  This paper explores the Navigation Among Movable Obstacles (NAMO) problem and
proposes joint path and push planning: which path to take and in what direction
the obstacles should be pushed at, given a start and goal position. We present
a planning algorithm for selecting a path and the obstacles to be pushed, where
a Rapidly-exploring Random Tree (RRT)-based heuristic is employed to calculate
a minimal collision path. When it is necessary to apply a pushing force to
slide an obstacle out of the way, the planners leverage means-end analysis
through a dynamic physics simulation to determine the sequence of linear pushes
to clear the necessary space. Simulation experiments show that our approach
finds solutions in higher clutter percentages (up to 49%) compared to the
straight-line push planner (37%) and RRT without pushing (18%).
