Fractional order control of a coupled tank

Fixed wing Unmanned Aerial Vehicles (FWUAVs) are widely utilized in both military and civilian sectors due to their ability to perform risky, inaccessible operations. The mathematical model of FWUAVs is complex, incorporating physical laws and coordinate systems with transformation matrices. In addition, controlling FWUAVs is challenging due to their nonlinear and coupled dynamics. This paper focuses on tracking trajectories for fixed wing unmanned aerial vehicles (FWUAVs) using a Robust Fractional Order Sliding Mode Controller (RFOSMC). An RFOSMC, which combines a conventional Sliding Mode Controller (SMC) with flexible fractional calculus, is proposed in this paper. Particle Swarm Optimization (PSO) is used to tune the control gains of RFOSMC. External disturbances and parameter variation are added to evaluate the controller’s performance. Comparative studies have been done with Linear Quadratic Regulator (LQR), Fractional Order PID (FOPID), SMC, and robust FOSMC. RFOSMC performs better than LQR, FOPID, and SMC in tracking accuracy, response speed, and overshoot. In addition, the performance comparison of RFOSMC and conventional SMC has been done based on performance index values of errors (ITAE), and RFOSMC showed a 76.5918% improvement. For a step input, RFOSMC showed the smallest settling time of 0.835s compared with 2.724s for SMC and 4.8573s for FOPID. Open-loop model verification and overall control system of FWUAV are done using MATLAB/Simulink software.

Fractional order neural sliding mode control based on the FO-Hammerstein model of piezoelectric actuator

This article maidenly presents a resilient hybrid fractional-order controller (hy-FOC) comprised of fractional-order proportional-integral-derivative (FOPID) controller and fractional-order sliding mode controller (FOSMC) for frequency regulation of an islanded hybrid power system (HPS) integrated with a doubly-fed induction generator (DFIG)-driven wind power generator. The slime mould algorithm is applied to obtain near-optimum gains of the hy-FOC via the minimization of an integral error criterion. Moreover, a Luenberger disturbance observer (Dob) is designed to estimate uncertain plant disturbances and incorporate estimated output into the control law to alleviate chattering in the output of sliding mode controller (SMC). The acceptability and superiority of the proposed hy-FOC are established by performing an extensive comparative study with the results of PI-derivative (PID), SMC, FOPID, and FOSMC under diverse operating conditions (model uncertainties and uncertain external disturbances). The simulation results are presented and discussed to authenticate proficiency of the proposed resilient control methodology over its other integral-order and fractional-order counterparts. Governor dead-band and generation rate constraint (thermal unit) as a provenance of physical limitations are also considered in the model to show the proposed controller's effectiveness for handling the practical challenges. Lastly, the sensitivity and robustness of the proposed approach have been affirmed by varying system parameters between ±25% of nominal settings.

In this paper, a robust Fractional order sliding mode controller (FOSMC) is proposed for the speed control of a permanent magnet synchronous motor (PMSM). The sliding mode controller (SMC), which is insensitive to uncertainties, is studied widely in the application of PMSM drive. Furthermore, it is remarkable to see the increasing number of studies related to the theory and application of fractional order controller (FOC), especially PIλDμ controller, in many areas of science and engineering. Research activities are focused on developing new analysis and design methods for fractional order controllers as an extension of classical control theory. In this study, with the exponent reaching law, a fractional order sliding surface is introduced and a FOSMC is designed and applied to a speed control of PMSM, which is typical nonlinear multivariable coupled system. The performance and robustness of the proposed method are tested for nonlinear load torque disturbance, and simulation results show the effectiveness of the proposed algorithm.

Adaptive fractional order sliding mode controller with neural estimator

Fractional order sliding mode control of a pneumatic position servo system

The main goal of vehicle active suspension system is to upgrade the ride quality and stability of heavy duty vehicle (HDV) regardless of road surface. The mathematical modelling of HDV with two degrees of freedom is developed and simulated in MATLAB/Simulink environment. The simple and effective control techniques such as proportional integral and derivative (PID) controller, sliding mode controller (SMC) and fractional order sliding mode controller (FOSMC) are designed to detach the vibration from the passenger under step, sinusoidal and random road profile. Literature reveals that the FOSMC can eliminate steady state error and chattering effect unlike SMC and PID. The dynamic analysis of designed controllers is examined in terms of time domain, frequency domain and ride comfort analysis as per ISO 2631. The stability of SMC and FOSMC is confirmed by Lyapunouv stability for three different road profiles. The FOSMC shows satisfactory simulation results than SMC, PID and passive suspension system in reducing suspension deflection and body acceleration of HDV to upgrade the ride quality. Further, the efficacy of proposed FOSMC is proved by comparing the simulation results against existing results of PID controller.

