  Collaboration between interconnected cyber-physical systems is becoming
increasingly pervasive. Time-delays in communication channels between such
systems are known to induce catastrophic failure modes, like high frequency
oscillations in robotic manipulators in bilateral teleoperation or string
instability in platoons of autonomous vehicles. This paper considers nonlinear
time-delay systems representing coupled robotic agents, and proposes
controllers that are robust to time-varying communication delays. We introduce
approximations that allow the delays to be considered as implicit control
inputs themselves, and formulate the problem as a zero-sum differential game
between the stabilizing controllers and the delays acting adversarially. The
ensuing optimal control law is finally compared to known results from
Lyapunov-Krasovskii based approaches via numerical experiments.
