Youbin Peng

Anti-windup, bumpless, and conditioned transfer techniques for PID controllers

Gives a simple and comprehensive review of anti-windup, bumpless and conditioned transfer techniques in the framework of the PID controller. We show that the most suitable anti-windup strategy for usual applications is the conditioning technique, using the notion of the realizable reference. The exception is the case in which the input limitations are too restrictive. In this case, we propose the anti-windup method with a free parameter tuned to obtain a compromise between the incremental algorithm and the conditioning technique. We also introduce the new notion of conditioned transfer, and we it to be a more suitable solution than bumpless transfer. All the discussions are supported by simulations.

Explicit solution to the singular LQ regulation problem

An explicit solution to the multivariable discrete linear quadratic (LQ) regulation problem is obtained in the limiting singular case where the input weighting matrix tends to zero. Such a solution follows from a suitable spectral factorization of the input spectrum density matrix under the assumption that the system is stabilizable and detectable and that its transfer function matrix is of full rank. The suitable spectral factor is shown to be the product of the systems minimum-phase image and its unitary interactor matrix. The unitary interactor matrix defined is a special case of the nilpotent interactor matrix defined by M.W. Rogozinski et al. (1987). >

A complete procedure for residual generation and evaluation with application to a heat exchanger

In this paper, we will build up the link between parity relation design and residual evaluation via generalized likelihood ratio (GLR) test. To this end, the so-called single-sensor parity relation (SSPR) and single-actuator parity relation (SAPR) are refined for stochastic systems in frequency domain by including a whitening filter. This result is also extended to the generalized parity relations in order to detect any failure mode. The proposed design procedure not only achieves failure detection and isolation, but also generates a special residual form which can be evaluated by a GLR test. Besides, a comprehensive summary of the GLR test with rules of thumb to select the design parameters is provided. The effectiveness of the proposed procedure is illustrated by processing measured data from a pilot heat exchanger to detect sensor faults, and by performing a simulation study to detect actuator faults.

Conditioning technique for controllers with time delays

The so-called conditioning technique has been shown to be a powerful antiwindup and bumpless transfer method. It gives a way to take into account, by appropriate design of the controller, any discrepancy which can occur between the actual control variables and the desired control variables. However, the original version of this method is restricted to the case where the controller has no time delay. The authors propose a modified version of the conditioning technique that can handle the case where the controller has a general time-delay structure. >

A general decoupling precompensator for linear multivariable systems with application to adaptive control

A general precompensator for decoupling a wide class of multivariable systems is presented. This class may include nonminimum-phase systems and/or open-loop unstable systems. It is also shown how pole placement control and adaptive control strategies can be incorporated with the precompensator. Several simulation results illustrate the good tracking performances of the proposed control scheme. As the closed-loop system obtained by combining the precompensator with SISO (single input, single output) controllers is always dynamically decoupled, the proposed control strategy is very suitable for tracking problems. >

Discrete-time LQG/LTR technique for systems with time delays

Loop transfer recovery (LTR) is applied for LQG controllers with prediction estimators for a class of square minimum-phase discrete-time linear systems with time delays. We consider the class of plants described by the triple (A, B, C) whose time-delay structure is characterized by the following hypothesis on the plant impulse response: CB = CAB = … = CAd−2B = 0, det(CAd−1B) ≠ 0. When the estimator gain is fixed by recovery technique, it is shown that the loop transfer matrix at the plant input is equal to the transfer matrix obtained with the optimal digital regulator having d-sample controller delays described in [6]. The dual result corresponding to the situation where the feedback gain is fixed by recovery technique is also analysed.

A complete procedure for residual generation and evaluation with application to heat exchanger

In this paper, we present generalized parity relations which not only achieve failure detection and isolation, but also have a special residual form to allow their evaluation by a generalised likelihood ratio test. The effectiveness of the proposed procedure is illustrated on a pilot heat exchanger.

An FIR prefilter leading to bounded overshoot and undershoot with application to deadbeat control

In this paper, a finite impulse response (FIR) prefilter design for an FIR system is proposed. The proposed method assures that the step response overshoot and undershoot of the given system and the prefilter in series do not exceed two prespecified bounds. This design is then applied to two deadbeat controllers, the first in the form of a unity feedback controller and the second in the form of a two-degree-of-freedom controller. Several numerical examples are given to illustrate the effectiveness of the proposed design.

On the link between generalized predictive control and deadbeat control for linear multivariable systems

Abstract This paper studies a special case on multivariable generalized predictive control (GPC) in which a deadbeat controller is obtained. It is shown that the multivariable GPC design can be made to be equivalent to the deadbeat control design by certain choices of the design parameters. The proposed procedure needs the introduction of different control horizons for different inputs. A tuning strategy is used to achieve deadbeat control for real-time implementation.

Deadbeat controllers leading to overshoot and undershoot within prespecified bounds

A finite impulse response (FIR) compensator design for an FIR system is proposed. The proposed method assures that the step response overshoot and undershoot of the given system and the compensator in series do not exceed two prespecified bounds. This design is then applied to two deadbeat controllers, the first in the form of a unity feedback controller and the second in the form of a two-degree-of-freedom controller.<<ETX>>