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V. Santibanez - One of the best experts on this subject based on the ideXlab platform.

  • Output-feedback proportional–integral– derivative-type control with simple tuning for the Global Regulation of robot manipulators with input constraints
    IET Control Theory & Applications, 2015
    Co-Authors: Marco Mendoza, V. Santibanez, Arturo Zavala-río, Fernando Reyes
    Abstract:

    An output-feedback proportional-integral-derivative-type control scheme for the Global position stabilisation of robot manipulators with bounded inputs is proposed. It guarantees the Global Regulation objective avoiding input saturation by releasing the feedback not only from the exact knowledge of the system structure and parameter values, but also from velocity measurements. With respect to previous approaches of the kind, the proposed scheme remains simple while increasing design/performance-adjustment flexibility. For instance, it does not impose the use of a specific sigmoidal function to achieve the required boundedness but involves a generalised type of saturation functions. More importantly, it is characterised by a very simple control-gain tuning criterion, the simplest hitherto obtained in the considered analytical context. Experimental tests on a 2-degree-of-freedom direct-drive manipulator corroborate the efficiency of the developed scheme.

  • On Global Regulation of Robot Manipulators: Saturated Linear State Feedback and Saturated Linear Output Feedback*
    European Journal of Control, 1997
    Co-Authors: V. Santibanez, R. Kelly
    Abstract:

    In this paper we address the problem of Global Regulation under actuator torque constraints of robot manipulators. To solve this problem, we propose a simple controller whose structure has a saturated proportional and saturated derivative part plus a gravity compensation. Also we provide a modification of this controller in case only position measurements are available for feedback purposes. The performance of the proposed controller is illustrated via experiments on a two degrees-of-freedom direct drive robot system.

  • Global Regulation for robot manipulators under SP-SD feedback
    Proceedings of IEEE International Conference on Robotics and Automation, 1996
    Co-Authors: V. Santibanez, R. Kelly
    Abstract:

    In this paper, we propose a simple controller: the saturated P-saturated D controller with gravity compensation to solve the Global Regulation problem under actuator torque constraints. The performance of the proposed controller is illustrated via simulations on a two degree-of-freedom robot.

  • ICRA - Global Regulation for robot manipulators under SP-SD feedback
    Proceedings of IEEE International Conference on Robotics and Automation, 1996
    Co-Authors: V. Santibanez, R. Kelly
    Abstract:

    In this paper, we propose a simple controller: the saturated P-saturated D controller with gravity compensation to solve the Global Regulation problem under actuator torque constraints. The performance of the proposed controller is illustrated via simulations on a two degree-of-freedom robot.

  • Strict Lyapunov functions for Global Regulation of robot manipulators
    Proceedings of 1995 IEEE International Conference on Robotics and Automation, 1995
    Co-Authors: V. Santibanez, R. Kelly
    Abstract:

    Proposes a systematic methodology, based on the energy shaping framework, to find strict Lyapunov functions for a class of Global regulators for robot manipulators. The class of controller is described by control laws composed by a gradient of an artificial potential energy plus a linear velocity feedback. The authors provide explicit sufficient conditions on the artificial potential energy which allows them to obtain in a straightforward manner a strict Lyapunov function. Based on this technique the authors establish strict Lyapunov functions for well known regulators and propose a new one.

R. Kelly - One of the best experts on this subject based on the ideXlab platform.

Ali Saberi - One of the best experts on this subject based on the ideXlab platform.

B Saidsalim - One of the best experts on this subject based on the ideXlab platform.

  • Global Regulation of staphylococcus aureus genes by rot
    Journal of Bacteriology, 2003
    Co-Authors: B Saidsalim, Paul M Dunman, Fionnuala Mcaleese, D Macapagal, Ellen Murphy, Peter J Mcnamara, Staffan Arvidson, Timothy J Foster, Steven J Projan
    Abstract:

    Staphylococcus aureus produces a wide array of cell surface and extracellular proteins involved in virulence. Expression of these virulence factors is tightly controlled by numerous regulatory loci, including agr, sar, sigB, sae, and arl, as well as by a number of proteins with homology to SarA. Rot (repressor of toxins), a SarA homologue, was previously identified in a library of transposon-induced mutants created in an agr-negative strain by screening for restored protease and alpha-toxin. To date, all of the SarA homologues have been shown to act as Global regulators of virulence genes. Therefore, we investigated the extent of transcriptional Regulation of staphylococcal genes by Rot. We compared the transcriptional profile of a rot agr double mutant to that of its agr parental strain by using custom-made Affymetrix GeneChips. Our findings indicate that Rot is not only a repressor but a Global regulator with both positive and negative effects on the expression of S. aureus genes. Our data also indicate that Rot and agr have opposing effects on select target genes. These results provide further insight into the role of Rot in the regulatory cascade of S. aureus virulence gene expression.

J. Huang - One of the best experts on this subject based on the ideXlab platform.

  • A unifying framework for Global Regulation via nonlinear output feedback: from ISS to iISS
    IEEE Transactions on Automatic Control, 2004
    Co-Authors: Z.p. Jiang, I. Mareels, D.j. Hill, J. Huang
    Abstract:

    This paper presents a unifying framework for the problem of robust Global Regulation via output feedback for nonlinear systems with integral input-to-state stable inverse dynamics, subject to possibly unknown control direction. The contribution of the paper is two-fold. Firstly, we consider the problem of Global Regulation, instead of Global asymptotic stabilization (GAS), for systems with generalized dynamic uncertainties. It is shown by an elementary example that GAS is not solvable using conventional smooth output feedback. Secondly, we reduce the stability requirements for the disturbance and demand relaxed assumptions for the system. Using our framework, most of the known classes of output feedback form systems are broadened in several directions: unmeasured states and unknown parameters can appear nonlinearly, restrictive matching and growth assumptions are removed, the dynamic uncertainty satisfies the weaker condition of Sontag's integral input-to-state stability, and the sign of high-frequency gain may be unknown. A constructive strategy is proposed to design a dynamic output feedback control law, that drives the state to the origin while keeping all other closed-loop signals bounded.

  • A unifying framework for Global Regulation via nonlinear output feedback
    42nd IEEE International Conference on Decision and Control (IEEE Cat. No.03CH37475), 2003
    Co-Authors: Z.p. Jiang, I. Mareels, D.j. Hill, J. Huang
    Abstract:

    This paper presents a unifying framework for the problem of robust Global Regulation via output feedback for nonlinear systems with integral input-to-state stable (iISS) inverse dynamics, subject to possibly unknown control direction. The contribution of the paper is two-fold. Firstly, we consider the problem of Global Regulation, instead of Global asymptotic stabilization (GAS), for systems with generalized dynamic uncertainties. It is shown by an elementary example that GAS is not solvable using conventional smooth output feedback. Secondly, we reduce the stability requirements for the disturbance and demand relaxed assumptions for the system. Using our framework, most of the known classes of output feedback form systems are broadened in several directions: unmeasured states and unknown parameters can appear non-linearly, restrictive matching and growth assumptions are removed, the dynamic uncertainty satisfies the weaker condition of Sontag's integral input-to-state stability, and the sign of high-frequency gain may be unknown. A constructive strategy is proposed to design a dynamic output feedback control law, that drives the state to the origin while keeping all other closed-loop signals bounded.