Closed-Loop Manual Control With Tactile or Visual Feedback Under Wireless Link Impairments

The emergence of low-latency wireless connectivity has opened significant new possibilities for closed-loop human-machine interaction (HMI) systems. However, data transmission, particularly over wireless links, suffers from impairments, such as random latency fluctuations and packet loss, affecting the overall control performance of HMI systems. In this study, we have evaluated the impact of wireless impairments for a closed-loop joystick-controlled trajectory tracking task. This has been done with two different types of feedback, visual and tactile, respectively. Wireless links were used both in the uplink transmission of command signal and the downlink transmission of feedback signal. The effects of wireless impairments were incorporated by artificially introducing latency, jitter, and packet loss recorded in real-life deployment scenarios, both in the uplink and the downlink. The results obtained across 12 able-bodied participants showed that the tracking performance was better with visual feedback than with tactile feedback across all impairment conditions. The average latency significantly affected performance, while random latency fluctuations did not. Interestingly, the performance degradation due to increasing impairments in case of tactile feedback was similar to the one observed for visual feedback. One of the main novelties brought by this study is the quantification of the impact of wireless impairments on closed-loop teleoperation tasks with tactile feedback. The results provide valuable insights for designing wireless infrastructure for tactile internet applications.