Showing papers in "Journal of Vibration and Control in 2017"
TL;DR: In this paper, an LMI-based second-order fast terminal sliding mode control technique is investigated for the tracking problem of a class of non-linear uncertain systems with matched and mismatched uncertainties.
Abstract: In this paper, an linear matrix inequalities (LMI)-based second-order fast terminal sliding mode control technique is investigated for the tracking problem of a class of non-linear uncertain systems with matched and mismatched uncertainties. Using the offered approach, a robust chattering-free control scheme is presented to prove the presence of the switching around the sliding surface in the finite time. Based on the Lyapunov stability theorem, the LMI conditions are presented to make the state errors into predictable bounds and the parameters of the controller are obtained in the form of LMI. The control structure is independent of the order of the model. Then, the proposed method is fairly simple and there is no difficulty in the use of this scheme. Simulations on the well-known Genesio's chaotic system and Chua's circuit system are employed to emphasize the success of the suggested scheme. The simulation results on the Genesio's system demonstrate that the offered technique leads to the superior impro...
98 citations
TL;DR: In this paper, a recursive terminal sliding mode structure for tracking control of third-order chained-form nonholonomic systems in the presence of unknown external disturbances is proposed, and a new reaching control law is proposed to guarantee the existence of the sliding mode around the recursive TSM surface.
Abstract: This paper proposes a novel recursive terminal sliding mode structure for tracking control of third-order chained–form nonholonomic systems in the presence of the unknown external disturbances. Finite-time convergence of the disturbance approximation error is guaranteed using the designed disturbance observer. Under the proposed terminal sliding model tracking control technique, the finite-time convergence of the states of the closed-loop system is guaranteed via Lyapunov analysis. A new reaching control law is proposed to guarantee the existence of the sliding mode around the recursive TSM surface in a finite-time. Simulation results are illustrated on a benchmark example of third-order chained-form nonholonomic systems: a wheeled mobile robot. The results demonstrate that the proposed control technique achieves promising tracking performance for nonholonomic systems.
95 citations
TL;DR: In this article, a dual implementation of the Kalman filter was proposed for simultaneous estimation of the states and input of structural systems, by means of numerical simulations, and the proposed method outperforms existing techniques in terms of robustness and accuracy for the estimated displacement and velocity time histories.
Abstract: In this study, a novel dual implementation of the Kalman filter proposed by Eftekhar Azam et al. (2014, 2015) is experimentally validated for simultaneous estimation of the states and input of structural systems. By means of numerical simulations, it has been shown that the proposed method outperforms existing techniques in terms of robustness and accuracy for the estimated displacement and velocity time histories. Herein, dynamic response measurements, in the form of displacement and acceleration time histories from a small-scale laboratory building structure excited at the base by a shake table, are considered for evaluating the performance of the proposed Dual Kalman filter and in order to compare this with available alternatives, such as the augmented Kalman filter (Lourens et al., 2012b) and the Gillijn De Moore filter (GDF) (2007b). The suggested Bayesian approach requires the availability of a physical model of the system in addition to output-only measurements from limited degrees of freedom. Two ...
95 citations
TL;DR: In this paper, a numerical scheme based on hybrid Chelyshkov functions (HCFs) is presented to solve a class of fractional optimal control problems (FOCPs).
Abstract: In this paper, a numerical scheme based on hybrid Chelyshkov functions (HCFs) is presented to solve a class of fractional optimal control problems (FOCPs). To this end, by using the orthogonal Chel...
93 citations
TL;DR: In this paper, a model was introduced for analyzing the influence of tooth shape deviations and assembly errors on the helical gear mesh stiffness, loaded transmission error, tooth contact stress and tooth root stress.
