Active Vibration Suppression Research Articles

A Continuous Robust Control Strategy for the Active Aeroelastic Vibration Suppression of Supersonic Lifting Surfaces

The model-free control of aeroelastic vibrations of a non-linear 2-D wing-flap system operating in supersonic flight speed regimes is discussed in this paper. A novel continuous robust controller design yields asymptotically stable vibration suppression in both the pitching and plunging degrees of freedom using the flap deflection as a control input. The controller also ensures that all system states remain bounded at all times during closed-loop operation. A Lyapunov method is used to obtain the global asymptotic stability result. The unsteady aerodynamic load is considered by resourcing to the non-linear Piston Theory Aerodynamics (PTA) modified to account for the effect of the flap deflection. Simulation results demonstrate the performance of the robust control strategy in suppressing dynamic aeroelastic instabilities, such as non-linear flutter and limit cycle oscillations.

A point-wise fiber Bragg grating displacement sensing system and its application for active vibration suppression of a smart cantilever beam subjected to multiple impact loadings

In this work, active vibration suppression of a smart cantilever beam subjected to disturbances from multiple impact loadings is investigated with a point-wise fiber Bragg grating (FBG) displacement sensing system. An FBG demodulator is employed in the proposed fiber sensing system to dynamically demodulate the responses obtained by the FBG displacement sensor with high sensitivity. To investigate the ability of the proposed FBG displacement sensor as a feedback sensor, velocity feedback control and delay control are employed to suppress the vibrations of the first three bending modes of the smart cantilever beam. To improve the control performance for the first bending mode when the cantilever beam is subjected to an impact loading, we improve the conventional velocity feedback controller by tuning the control gain online with the aid of information from a higher vibration mode. Finally, active control of vibrations induced by multiple impact loadings due to a plastic ball is performed with the improved velocity feedback control. The experimental results show that active vibration control of smart structures subjected to disturbances such as impact loadings can be achieved by employing the proposed FBG sensing system to feed back out-of-plane point-wise displacement responses with high sensitivity.

New design of active vibroprotection devices

A principally new design of active vibroprotection devices has been developed, which can overcome limitations with respect to the active frequency range and maximum vibration suppression coefficient, which are inherent in the existing devices. It is shown that these limitations are related to the parasitic signal of accelerometer inclination in the Earth’s gravity field. A method is proposed to compensate for this effect so that, even with simple electronic circuits, the lower frequency boundary of active vibroprotection decreases from 2 to 0.2 Hz and the maximum vibration suppression coefficient increases from 40 to 60 dB.

Active Vibration Suppression of Flexible Sprayer-Boom by Sky-Hook with Adaptive Disturbance Cancellation Control Unit

Active Vibration Suppression of Flexible Sprayer-Boom by Sky-Hook with Adaptive Disturbance Cancellation Control Unit

Vibration Suppression of a Flexible Structure

Abstract This work addresses the solution to the problem of active vibration suppression of a cantilever beam using piezoelectric actuation. For this purpose, we are taking advantage of the effectiveness of the positive position feedback control strategy (PPF) in order to control first mode vibrations of the analyzed beam. This control technique is well-known in the literature as a modal control method for vibration attenuation. The PPF controller accomplishes its best performance if tuned properly to the characteristics of the structure to be controlled. According to this we are going to realize the modal analysis of the cantilever beam utilizing the finite element method in Ansys to determine the structural frequency corresponding to the first mode, which is used as PPF controller frequency. On the other hand, we shall obtain the state-space representation of the cantilever beam using the subspace identification method in frequency domain applying the fast fourier transformation (FFT). Furthermore, we will simulate the discrete-time PPF controller using Matlab/Simulink. Lastly, the simulink designed discrete-time PPF controller will be tested using an xPC Target real-time system.

