Haptic Data Reduction for Time-delayed Teleoperation Using the Input-to-State Stability Approach

There are two major challenges for time-delayed teleoperation with haptic feedback over packet-switched networks: the high packet rate of the bidirectionally exchanged haptic data and the maintenance of system stability in the presence of communication delay. Concerning the former, ensuring the required high update rate for haptic information (≥1 kHz) requires significant transmission resources. Regarding the latter, stability-ensuring control architectures must be employed to guarantee system stability. In order to achieve both stable system design and efficient haptic data communication, joint consideration of haptic data reduction and stability-ensuring control is necessary for teleoperation systems. In this paper, we propose a novel haptic data communication solution for time-delayed teleoperation which integrates the perceptual deadband-based haptic data reduction method with the input-to-state stability (ISS) controller. In particular, the proposed ISS-based haptic data reduction solution is able to reduce the haptic packet rate while preserving the system stability in the presence of constant communication delay. Experimental results show that our approach reduces the overall haptic data by up to 80% without introducing significant perceptual distortion. Compared with the state-of-the-art time-domain passivity approach-based haptic data reduction approach [1], our method provides an improved user experience at a similar packet rate when the delay is less than 100 ms. Moreover, the experimental results also indicate that a joint optimization of communication and control may achieve the best possible teleoperation quality when the requirements of network quality of service and user experience vary.