Synchronization between master and slave sites in telerobotic systems: An Internet OWTD jitter prediction approach

Abstract

In virtual reality (VR)-based telerobotic systems, system performance depends highly on the accuracy of the virtual model constructed at the master site. However, state errors between virtual and slave system exist inevitably due to unknown environment parameters and random time delay of communication media. A popular strategy to tackle the problem is by means of virtual environment technology, in which the environment impedance is estimated on slave site and transmitted and recreated as a virtual environment on master site, and then, the virtual model is updated on the fly according to estimated parameters from slave site. As distinct from the existing parameter estimation methods, this article tries to synchronize master and slave sites of telerobotic systems with an Internet one way time delay (OWTD) jitter prediction approach. A virtual manipulator system is constructed as the slave system and can be controlled with an identical virtual manipulator model displayed on the screen of the master site, which is corrected and updated according to historical commands transmitted to the slave site and Internet OWTD jitter prediction results. Three prediction algorithms for time series prediction, i.e., multiple linear regression (MLR), grey model (GM), and autoregressive moving average model (ARMA), are adopted during the implementation of the proposed approach. The developed approach has been validated with a teleoperated free motion task and experimental results indicate that the proposed approach can be used to synchronize master and slave sites and ARMA outperforms GM and MLR in Internet OWTD jitter prediction.