Input-output Feedback Linearization Research Articles

Combined Sliding Mode Control with a Feedback Linearization for Speed Control of Induction Motor

Induction Motor (IM) speed control is an area of research that has been in prominence for some time now. In this paper, a nonlinear controller is presented for IM drives. The nonlinear controller is designed based on input-output feedback linearization control technique, combined with sliding mode control (SMC) to obtain a robust, fast and precise control of IM speed. The input-output feedback linearization control decouples the flux control from the speed control and makes the synthesis of linear controllers possible. To validate the performances of the proposed control scheme, we provided a series of simulation results and a comparative study between the performances of the proposed control strategy and those of the feedback linearization control (FLC) schemes. Simulation results show that the proposed control strategy scheme shows better performance than the FLC strategy in the face of system parameters variation.

Input output feedback linearization control and variable step size MPPT algorithm of a grid-connected photovoltaic inverter

In this paper, the power factor of a grid-connected photovoltaic inverter is controlled using the input output Feedback Linearization Control (FLC) technique. This technique transforms the nonlinear state model of the inverter in the d–q reference frame into two equivalent linear subsystems, and then applies a pole placement linear control loops on this subsystem in order to separately control the grid power factor and the dc link voltage of the inverter. Maximum Power Point Tracker (MPPT) that allows extraction of maximum available power from the photovoltaic (PV) array has been included. This MPPT is based on variable step size incremental conductance method. Compared with conventional fixed step size method, the variable step MPPT improves the speed and the accuracy of the tracking.

Multiinput Direct DC–AC Converter With High-Frequency Link for Clean Power-Generation Systems

This paper proposes a new topology for bidirectional multiinput direct dc–ac converter for clean-power-generation system, therefore, at the input port, a boost converter is used to meet the requirement of many distributed generation systems, such as photovoltaic, and fuel cell systems. The boost converter can increase the dc input voltage. This point results in a turn ratio reduction of high-frequency isolating link transformer. Furthermore, the boost inductor reduces the input current ripple, therefore, the saturation of the transformer can be avoided for higher output currents. The count of used devices has been reduced in the proposed converter. As a result, the cost, size, and the volume of the converter can be reduced. The reduced conversion steps increase the efficiency of the converter. The converter is analyzed step by step to show the principles of the operation in providing energy management based on duty-cycle variations. The system capability in different operation conditions has been simulated, and the simulation results have been compared with measurement results. Dynamic analysis and control design of the bidirectional dc–ac converter is presented based on nonlinear control by input–output feedback linearization.

Combined Sliding Mode Control with a Feedback Linearization for Speed Control of Induction Motor

Induction Motor (IM) speed control is an area of research that has been in prominence for some time now. In this paper, a nonlinear controller is presented for IM drives. The nonlinear controller is designed based on input-output feedback linearization control technique, combined with sliding mode control (SMC) to obtain a robust, fast and precise control of IM speed. The input-output feedback linearization control decouples the flux control from the speed control and makes the synthesis of linear controllers possible. To validate the performances of the proposed control scheme, we provided a series of simulation results and a comparative study between the performances of the proposed control strategy and those of the feedback linearization control (FLC) schemes. Simulation results show that the proposed control strategy scheme shows better performance than the FLC strategy in the face of system parameters variation.

Approximate Nonlinear Modeling and Feedback Linearization Control for Aeroengines

This paper aims to develop an applicable nonlinear control technique for aeroengines. An approximate nonlinear model is presented and a rational identification procedure is given. Exact input-output feedback linearization can be easily performed on this model. The controller derived can approximately linearize the plant such that the close-loop system exhibits linear input-output dynamics locally. Modeling and controlling are exemplified and validated by a small turbofan engine. Simulation results illustrate that the modeling accuracy is good and linear close-loop system dynamics are achieved.

