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Adaptive asymptotic tracking control of uncertain fractional-order nonlinear systems with unknown quantized input and control directions subject to actuator failures
, Article JVC/Journal of Vibration and Control ; Volume 28, Issue 19-20 , 2022 , Pages 2625-2641 ; 10775463 (ISSN) ; Shahrokhi, M ; Moradvandi, A ; Sharif University of Technology
SAGE Publications Inc
2022
Abstract
This article addresses an adaptive backstepping control design for uncertain fractional-order nonlinear systems in the strict-feedback form subject to unknown input quantization, unknown state-dependent control directions, and unknown actuator failure. The system order can be commensurate or noncommensurate. The total number of failures is allowed to be infinite. The Nussbaum function is used to deal with the problem of unknown control directions. Compared with the existing results, the control gains can be functions of states and the knowledge of quantization parameters and characteristics of the actuator failure are unknown. By applying the backstepping control approach based on the...
Adaptive fixed-time consensus control for a class of non-strict feedback multi-agent systems subject to input nonlinearities, state constraints, unknown control directions, and actuator faults
, Article European Journal of Control ; Volume 66 , 2022 ; 09473580 (ISSN) ; Shahrokhi, M ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
In this work, an adaptive fixed-time controller has been designed for a class of uncertain non-strict feedback multi-agent systems (MASs) subject to different types of input nonlinearities, time-varying asymmetric state constraints, unknown control directions, infinite number of actuator faults and external disturbances. Compared to the existing consensus control schemes, the proposed controller can handle input nonlinearities, actuator faults and unknown control directions simultaneously, while guaranteeing fixed-time convergence of the consensus tracking error and satisfying state constraints for non-strict feedback MASs. By employing a nonlinear mapping, the constrained MAS has been...
Impact of dielectric barrier discharge plasma on the wake of a wind turbine blade section oscillating in plunge
, Article Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy ; Volume 236, Issue 2 , 2022 , Pages 320-335 ; 09576509 (ISSN) ; Davari, A. R ; Soltani, M. R ; Sharif University of Technology
SAGE Publications Ltd
2022
Abstract
Effects of dielectric barrier discharge plasma have been studied on the wake velocity profiles of a section of a 660 kW wind turbine blade in plunging motion in a wind tunnel. The corresponding unsteady velocity profiles show remarkable improvement when the plasma actuators were operating and the angles of attack of the model were beyond the static stall angles of the airfoil. As a result the drag force was considerably reduced. It is further observed that the plasma-induced flow attenuates the leading edge vortices that are periodically shed into wake and diminishes the large eddies downstream. The favorable effects of the plasma augmentation are shown to occur near the uppermost and...
Fault-tolerant adaptive fractional controller design for incommensurate fractional-order nonlinear dynamic systems subject to input and output restrictions
, Article Chaos, Solitons and Fractals ; Volume 157 , 2022 ; 09600779 (ISSN) ; Shahrokhi, M ; Sadeghi, H ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
In this article, a fault-tolerant adaptive neural network fractional controller has been proposed for a class of uncertain multi-input single-output (MISO) incommensurate fractional-order non-strict nonlinear systems subject to five different types of unknown input nonlinearities, infinite number of actuators failures and arbitrary independent time-varying output constraints. The barrier Lyapunov function (BLF)-based backstepping technique and fractional Lyapunov direct method (FLDM) have been used to design the controller and establish system stability. To tackle the incommensurate derivatives problem, in each step of the backstepping technique, an appropriate Lyapunov function has been...
Fault-tolerant control of flexible satellite with magnetic actuation and reaction wheel
, Article Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering ; Volume 236, Issue 6 , 2022 , Pages 1222-1238 ; 09544100 (ISSN) ; Assadian, N ; Sharif University of Technology
SAGE Publications Ltd
2022
Abstract
The attitude fault-tolerant control of a flexible satellite actuated by reaction wheels and magnetic torquer bars is investigated in this article. A low earth orbit is considered for moment perturbations such as drag and gravity gradient. Furthermore, the flexible panels attached to a rigid central body are modeled through the assumed mode approach by a finite set of bending modal motion. The ordinary differential equations of their generalized coordinates are found using Lagrange’s equation, and the resulting dynamical model is validated by comparing its simulation results to the NX Siemens software results. Finally, a fault-tolerant controller based on sliding mode control is suggested and...
