A robotic surface treatment apparatus treats corners of rooms more effectively through intricate guidance of the apparatus through inside and outside corners. In one aspect, contact and/or non-contact sensors provide information to one or more on-board processors on the apparatus to enable selective overriding of obstacle avoidance program code and allow the apparatus to get closer to walls to facilitate treatment. In another aspect, the sensors provide information to the on-board processors to control backup motion of the apparatus to cover previously-missed areas when turning corners. In yet another aspect, the apparatus is shaped to have its treatment mechanism positioned more closely to the front of the apparatus to enable treatment more closely to walls near corners. In one embodiment, the robotic surface treatment apparatus is a robotic vacuum. The vacuum may have its cleaning brush positioned near a flat front portion of the apparatus.