Design and Control of a Novel Hybrid Typed Outdoor Mobile Robot Platform: MobED

Abstract

Mobile robot platforms are increasingly utilized in various automation applications due to advancements in platforms and autonomous navigation. Outdoor mobility places tougher requirements on robot platforms than indoor environments, and is thus being actively researched. In this paper, we propose a novel mobile robot platform with a unique mechanical design and control methodology developed to address the limitations of previous mobile robots. The robot, with 12 active degrees of freedom (DoFs), is devised to combine the ground-adaptability of legged platforms with the advantages of a wheeled platform such as high payload and energy efficiency. Its independent steering/driving system enables mobility beyond car-like driving, and the posture control system based on an eccentric mechanism allows body roll/pitch control and body height adjustment, which enable stable driving and carrying payloads. A modular control architecture was developed to provide a holonomic driving mode with ground adaptation. In this architecture, the driving control was implemented based on kinematics and the balance control was implemented by combined position/force control adjusted via a gain scheduling technique. We verified that the robot achieved stable driving on irregular terrain despite disturbed roll-pitch body posture and was capable of carrying a payload up to 56 kg indoors and outdoors.