Abstract: A model is introduced for analyzing the influence of tooth shape deviations and assembly errors on the helical gear mesh stiffness, loaded transmission error, tooth contact stress and tooth root stress. The helical gear is approximated as a series of independent spur gear slices along axial direction whose face-width is relatively small. The relative position relationships among those sliced teeth in mesh are developed with tooth profile errors and the stiffness of the sliced tooth is calculated by the potential energy method. From the equilibriums of the forces, gear mesh stiffness, loaded transmission error, tooth contact stress and tooth root stress are calculated. Then two cases are presented for validation of the model. It is demonstrated that the model is effective for calculating the stiffness of helical gear pairs. Finally, the effects of the tooth tip reliefs, lead crown reliefs and misalignments on the gear mesh stiffness, transmission error, tooth contact stress and tooth root stress are analyz...
85 citations
TL;DR: The outstanding aspect of the proposed EENN pitch controller is that, they can smoothen the output power fluctuation, when the wind speed is above or below rated speed of the WT.
Abstract: Frequent variation in the wind flow affects the Wind Turbine (WT) to generate fluctuating output power and this can negatively impact the entire power network. This paper aims at modelling an Enhanced-Elman Neural Network (EENN) based pitch angle controller to mitigate the output power fluctuation in a grid connected Wind Energy Conversion System. The outstanding aspect of the proposed controller is that, they can smoothen the output power fluctuation, when the wind speed is above or below rated speed of the WT. The proposed EENN pitch controller is trained online using Gradient Descent (GD) algorithm and the network learning is carried out using Customized-Particle swarm optimization (C-PSO) algorithm. The C-PSO is adopted, in order to increase the learning capability of the training process by adjusting the networks learning rate. Further, the node connecting weights of the EENN is updated by means of GD algorithm using back-propagation methodology. The performance of the proposed controller is analysed...
77 citations
TL;DR: In this article, the numerical solution of a fractional optimal control problem having a quadratic performance index is proposed and analyzed, and the performance index of the fractional OCC problem is cons...
Abstract: The numerical solution of a fractional optimal control problem having a quadratic performance index is proposed and analyzed. The performance index of the fractional optimal control problem is cons...
75 citations
TL;DR: In this article, a global sliding mode control technique for the stabilization of a class of uncertain and nonlinear dynamic systems with perturbation is presented, where sufficient conditions are deduced to guarantee the asymptotic stabilization of system states and to modify the robustness of the system.
Abstract: This paper presents a novel global sliding mode control technique for the stabilization of a class of uncertain and nonlinear dynamic systems with perturbation. Using the Lyapunov stability theory and linear matrix inequality, some sufficient conditions are deduced to guarantee the asymptotic stabilization of the system states and to modify the robustness of the system. To improve the robust performance, an innovative reaching control law is designed to guarantee a chattering-free finite time performance under the uncertainty and nonlinearities and is optimally tuned using a modified random search algorithm. Simulation results are provided to show the effectiveness of the suggested technique.
64 citations
TL;DR: In this article, a unified solution for coupled cylindrical shell and annular plate systems with general boundary and coupling conditions is presented by using a modified Fourier-Ritz method.
Abstract: A unified solution for coupled cylindrical shell and annular plate systems with general boundary and coupling conditions is presented in the study by using a modified Fourier-Ritz method. Under the framework, regardless of the boundary and continuity conditions, each displacement for the cylindrical shell and the annular plate is invariantly expressed as the modified Fourier series composed of the standard Fourier series and auxiliary functions. The introduction of the auxiliary functions can not only remove the potential discontinuities at the junction and the extremes of the combination but also accelerate the convergence of the series expansion. All the expansion coefficients are determined by the Rayleigh-Ritz method as the generalized coordinates. The arbitrary axial position of the annular plate coupling with the cylindrical shell considered in the theoretical formulation makes the present method more general. The theoretical model established by present method can be conveniently applied to cylindr...
63 citations
TL;DR: In this article, the effects of the rubbing under different rotating speeds and penetration depths on the blade vibration response and contact behaviors of dovetail interface are analyzed and the results show that the rubbing will cause amplitude amplification phenomenon when the multiple frequency components are close to the first bending and first torsion natural frequencies.
