Bilateral teleoperation for robots with time delay and varying dynamics

Teleoperation involves using robots to explore or manipulate objects at a distance in dangerous and inhospitable environments. From search and rescue operations here on Earth to space exploration on Mars, robots play a pivotal role in accessing environments that might be considered difficult or impossible for humans to enter. Bilateral teleoperation provides the operator with force feedback via a master device used to control the remote robot during teleoperation. The force feedback enhances teleoperation for the operator providing them the ability to feel interactive forces rather than just visual and/or auditory cues.;Unfortunately, time delay across the communication link between the local device and remote robot can cause instability in the system. The wave variable method is a common approach applied to provide stability for bilateral teleoperated systems with time delay. In this research, we extend the wave variable method by alleviating transient oscillations, known as wave reflections, for varying slave dynamics. Wave reflections affect teleoperation performance when using the wave variable method and become more prominent when there exists mismatched impedance.;Prior to this work, the frequency at which these wave reflections occur were considered to be primarily related to the time delay across the communication channel. In this work, we show that the frequency characteristics of wave reflections are also affected by changes in the dynamics of the teleoperated system. We propose a novel wave-variable-based controller that diminishes the effects of wave reflections as the slave dynamics changes during teleoperation using a filter based technique. Simulation and experimental results using our proposed method is compared to the traditional wave variable method and most recent filter based technique found in literature. The contributions proposed in this work enhances the teleoperation experience for the operator especially when manipulating objects of different masses which could change the system dynamics.