Improving Perception in Time Delayed Teleoperation

Abstract

Telerobotics has long struggled to provide realistic force feedback to the user, especially across substantial time delays. Wave variable based controllers provide stable force reflection at frequencies up to a few Hertz for typical communication delays; however, the bandwidth of human perception extends to a thousand Hertz. We address this problem by incorporating a force sensor at the slave end effector and creating an additional feedback path to provide high frequency force information to the user. We build this augmented feedback system on top of a normal wave variable controller, leveraging the separation of power flows provided by the wave variable formalism and building a fundamentally asymmetric controller that better matches the sensory capabilities of the human operator. To further improve the user’s perception of the slave site, we investigate the use of wave filters to compensate for wave reflections without introducing the excessive damping inherent to impedance matching. Both of these improvements are validated experimentally in a simple three degree of freedom teleoperator.