Super-twisting algorithm based time-varying delay estimation with external signal

This article provides an online time-varying delay estimation method by using an external signal sent along with control inputs and output measurements. Since the external signal is isolated from the system, the lin-earity and delay-identifiability of the system are no longer required. Moreover, the sliding mode method guarantees the finite-time convergence of the delay estimation. By comparing with the standard sliding mode method, the super-twisting algorithm reduces the chattering and provides better performances. Furthermore, the super-twisting algorithm based delay estimator is implemented on a real remote data transmission system and its performances are illustrated by experimental results.