Showing papers in "International Journal of Adaptive Control and Signal Processing in 2000"
TL;DR: In this article, problems of optimizing observer-based fault detection (FD) systems in the sense of increasing the robustness to the unknown inputs and simultaneously enhancing the sensitivity to the faults are studied.
Abstract: In this paper, problems of optimizing observer-based fault detection (FD) systems in the sense of increasing the robustness to the unknown inputs and simultaneously enhancing the sensitivity to the faults are studied. The core of the study is the development of an approach that simultaneously solves four optimization problems. Different algorithms are derived for the application of this approach to the optimal selection of post-filters as well as optimization of fault detection filters, and to the systems with and without structure constraints. The achieved results also reveal some interesting relationships among the optimization problems considered. Copyright © 2000 John Wiley & Sons, Ltd.
423 citations
TL;DR: In this paper, an adaptive Kalman filtering algorithm is developed for use to estimate the reduction of control effectiveness in a closed-loop setting, which is used to quantify faults entering control systems through actuators.
Abstract: In this paper, an adaptive Kalman filtering algorithm is developed for use to estimate the reduction of control effectiveness in a closed-loop setting. Control effectiveness factors are used to quantify faults entering control systems through actuators. A set of covariance-dependent forgetting factors is introduced into the filtering algorithm. As a result, the change in the control effectiveness is accentuated to help achieve a more accurate estimate more rapidly. A weighted sum-squared bias estimate is defined for the change detection. The state estimate is fed back to achieve the steady-state regulation, while the control effectiveness estimate is used for the on-line tuning of the control law. A stability analysis is performed for the adaptive regulator. Copyright © 2000 John Wiley & Sons, Ltd.
258 citations
TL;DR: In this paper, state feedback adaptive control of parametric-strict-feedback (triangular) non-linear systems with unknown virtual control coefficients is studied, and asymptotic tracking of smooth reference signals is achieved while all the variables remain bounded.
Abstract: This paper deals with state feedback adaptive control of parametric-strict-feedback (triangular) non-linear systems with unknown virtual control coefficients. A priori knowledge of the signs of the virtual coefficients is not required, and control signals and adaptive laws are smooth. Asymptotic tracking of smooth reference signals is achieved while all the variables remain bounded. The proposed algorithms make use of backstepping and tuning functions, and enlarge the class of non-linear systems with unknown parameters for which asymptotic output tracking can be achieved. Copyright (C) 2000 John Wiley & Sons, Ltd.
80 citations
70 citations
66 citations
TL;DR: It is shown from the results that the proposed method improves learning/classification ability for stationary and non-stationary EMG signals during a series of continuous motions.
Abstract: This paper proposes a pattern classification method of time-series EMG signals for prosthetic control. To achieve successful classification for non-stationary EMG signals, a new neural network structure that combines a common back-propagation neural network with recurrent neural filters is used. A convergence time of the network learning can be regulated by a new learning method based on dynamics of a terminal attractor. The experiments of pattern classification and prosthetic control are carried out for several subjects including an amputee. It is shown from the results that the proposed method improves learning/classification ability for stationary and non-stationary EMG signals during a series of continuous motions. Copyright © 2000 John Wiley & Sons, Ltd.
49 citations
TL;DR: In this paper, a non-linear sliding mode controller for induction motors is proposed, which assumes that only the motor speed and stator currents are measured and seeks to provide asymptotic tracking of speed and #ux.
Abstract: SUMMARY This paper proposes a new non-linear sliding mode controller for induction motors. The controller assumes that only the motor speed and stator currents are measured and seeks to provide asymptotic tracking of speed and #ux. The control law incorporates a sliding mode observer and uses backstepping ideas to synthesise the non-linear controller sliding surfaces. Good results have been obtained in the benchmark simulations. Copyright ( 2000 John Wiley & Sons, Ltd.
49 citations
TL;DR: In this paper, a method for adaptive and recursive estimation in a class of non-linear autoregressive models with external input is proposed, which is a combination of recursive least squares with exponential forgetting and local polynomial regression.
