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The positioning accuracy of pipeline leakage mainly depends on denoising effect and time delay estimation performance. In view of the problem of poor positioning accuracy of current pipeline leak, Non-Local Means-Empirical Mode Decomposition(NLM-EMD) autocorrelation method for denoising and Fuzzy C-Means clustering(FCM)-second correlation method for adaptive time delay estimation are proposed. NLM is used for noise reduction pretreatment, and the signal is recombined and de-noised according to autocorrelation criterion of EMD, then FCM is used to adaptively extract the pressure drop signal with higher correlation, and second correlation can estimate the delay of the signal. The results show that NLM-EMD autocorrelation method can effectively reduce noise interference and improve the decomposition quality of EMD, FCM-second correlation method can enhance the correlation of the two leakage signals, and the positioning accuracy is improved by 0.817% compared with the direct second correlation.

In this article, the H∞$$ {H}_{\infty } $$ safe control problem of continuous‐time affine nonlinear safety‐critical systems is studied based on the barrier function (BF) and adaptive dynamic programming (ADP). We show that the safety constraints in this article occur under the condition that the system initial state is unsafe and have not been adequately addressed in the existing work. First, the H∞$$ {H}_{\infty } $$ control problem is transformed into a zero‐sum game problem, and a new safe Hamilton–Jacobi–Isaacs equation is proposed by combining with the BF, which makes the unsafe behavior be punished in the learning process. In addition, a damping coefficient is introduced into the BF to punish the unsafe behavior more flexibly. Aiming at the requirement that the initial system state must be strictly constrained in the safe set, a new weight updating method based on ADP is proposed, which can reasonably avoid the influence of the BF on neural network (NN) parameters when the initial system state is unsafe. Furthermore, based on the Lyapunov stability theory, it is proved that the system states of safety‐critical systems and the NN parameters are uniformly ultimately bounded under the safety constraints and disturbances effect. Finally, the effectiveness of the proposed method is verified by two simulation examples. [ABSTRACT FROM AUTHOR]