Robert Veillette - Academia.edu (original) (raw)

Papers by Robert Veillette

1993 American Control Conference

A method is developed for computing optimal observers for linear decentralized feedback control s... more A method is developed for computing optimal observers for linear decentralized feedback control systems. Necessary conditions are derived for the decentralized output-feedback control to optimally approximate a given state-feedback control. The observer gains that satisfy the necessary conditions are found using a numerical gradient-type optimization. A control structure where decentralized observers share control-input information is also considered. For this structure, the optimal observers can be computed directly from a set of decoupled algebraic Riccati equations. Centralized control is treated as a special case, resulting in a simple and novel derivation of the known results for computing optimal centralized observers.

This paper applies the Rayleigh-Ritz method to approximating the Hankel singular values of fracti... more This paper applies the Rayleigh-Ritz method to approximating the Hankel singular values of fractional-order systems. The algorithm is presented, and estimates of the first ten Hankel singular values of G(s) = 1 /(sq +1 ) for several values of q ∊ (0 , 1 ] are given. The estimates are computed by restricting the operator domain to a finite-dimensional space. The Hankel-norm estimates are found to be within 15% of the actual values for all q ∊ (0 , 1 ].Copyright © 2009 by ASME

Springer eBooks, Oct 16, 2009

ABSTRACT Ultracapacitors display long-term transients lasting for many months. This paper shows t... more ABSTRACT Ultracapacitors display long-term transients lasting for many months. This paper shows that these long-term transients can be accurately represented using a fractional-order system model for the ultracapacitor impedance. Time-domain data is used to determine the impedance transfer-function coefficients. A circuit realization for the ultracapacitor is given which explicitly shows the fractional-order component. These long-term transient models will allow the development of improved ultracapacitor management systems.

This paper presents preliminary results on the design of reliable control systems characterized b... more This paper presents preliminary results on the design of reliable control systems characterized by open-loop stable controllers, and capable of withstading the outage of any sensor in a predefined subset or of any actuator in a predefined subset of control loops. The approach is based on the relationship between the existence of solutions to an algebraic Riccati inequality and the

Elsevier eBooks, 1996

This chapter explores the development of deadbeat control and one-step-ahead control. Deadbeat co... more This chapter explores the development of deadbeat control and one-step-ahead control. Deadbeat control and one-step-ahead control, each have a long history, the two were developed in separate research streams, and it was many years before these streams merged. It compares and contrast deadbeat and one-step-ahead control strategies, to contribute to the unification of the two areas, and to clear up some possible points of confusion. The chapter discusses that system identification, deadbeat control, and one-step-ahead control are possible because discrete-time systems are described by difference equations, which define an algebraic relation between the system inputs and outputs. Such procedures cannot be applied to continuous-time systems, whose inputs and outputs are related by differential equations. As a result, for example, deadbeat response in a continuous-time system cannot be achieved via linear time invariant feedback. No matter how rapid the step response of a continuous-time control system is made, the exponentially decaying error vanishes only as time goes to infinity.

Page 1. An Ultracapacitor Model Derived Using Time-Dependent Current Profiles Yang Wang, Joan E. ... more Page 1. An Ultracapacitor Model Derived Using Time-Dependent Current Profiles Yang Wang, Joan E. Carletta, Tom T. Hartley, and Robert J. Veillette Department of Electrical and Computer Engineering The University of Akron Akron, Ohio, USA ...

New procedures for the design of reliable linear, time-invariant control systems are introduced. ... more New procedures for the design of reliable linear, time-invariant control systems are introduced. The reliable designs are of two classes: state-feedback designs that tolerate actuator outages, and observer-based designs that tolerate sensor outages. The design methods always yield a reliable controller, provided one exists, and provided that the resulting control systems retain stability and a prescribed H/sub infinity /-norm bound despite any outages within a prespecified subset of actuators or sensors. The development of the reliable observers assumes that the sensor failures are detected and that the observer dynamics is accordingly adjusted. An alternative output-feedback design approach is also given for which failure detection is not required; however, the reliability of the resulting designs must be verified by checking an auxiliary sufficient condition, or by analysis. An example shows that this condition is not always necessary for reliability.<<ETX>>

Automatica, 1995

paper introduces a procedure for the design of modified linear-quadratic (LQ) state-feedback cont... more paper introduces a procedure for the design of modified linear-quadratic (LQ) state-feedback controls that tolerate actuator outages. The controls improve on the known stability gain-margin properties of the standard LQ regulator by tolerating the insertion of any independent gains from zero to infinity into selected feedback loops. They also guarantee a given performance bound despite the insertion of gains from zero to two into those loops. The reliable LQ design is shown to be equivalent to a standard LQ-optimal design with a modified performance index. Thus, the design procedure is seen as a means of choosing a particular quadratic performance index for which the optimal control will possess the desired reliability properties.

The electrical engineering handbook, Feb 28, 2011

$Research paper thumbnail of Hankel-norm estimation for fractional-order systems using the Rayleigh–Ritz method$

Computers & mathematics with applications, Mar 1, 2010

In this paper, the Rayleigh-Ritz method of estimating the eigenvalues of an operator on a Hilbert... more In this paper, the Rayleigh-Ritz method of estimating the eigenvalues of an operator on a Hilbert space is utilized to determine the magnitude of the largest eigenvalue for the Hankel operator of fractional-order systems, the Hankel norm. This provides a measure of the possible retrievable energy from the system in the future compared to the energy that was put into the system in the past. The application of the Rayleigh-Ritz method to obtaining underestimates of the Hankel norm of a fractional-order system is described. Several examples are given, demonstrating the method.