Set point stabilization of a 2DOF underactuated manipulator

Controlling an underactuated manipulator with less actuators than degrees of freedom is a challenging problem, specifically when it is to force the underactuated manipulator to track a given trajectory or to be configurated at a specific position in the work space. This paper presents two controllers for the set point regulation of 2-DOF underactuated manipulators. The first one is a cascade sliding mode tracking controller while the second one uses an inputoutput feedback linearization approach. The first algorithm builds on an observation that an underactuated manipulator can be treated as two subsystems. Consequently, a cascade sliding mode tracking controller has been designed. Firstly, a sliding mode surface is designed for both subsystems, these two sliding surfaces represent a first layer in the design architecture. A second layer sliding mode surface is then constructed based on the first layer sliding surface. The cascaded sliding mode controller is therefore deduced in terms of Lyapunov stability theorem. Robustness issues to bounded disturbances are then investigated. In a second stage of the paper, the input output feedback linearization (IOFL) control is presented. The latter, is then mixed to the sliding mode control scheme for robustness issues. Simulation results on 2-DOF whirling pendulum are presented to demonstrate the effectiveness of the proposed approach.

Reduction of torque ripple in DTC for induction motor using input-output feedback linearization

Direct torque control (DTC) is known to produce fast response and robust control in AC adjustable-speed drives. However, in the steady-state operation, notable torque, flux, and current pulsations occur. In this paper a nonlinear DTC of IM drives is presented based on a Space Vector PWM scheme combined with Input-Output Feedback Linearization (IOFL) technique. The variation of stator and rotor resistance due to changes in temperature or frequency deteriorates the performance of DTC controller by introducing errors in the estimated flux linkage and the electromagnetic torque. As a result, this approach will not be suitable for high power drives such as those used in tractions, as they require good torque control performance at considerably lower frequency. Finally, extensive simulation results are presented to validate the proposed technique. The system is tested at different speeds and a very satisfactory performance has been achieved.

Modelling and control of a DC–DC multilevel boost converter

This study proposes several dynamic models for a DC–DC multilevel boost converter. A full-order non-linear dynamic model, a reduced-order non-linear model and a small-signal model are derived. These models are based on the equivalent circuits that depend on the switching states of the converter. In addition, an input–output feedback linearisation controller is derived and implemented. The stability of the closed-loop system is analysed. A Linux-based real-time software is employed for obtaining the experimental results of the closed-loop system.

Comparative control analysis of the Vienna rectifier based on its averaged model

This paper presents a comparative evaluation of two multiple-loops duty-cycle-based control schemes applied to a three-phase three-switch three-level boost-type rectifier. The control laws are both elaborated on the basis of a state-space averaged model of the converter, expressed in the synchronous rotating frame. On the one hand, a control scheme that uses linear regulators is designed by using the small-signal transfer functions of the converter’s model, which was linearised on the neighbourhood of a suitable steady-state operating point. On the other hand, a non-linear control scheme that uses the input-output feedback linearisation approach is also designed in order to satisfy the same requirements as for the linear control system. For comparison purpose, both control schemes are implemented numerically using the Simulink tool of Matlab, and simulation experiments are carried out in order to test and verify the tracking and regulation performance of each control law, as well as their robustness towards load or mains source disturbance. For the same operating conditions, the performance of the two control laws are analysed and compared in terms of line currents total harmonic distortion (THD) and DC voltage regulation.

Linear Slip Control Formulation for Vehicular Anti-Lock Braking System with Suspension Effects

AbstractThis paper presents the formulation of a slip-control model for purposes of performing slip tracking of target slip. System modeling is performed to develop a braking model incorporating an active suspension. Linearisation of the highly non-linear multi-input multi-output developed Anti-lock Braking System model is performed by way of input-output feedback linearisation. Feedback linearisation is shown to provide a transformed linear ABS model while ensuring a verifiable stable state transformation. Lie algebra is used to find the stability of the internal dynamics through zero dynamics analysis. Simulation results demonstrate the validity of the approach along with the development of a stabilising condition for the linearisation approach.