Abstract: A cyclic sector corresponding to blade-disk structure with dovetail connection (1/38 blade-disk) is studied and the finite element (FE) model of this structure is established based on ANSYS software. A revised normal rubbing force model is developed and a pulse force model is established to simulate the local rubbing phenomenon between the blade and elastic casing based on the revised model. The effects of the rubbing under different rotating speeds and penetration depths on the blade vibration response and contact behaviors of dovetail interface are analyzed. The results show that the rubbing will cause amplitude amplification phenomenon when the multiple frequency components are close to the first bending and first torsion natural frequencies. The arch bending of the blade caused by blade-tip rubbing can be identified by evaluating the displacement and stress of the blade in the radial direction (y-direction). The dynamic stress in the process of rubbing gradually changes from alternation between tensio...
59 citations
TL;DR: In this article, a multi-objective genetic algorithm (MOGA) was proposed to optimize the FOPID controller gains to enhance the ride comfort of heavy vehicles by using magnetorheological (MR) damper in seat suspension system.
Abstract: Recently, fractional-order proportional–integral–derivative (FOPID) controllers are demonstrated as a general form of the classical proportional–integral–derivative (PID) using fractional calculus In FOPID controller, the orders of the derivative and integral portions are not integers which offer more flexibility in succeeding control objectives This paper proposes a multi-objective genetic algorithm (MOGA) to optimize the FOPID controller gains to enhance the ride comfort of heavy vehicles The usage of magnetorheological (MR) damper in seat suspension system provides considerable benefits in this area The proposed semi-active control algorithm consists of a system controller that determines the desired damping force using a FOPID controller tuned using a MOGA, and a continuous state damper controller that calculates the input voltage to the damper coil A mathematical model of a six degrees–of–freedom seat suspension system incorporating human body model using an MR damper is derived and simulated us
TL;DR: In this paper, a hybrid damper is configured to operate with hydraulic and electromagnetic components, which produces a large fail-safe baseline damping force, while the electromagnetic component adds energy regeneration and adaptability to the suspension.
Abstract: This paper reports work on the optimization and performance evaluation of a hybrid electromagnetic suspension system equipped with a hybrid electromagnetic damper. The hybrid damper is configured to operate with hydraulic and electromagnetic components. The hydraulic component produces a large fail-safe baseline damping force, while the electromagnetic component adds energy regeneration and adaptability to the suspension. For analyzing the system, the electromagnetic component was modeled and integrated into a 2DOF quarter-car model. Three criteria were considered for evaluating the performance of the suspension system: ride comfort, road holding and regenerated power. Using the genetic algorithm multi-objective optimization (NSGA-II), the suspension design was optimized to improve the performance of the vehicle with respect to the selected criteria. The multi-objective optimization method provided a set of solutions called Pareto front in which all solutions are equally good and the selection of each one...
TL;DR: In this paper, a modified numerical technique was developed to solve a wide class of variable order fractional optimal control problems in the sense of Riemann Liouville or Caputo derivatives.
Abstract: A modified numerical technique was developed to solve a wide class of variable order fractional optimal control problems in the sense of Riemann Liouville or Caputo derivatives. The modified algorithm is based on the non-standard finite difference method of solving fractional differential equations of variable order. Important property of a reflection operator is used to simplify the variable order right Riemann Liouville or Caputo derivatives to the variable order left Riemann Liouville or Caputo derivatives. Necessary and sufficient conditions that guarantee the existence and the uniqueness of the solution of the resulting systems are given. Illustrative examples are included to demonstrate the validity and the effectiveness of the established approach.
TL;DR: In this article, the free vibration of rotating tap beam was examined and the frequency and mode shape of the Timoshenko beam was determined for a rotating tapered beam with the objective of determining its natural frequencies and mode shapes.
Abstract: Accurate determination of natural frequencies and mode shapes of the rotating tapered Timoshenko beam is important in engineering practice. This paper re-examines the free vibration of rotating tap...
