In one branch of robotics, called telerobotics, control of robots in distant or inaccessible places is investigated. Human operator takes a manipulator and moves one robot (master), giving necessary commands to move another robot (slave) in another environment. For a sense of appreciation of that environment, information such as force or position is feedback to the operator. Transparency is a measure of how the operator feels the distant environment. In this thesis, we have expanded one of the methods in improving transparency to a robust control problem. Time delay in information transition is one of the hardships of control design, which is considered as uncertainty, augmented to a linear system. Robust performance is obtained by adding transparency function to the robust control structure. In force-position structure, a robust controller can be designed in a mixed sensitivity problem to optimize transparency, while guaranteeing stability. Robust control problem has been simulated on a master-slave system. Eventually, the proposed structure is implemented on a real system, with phantom omni haptic device as the master, and Cartesian robot as the slave parts. In order to correctly model the real system as a linear one, friction and un-modeled dynamics in the Cartesian robot have been compensated. Environment force has been estimated by Kalman filter and is feedback to the phantom. The results reveal robust stability, with an acceptable transparency