Multilateral control under time delay for decoupling force and velocity controllers

The study proposes a control structure for multilateral control under communication delay that force and velocity, or position controllers are decoupled. Multilateral control realizes haptic sensation transmission between several points, which is a extended structure of a bilateral control system. In multilateral teleoperation, subsystems are placed far from each other, consequently containing a time delay inside the control system. The time delay induces an interference of the controllers, which are in the relation of duality, and it deteriorates the overall performance of transmitting tactile sensation to other subsystems. In this study, a multilateral teleoperation system that the interference phenomenon is eliminated is proposed. The concept of the proposed method is based on modal transformation. The interference between the controllers is eliminated by adequately defining a modal transformation matrix, which is called a network quarry matrix in this paper. The method to determine the network quarry matrix is explained in detail. A multi-master-single-slave system is assumed in this study, and in order to enhance the generality of the proposed method, all of the delay times are assumed to be different. The validity of the proposed method is confirmed through experiments.