TL;DR: Results of analyzing the pinion’s vibration displacement show that the proposed approach denoted (HEWT) successfully detect the tooth crack at a much earlier stage of damage development even though in noisy environment.
Abstract: Hilbert-Huang Transform (HHT) has been renowned for its capacity to reveal fault indicating information issue from vibration signals. It uses Empirical Mode Decomposition (EMD) to decompose a signal accordingly to its contained information into a set of Intrinsic Mode Functions (IMFs). Then, the instantaneous frequencies are performed of each IMF using Hilbert Transform (HT). However, the HHT has some disadvantages which are caused by the EMD technique. The EMD has the mode mixing problem that may occur between IMFs, it causes the End Effect phenomenon, which leads to a wrong instantaneous values at both sides of the signal. Furthermore, its lack of mathematical basis. To overcome the HHT inherent problems, we propose the use of the Empirical Wavelet Transform (EWT) which designs an appropriate wavelet filter bank fully depends on the processed signal with HT in the early detection and condition monitoring of tooth crack fault. In this paper, we develop a dynamic model describing a single stage spur gear ...
TL;DR: In this article, nonlinear energy sinks (NES) are used as a possible engineering solution for mitigation of steady-state, impulsive and transient broadband excitations, and they have been shown to be effective in the case of high-frequency broadband excitation.
Abstract: Nonlinear energy sinks (NES) are widely studied as a possible engineering solution for mitigation of steady-state, impulsive and transient broadband excitations. Current work is devoted to the appl...
TL;DR: In this paper, a free-of-axledetector (FAD) algorithm, which eliminates the use of axle detectors, was proposed to solve the problem of poor durability due to the direct exposure to the traffic.
Abstract: Bridge weigh-in-motion (BWIM) technique uses an instrumented bridge as a weighing scale to estimate vehicle weights. Traditional BWIM systems use axle detectors placed on the road surface to identify vehicle axles. However, the axle detectors have poor durability due to the direct exposure to the traffic. To resolve this issue, a free-of-axle-detector (FAD) algorithm, which eliminates the use of axle detectors, was proposed. As a further improvement to simplify the BWIM systems, the concept of nothing-on-road (NOR) BWIM was recently introduced. The axle identification method proposed in this paper is an attempt to achieve the NOR BWIM, i.e., using bridge global responses to identify vehicle axles. Wavelet analysis is applied to extract the axle information from the global responses. This allows the BWIM technique to be achieved with only weighing sensors. Numerical simulations are conducted using three-dimensional vehicle and bridge models and the effect of several parameters, including sampling frequency...
TL;DR: In this paper, a two-link manipulator with flexible members is considered and the end point vibration signals are simulated by developing a MatLAB code based on the finite element theory and Newmark solution.
Abstract: In this study, a two-link manipulator with flexible members is considered. The end point vibration signals are simulated by developing a MatLAB code based on the finite element theory and Newmark solution. Experimental results are also presented and compared with simulation results. The mass and stiffness matrices are time dependent because the angular positions of the links change during the motion. Trapezoidal velocity profiles for the actuating motors are used. The time dependent inertia forces are calculated by using the rigid body dynamics. The inertia forces are due to the motors, end point payload mass and distributed masses of the links. The acceleration, constant velocity and deceleration time intervals of the trapezoidal velocity profile are selected by considering the lowest natural frequency of the manipulator structure at the stopping position. Various starting and stopping positions are considered. The root mean square (RMS) acceleration values of the vibration signals after stopping are cal...
TL;DR: In this paper, the performance of a smooth nonlinear energy sink (NES) to mitigate vibration of a rotating beam under an external force is investigated, and the most important parameter to study NES performance is SMR occurrence range in the detuning parameter span.