Aerodynamic performance of a dragonfly-inspired tandem wing system for a biomimetic Micro air vehicle
, Article Frontiers in Bioengineering and Biotechnology ; Volume 10 , 2022 ; 22964185 (ISSN) ; Montazer, E ; Ward, T. A ; Nik Ghazali, N. N ; Anjum Badruddin, I ; Sharif University of Technology
Frontiers Media S.A
2022
Abstract
The flying agility demonstrated by dragonflies is accomplished by means of complex aerodynamic forces produced by flapping their four wings arranged in a tandem configuration. The current study presents a novel tandem flapping wing mechanism for a biomimetic air vehicle that was designed and manufactured to experimentally investigate the aerodynamic forces. By optimizing the configuration and using spatial network analysis, it is shown that the designed structure can flap the wings in a linear up–down stroke motion and is capable of maintaining good consistency and aerodynamic performance. Such a mechanism could be used in a future biomimetic micro air vehicle (BMAV) design. The mechanism...
Plasma actuator effects on the flow physics of dynamic stall for a vertical axis wind turbine
, Article Physics of Fluids ; Volume 34, Issue 7 , 2022 ; 10706631 (ISSN) ; Ebrahimi, A ; Sharif University of Technology
American Institute of Physics Inc
2022
Abstract
Darrieus type vertical axis wind turbines have several advantages over other wind turbines for local electricity generation in urban environments. However, the main aerodynamic challenge is the negative impacts of the dynamic stall phenomenon on the turbine performance. This study numerically scrutinizes the effects of plasma actuators on the dynamic stall control and performance improvement of a Darrieus turbine. For this sake, unsteady Reynolds-averaged Navier-Stokes equations are solved using a pressure-based finite volume method. The Suzen-Hoang plasma actuator model is employed to calculate the body forces attributed to the plasma actuator. First, the dynamic stall characteristics of...
Active flow control of a wing section in stall flutter by dielectric barrier discharge plasma actuators
, Article Physics of Fluids ; Volume 34, Issue 7 , 2022 ; 10706631 (ISSN) ; Ebrahimi, A ; Amandolese, X ; Sharif University of Technology
American Institute of Physics Inc
2022
Abstract
This paper investigates the potential of using an active flow control technique to modify stall flutter oscillations of a NACA (National Advisory Committee for Aeronautics) 0015 wing section. Wind tunnel experiments have been performed with a test-rig that provides the elastic degree of freedom in pitch. Measurements of the clean airfoil are taken at preset angles of θ 0 = 6 ° - 12 °, and for Reynolds numbers of R e c = 6.2 × 10 4 - 1.25 × 10 5, which reveal the dependency of the stall flutter oscillations to Rec and θ0. Then, flow control experiments are carried out at θ 0 = 10 ° and R e c = 1.04 × 10 5. Two dielectric barrier discharge plasma actuators have been employed simultaneously to...
Micro-plasma actuator mechanisms in interaction with fluid flow for wind energy applications: operational parameters
, Article Engineering with Computers ; 2022 ; 01770667 (ISSN) ; Mazaheri, K ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2022
Abstract
Plasma actuator is a flow control device which may be used to improve the performance of wind turbine blades at low airspeeds. One of the most robust numerical models to simulate the interaction of the plasma actuator with the fluid flow is the electrostatic model. This model is improved by the authors. Due to the high cost of performing experimental optimization, the optimization of plasma actuators may be investigated by this numerical model. To optimize the aerodynamic performance of a Delft University (DU) wind turbine airfoil in a full stall condition, we used the operational parameters (voltage, frequency and the waveform) applied to the plasma actuator as the main design variables. We...
Adaptive actuator failure compensation on the basis of contraction metrics
, Article IEEE Control Systems Letters ; Volume 6 , 2022 , Pages 1376-1381 ; 24751456 (ISSN) ; Tavazoei, M. S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
Abstract
This letter develops an adaptive actuator failure compensation method for nonlinear systems with unmatched parametric uncertainty based on contraction metrics. The proposed method, which is constructed by benefiting from the recent achievements on contraction metrics based adaptive control techniques, ensures the closed-loop stability and asymptotic tracking of the desired trajectory in the presence of actuator failures. In particular, a sufficient convex condition is derived for constructing a valid metric, by which a quadratic program-based controller is obtained to determine the inputs of the actuators. The introduced method is more general than the common adaptive actuator failure...
