Fractional Order Fault Tolerant Control - A Survey

In this paper, a comprehensive review of recent advances and trends regarding Fractional Order Fault Tolerant Control (FOFTC) design is presented. This novel robust control approach has been emerging in the last decade and is still gathering great research efforts mainly because of its promising results and outcomes. The purpose of this study is to provide a useful overview for researchers interested in developing this interesting solution for plants that are subject to faults and disturbances with an obligation for a maintained performance level. Throughout the paper, the various works related to FOFTC in literature are categorized first by considering their research objective between fault detection with diagnosis and fault tolerance with accommodation, and second by considering the nature of the studied plants depending on whether they are modelized by integer order or fractional order models. One of the main drawbacks of these approaches lies in the increase in complexity associated with introducing the fractional operators, their approximation and especially during the stability analysis. A discussion on the main disadvantages and challenges that face this novel fractional order robust control research field is given in conjunction with motivations for its future development. This study provides a simulation example for the application of a FOFTC against actuator faults in a Boeing 747 civil transport aircraft is provided to illustrate the efficiency of such robust control strategies

Indirect fractional order pole assignment based adaptive control

The design method of polynomial control laws by mean of pole placement are actually smart solutions to many industrial applications. This category of controllers is very popular in the industry; however most of their applications concern only problems with constant reference signals. In this paper, we propose an indirect adaptive controller by fractional order pole placement. The proposed control strategy is based on the self-tuning control structure and on-line estimation of the plant model parameters using the Recursive Least Squares (RLS) algorithm. To show the effectiveness of the proposed control scheme two simulation examples are presented. The first example is the control of a DC motor angular speed and the second one is the control of an air-lubricated capstan drive for precision positioning. Improvement in the system control dynamical behavior compared to classical control scheme has been shown for the two illustrative examples

Robust Fuzzy Adaptive Sliding Mode Stabilization for Fractional-Order Chaos

In this paper, a new adaptive fuzzy sliding mode control (AFSMC) design strategy is proposed for the control of a special class of three-dimensional fractional order chaotic systems with uncertainties and external disturbance. The design methodology is developed in two stages: first, an adaptive sliding mode control law is proposed for the class of fractional order chaotic systems without uncertainties, and then a fuzzy logic system is used to estimate the control compensation effort to be added in the case of uncertainties on the system’s model. Based on the Lyapunov theory, the stability analysis of both control laws is provided with elimination of the chattering action in the control signal. The developed control scheme is simple to implement and the overall control scheme guarantees the global asymptotic stability in the Lyapunov sense if all the involved signals are uniformly bounded. In the present work, simulation studies on fractional-order Chen chaotic systems are carried out to show the efficiency of the proposed fractional adaptive controllers

MRAC Adaptive Control Design for an F15 Aircraft Pitch Angular Motion Using Dynamics Inversion and Fractional-Order Filtering

This study proposes a fractional adaptive control scheme design for a longitudinal pitch angular motion control of a military F15 aircraft. The aircraft behavior will be forced to follow a chosen model reference in an MRAC (Model Reference Adaptive Control) configuration combined with dynamics inversion technique such that the transient response becomes invariant even in the presence of uncertainties or variations for a reference input by introducing a fractional-order transfer function pre-filter. Based on Lyapunov theory, the updating control law minimizes the error between the plant output and the model reference one. This controller is set in a cascade with a linear dynamic compensator. Simulation results on a military aircraft model with comparison to preceding results illustrate the effectiveness and the superiority of the proposed control strategy

Robust Fuzzy Adaptive Control with MRAC Configuration for a Class of Fractional Order Uncertain Linear Systems

This paper investigates a novel robust fractional adaptive control design for a class of fractional-order uncertain linear systems. Based on the Model Reference Adaptive Control (MRAC) configuration, the objective of the proposed controller is to ensure the output of the controlled plant to track the output of a given reference model system, while maintaining the overall closed-loop stability despite external disturbances and model uncertainties. An adaptive fuzzy logic controller is employed to eliminate unknown dynamics and disturbance. Lyapunov stability analysis demonstrates and verifies the desired fractional adaptive control system stability and tracking performance. Numerical simulation results illustrate the efficiency of the proposed adaptive fuzzy control strategy to deal with uncertain and disturbed fractional-order linear systems

Fractional order extremum seeking approach for maximum power point tracking of photovoltaic panels

International audienceDue to the high interest in renewable energy and diversity of research regarding photovoltaic (PV) array, a great research effort is focusing nowadays on solar power generation and its performance improvement under various weather conditions. In this paper, an integrated framework was proposed, which achieved both maximum power point tracking (MPPT) and minimum ripple signals. The proposed control scheme was based on extremum-seeking (ES) combined with fractional order systems (FOS). This auto-tuning strategy was developed to maximize the PV panel output power through the regulation of the voltage input to the DC/DC converter in order to lead the PV system steady-state to a stable oscillation behavior around the maximum power point (MPP). It is shown that fractional order operators can improve the plant dynamics with respect to time response and disturbance rejection. The effectiveness of the proposed controller scheme is illustrated with simulations using measured solar radiation data

Analysis and Control Design for a Class of Fractional Order Time-Delay Systems

International audienceIn this paper, we consider a class of fractional order time-delay systems and propose a fractional order PI D control design for their stabilization. The controller parameter's adjustment is achieved in two steps: first, the relay approach is used to compute satisfactory classical PID coefficients, namely kp, Ti and Td. Then, the fractional orders and are optimized using performance criteria. Simulation results show the efficiency of the proposed design technique and its ability to enhance the PID control performance

Fractional order tube model reference adaptive control for a class of fractional order linear systems

We introduce a novel fractional order adaptive control design based on the tube model reference adaptive control (TMRAC) scheme for a class of fractional order linear systems. By considering an adaptive state feedback control configuration, the main idea is to replace the classical reference model with a single predetermined trajectory by a fractional order performance tube guidance model allowing a set of admissible trajectories. Besides, an optimization problem is formulated to compute an on-line correction control signal within specified bounds in order to update the system performance while minimizing a control cost criterion. The asymptotic stability of the closed loop fractional order control system is demonstrated using an extension of the Lyapunov direct method. The dynamical performance of the fractional order tube model reference adaptive control (FOTMRAC) is compared with the standard fractional order model reference adaptive control (FOMRAC) strategy, and the simulation results show the effectiveness of the proposed control method