, kinodynamic trajectory generation through rectangular channels using path and motion primitives

We present a motion planning scheme for ground vehicles operating in a partially known environment. Kinematic constraints stemming from vehicle dynamics and from the requirement that the path must remain inside a free channel of a rectangular cell decomposition of the environment at all times, are dealt with by constructing a time-parameterized path using an appropriate combination of a finite number of path and motion primitives. This simplifies considerably the motion planning problem and, furthermore, reduces the computational cost of replanning at each time instant. Our analysis also provides closed-form expressions on the size of each cell so that the ensuing cell decomposition is compatible to the vehicle dynamics.