Identification of Continuous-time Systems with Unknown Time Delay by Nonlinear Least-squares and Instrumental Variable Methods
نویسندگان
چکیده
This paper considers the identification problem of continuous-time systems with unknown time delay from sampled input-output data. By using a digital prefilter, an approximated discrete-time estimation model is first derived, in which the system parameters remain in their original form and the time delay need not be an integral multiple of the sampling period. Then an iterative separable nonlinear least-squares (SEPNLS) method which estimates the time delay and transfer function parameters separably is derived. Furthermore, through investigation of the properties of the SEPNLS estimate, a novel separable nonlinear instrumental variable (SEPNIV) method is also proposed. Simulational results show that the SEPNIV method yields consistent estimates. Copyright c ©2003 IFAC
منابع مشابه
A Global Nonlinear Instrumental Variable Method for Identification of Continuous-Time Systems with Unknown Time Delays
This paper considers the identification problem of continuous-time systems with unknown time delays from sampled input-output data. An iterative global separable nonlinear least-squares (GSEPNLS) method which estimates the time delays and transfer function parameters separably is derived, by using stochastic global-optimization technique to avoid convergence to a local minimum. Futhermore, the ...
متن کاملIterative Methods for Identification of Multiple Input Continuous-time Systems with Unknown Time Delays
Many practical systems such as thermal processes, chemical processes and biological systems, etc., have inherent time-delay. If the time-delay used in the system model for controller design does not coincide with the actual process time-delay, a closed-loop system may be unstable or exhibits unacceptable transient response characteristics. Therefore, the problem of identifying such a system is ...
متن کاملADAPTIVE FUZZY OUTPUT FEEDBACK TRACKING CONTROL FOR A CLASS OF NONLINEAR TIME-VARYING DELAY SYSTEMS WITH UNKNOWN BACKLASH-LIKE HYSTERESIS
This paper considers the problem of adaptive output feedback tracking control for a class of nonstrict-feedback nonlinear systems with unknown time-varying delays and unknown backlash-like hysteresis. Fuzzy logic systems are used to estimate the unknown nonlinear functions. Based on the Lyapunov–Krasovskii method, the control scheme is constructed by using the backstepping and adaptive techniqu...
متن کاملOn-line Parameter and Delay Estimation of Continuous-Time Dynamic Systems
The problem of on-line identification of non-stationary delay systems is considered. The dynamics of supervised industrial processes are usually modeled by ordinary differential equations. Discrete-time mechanizations of continuous-time process models are implemented with the use of dedicated finite-horizon integrating filters. Least-squares and instrumental variable procedures mechanized in re...
متن کاملA numerical approach for variable-order fractional unified chaotic systems with time-delay
This paper proposes a new computational scheme for approximating variable-order fractional integral operators by means of finite element scheme. This strategy is extended to approximate the solution of a class of variable-order fractional nonlinear systems with time-delay. Numerical simulations are analyzed in the perspective of the mean absolute error and experimental convergence order. To ill...
متن کامل