J. De Leon

An Adaptive Interconnected Observer for Sensorless Control of PM Synchronous Motors With Online Parameter Identification

This paper proposes an adaptive interconnected observer for sensorless control of a synchronous motor. The corresponding observer is used to estimate the rotor speed, the rotor position, and the load torque and, moreover, to estimate the stator inductance and the stator resistance. The convergence of the observer estimation error is analyzed, and sufficient conditions are given to prove the practical stability. Experimental results are shown to confirm the effectiveness of the proposed method.

Sensorless Induction Motor: High-Order Sliding-Mode Controller and Adaptive Interconnected Observer

An adaptive interconnected observer and high-order sliding-mode control of induction motors without mechanical sensors (speed sensor and load torque sensor) are proposed and experimentally evaluated. The adaptive interconnected observer estimates fluxes, angular velocity, load torque, and stator resistance. Stability based on Lyapunov theory is proved to guarantee the ldquoobserver-controllerrdquo stability.

A robust sensorless output feedback controller of the induction motor drives: new design and experimental validation

In this article, a sensorless output feedback controller is designed in order to drive the induction motor (IM) without the use of flux and speed sensors. First, an observer that uses only the measured stator currents is synthesised to estimate the mechanical variables (speed and load torque) and the magnetic variables (fluxes) by structurally taking into account the unobservability phenomena of the sensorless IM (SIM) and the parametric uncertainties. Second, a current-based field-oriented sliding mode control that uses the flux and the speed estimates given by the former observer is developed so as to steer the estimated speed and flux magnitude to the desired references. Since the observer error dynamic is independent from the known input control and depends on the IM parametric uncertainties, a kind of separation principle is introduced to guarantee the practical stability of the whole closed-loop system ‘observer–controller’ (‘O-C’) according to observability and unobservability time variation. A significant benchmark taking into account the unobservability phenomena of the SIM is presented to show the performances of the whole control scheme against experimental set-up.

Observability Study and Observer-Based Interconnected Form for Sensorless Induction Motor

In this paper, the observability analysis of induction motor is studied. The aim is to clarify observability problems found in particular when the motor operates at low frequencies. From this study, a sensorless observer benchmark is defined for sensorless induction motor observers validation. An observer based on interconnected form to estimate the mechanical and magnetic states of sensorless induction motor is designed. Taking into account the parameter uncertainties of induction motor and based on Lyapunov theory, the proof of the observer convergence is given. The proposed observer is tested and validated on reference trajectories of our bench-mark.This benchmark is applied on an experimental set-up located at IRCCyN (Nantes, France). Robustness tests with respect to parameters variations show the applicability of the designed observer

Adaptive interconnected observer for sensorless induction motor

An adaptive interconnected observer for induction motor (IM) drive without mechanical sensors (speed sensor and load torque sensor) is presented. The observer estimates the fluxes, the angular velocity, the load torque and the stator resistance even under or near unobservable conditions. Practical stability based on Lyapunov theory is proved to guarantee the strongly uniformly practical stability of the estimation error dynamics. A contribution of this article is the experimental validation of the observer on reference trajectories of a sensorless IM observer benchmark. The trajectories of this benchmark are chosen to test the motor near and under conditions of unobservability. Robustness with respect to parameters variations is proved and experimentally verified.

High order sliding mode and adaptive observers for a class of switched systems with unknown parameter: A comparative study

This paper deals will the observation of a particular class of switched system. Two methodologies of designing an observer are considered in order to estimate the state of the switched system and unknown parameters. The first approach is based on a robust differentiator via a sliding mode technique, the other one is based on an adaptive observer. Furthermore, an analysis of convergence for both observers is introduced. Finally some illustrative results are given in order to show the efficiency of the designed observers

High-order sliding mode observers and integral backstepping sensorless control of IPMS motor

This paper presents a robust high-order sliding mode interconnected observer and an integral backstepping controller for a sensorless interior permanent magnet synchronous motor. To limit the chattering phenomenon on the observed state, a super twisting algorithm is combined with an interconnected observer to design a new high-order sliding mode observer which will be used for multiple-input multiple-output systems. The proposed observer is used to estimate in finite time the rotor position, the speed and the stator resistance. Moreover, a robust nonlinear controller based on the backstepping algorithm is designed where integral actions are introduced step by step. This controller allows to track a desired reference which is computed by using a maximum-torque-per-ampere strategy. Simulation results are shown to illustrate the performance of the proposed scheme by using significant trajectories including the zero speed and under parametric uncertainties.

Mechanical systems tracking using neural networks and state estimation simultaneously

In this paper, we analyze how to implement a nonlinear observer, which combined with a structured neural network, allows tracking of an artificial output, even when the state is not fully measurable; as an effect of this tracking, the system state converges to any selected equilibrium point. We establish and prove a theorem about the stability of the tracking error and of the state estimation error. The applicability of the approach is illustrated by simulation results.<<ETX>>

Delay and state observer for SISO LTI systems

This paper deals with the problem of state and delay estimation for SISO LTI systems, with unknown time-varying delay in the input. Thanks to an adequate approximation of the delayed input by the Taylors theorem, an original approach based on observer design is proposed in order to estimate both state and delay. This new technique allows the estimation of time-varying delay. The convergence of the observer is formally proved. The efficiency of the method is widely illustrated by simulations.

A Sliding Mode-Based Impedance Control for Bilateral Teleoperation under Time Delay

Abstract Several control strategies have been proposed to deal with time delay, parametric uncertainties and nonlinearities for bilateral teleoperation. Furthermore, published works had shown that sliding mode control is a viable option to deal with parametric uncertainty and hard nonlinearities. In this paper, an impedance control based on sliding mode techniques is presented, to guarantee robust tracking under unknown constant time delay. Furthermore, in order to implement the proposed impedance controller, it is necessary to know the velocity and acceleration of the slave system, then to overcome this problem, i.e the estimation in teleoperation in presence the unknown time-delays in the communication channel, a nonlinear observer designed via the super twisting algorithm is presented in order to estimate velocity and acceleration. Simulation results are presented and discussed, which reveal the effectiveness of the proposed observer with the sliding mode control.