Abstract: SUMMARY A method for adaptive and recursive estimation in a class of non-linear autoregressive models with external input is proposed. The model class considered is conditionally parametric ARX-models (CPARX-models), which is conventional ARX-models in which the parameters are replaced by smooth, but otherwise unknown, functions of a low-dimensional input process. These coe$cient functions are estimated adaptively and recursively without specifying a global parametric form, i.e. the method allows for on-line tracking of the coe$cient functions. Essentially, in its most simple form, the method is a combination of recursive least squares with exponential forgetting and local polynomial regression. It is argued, that it is appropriate to let the forgetting factor vary with the value of the external signal which is the argument of the coe$cient functions. Some of the key properties of the modi"ed method are studied by simulation. Copyright ( 2000 John Wiley & Sons, Ltd.
47 citations
TL;DR: In this paper, a generalized least-squares fault detection filter was proposed for both linear time-invariant and time-varying systems, where the objective is to monitor a single fault called the target fault and block other faults which are called nuisance faults.
Abstract: A fault detection and identification algorithm is determined from a generalization of the least-squares derivation of the Kalman filter. The objective of the filter is to monitor a single fault called the target fault and block other faults which are called nuisance faults. The filter is derived from solving a min–max problem with a generalized least-squares cost criterion which explicitly makes the residual sensitive to the target fault, but insensitive to the nuisance faults. It is shown that this filter approximates the properties of the classical fault detection filter such that in the limit where the weighting on the nuisance faults is zero, the generalized least-squares fault detection filter becomes equivalent to the unknown input observer where there exists a reduced-order filter. Filter designs can be obtained for both linear time-invariant and time-varying systems. Copyright © 2000 John Wiley & Sons, Ltd.
47 citations
46 citations
TL;DR: In this article, a technique to localize the vehicle with respect to known landmarks using on-board navigation sensors, overcoming uncertainities in vehicle dynamics and its operating environment is presented.
Abstract: This paper presents a technique to localize the vehicle with respect to known landmarks using on-board navigation sensors, overcoming uncertainities in vehicle dynamics and its operating environment. Results of computer simulation and pool experimentation are presented. Those results show that the system is capable of controlling the vehicle with high accuracy using the estimated position and velocity from the on-board sensor-based navigation system. Copyright © 2000 John Wiley & Sons, Ltd.
TL;DR: The basic theory behind SAEC, solutions to the singularity problem, and a number of classical two-channel adaptive algorithms suited to the problem are reviewed.
Abstract: Stereophonic acoustic echo cancellation (SAEC), has been studied since the early 1990s. Because of spatial realism, two-channel audio is now becoming more interesting in a number of hands-free applications such as teleconferencing, multi-participant desktop conferencing, and televideo gaming. From a theoretical point of view, SAEC differs considerably from traditional mono echo cancellation since the normal equation to be solved by the adaptive algorithm is singular. Of course, this also affects the practical considerations that have to be made when designing a SAEC system, e.g. choice of adaptive algorithm. This paper reviews the basic theory behind SAEC, solutions to the singularity problem, and a number of classical two-channel adaptive algorithms suited to the problem. Copyright © 2000 John Wiley & Sons, Ltd.
TL;DR: The application of these algorithms as Receiver Autonomous Integrity Monitoring (RAIM) schemes to the problem of the Global Positioning Systems (GPS) integrity monitoring is discussed — these self-contained schemes are of great interest today for many safety-critical applications.
Abstract: The goal of this paper is to discuss two special aspects of fault detection in measurement systems. First, the main goal of fault detection in measurement systems is to detect the system degradation when it leads to an unacceptable growth of the output errors. All other faults are of no importance; moreover, their detection can be considered by the user as a false alarm. Second, the traditional on-line fault detection methods are formulated as that of the quickest detection of abrupt changes in a stochastic process. A sensor fault also should be detected quickly but sometimes (especially for safety-critical applications) the user imposes the constraint on the maximum delay for the detection. Specifically, the user fixes the probability of missed detection within a given time-to-alarm.
A new performance criterion for this reliable detection of changes in stochastic systems is proposed and two suboptimal change detection algorithms are considered in the paper. The application of these algorithms as Receiver Autonomous Integrity Monitoring (RAIM) schemes to the problem of the Global Positioning Systems (GPS) integrity monitoring is discussed — these self-contained schemes are of great interest today for many safety-critical applications. Copyright © 2000 John Wiley & Sons, Ltd.