Critical voltage, thermal buckling and frequency characteristics of a thermally affected GPL reinforced composite microdisk covered with piezoelectric actuator
, Article Mechanics Based Design of Structures and Machines ; Volume 50, Issue 4 , 2022 , Pages 1331-1353 ; 15397734 (ISSN) ; Ghabussi, A ; Forooghi, A ; Shavalipour, A ; Habibi, M ; won Jung, D ; Safa, M ; Sharif University of Technology
Taylor and Francis Ltd
2022
Abstract
Due to the remarkable progress in the field of the manufacturing process, smart composites have become the desired target for high-tech engineering applications. Accordingly, for the first time, thermal buckling, critical voltage and vibration response of a thermally affected graphene nanoplatelet reinforced composite (GPLRC) microdisk in the thermal environment are explored with the aid of generalized differential quadrature method (GDQM). Also, the current microstructure is coupled with a piezoelectric actuator (PIAC). The extended form of Halpin-Tsai micromechanics is used to acquire the elasticity of the structure, whereas, the variation of thermal expansion, Poisson’s ratio, and density...
Observation of stage position in a two-axis nano-positioner using hybrid Kalman filter
, Article Scientia Iranica ; Volume 28, Issue 5 B , 2021 , Pages 2628-2638 ; 10263098 (ISSN) ; Nejat Pishkenari , H ; Salarieh, H ; Sharif University of Technology
Sharif University of Technology
2021
Abstract
This study presents a novel method for observation of stage position in a 2D nano-positioning system based on a hybrid Kalman filter. The proposed method obviates the need to measure the stage position directly using complex and costly capacity sensors. Instead, traditional piezo actuators equipped with strain gauge sensors are utilized to measure the deection of the magnification system at the position of actuators. Then, a powerful estimation algorithm called Kalman filter was employed to observe stage displacements. The designed hybrid Kalman filter uses dynamical equations of motion in the prediction step. The piezo actuators deections are measured and exploited to correct the predicted...
Size-dependent analysis of thermoelastic damping in electrically actuated microbeams
, Article Mechanics of Advanced Materials and Structures ; Volume 28, Issue 9 , 2021 , Pages 952-962 ; 15376494 (ISSN) ; Asghari, M ; Sharif University of Technology
Bellwether Publishing, Ltd
2021
Abstract
This paper presents an analytical expression for the thermoelastic damping (TED) in electrically actuated microbeams based on the nonclassical continuum theory of the modified couple stress (MSC) and the nonclassical heat conduction model of the dual-phase-lag (DPL). This expression for TED captures small-scale effects. The coupled equations of motion and heat conduction are first derived. Then, the set of coupled governing equations are analytically dealt, and the real and imaginary parts of frequency are extracted in the framework of the complex frequency approach. Next, a closed-form relation for describing TED in electrically actuated microbeams is obtained which captures the small-scale...
Analysis of separation control authority of DBD plasma actuator using hot-film sensor array
, Article Journal of Applied Fluid Mechanics ; Volume 14, Issue 5 , 2021 , Pages 1421-1435 ; 17353572 (ISSN) ; Maghrebi, M. J ; Soltani, M. R ; Sharif University of Technology
Isfahan University of Technology
2021
Abstract
The boundary-layer control authority of a DBD plasma actuator using surface mounted hot-film sensors is evaluated. Wind tunnel experiments on a wind-turbine blade section were established at a Reynolds number of 0.27 x 106. Aerodynamic performance of the wind-turbine blade section for both plasma-ON and plasma-OFF modes are evaluated using measurements made by both surface pressure and wake survey behind the model. Two distinct boundary-layer states are recognized. A state which occurs at the onset and in proximity of the deep stall, which is affected by the low-frequency instabilities of the separated flow. In this case, the steady actuation of plasma imparts local momentum on the nearby...
Wave propagation analysis of a spinning porous graphene nanoplatelet-reinforced nanoshell
, Article Waves in Random and Complex Media ; Volume 31, Issue 6 , 2021 , Pages 1655-1681 ; 17455030 (ISSN) ; Mohammadi, K ; Barouti, M. M ; Habibi, M ; Sharif University of Technology
Taylor and Francis Ltd
2021
Abstract
In this article, wave propagation behavior of a size-dependent spinning graphene nanoplatelet-reinforced composite (GNPRC) cylindrical nanoshell with porosity is presented. The effects of small scale are analyzed based on nonlocal strain gradient theory (NSGT), this accurate theory employs exact length scale parameter and nonlocal constant. The governing equations of GNPRC cylindrical nanoshell coupled with piezoelectric actuator (PIAC) are evolved by minimum potential energy principle and solved by the analytical method. For the first time in the current study, wave propagation-porosity behavior of a GNPRC cylindrical nanoshell coupled with PIAC is examined based on NSGT. The results show...
