Towards an Elevated Work Robot: the Traveling Performance of the Developing Omni-directional Inverted Pendulum Type Mobile Platform using Mecanum Wheels and/or Omni-wheels

Abstract

In this paper, an omni-directional mobile platform for high-place work robot is developed and movability is demonstrated in barrier-free environment. The newly coined term: high-place work means the high-place work where the height is within few meters and usually done with a ladder and stepladder. Generally, the machines which is used for the high-place work (like a mobile lift) have to have heavy base body and big footprint by outriggers for stability. An inverted pendulum balance controlled mobile platform is alternatively used to develop the robot which has a small footprint and high COG (center of gravity). The inverted pendulum type high COG robot needs to have omni-directional movability to keep balance in a three-dimensional world, not like a parallel two wheel type inverted pendulum robot, which has only the fore-aft directional dynamical stability. The proposed omni-directional inverted pendulum mobile platform is developed by adding omni-directional movability to an parallel two wheel type mobile platform like Segway. The additional omni-directional movability is implemented by substituting the tires by drive units which are constructed of combination of mecanum wheels and/or omni-wheels. The control system is also extended to integrate the additional lateral motion into the parallel two wheel inverted pendulum control with the intuitional maneuvering system. As the first step toward the high-place work robot, the various test driving in a barrier-free environment are done to show the movability of the mobile platform in real environment. The vehicle was able to move on a low step, over a small ditch, through a narrow corner, and over gentle slope; block pavement; braille blocks; threshold sill; and grating covers.