I. Introduction
As mobile robots are deployed in ever more demanding tasks, they must traverse unknown environments containing obstacles while relying on sensors and on-board information storage. Examples of autonomous mobile robots in everyday use are vacuum cleaners [4], lawn mowers [1], and industrial warehouse robots [2]. With few exceptions of tethered mobile robots [5], [19], [25], [31], [32], mobile robots operate with on-board batteries that allow only a few hours of continuous operation [11]. The need to return for battery recharge is a major concern in mobile robot tasks that require high-power consumption or long periods of continuous operation.