Passivity-based control of human-robotic networks with inter-robot communication delays and experimental verification

In this paper, we propose a cooperative control law of human-robotic networks in the presence of inter-robot communication delays. The objective is to guarantee human enabled synchronization of positions of robotic network to desired reference. We first design a cooperative controller to be implemented on each robot so that their motion are synchronized to a reference motion desired by a human operator. Then, we point out that each robot motion ensures passivity. Furthermore, inter-robot communication channels are designed via so-called scattering transformation which is a technique to passify the delayed channel. The resulting robotic network is then connected with human operator based on passivity theory. In order to demonstrate the present control architecture, we build an experimental testbed consisting of multiple robots and an interface for interactions with human operator. In particular, we analyze the effects of the communication delays on the human operator's behavior.