“…Inspired by PID theory, integral, proportional, and derivative denote the information about past, present, and future, respectively, a set of time series about the integral of the state vector, the state vector, and the derivative of the state vector are utilized in the quadratic term of the augmented LKF. In some existing literature, 21–23 only the derivative of the state vector and the state vector are considered in the quadratic term of the LKF; if more integral terms of the state vector are considered, then more information about the instant vector and the delayed state vectors can be utilized. Hence, by adding the integral terms to χ ( t ), an augmented LKF is tailored for the use of the DPT integral inequality; then, the integral terms can be closely coupled by P , that is, the relationship between the integral terms on the LKF derivative can be enhanced by the coupling.…”