TL;DR: In this paper, the authors proposed two simple flux observers assuming that the rotor velocity and the stator currents are measured: the first observer makes use of a natural "passivity" property (in fact, it requires only velocity measurements); the second observer [1] relies on a reparametrization of time and can be rendered as fast as desired.
Abstract: The induction motor has very good qualities—reliability, ruggedness, relatively low cost, etc., for industrial applications. The reason for this is that there is no mechanical commutation: the rotor consists simply of closed windings in which currents are induced by a rotating magnetic field set up by the stator, hence creating a torque. But the control of the induction motor is not so easy, mainly because of the three following points: the model is rather non-linear, some variables (in particular, the magnetic fluxes, or equivalently, the rotor currents) cannot easily be measured, and some parameters (rotor resistance, load torque, inertia) vary a lot in operation. This has motivated a growing literature in the control community.
We propose here two simple flux observers assuming that the rotor velocity and the stator currents are measured: the first observer makes use of a natural “passivity” property (in fact, it requires only velocity measurements); the second observer [1] relies on a “reparametrization of time” and can be rendered as fast as desired.
It is worth mentioning that all the computations are straightforward mainly because they are carried out using the complex variable notation (time-varying phasor) model of the induction motor. Copyright © 2000 John Wiley & Sons, Ltd.
TL;DR: In this paper, an adaptive non-linear observer-based controller is designed for a full model of an induction motor including both electrical and mechanical dynamics, which is designed primarily for speed control.
Abstract: An adaptive non-linear observer-based controller is designed for a full model of an induction motor including both electrical and mechanical dynamics. The controller is designed primarily for speed...
TL;DR: This paper proposes a new approach of design using a monovariable generalized predictive control law, with multiple reference model (GPC/MRM) to control, firstly, rotor speed and rotor flux amplitude of an induction machine, and will be extended and applied to answer a second objective.
Abstract: Proposed in this paper is a new approach of design using a monovariable generalized predictive control law, with multiple reference model (GPC/MRM) to control, firstly, rotor speed and rotor flux amplitude of an induction machine. The control law will be extended and applied, secondly, to answer a second objective which is the control of the rotor position and rotor flux amplitude of the same machine. The non-linear dynamical model of the machine is described in the stator fixed reference frame. The GPC algorithm is combined with the non-linear input–output linearizing control properties; moreover, we establish a new formulation of the reference signals, which enables one to track flux and speed/position nominal profiles, satisfying motor constraints. The global controller synthesis is given under an RST form which introduces a novel definition of the prefiltering polynomial. Copyright © 2000 John Wiley & Sons, Ltd.
TL;DR: In this paper, an adaptive ship steering autopilot is proposed based on the internal model control method, which is characterized by a model-based design approach that provides clear connections between the structure of the controller and that of the ship model.
Abstract: The proposed adaptive ship steering autopilot is based on the internal model control method, which is characterized by a model-based design approach that provides clear connections between the structure of the controller and that of the ship model. Specifically, the controller parameters depends explicitly on the ship model parameters and on a design parameter that specifies the closed-loop system response speed. Once the ship model parameters are estimated on-line, the controller parameters are adjusted accordingly to adapt to different operating conditions. A key feature of the proposed approach being that the rudder limit and rudder rate limit are directly taken into the adaptation design consideration. Specifically, a reference conditioning technique that modifies the reference input in such a way that the rudder command is always equal to the actual rudder input into the plant. This allows the controller to exert its full power without attempting to take on values beyond the bounds imposed by the rudder limit and rudder rate limit. Consequently, under different operating conditions, rapid course-changing manoeuvres are achievable without introducing possible instability problem caused by the controller integrator wind-up. Copyright © 2000 John Wiley & Sons, Ltd.
TL;DR: In this paper, a simple but effective control law for speed regulation is proposed based on a novel dynamic model obtained under a special nonlinear co-ordinate transform on a d}q-axis model (w.r.t. the stationary reference frame) of an induction motor.
Abstract: SUMMARY On the basis of a novel dynamic model obtained under a special non-linear co-ordinate transform on a d}q-axis model (w.r.t. the stationary reference frame) of an induction motor, a simple but e!ective control law for speed regulation is proposed in this paper. This controller is designed using the concept of the "eld orientation and the property of linear PI-controller, and is shown to be robust with respect to variation of system parameters and load structure. To be rigorous, a Lyapunov theorem with a simple iterative criterion derived in this paper proves the local exponential stability of the system around any desired speed. Numerical simulations are also given to show the e!ectiveness of the presented control law. Copyright ( 2000 John Wiley & Sons, Ltd.
