211 research outputs found
Comments on “Repetitive learning control for a class of partially linearizable uncertain nonlinear systems”, [Automatica, 85 (2017) 397–404]
No full textThis correspondence points out connections between the results achieved in Verrelli (2016) and the ones obtained in Chen and Liu (2017). Problem formulation, control structure, and stability proof in Chen and Liu (2017) can be revisited and recast to reveal similarities that provide a new interpretation of such a paper in the light of Verrelli (2016). (C) 2019 Elsevier Ltd. All rights reserved
Nonlinear tracking control for sensorless permanent magnet synchronous motors with uncertainties
No full textThe recent advanced solution in Marino, Tomei, and Verrelli (2013) to the tracking control problem for sensorless IMs with parameter uncertainties is translated on the basis of letter swap connections between the models of (nonsalient-pole surface) permanent magnet synchronous motors (PMSMs) and induction ones (IMs). The (stability proof-based) nonlinear adaptive position/speed tracking control for sensorless PMSMs (with simultaneous estimation of uncertain constant load torque and stator resistance), which is accordingly obtained by exploring and decoding the design paths in Marino et al. (2013) and which surprisingly represents a simple generalization of the controller in Tomei and Verrelli (2011), constitutes an innovative solution to the related open problem. Illustrative experimental results are included
Learning control in spatial coordinates for the path-following of autonomous vehicles
No full textWe prove the existence of a P-type (proportional-type) space-learning control, which, on the basis of a kinematic third order nonlinear model of an autonomous nonholonomic vehicle and by a proper choice of the proportional control gain, guarantees asymptotic tracking of planar curves whose uncertain curvature is LL-periodic in the curvilinear abscissa. The behavior of a human driver, who repetitively learns the correct action from the past experience in the space, is mathematically reproduced. A stability analysis is presented while simulation results demonstrate the effectiveness of the presented approach
Global stability for the inner and outer PI control actions in non-salient-pole PMSMs
No full textThe aim of this brief is to positively answer the following question. Is it possible to go beyond the limitations outlined in the very recent paper by Ortega et al. and show that the smooth version of the (maximum-torque-per-ampere) industry standard control scheme for non-salient-pole PMSMs (Permanent Magnet Synchronous Motors) - even including the outer Proportional-Integral control action on the rotor speed regulation error - guarantees global asymptotic (exponential on compact sets) stabilization of the desired equilibrium? The key technical point relies on the repeated use of the Persistency of Excitation Lemma, whereas a remarkable feature of the proposed analysis is constituted by the direct possibility of recovering, as a special case, the recent passivity-based arguments presented by Ortega et al. for non-salient-pole PMSMs. (C) 2020 Elsevier Ltd. All rights reserved
New exponential convergence properties for Bernard-Praly observer and adaptive sensorless control of PMSMs
No full textIt is innovatively established, through a nonlinear Persistency of Excitation (PE) analysis, that the latest Bernard-Praly gradient adaptive observer - for nonsalient-pole surface Permanent Magnet Synchronous Motors (PMSMs) with uncertain flux of the permanent magnet (PM) - owns exponential convergence properties under well-known observability conditions. Such exponential properties can be crucially used to provide a new solution to the long-standing problem of guaranteeing position/speed tracking in sensorless PMSMs, in the presence of uncertain constant parameters such as load torque, PM flux and possibly stator resistance. (C) 2020 Elsevier Ltd. All rights reserved
La Matematica Elementare del Feedback - Introduzione ragionata a concetti e metodi della teoria dei sistemi
No full text
Repetitive learning control design and period uncertainties
No full textThe aim of this brief is to show how stability proofs in the time-domain involving suitable quadratic-integral Lyapunov-like functions can be derived in the repetitive control design scenario in the case of uncertain period for the reference signals/disturbances to be tracked/rejected. Even though the presented arguments are rather general, we apply them to the generalization of the proportional-integral-derivative (PID)-like learning control that has been recently designed. The use of the presented results in multi-link robot synchronization tasks provides simple and intuitive solutions to as yet unsolved problems
AC motors: Letter swap potentialities
No full textThis technical communique illustrates the potentialities of the recently found letter swap connections between the models of AC induction motors (IMs) and (nonsalient-pole surface) permanent magnet synchronous motors (PMSMs): observability and observer design issues for PMSMs are immediately addressed by directly exploring and decoding the logical paths characterizing the recent corresponding analysis for IMs, without re-performing the related analysis/design from the beginning. (C) 2019 Elsevier Ltd. All rights reserved
Virtual control strategy and conditioning technique for tracking and learning controls under input restrictions
No full textThe virtual control strategy for mechanical systems has been recently proposed (Gnucci and Marino, 2021) in the context of under-actuated mechanical systems. Such a strategy views and represents an under-actuated mechanical system as a fully actuated system with virtually added inputs and outputs having to satisfy, through a suitable choice of the virtual output reference signals, the virtual input zero-equality constraint: the related adaptive tracking control problem is then solved through standard design techniques. This paper exhibits a twofold aim. The first one is: to enlarge the concept of zero-input constraint and thus naturally adapt the virtual control approach to the case in which an actuator fault can occur. The second aim is: to show how the application and transposition of such an adaptation to two well-known classes of nonlinear systems (special systems in multi-variable tracking form with two inputs and outputs under actuator faults; one-relative-degree, single-input, single-output systems in output feedback form under input saturation) not only own strong connections with the conditioning technique, originally conceived in the context of anti-windup problems under input constraints, but they also gain original results
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