Closed-loop Identification with an Unstable or Nonminimum Phase
نویسنده
چکیده
In many practical cases, the identi cation of a system is done using data measured on the plant in closed loop with some controller. In this paper, we show that the internal stability of the resulting model, in closed loop with the same controller, cannot always be guaranteed if this controller is unstable and/or nonminimum phase, and that the direct, indirect and joint input-output approaches of closed-loop prediction-error identi cation present di erent properties regarding this stability issue. We give some guidelines to avoid the emergence of this problem; these guidelines concern both the experiment design and the identi cation method. Copyright c 2000 IFAC.
منابع مشابه
Identification Santa Barbara , California , USA , 2000 CLOSED - LOOP IDENTIFICATION W I T H AN UNSTABLE O R NONMINIMUM PHASE CONTROLLER Benoit Codrons ' , Brian
In many practical cases, the identification of a system is done using data meamred on the plant in closed loop with some contmller. In this paper, we show that the internal stability of the resulting model, in closed loop with the same controller, cannot always be guaranteed if this controller is unstable and/or nonminimum phase, and that the direct, indirect and joint input-output approaches o...
متن کاملClosed-loop identification with an unstable or nonminimum phase controller
In many practical cases, the identification of a system is done in closed loop with some controller. In this paper, we show that the internal stability of the resulting model, in closed loop with the same controller, is not always guaranteed if this controller is unstable and/or nonminimum phase, and that the classical closed-loop prediction-error identification methods present different proper...
متن کاملClosed Loop Identification of Unstable Poles and Non-minimum Phase Zeros
This paper addresses estimation of poles and zeros in closed loop systems. For many quantities of interest, e.g. frequency function estimates, overparameterization results in a large increase of the variance but this is not the case for estimates of nonminimum phase zeros and unstable poles. Variance expressions that are asymptotic in model order and sample size are derived and for some systems...
متن کاملA New Stabilizing GPC for Nonminimum Phase LTI Systems Using Time Varying Weighting
In this paper, we show that the stability can not be achieved with current stabilizing MPC methods for some unstable processes. Hence we present a new method for stabilizing these processes. The main idea is to use a new time varying weighted cost function for traditional GPC. This stabilizes the closed loop system without adding soft or hard constraint in optimization problem. By studying diff...
متن کاملDesign of an Stable GPC for Nonminimum Phase LTI Systems
The current methods of predictive controllers are utilized for those processes in which the rate of output variations is not high. For such processes, therefore, stability can be achieved by implementing the constrained predictive controller or applying infinite prediction horizon. When the rate of the output growth is high (e.g. for unstable nonminimum phase process) the stabilization seems to...
متن کامل