L₂ stable four-channel control architecture for bilateral teleoperation with time delay

Passivity theory is very useful for stability analysis of bilateral teleoperation. Many researchers use passivity-based stabilization method such as scattering theory or wave variables. However, passivity-based stabilization is too conservative to design a high performance teleoperation system. High performance means that human operators can feel high-accuracy reaction force from environments. In this paper, we analyze l₂ stability of some bilateral control systems with communication delay using small gain theorem. This theorem is renowned as a stable condition of multi-input multi-output feedback systems. And a novel control architecture which satisfies l₂ stable condition of the theorem is proposed. The proposed control system has four communication channels. The validity of the proposed control system is shown by experimental results.