IEEE Industry Applications Magazine, Mar 1, 2010

Abstract : This thesis presents a new method of decentralized linear, time- invariant control sys... more Abstract : This thesis presents a new method of decentralized linear, time- invariant control systems synthesis based on the algebraic Riccati equation (ARE). The basic decentralized design guarantees closed-loop stability and a predetermined level of worst-cast disturbance attenuation. Certain modifications of the basic design guarantee the stability and disturbance attenuation to be robust despite plant uncertainty or reliable despite control-component outages. Other modifications guarantee that a subset of the controllers will be open-loop stable. The derived decentralized control law consists of a full-order observer of the plant in each control channel. Each observer includes estimates of the controls generated by the other channels and of plant disturbance inputs, based on its own estimate of the state of the plant. All of the observer gains are computed from the solution of a single Riccati-like algebraic equation, while feedback gains are computed from a state-feedback design ARE. The existence of appropriate solutions to the design equations in sufficient to guarantee the various properties of the closed-loop system. A convexity property of a certain matrix Riccati function allows parameterization of families of control laws with the same desired properties. Each value of the parameter results in controller of the same order as the plant.

The stability properties of the fundamental linear conjugate-order system are studied. The values... more The stability properties of the fundamental linear conjugate-order system are studied. The values of the complex order for which this system is stable and causal are determined. It is shown that all stable, causal systems have orders that lie within unit-radius circles centered at ±1 or on the imaginary axis in the order plane. Plots are given to illustrate these

... Jared A. Hicks, Robert Gruich, Alex Oldja, Dustin Myers,Tom T. Hartley, Robert Veillette, and... more ... Jared A. Hicks, Robert Gruich, Alex Oldja, Dustin Myers,Tom T. Hartley, Robert Veillette, and Iqbal Husain Department of Electrical and Computer ... powertrain to im-prove the fuel economy, reduce the pollution, and improve the performance of a stock 2005 Chevrolet Equinox. ...

The internal efficiency of the energy storage in a general fractional-order circuit element is an... more The internal efficiency of the energy storage in a general fractional-order circuit element is analyzed. By use of distributed-circuit representations, integral expressions are derived for the energy stored in a fractional-order integrator or a fractional-order differentiator for any given profile of the distributed state. For either constant-current or constant-voltage charging, these expressions for the stored energy are evaluated and compared with the energy supplied at the terminals of the element, so that the efficiency of the charging process is determined. The result is found to verify a published conjecture on the constant-input charging efficiency of the fractional-order elements.Copyright © 2015 by ASME

The stability property of a wavelet-based controller design is investigated by applying it to lin... more The stability property of a wavelet-based controller design is investigated by applying it to linear time-invariant (LTI) systems. Bounds for the design parameters of a wavelet controller are obtained, which guarantee the stability of the wavelet-controlled LTI plants. Numerical simulations indicate that those bounds are well achievable and applicable in the design

A method for the design of reduced-order controllers is developed based on the projective control... more A method for the design of reduced-order controllers is developed based on the projective controls approach. The projective controls, previously derived to preserve the dynamic modes of a state-feedback reference system, are extended to allow the preservation of the modes of an output-feedback reference system. This extension is useful if the best available reference control for the system is an output-feedback control. In addition, it allows more design freedom than the projective controls with state-feedback reference.<<ETX>>

Two control schemes for a two-Degree-Of-Freedom quarter-car suspension are studied here. Both sch... more Two control schemes for a two-Degree-Of-Freedom quarter-car suspension are studied here. Both schemes use projective controls to approximate a reference state-feedback control law. The first control scheme assumes a reactive suspension-force input generated by nondynamic control components. Since no actuator dynamics are included, the suspension model is 4th order. Static projective controls are utilized to yield both passive and active suspension controls, depending on the measurement structure assumed. The second control scheme assumes two reactive force inputs. The first input is generated by (nondynamic) passive components, the second by an actuator which includes its own first-Order dynamics. In this case, the suspension model is 5th order, since it includes the actuator dynamics. The separation of passive and active components in this control scheme leads to a decentralized control structure. For the example considered, fist-order dynamic projective controllers are introduced in order to stabilize the system.

... V. CONCLUSION This paper introduces new speed controllers for electric machines called the br... more ... V. CONCLUSION This paper introduces new speed controllers for electric machines called the bridged-T and the modified bridged-T controllers. The controllers have been simulated and implemented for speed control of an SRM drive. ... [3] S. Paramasivam, R. Arumugam, and S ...

Signal, Image and Video Processing, May 22, 2012

The fundamental system theory is presented for a class of real systems whose derivative order is ... more The fundamental system theory is presented for a class of real systems whose derivative order is complex. It is demonstrated that these so-called conjugate-order systems have a scale-invariance property in both the time and frequency domains, which makes them useful for describing certain phenomena in continuous media. The conditions for which these systems are guaranteed to be causal and stable are reviewed. The compactness properties of their Hankel operators, which allow them to admit finite-order approximations, are also discussed. A procedure is developed for choosing appropriate transfer-function parameter values to design a stable conjugate-order system whose frequency response meets given bandwidth, resonance, and ripple specifications.