Abstract: In this paper, the performance of a smooth nonlinear energy sink (NES) to mitigate vibration of a rotating beam under an external force is investigated. The rotating beam is modeled using the Euler-Bernoulli beam theory, and the centrifugal stiffening effect is considered. It is assumed that the nonlinear energy sink has a linear damping and an essentially nonlinear (nonlinearizable or cubic) stiffness. Required conditions for occurring Hopf bifurcation, saddle-node bifurcation and strongly modulated responses (SMR) in the system are investigated. The most important parameter to study NES performance is SMR occurrence range in the detuning parameter span. Effects of position and damping of the NES and magnitude of the external force on the vibration mitigation of the rotating beam are studied. The Complexification-Averaging and the Runge Kutta methods are employed for analytical and numerical investigations, respectively. Finally, the efficiency of an optimal linear absorber and an optimal NES in the vibr...
TL;DR: In this article, a new dynamic model (TDCE model) considering both the time-varying deflection excitation and contact stiffness excitation, and the lubricating oil film is proposed to investigate vibration responses of a lubricated roller bearing with a uniform and a nonuniform surface waviness on its races.
Abstract: Surface waviness is one important source of vibrations in a roller bearing. When the surface waviness occurs on the surface of the inner or outer race of a roller bearing, a time-varying deflection excitation and a time-varying contact stiffness excitation can be generated due to the changes in the curvature radii of the race with surface waviness at the contact position between the roller and the race of the roller bearing. In this paper, a new dynamic model (TDCE model) considering both the time-varying deflection excitation, the time-varying contact stiffness excitation, and the lubricating oil film is proposed to investigate vibration responses of a lubricated roller bearing with a uniform and a nonuniform surface waviness on its races, which cannot be accurately modelled by the previous time-varying deflection excitation (PTDE) model in the literature. Effects of the number, the maximum amplitude, and the nonuniform distribution of the surface waviness on the contact stiffness between one roller and ...
TL;DR: In this paper, modified couple stress theory (MCSTT) was used to see the effects of being micro-sized, and the nonlinear equations of motion for the fluid conveying micro beam were obtained by using Hamilton's principle.
Abstract: In this study, fluid conveying continuous media was considered as micro beam. Unlike the classical beam theory, the effects of shear stress on micro-structure's dynamic behavior not negligible. Therefore, modified couple stress theory (MCST) were used to see the effects of being micro-sized. By using Hamilton's principle, the nonlinear equations of motion for the fluid conveying micro beam were obtained. Micro beam was considered as resting on an elastic foundation. The obtained equations of motion were became independence from material and geometric structure by nondimensionalization. Approximate solutions of the system were achieved with using the multiple time scales method (a perturbation method). The effects of micro-structure, spring constant, the occupancy rate of micro beam, the fluid velocity on natural frequency and solutions were researched. MCST compared with classical beam theory and showed that beam models that based on classical beam theory are not capable of describing the size effects. Co...
TL;DR: In this paper, a low-pass filter was used to estimate the impeller performance degradation and then estimate its remaining useful life (RUL), which was then applied to reduce the dimensionality of the extracted statistical features.
Abstract: Slurry pumps are widely used to transport abrasive slurry that contains oil and sands. Because of the abrasive nature, the impellers inside the pumps wear easily. Severe impeller wear may cause unexpected pump failure that leads to substantial oil production loss. To assess the impeller performance degradation and then estimate its remaining useful life (RUL), an efficient prognostic method has been designed. For assessing the impeller performance degradation, statistical features were extracted from vibration signals collected from on-site operating slurry pumps. Their corresponding frequency spectra were generated after the vibration signals were processed by a low-pass filter. Here, the low-pass filter aims to retain impeller-related vibration components, such as the pump vane-passing frequency and its harmonics. Principal component analysis was then applied to reduce the dimensionality of the extracted statistical features to one dimensionality, which was used to construct a health indicator to reflec...
TL;DR: In this article, the vibration and damping analysis of functionally graded carbon nanotubes reinforced hybrid composite (FG-CNTRHC) shell structure which consists of conventional carb carburettors is discussed.
Abstract: The present article deals with the vibration and damping analysis of functionally graded carbon nanotubes reinforced hybrid composite (FG-CNTRHC) shell structure which consists of conventional carb...
