Communication Delay Compensation for Precise Force Matching in Teleoperation Teleoperation technology is widely employed in the fields of industry and human support. Bilateral control, which is one of the possible methods to achieve teleoperation, enables mutual transmission of operational force of an operator and reaction force from remote environment. However, teleoperation often involves non negligible communication delays, due to the limits of the communication networks. As a countermeasure against communication delays, bilateral control using a forcecontrolbased communication delay compensation has been proposed. This approach is effective in stabilizing system behavior and in maintaining the force states, so that operatorxe2x80x99s operational force and reaction force from environment can act in pairs and opposite direction, even during contact tasks. In this paper, we introduce a bilateral control that makes use of a forcecontrolbased communication delay compensation, with a new control structure in which structural redundancy of conventional system is removed. The proposed bilateral control system demonstrates through experiments a stable teleoperation and an accurate force matching performance through experiments.

Powerbased Restoration of Haptic Teleoperation from Communication Blackout Recently, networkbased control systems attract a lot of attentions. One of the applications of such control systems is haptic transmission using a bilateral control system. In order to construct the bilateral control system over the time delayednetwork, many researchers have proposed many methods and succeeded to improve the stability and performance of the system. By assuring the systemxe2x80x99s passivity, some of conventional methods have succeeded to stabilize the system even when the communication blackout occurs. However, the passivitybased methods are conservative and deteriorate the performance. In this paper, the mode shifting method is proposed to deal with the communication blackout without considering the systemxe2x80x99s passivity. In the proposed method, the bilateral controller is shifted to a local controller when the communication blackout occurs. By shifting to the local controller, the system is not destabilized by the blackout. Moreover, when the communication recovers, the bilateral controller is gradually restored to regulate the robotxe2x80x99s output power. Owing to the power regulation, the robots never damage environmental objects during and after the communication blackout. Therefore, the proposed method realizes stable and safe control even under the blackout. The validity of the proposed method is confirmed by simulations and a experiment.