TL;DR: The performance of frequency-domain adaptive algorithms is analysed and, when properly designed, shown to be equivalent to time-domain algorithms with uncorrelated input signals.
Abstract: For adaptive filters with long impulse responses and requiring modelling by an FIR filter, algorithms incorporating computationally efficient DFT-based adaptive block filters are the design of choice. The reduction in computational complexity is very significant in applications such as active noise control and the hands-free telephone system echo cancellation problem where impulse responses of more than a 1000 samples are common. The performance of frequency-domain adaptive algorithms is analysed and, when properly designed, shown to be equivalent to time-domain algorithms with uncorrelated input signals. The design parameters include: block length, DFT length and partitioning of the impulse response. The study includes both constrained and unconstrained parameter adaptation. Guidelines to the design of partitioned frequency-domain LMS (PFLMS) algorithms are given. Copyright © 2000 John Wiley & Sons, Ltd.
TL;DR: In this paper, a limited authority adaptive PD control method is proposed and applied to ship steering control, where the controller is designed by using the Nomoto's model and its ARMA description.
Abstract: In this paper, a limited authority adaptive PD control method is proposed and applied to ship steering control. The controller is designed by using the Nomoto’s model and its ARMA description. Efficiency of the proposed control scheme is studied and illustrated by simulations carried out with linear and nonlinear models.
TL;DR: In this paper, a performance-constrained sliding mode controller is proposed to satisfy the pole assignment, H∞ norm, and individual variance constraints for linear perturbed MIMO systems.
Abstract: A performance-constrained sliding mode controller will be proposed to satisfy the pole assignment, H∞ norm, and individual variance constraints for linear perturbed MIMO systems. Application of this controller involves a simulation of the linearized perturbed ship steering yaw-motion systems which will be provided for demonstration of the effectiveness of the present methodology. The control law developed in this paper is designed in the framework of a combination of the concept of the sliding mode control with the theory of upper bound covariance control. Copyright © 2000 John Wiley & Sons, Ltd.
Abstract: A Lyapunov-based inverse optimal adaptive control-system design problem for non-linear uncertain systems with exogenous ℒ2 disturbances is considered. Specifically, an inverse optimal adaptive non-linear control framework is developed to explicitly characterize globally stabilizing disturbance rejection adaptive controllers that minimize a nonlinear-nonquadratic performance functional for non-linear cascade and block cascade systems with parametric uncertainty. It is shown that the adaptive Lyapunov function guaranteeing closed-loop stability is a solution to the Hamilton–Jacobi–Isaacs equation for the controlled system and thus guarantees both optimality and robust stability. Additionally, the adaptive Lyapunov function is dissipative with respect to a weighted input–output energy supply rate guaranteeing closed-loop disturbance rejection. For special integrand structures of the performance functionals considered, the proposed adaptive controllers additionally guarantee robustness to multiplicative input uncertainty. In the case of linear-quadratic control it is shown that the operations of parameter estimation and controller design are coupled illustrating the breakdown of the certainty equivalence principle for the optimal adaptive control problem. Finally, the proposed framework is used to design adaptive controllers for jet engine compression systems with uncertain system dynamics. Copyright © 2000 John Wiley & Sons, Ltd.
TL;DR: In this article, a robust output feedback control for a 6-order model of an induction motor is proposed, which is robust to uncertainties in the rotor and stator resistances and a bounded time-varying load torque.
Abstract: A non-linear robust output feedback control is designed for a sixth-order model of an induction motor. The control uses only measurement of the rotor position and stator currents. It contains two observers, a second-order observer to estimate the rotor flux from the stator current and a third-order high-gain observer to estimate the rotor speed and acceleration from its position. The control is robust to uncertainties in the rotor and stator resistances, and a bounded time-varying load torque. It guarantees that the speed tracking error can be made arbitrarily small by choice of certain design parameters. Moreover, when the speed reference and load torque and constant, it ensures asymptotic regulation. The controller is applied, via simulation, to a benchmark example. Copyright © 2000 John Wiley & Sons, Ltd.