Online Passive Reconstruction -Based Bilateral Control under Time-Varying Communication Delay and Packet-Loss

Abstract

In force reflecting teleoperation systems, master and slave mechanisms are connected through a communication means to exchange information. Most communication channels induce time delays which make the control design process difficult from the stability point of view. The wave variable method introduced in the mid-90’s, based on the theory of passivity, ensures the passivity of the communication block in presence of arbitrary constant time delays. This paper demonstrates that in channels with timevarying delays and data-loss (typical for the Internet and satellite radio communication links), the passivity of the channel using the basic wave variable method cannot be guaranteed. Modifications are applied to this method to cope with the effect of data-loss and variations of delay to provide the passivity framework for stability proof. The method is implemented on two 7 degrees of freedom DLR–LWR robots. The test results are presented and show the effectiveness of our method.