Continuous Path Controller for the Remote Ultrasound Diagnostic System

A master-slave type remote ultrasound diagnostic system has been developed. The impedance controller has been implemented and reported for the positions of the master and slave manipulators to display and control the contact force between the ultrasound probe and the affected area. The present paper introduces an alternative orientation controller utilizing continuous path (CP) control in the remote ultrasound diagnostic system. The major contribution of the present paper is an introduction to the velocity-control-based CP controller for the master-slave type remote medical system, which realizes the continuous motion of the slave manipulator without a reduction in the master motion tracking performance. It is difficult to communicate information for control at high sampling rates between the master and slave site because the communication network between the master and slave site (local area network, integrated services digital network, asymmetric digital subscriber line, etc.) is limited. To cope with this problem, the CP controller was introduced to the orientation controller in special remote medical systems. The CP control realizes the continuous motion of the slave manipulator under the limited sampling rate of the orientation data transmitted by the master manipulator and high master motion tracking performance of the slave manipulator. This allows the slave manipulator safety to be improved and decreases the volume of the transmitted data. The experimental results demonstrate the accuracy of the path control of the slave manipulator using the CP control in the master--slave manipulation system, compared with the conventional point-to-point control.