Polyvinylidene fluoride film sensors in collocated feedback structural control: application for suppressing impact-induced disturbances

Polyvinylidene fluoride (PVDF) films are light, flexible, and have high piezoelectricity. Because of these advantages, they have been widely used as sensors in applications such as underwater investigation, nondestructive damage detection, robotics, and active vibration suppression. PVDF sensors are especially preferred over conventional strain gauges in active vibration control because the PVDF sensors are easy to cut into different sizes or shapes as piezoelectric actuators and they can then be placed as collocated pairs. In this work, to focus on demonstrating the dynamic sensing performance of the PVDF film sensor, we revisit the active vibration control problem of a cantilever beam using a collocated lead zirconate titanate (PZT) actuator/PVDF film sensor pair. Before applying active vibration control, the measurement characteristics of the PVDF film sensor are studied by simultaneous comparison with a strain gauge. The loading effect of the piezoelectric actuator on the cantilever beam is also investigated in this paper. Finally, four simple, robust active vibration controllers are employed with the collocated PZT/PVDF pair to suppress vibration of the cantilever beam subjected to impact loadings. The four controllers are the velocity feedback controller, the integral resonant controller (IRC), the resonant controller, and the positive position feedback (PPF) controller. Suppression of impact disturbances is especially suitable for the purpose of demonstrating the dynamic sensing performance of the PVDF sensor. The experimental results also provide suggestions for choosing between the previously mentioned controllers, which have been proven to be effective in suppressing impact-induced vibrations.

Active vibration suppression of flexible structure using a LMI-based control patch

Based on the linear matrix inequality, a linear feedback control is presented to realize active vibration suppression of a class of flexible structure. By introducing an appropriate modal transformation, the controller design procedure can be simplified greatly. A specific Lyapunov function is adopted to induce the asymptotical stability of the flexible structure. Simulation results for flexible spacecraft are provided to illustrate the effectiveness of the proposed scheme.

Analysis and implementation of MIMO FULMS algorithm for active vibration control

This correspondence focuses on the analysis and implementation of multi-input multi-output (MIMO) filtered-u least mean square (FULMS) algorithm for active vibration suppression of a cantilever smart beam with surface bonded lead zirconate titanate patches. By analysing a single-input single-output FULMS algorithm, the MIMO FULMS controller structure is given. Then an active vibration control experimental platform is established, with optimal placement of the actuators and sensors based on the maximal modal force rule. Simulation contrast analysis of FULMS algorithm and the most famous filtered-x least mean square (FXLMS) algorithm is performed while the reference signal is extracted from the exciter as well as directly from the controlled structure. Simulation results show that if the feedback information reflects the reference signal collected by the reference transducers, the FXLMS controller could hardly suppress the vibration while the FULMS controller is still effective. Then the actual control experiment is performed, and the result confirms the simulation results. The designed MIMO FULMS vibration controller has a good control performance, suppressing the vibration significantly with rapid convergence.

Adaptive regulation—Rejection of unknown multiple narrow band disturbances (a review on algorithms and applications)

The paper addresses the problem of attenuation (rejection) of unknown and time varying multiple narrow band disturbances without measuring them. In this context the disturbance model is unknown and time varying while the model of the plant is known (obtained by system identification) and almost invariant. This requires to use an adaptive feedback approach. The term “adaptive regulation” has been coined to characterize this control paradigm. Application domains include: mechanical and mechatronics systems, active vibration and noise suppression systems, some types of bio-chemical reactors. The paper reviews the various techniques proposed for solving this problem. It will focus on the presentation of the direct and indirect adaptive regulation strategies using the internal model principle and the Youla–Kucera parametrization which have been extensively used in applications. The paper also reviews a number of applications including: active suspension systems, active vibration control systems, active noise control, bio-chemical reactors, distributed flexible mechanical structures and Blu-ray disc drives. Real time results obtained on various applications will illustrate the methodology.

Performance evaluation of piezoelectric sensor/actuator on active vibration control of a smart beam

In this paper the performance of a piezoelectric sensor/actuator pair and self-sensing piezoelectric actuator on the investigation of vibration characteristics and active vibration control of a smart beam are presented. The performance of piezoelectric patches on actuation and sensing is evaluated by investigating the vibration characteristics of the smart beam via various excitation mechanisms and transduction systems. For active vibration suppression of the smart beam, robust controllers are designed and experimentally implemented by using a piezoelectric sensor/actuator pair and self-sensing piezoelectric actuator. Finally, experimental results for active control of free and the first-resonance forced vibration of the smart beam are presented.

