In this paper, we propose a decentralized motion control algorithm of multiple mobile robots referred to as DR Helper for transporting a single object in cooperation with a human. DR Helper consists of an omni-directional mobile base, a six-axis body force sensor, a folk lift, and an onboard controller. Each robot is controlled by its own controller as if it has a caster-like dynamics and transports a single object together with other robots based on an intentional force/moment applied by a human. The adaptive dual caster action is also proposed to improve the maneuverability of the system. Experiments using multiple DR Helpers will illustrate the validity of the proposed control algorithm.
