  This paper investigates bilateral control of teleoperators with closed
architecture and subjected to arbitrary bounded time-varying delay. A prominent
challenge for bilateral control of such teleoperators lies in the closed
architecture, especially in the context not involving interaction force/torque
measurement. This yields the long-standing situation that most bilateral
control rigorously developed in the literature is hard to be justified as
applied to teleoperators with closed architecture. With a new class of dynamic
feedback, we propose kinematic and adaptive dynamic controllers for
teleoperators with closed architecture, and we show that the proposed kinematic
and dynamic controllers are robust with respect to arbitrary bounded
time-varying delay. In addition, by exploiting the input-output properties of
an inverted form of the dynamics of robot manipulators with closed
architecture, we remove the assumption of uniform exponential stability of a
linear time-varying system due to the adaptation to the gains of the inner
controller in demonstrating stability of the presented adaptive dynamic
control. The application of the proposed approach is illustrated by the
experimental results using a Phantom Omni and a UR10 robot.