Adaptive fractional-order sliding-mode disturbance observer-based robust theoretical frequency controller applied to hybrid wind–diesel power system

In this paper a novel controller for a flexible link manipulator based on fractional calculus is proposed. A hybrid system that combines the advantages in terms of robustness of the fractional control and the sliding mode control is proposed. Due to adding the extra degree of freedom, the fractional order sliding mode controller can achieve better control performance than the integer order sliding mode controller. For the problem of determining the design parameters, the particle swarm optimization (PSO) algorithm is used. The proposed controller is applied for a single‐link flexible manipulator robot. Finally, the performance and the significance of the closed loop system are investigated. The simulation results signify the performance of the proposed controller.

Fractional Order Sliding Mode Controller (FOSMC) is a hybrid one and has been integrated to escalate low voltage ride through (LVRT) during faults in a modular multilevel converter (MMC) based doubly fed induction generator (DFIG) connected wind energy conversion system (WECS). Voltage sag at grid directly affects stator of DFIG, due to its immediate connection. The machine’s rotor is joined to power electronic converters i.e. a rectifier (MSC) and an inverter (GSC) via a DC link. A Fractional Order Sliding Mode controller is used at Grid Side Converter to mitigate fault current and ameliorate parameters at stator, rotor terminals. This paper infers that proposed Fractional Order Super Twisting Algorithm (FOSTA) deployed Sliding Mode Controller (FOSMC) is the exceptional in dealing with symmetrical and asymmetrical faults by refining power quality parameters, LVRT problem. The fault ride capability with FOSMC is good compared to FOPI and SMC controllers.

Fractional order sliding mode control is studied in this paper. The control objectives are achieved by adopting the reaching law approach of sliding mode control. The main contribution of this work is to show that the philosophy of integer order sliding mode control is valid also for the systems represented by fractional order operators. A sufficient condition and its implications for stability are given. Matched and unmatched uncertainties are studied. The attractor nature of the switching manifold is analyzed together with a stable sliding subspace design condition. The claims are justified through a set of simulations and the results obtained are found promising.

<p>This paper presents a new approach of fractional order sliding mode <br />controllers (FOSMC) for a class of nonlinear systems which have a single input and two outputs (SITO). Firstly, two fractional order sliding surfaces S1 and S2 were proposed with an intermediate variable z transferred from S2 to S1 in order to hierarchy the two sliding surfaces. Secondly, a control law was determined in order to control the two outputs. A sliding control stability condition was obtained by using the properties of the fractional order calculus. Finally, the effectiveness and robustness of the proposed approach were demonstrated by comparing its performance with the one of the conventional sliding mode controller (SMC), which is based on integer order derivatives. Simulation results were provided for the cases of controlling a ball-beam and inverted pendulum systems.</p>

This paper studies the synchronization control of fractional order chaotic systems based on memristor and its hardware implementation. This paper takes the complex dynamic phenomena of memristor turbidity system as the research background. Starting with the integer order memristor system, the fractional order form is derived based on the integer order turbid system, and its dynamics is deeply studied. At the same time, the turbidity phenomenon is applied to the watermark encryption algorithm, which effectively improves the confidentiality of the algorithm. Finally, in order to suppress the occurrence of turbidity, a fractional order sliding mode controller is proposed. In this paper, the sliding mode controller under the function switching control method is established, and the conditions for the parameters of the sliding mode controller are derived. Finally, the experimental results analyze the stability of the controlled system under different parameters, and give the corresponding time-domain waveform to verify the correctness of the theoretical analysis.

In this paper, designing of Fractional Order Sliding Mode Controller (FOSMC) for Twin Rotor MIMO System (TRMS) is done. The sliding surface in fractional order for TRMS is formulated, and control input of TRMS is derived by decoupling the system, i.e., neglecting the inter dependency between both (horizontal and vertical) planes. The stability and the convergence of the decoupled control input in finite time is verified through Lyapunov’s criteria for stability. The parameters like angle error, sliding surface, control law for horizontal plane and the vertical plane are separately matched with the Sliding Mode Control (SMC) in MATLAB/Simulation. Overall controlled trajectory after combining trajectory of vertical plane and horizontal plane respectively is obtained, and the chattering effect due to SMC is dampened out to considerable rate.

The ride quality and travel comfort of the passenger is based on the type of the suspension system used in the vehicle. The active suspension system is one of the good choices to reduce the vibration and enhance the travel comfort. In this study, a quarter car with integrated seat suspension and driver model (QCSD) is considered for analysis. The controllers are designed for both single actuator (SA) and dual actuator (DA). To reduce the vibration and increase the travel comfort, different types of sliding mode controllers (SMCs) such as fuzzy SMC (FSMC), fractional order SMC and fractional order FSMC (FrFSMC) are designed and simulated in the active suspension system of the QCSD. Three types of road disturbances are used to stimulate the vibration in the system. The responses of the controllers with the QCSD are compared with the passive system and existing state feedback controller. The result shows that the FrFSMC performs better than the other controllers for DA as well as SA. While comparing the DA and SA, DA performs better than SA.