Path following controller design for a class of mechanical systems

AbstractWe present an approach to designing feedback controllers that solve a path following control problem for a large class of mechanical systems. Our approach involves set stabilization via transverse feedback linearization: a coordinate and feedback transformation that yields a normal form convenient for control design making desired path attractive. Our approach also involves refining the normal form by imposing additional structure on the system, such that the dynamics governing the output motion along the path are linear and controllable. This approach amounts to local input-output feedback linearization for a particular choice of “virtual output”. We present necessary and sufficient checkable conditions for the particular virtual output to yield a well-defined relative degree. When these conditions hold, it is possible to put the mechanical system in the desired normal form, simplifying path following controller design.

A new series-parallel hybrid electric vehicle configuration based on an induction motor coupled to a DC machine

With emphasis on a cleaner environment and efficient operation, vehicles today rely more and more heavily on electrical power generation for success. In this paper, to improve the speed performance of the drive against uncertainties caused by load disturbances, an integral switching surface couple mode speed controller was proposed. As such, mathematical modeling of the HEV components as the three phase induction motor coupled to the DC motor in hybrid electric vehicle was introduced. The controller of the ‘induction motor’ (IM) was designed based on input-output feedback linearization technique. It allowed greater electrical generation capacity and the fuel economy and emissions benefits of hybrid electric automotive propulsion. Hybrids transient torque allows the use of start/stop operation as well as brake energy regeneration. Thus, the results of Matlab-Simulink simulations and a comparison between the control schemes are presented. Key words: Hybrid electrical vehicle, induction motor control, D.C motor.

Model Following Sliding-Mode Control of a Six-Phase Induction Motor Drive

In this paper an effective direct torque control (DTC) and stator flux control is developed for a quasi six-phase induction motor (QIM) drive with sinusoidally distributed windings. Combining sliding-mode (SM) control and adaptive input-output feedback linearization, a nonlinear controller is designed in the stationary reference frame, which is capable of tracking control of the stator flux and torque independently. The motor controllers are designed in order to track a desired second order linear reference model in spite of motor resistances mismatching. The effectiveness and capability of the proposed method is shown by practical results obtained for a QIM supplied from a voltage source inverter (VSI).

Virtual Holonomic Constraints for Euler-Lagrange Systems

This paper investigates virtual holonomic constraints for Euler-Lagrange systems with n degrees-of-freedom and n − 1 controls. The constraints have the form q1 = ϕ1 (qn), …, qn – 1 = ϕn ∓ 1 (qn), where qn is a cyclic configuration variable, so their enforcement corresponds to the stabilization of a desired oscillatory motion. We give conditions under which such a set of constraints is feasible, meaning that it can be made invariant by feedback. We show that it is possible to systematically determine feasible virtual constraints as periodic solutions of a scalar differential equation, the virtual constraint generator. Moreover, under a symmetry assumption we show that the motion on the constraint manifold is a Euler-Lagrange system with one degree-of-freedom, and use this fact to complete characterize its dynamical properties. Finally, we show that if the constraint is feasible then the virtual constraint manifold can always be stabilized using input-output feedback linearization.

Nonlinear Multivariable Power Plant Coordinate Control by Constrained Predictive Scheme

A coordinated control strategy is often used to ensure a thermal power plant to have a higher rate of load change, but without violating the thermal constraints. Although model predictive control has been widely used for controlling power plant, handling input constraints is a major problem especially as these plants are nonlinear. Two alternative methods of exploiting the nonlinear predictive control are presented in this paper. One is the input-output feedback linearization technique based on a suitably chosen approximated linear model. The other is based on neuro-fuzzy networks to represent a nonlinear dynamic process using a set of local models. From the criteria based on the integral absolute errors and the relative optimization time for completing the simulation, it is shown that the performance of the coordinated control of a steam-boiler generation plant using these two nonlinear predictive methods are better than the conventional predictive method.