Lookup table control method for vibration suppression of a flexible manipulator with optimization of the minimum settling time and energy consumption

Active vibration suppression of flexible manipulators is important in many engineering applications, such as robot manipulators and high-speed flexible mechanisms. The demand for a short settling time and low energy consumption of vibration suppression requires consideration of optimal control. Under a wide range of operating conditions, however, the fixed optimal parameters determined for a control algorithm might not produce the best performance. Therefore, to enhance performance, this paper suggests a lookup table control method for a flexible manipulator. This method can tune itself to the optimal parameters on the basis of initial maximum responses to the controlled system. In this study, a multi-objective genetic algorithm is used to search for optimal parameters with regard to positive position feedback to the control algorithm. In turn, with the optimal parameters, the multi-objective functions of the settling time and energy consumption during the vibration control of a flexible manipulator can be minimized. The simulation and experimental results both indicate that the energy consumption can be reduced significantly if the settling time is slightly increased. Copyright © 2011 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society

Active vibration suppression of moderately thick rectangular plates

In the present work, active vibration suppression of moderately thick rectangular plates by means of piezoelectric actuators is investigated. Based on Lagrange energy method, a finite element formulation is presented for mathematical modeling of the system. Using modal controllability criterion, a simple method is offered for optimal placement of the piezoelectric actuator. For a cantilevered plate with specific characteristics, the optimal position of a piezoelectric patch is investigated. Then, for suppression of plate vibrations, an active damping controller is designed using modal velocity feedbacks. Numerical simulations are then performed for studying the performance of the designed controller. Presented simulations indicate the feasibility of vibration control of moderately thick plates by means of high voltage piezoelectric actuators. These simulations also show that, for a specific excitation force, the maximum required voltage for vibration suppression approaches to an asymptotic value as the values of modal feedback gains increase. This conclusion is of high importance in practical controller design.

Flutter stabilization of cantilevered plates using a bonded patch

In recent years, many researchers have studied active vibration suppression of fluttering plates using piezoelectric actuators. Lots of these researchers have focused on optimal placement of piezoelectric patches to obtain maximum controllability of the plate. Although mass and stiffness characteristics of bonded patches can alter the aeroelastic behavior of fluttering plates, few of the investigators have considered the effect of the mentioned parameters in the optimization process. This paper investigates the effect of a bonded patch on the aeroelastic behavior of cantilevered plates in supersonic flow and examines the optimal location of the patch for the best controllability performance. For mathematical simulation of the structure, linear von Karman plate theory along with first-order piston theory is employed. The results obtained through this study reveal that a bonded patch with a small mass ratio can change the system critical dynamic pressure significantly. The maximum raise of the critical dynamic pressure is acquired when the bonded patch is placed on the leading edge of the plate. A variation of the system’s aerodynamic characteristics, subsequently, influences the control performance of the bonded patch and alters the optimal patch location.

Active multimodal vibration suppression of a flexible structure with piezoceramic sensor and actuator by using loop shaping

This paper represents active multimodal vibration control of a flexible beam structure with piezoceramic (PZT) actuators and sensors using the loop shaping method. With surface-bonded PZT patch actuators and sensors, the flexible beam has both sensing and actuating capacities. Due to its flat auto spectrum in the specified frequency range, the Schroeder wave is used as an excitation signal for the non-parametric identification of the flexible beam structure. The identified open loop model is then used for the closed loop design by using the loop shaping method based on the extended sensitivity charts. A loop shaping compensator is designed to achieve multimodal vibration suppression. Numerical results showed a reduction of 8 decibels for the first mode and 12–14 decibels for the second and third modes. Experimental results closely match the simulation results. Furthermore, the results of loop shaping method are compared with those of the methods of linear quadratic regulator and pole-placement control, which are designed based on state space models via the parametric identification of the flexible beam. Comparisons show that the loop shaping method is easier to design since a parametric identification is not required and requires less control effort while maintaining the effectiveness in vibration suppression.

