Virtual-Environment Modeling and Correction for Force-Reflecting Teleoperation With Time Delay

Virtual environment (VE) is an effective method to deal with time delay in teleoperation, but it depends heavily on the accuracy of the virtual model. In this paper, a novel approach is proposed to create and verify geometric and dynamic model of the remote physical environment. The geometric errors of the virtual model are corrected by overlaying the graphics over video images and also by fusing the position and force information from the remote. A sliding-average least-square algorithm is proposed to identify dynamic parameters of the remote environment, and the corresponding virtual-model parameters are updated online to keep equal to the real environment. The VE-based teleoperation system developed in our laboratory is described. Experimental results show that the relative errors of forces provided by the corrected VE are 2.82%, 2.22%, and 2.60%, respectively, with time delay of 5, 10, and 15 s. Results indicate that VE built by this method can provide the operator with appropriate predictive virtual forces with a certain time delay