• wave variables
• Bilateral teleoperation
• passivity
• varying delays

Bilateral teleoperation systems submitted to time delay are affected by serious stability problems. It's well known than even a small amount of time delay in a closed-loop control system, if untreated, can cause instability. Anyway stability remains the first requirement for any dynamical system.

Wave variables method is an important approach that guarantees stability regardless of the time delay. However this method is able to deal with constant time delays.

In the thesis wave variables method is reviewed. Particular attention is focused on bilateral teleoperation schemes under time-varying communication delays. Based on the wave variables framework a method to treat with time-varying delay problems is also developed and systematically analyzed.