Adaptive feedback linearizing control of nonholonomic wheeled mobile robots in presence of parametric and nonparametric uncertainties

In this paper, the integrated kinematic and dynamic trajectory tracking control problem of wheeled mobile robots (WMRs) is addressed. An adaptive robust tracking controller for WMRs is proposed to cope with both parametric and nonparametric uncertainties in the robot model. At first, an adaptive nonlinear control law is designed based on input-output feedback linearization technique to get asymptotically exact cancellation of the parametric uncertainty in the WMR parameters. The designed adaptive feedback linearizing controller is modified by two methods to increase the robustness of the controller: (1) a leakage modification is applied to modify the integral action of the adaptation law and (2) the second modification is an adaptive robust controller, which is included to the linear control law in the outer loop of the adaptive feedback linearizing controller. The adaptive robust controller is designed such that it estimates the unknown constants of an upper bounding function of the uncertainty due to friction, disturbances and unmodeled dynamics. Finally, the proposed controller is developed for a type (2, 0) WMR and simulations are carried out to illustrate the robustness and tracking performance of the controller.

Novel Direct Torque Control Based on Space Vector Modulation With Adaptive Stator Flux Observer for Induction Motors

This paper describes a combination of direct torque control (DTC) and space vector modulation (SVM) for an adjustable speed sensorless induction motor (IM) drive. The motor drive is supplied by a two-level SVPWM inverter. The inverter reference voltage is obtained based on input-output feedback linearization control, using the IM model in the stator D-Q axes reference frame with stator current and flux vectors components as state variables. Moreover, a robust full-order adaptive stator flux observer is designed for a speed sensorless DTC-SVM system and a new speed-adaptive law is given. By designing the observer gain matrix based on state feedback H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> control theory, the stability and robustness of the observer systems is ensured. Finally, the effectiveness and validity of the proposed control approach is verified by simulation results.

Adaptive trajectory tracking control of a differential drive wheeled mobile robot

SUMMARYThis paper presents an adaptive trajectory tracking controller for a non-holonomic wheeled mobile robot (WMR) in the presence of parametric uncertainty in the kinematic and dynamic models of the WMR and actuator dynamics. The adaptive non-linear control law is designed based on input–output feedback linearization technique to get asymptotically exact cancellation for the uncertainty in the given system parameters. In order to evaluate the performance of the proposed controller, a non-adaptive controller is compared with the adaptive controller via computer simulation results. The results show satisfactory trajectory tracking performance by virtue of SPR-Lyapunov design approach. In order to verify the simulation results, a set of experiments have been carried out on a commercial mobile robot. The experimental results also show the effectiveness of the proposed controller.

Feedback Linearization Control of Three-Phase UPS Inverter Systems

In this paper, a feedback linearization technique is proposed to control the output voltage control of three-phase uninterruptible power supply systems. First, a nonlinear model including the output LC filters is derived from the power balance condition between the inverter output terminal and the load side. Then, input-output feedback linearization is applied to the nonlinear model to make it linear. The controller of the linearized model is designed by linear control theory. The tracking control law is obtained with a pole placement technique. It is shown experimentally that the proposed control scheme gives high dynamic responses in response to load variation as well as a zero steady-state error.

An advanced fuzzy logic gain scheduling trajectory control for nonlinear systems

This paper investigates a novel fuzzy control approach developed for a class of nonlinear continuous systems. We combine an input–output feedback linearization (IOFL) method and a gain scheduling (GS) approach to obtain a tracking control structure. The latter is mainly based on the reversing trajectory method which allows us to estimate the asymptotic stability region around operating points. Needless to say that the limitation of this analytical approach lies in the challenge of determining the intermediate operating points in order to ensure a smooth transition from actual operating conditions to desired ones. This happens when there is no intersection between successive stability regions. The proposed fuzzy logic controller (FLC) is synthesized in order to determine the intermediate operating points which, in turn, will allows us to online implement the tracking control for nonlinear systems. Finally, the effectiveness of the fuzzy gain scheduling schema is demonstrated through its simulation to a temperature control problem in a CSTR.