Precise Position/Force Hybrid Control With Modal Mass Decoupling and Bilateral Communication Between Different Structures

In this study, we achieve haptic communication between different structures. In haptic communication, tactile sensation is transmitted to a remote place by cooperating robots. Conventional haptic communication is implemented under the assumption that the masses of the actuators are equal. We have found that haptic communication system is a kind of position/force hybrid control system and that it is not necessary to follow that assumption. In addition, exact modeling of haptic communication system and decoupling of tasks are essential for highly precise haptic communication. First, we describe the kinetic and dynamic behaviors of haptic communication system for cardiac surgery. The deterioration of haptic performance is shown to depend on an interference term, due to off-diagonal parameters in the modal mass matrix. Second, we propose a novel hybrid controller for the decoupling of the responses, and we analyze its performance, stability, and robustness. Simulations and experiments toward cardiac surgery are shown, and the effectiveness of the proposed method is verified.