Piece-Wise Causal Inversion by Output Redefinition for a Flexible Link Manipulator

Vakil, M.; Fotouhi, Reza; Nikiforuk, P.N.

doi:10.1139/tcsme-2009-0018

Cited by 11 publications

(3 citation statements)

References 26 publications

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“…Using a preview of the desired output, these methods require a finite pre-actuation [27,26,28]. Other approximated approaches make use of particular redefinitions of the desired output [2], [25] or consider a particular analytic form of the desired behaviour [18], [19].…”

Section: Introductionmentioning

confidence: 99%

A general framework for approximated model stable inversion

Romagnoli

Garone

2019

Automatica

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In this paper we propose a generalized method for designing feedforward actions based on model stable inversion. In the proposed framework the solution of the model stable inversion can be approximated in the least squares sense by any arbitrary set of basis functions. The paper makes use of operator theory to derive a closed-form formula to compute such approximation and to provide boundedness properties for the computed solution. Some simulations are provided to show the effectiveness of the proposed method with different families of basis functions.

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Section: Introductionmentioning

confidence: 99%

A general framework for approximated model stable inversion

Romagnoli

Garone

2019

Automatica

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“…This approach is not systematic and degrades the tracking performance. Other inversion techniques have been developed with reference to one‐link flexible manipulators and require a proper redefinition of the output , thus preventing the tracking of an arbitrary prespecified trajectory; arbitrary (possibly uncertain) initial conditions can be considered ; the method can be directly extended to deal with the more general tracking problem of an output, which is required to track a repeatedly and non‐periodically switching set point, and only a limited preview information is available.…”

Section: Introductionmentioning

confidence: 99%

Optimal transient performance under output set‐point reset

Jetto

Orsini

Romagnoli

2015

Intl J Robust & Nonlinear

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The purpose of this paper is to propose a new method for the optimization of the output transition in the case of set-point reset for LTI, non-minimum phase, possibly non-hyperbolic plants. Assuming that the plant is stabilized by a proper feedback controller, the problem consists in finding a feedforward linear filter yielding a suitable reference trajectory for the closed-loop system. The approach situates in the framework of model pseudo-inversion because the external reference trajectory is computed starting from some desired features of the transient output between the two set points. A significant aspect of the new method is that the transition trajectory is not 'ad hoc' exactly prespecified by the designer. Rather, it is implicitly defined by the procedure for the minimization of a suitable multi-objective quadratic cost functional. As no pre-actuation is required, the method can be practically implemented on line and also works for the critical class of non-hyperbolic systems.L. JETTO, V. ORSINI AND R. ROMAGNOLIBy (4), the solution of (1) is given by

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“…This implies that: (i) the desired

{\overset{y}{true}}_{t} (k)

can be freely assigned without requiring it to be null over an initial time interval; (ii) the method can be easily applied to the class of non‐hyperbolic (or near non‐hyperbolic) systems. For the continuous time case, the existing approaches require the ad hoc modification of the internal dynamics or a proper redefinition of the output .…”

Section: Introductionmentioning

confidence: 99%

Spline Based Pseudo‐Inversion of Sampled Data Non‐Minimum Phase Systems for an Almost Exact Output Tracking

Jetto¹,

Orsini²,

Romagnoli³

2014

Asian Journal of Control

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This paper considers the problem of achieving a very accurate tracking of a pre-specified desired output trajectorỹ y(k), k ∈ ∠ Z + , for linear, multiple input multiple output, non-minimum phase and/or non hyperbolic, sampled data, and closed loop control systems. The proposed approach is situated in the general framework of model stable inversion and introduces significant novelties with the purpose of reducing some theoretical and numerical limitations inherent in the methods usually proposed. In particular, the new method does not require either a preactuation or null initial conditions of the system. The desiredỹ(k) and the corresponding sought input are partitioned in a transient component (ỹ t (k) and u t (k), respectively) and steady-state (ỹ s (k) and u s (k), respectively). The desired transient componentỹ t (k) is freely assigned without requiring it to be null over an initial time interval. This drastically reduces the total settling time. The structure of u t (k) is a priori assumed to be given by a sampled smoothing spline function. The spline coefficients are determined as the least-squares solution of the over-determined system of linear equations obtained imposing that the sampled spline function assumed as reference input yield the desired output over a properly defined transient interval. The steady-state input u s (k) is directly analytically computed exploiting the steady-state output response expressions for inputs belonging to the same set ofỹ s (k). Key Words:Model stable inversion, sampled data non-minimum phase systems, optimal transient tracking.

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Piece-Wise Causal Inversion by Output Redefinition for a Flexible Link Manipulator

Cited by 11 publications

References 26 publications

A general framework for approximated model stable inversion

A general framework for approximated model stable inversion

Optimal transient performance under output set‐point reset

Spline Based Pseudo‐Inversion of Sampled Data Non‐Minimum Phase Systems for an Almost Exact Output Tracking

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