Remote Tactile Transmission with Time Delay for Robotic Master–Slave Systems

This study develops a method to compensate for the communication time delay for tactile transmission systems. For transmitting tactile information from remote sites, the communication time delay degrades the validity of feedback. However, so far time delay compensation methods for tactile transmissions have yet to be proposed. For visual or force feedback systems, local models of remote environments were adopted for compensating the communication delay. The local models cancel the perceived time delay in sensory feedback signals by synchronizing them with the users' operating movements. The objectives of this study are to extend the idea of the local model to tactile feedback systems and develop a system that delivers tactile roughness of textures from remote environments to the users of the system. The local model for tactile roughness is designed to reproduce the characteristic cutaneous deformations, including vibratory frequencies and amplitudes, similar to those that occur when a human finger scans rough textures. Physical properties in the local model are updated in real-time by a tactile sensor installed on the slave-side robot. Experiments to deliver the perceived roughness of textures were performed using the developed system. The results showed that the developed system can deliver the perceived roughness of textures. When the communication time delay was simulated, it was confirmed that the developed system eliminated the time delay perceived by the operators. This study concludes that the developed local model is effective for remote tactile transmissions.