Hybrid one-way delay estimation for networked control system

One-way delay estimation in the forward and feedback channels is crucial for a networked control system (NCS) due to its important role in the reliability and availability design. Problems existing in current one-way delay estimation schemes are investigated in this paper. A novel hybrid one-way delay estimation scheme, utilizing the hybrid technique that contains an online monitoring mechanism and an end-to-end estimation method, is proposed to overcome the effects of network asymmetry and delay dynamics in the NCS. Therefore, accurate one-way delay values in the forward and feedback channels can be obtained. In the proposed scheme, only the delay value of the initial packet starting the control loop of the NCS is estimated by the online monitoring mechanism, all the other estimations are performed by the host using the end-to-end method. The experimental results demonstrate that the performance of the proposed novel hybrid one-way delay estimation scheme is better than the other current estimation schemes for the NCS in terms of its high accuracy in tracking delay values as well as requiring lower computation complexity of the system.