TL;DR: It is demonstrated through both simulation and experiment that the proposed controller can provide much better than vibration control performance compared with the conventional controllers showing more robust stability.
Abstract: This paper presents a new hybrid controller which is a combination of three control schemes: fuzzy neural control, PI control and sliding mode control. The interval type 2 fuzzy model featuring upd...
TL;DR: In this paper, a rotation-based mechanical adaptive passive device for seismic protection of structures is presented, which is able to mechanically change stiffness, either by adding positive or negative stiffness, by using different types of rotational elements.
Abstract: Researchers worldwide have developed various semi-active control devices for seismic protection of structures. Most of these devices are electromechanical in nature and thus require a power source for their operation. In this paper, a newly developed rotation-based mechanical adaptive passive device is presented. These unique devices are able to mechanically change stiffness, either by adding positive or negative stiffness, by using different types of rotational elements. The devices are compact due to their use of rotational elements, facilitating their implementation in structures. The conceptual development of these devices is presented herein along with analytical models and numerical simulation results that demonstrate their potential for providing seismic protection. In addition, an extension of the stiffness modulation concept is introduced wherein damping is modulated.
TL;DR: In this article, a tracking controller for a crane attached to a mobile harbor equipped with a dual-stage trolley system is proposed to dynamically position a container from the mobile harbor to the container ship or container ship.
Abstract: A tracking controller is proposed for a crane attached to a mobile harbor (MH) equipped with a dual-stage trolley system, to dynamically position a container from the MH to the container ship or vi...
TL;DR: In this article, an H∞ controller with actuator saturation consideration is proposed to attenuate the vibration of periodic piecewise vibration systems, based on a continuous Lyapunov function with a time-varying L 2 matrix.
Abstract: In this paper, an H∞ controller with actuator saturation consideration is proposed to attenuate the vibration of periodic piecewise vibration systems. Based on a continuous Lyapunov function with a time-varying Lyapunov matrix, the H∞ performance index of periodic piecewise vibration systems is studied first. On the basis of the obtained H∞ criterion, the conditions of designing a state-feedback active vibration controller are proposed in matrix inequality form with actuator saturation taken into account. Because of the nonconvexity of the conditions, a corresponding algorithm to compute the controller gain is developed as well. A representative numerical example is used to verify the effectiveness of the proposed method.
TL;DR: In this paper, the nonlinear vibration and stability analysis of a doubly clamped piezoelectric nanobeam, as a nano resonator actuated by a combined alternating current and direct current, was investigated.
Abstract: This paper investigates the nonlinear vibration and stability analysis of a doubly clamped piezoelectric nanobeam, as a nano resonator actuated by a combined alternating current and direct current ...
TL;DR: In this article, a hybrid empirical mode decomposition (EMD) method is proposed to undertake ambient modal identification of civil structures, where the mode mixing in the resulting modal responses from MEMD is circumvented using ensemble EMD (EEMD).
Abstract: In this paper, a hybrid empirical mode decomposition (EMD) method is proposed to undertake ambient modal identification of civil structures. Unlike univariate EMD that uses single channel measurement independently, multivariate EMD (MEMD) is employed to estimate the joint information of multichannel vibration measurements of structural systems. The mode mixing in the resulting modal responses from MEMD is then circumvented using ensemble EMD (EEMD). The proposed hybrid MEMD method is validated using a suite of numerical models and experimental studies including the presence of low energy modes, closely-spaced frequencies, measurement noise and reduced sensor densities. The results show the improved performance of the proposed method over the traditional EMD method and reveal the potential of MEMD as a possible candidate for the ambient modal identification method.
TL;DR: To realize a vibration suppression of flexible structures like a membrane, Wang et al. as mentioned in this paper focused on introducing smart structures technology into the membrane structure, which can be used to improve the performance of the membrane.
Abstract: To realize a vibration suppression of flexible structures like a membrane, our research focuses on introducing smart structures technology into the membrane structure. In this study, the membrane s...