Free vibration analysis of an electro-elastic GPLRC cylindrical shell surrounded by viscoelastic foundation using modified length-couple stress parameter
, Article Mechanics Based Design of Structures and Machines ; Volume 49, Issue 5 , 2021 , Pages 738-762 ; 15397734 (ISSN) ; Ashrafi, N ; Shavalipour, A ; Hosseinpour, A ; Habibi, M ; Moayedi, H ; Babaei, B ; Safarpour, H ; Sharif University of Technology
Bellwether Publishing, Ltd
2021
Abstract
Due to the rapid development of process manufacturing, composite materials with graphene-reinforcement have obtained commercially notices in promoted engineering applications. For this regard, vibrational characteristics of a cylindrical nanoshell reinforced by graphene nanoplatelets (GPL) and coupled with piezoelectric actuator (PIAC) is investigated. Also, the nanostructure is embedded in a viscoelastic medium. The material properties of piece-wise graphene-reinforced composite (GPLRC) are assumed to be graded in the thickness direction of a cylindrical nanoshell and estimated through a nanomechanical model. For the first time in the current study is considering the effects of...
A holistic survey on mechatronic Systems in Micro/Nano scale with challenges and applications
, Article Journal of Micro-Bio Robotics ; 2021 ; 21946418 (ISSN) ; Jalili, N ; Ahmadian, M. T ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2021
Abstract
Micro/Nano mechatronic systems might be defined as systems that include nano- or micro-scale components. These components can be sensors, actuators, and/or physical structures. Furthermore, the high-precision control laws for such small scales are important to ensure stability, accuracy, and precision in these systems. In this writing, four categories of such small-scale systems are considered by providing multifarious novel or key examples from the literature: control engineering and modeling, design and fabrication, measurement engineering, and sensor/actuator development. The applications discussed in the examples vary from nano-positioners, crucial in systems such as atomic force...
Event-triggered adaptive control of a class of nonlinear systems with non-parametric uncertainty in the presence of actuator failures
, Article Transactions of the Institute of Measurement and Control ; Volume 43, Issue 12 , 2021 , Pages 2628-2636 ; 01423312 (ISSN) ; Tavazoei, M. S ; Sharif University of Technology
SAGE Publications Ltd
2021
Abstract
This paper deals with event-triggered adaptive tracking control of a class of nonlinear systems with non-parametric uncertainty and unknown control input direction, in the presence of actuator faults. The proposed event-triggered control method takes advantage of the radial basis function neural networks to approximate the non-parametric uncertainties. Moreover, this control method benefits from the Nussbaum-type function-based adaptation laws for simultaneously dealing with unknown input direction and actuator faults. Numerical simulation results confirm the efficiency of the proposed control method to confront the above mentioned limitations. © The Author(s) 2021
Dynamic and vibration analysis of a 3-serial-link micro/nano-manipulator with piezoelectric actuation
, Article Microsystem Technologies ; Volume 27, Issue 3 , 2021 , Pages 703-721 ; 09467076 (ISSN) ; Ahmadian, M. T ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2021
Abstract
In this work, the dynamic and vibrational behavior of a micro/nano-manipulator has been studied. The manipulator comprises three links attached serially. While the connection of the links is rigid, which makes the whole body a monolithic structure, the movement of the manipulator is derived from the links deflection. Piezoelectric layers were employed as an actuator to impose deflection on the links, thereby moving the manipulator. After defining the dynamic behavior of each link, manipulator equations of motion were developed. To evaluate the validity of the mathematical model, two FEM models were constructed. The observed results showed a good agreement between the models, and they...
A PID controller design to suppress chatter vibrations in the turning process studying its effect in nonlinear delayed process
, Article 10th International Conference on Modern Circuits and Systems Technologies, MOCAST 2021, 5 July 2021 through 7 July 2021 ; 2021 ; 9781665418478 (ISBN) ; Moradi, H ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
High-quality, high-production-rate machining operations are significantly hindered by the regenerative chatter. Therefore, chatter suppression is of great significance; and active control is one of the best ways to curb it. In this paper, the orthogonal turning process is modeled as a single-degree-of-freedom system that includes the effect of tool wear; and described through a delay differential equation (DDE). Based on the model, stability lobes diagrams are obtained by the trial and error. The actuator force is the input for the control system and the tool vibration is the output. A classical PID controller is designed to improve the stability of the process and curb the self-excited...