Concept and design a new indoor service robot locomotion technology are described in the paper. The proposed solution extends the workspace of existing indoor ground based service robots in the vertical direction, while ensuring higher payload capability than aerial robots and less environment invasive than industrial gantry robots. The concept under development is highly innovative in the sense that it will combine the planar stepping motion of an arm on the ceiling, and the 3D controlled pendulum like motion of the working unit relative to the arm. This is a novel approach to cover the whole volume of a room. In addition, the ACROBOTER is designed to work autonomously or in close cooperation with humans and to be capable of collaborating with other robotic devices.