Haptic media synchronization using time adjustment algorithm for noncollaborative telehaptics

Haptic applications in noncollaborative telehaptics include remote surgery and remote manipulation that use a haptic device as a robot arm in master/slave manner. The problem of haptic applications in the noncollaborative telehaptics comes from a delay variation on networks. The delay variation causes in change of an update sequence interval of haptic media at a remote haptic process. Thereby, it results in operational instability of the remote haptic device that appears in the form of jolting and buzzing of haptic display. This paper introduces a method of synchronization to solve an interval fluctuation of the update haptic sequence resulting from the delay variation. The control mechanism of our synchronization employs a buffer to compensate the delay and uses the time adjustment algorithm to solve the interval fluctuation for smoothing the haptic display. The model of noncollaborative telehaptics applications and the derivation of synchronization control mechanism are detailed in the paper. Performance measurement of the synchronization is investigated by simulations under the regional network delay and the delay variations resulting from light, moderate, and high traffic conditions. The optimum buffer criteria under each traffic condition are also verified in the simulation. The results express that the operational stability of remote haptic device can be achieved by the proposed synchronization when the optimum buffer criteria are chosen as specified on each traffic condition.