A SIMPLE APPROACH FOR DETERMINATION OF ACTUATOR AND SENSOR LOCATIONS IN SMART STRUCTURES SUBJECTED TO THE DYNAMIC LOADS

The present work demonstrates the successful application of a simple active vibration control procedure based on structural dynamics. Based on mathematical and structural dynamics’ theories, the appropriate locations of sensor and actuator locations of the smart structure are predicted. Also, the optimum value of actuator force which controls the structural vibrations as quickly as it is possible is formulated so that the first damping coordinates becomes critical. The validity and efficiency of the proposed method have been examined by investigating the active vibration suppression of some classic structural models. The results presented here, show the ability of suggested active control processes in suppression of the unwanted structural vibrations.

Hybrid Swarm Algorithms for Parameter Identification of an Actuator Model in an Electrical Machine

Efficient identification and control algorithms are needed, when active vibration suppression techniques are developed for industrial machines. In the paper a new actuator for reducing rotor vibrations in electrical machines is investigated. Model‐based control is needed in designing the algorithm for voltage input, and therefore proper models for the actuator must be available. In addition to the traditional prediction error method a new knowledge‐based Artificial Fish‐Swarm optimization algorithm (AFA) with crossover, CAFAC, is proposed to identify the parameters in the new model. Then, in order to obtain a fast convergence of the algorithm in the case of a 30 kW two‐pole squirrel cage induction motor, we combine the CAFAC and Particle Swarm Optimization (PSO) to identify parameters of the machine to construct a linear time‐invariant(LTI) state‐space model. Besides that, the prediction error method (PEM) is also employed to identify the induction motor to produce a black box model with correspondence to input‐output measurements.

D204 スカイフック-適応外乱相殺併合制振制御ユニットによるスプレーヤブームのアクティブ振動抑制(OS14 農業機械の運動と制御2)

D204 スカイフック-適応外乱相殺併合制振制御ユニットによるスプレーヤブームのアクティブ振動抑制(OS14 農業機械の運動と制御2)

A Neural Fuzzy System for Vibration Control in Flexible Structures

An adaptive neural fuzzy (NF) controller is developed in this paper for active vibration suppression in flexible structures. A recurrent identification network (RIN) is developed to adaptively identify system dynamics of the plant. A novel recurrent training (RT) technique is suggested to train the RIN so as to optimize nonlinear input-output mapping and to enhance convergence. The effectiveness of the developed controller and the related techniques has been verified experimentally corresponding to different control scenarios. Test results show that the proposed RIN can effectively recognize the time-varying dynamics of the plant. The RT-based hybrid training technique can improve the adaptive capability of the control system to accommodate different system conditions and enhance the training convergence. The developed NF controller is a robust and stable vibration suppression system, and it outperforms other related NF controllers.

Robust Adaptive Attitude Tracking Control With L2-Gain Performance and Vibration Reduction of an Orbiting Flexible Spacecraft

This paper presents a dual-stage control system design method for flexible spacecraft attitude tracking control and active vibration suppression by an embedded smart material as sensors/actuators. More specifically, a conventional sliding mode controller with the assumption of knowing system parameters is first designed that ensures asymptotical convergence of attitude tracking error described by error quaternion and its derivative in the presence of bounded parameter variation/disturbance. Then it is redesigned, such that the need for knowing the system parameters in advance is eliminated by using an adaptive updating law. For the synthesis of the controller, to achieve the prescribed L2-gain performance criterion, the control gains are designed by solving a linear matrix inequality problem. Indeed, external torque disturbances/parametric error attenuations with respect to the performance measurement along with the control input penalty are ensured in the L2-gain sense. Even if this controller has the ability to reject the disturbance and deal with actuator constraint, it excites the elastic modes of flexible appendages, which will deteriorate the pointing performance. Then the undesirable vibration is actively suppressed by applying feedback control voltages to the piezoceramic actuator, in which the modal velocity feedback control method is employed for determining the control voltages. Numerical simulations are performed to show that attitude tracking and vibration suppression are accomplished, in spite of the presence of disturbances/parameter uncertainties and even control input constraint.

Active vibration suppression of lightweight railway vehicle body by combined use of piezoelectric actuators and linear actuators

In recent years, railway vehicle are becoming lighter because this corresponds not only to the improvement of the running speed but also to the reduction of running cost and environmental noise, especially for ultra-high-speed vehicle such as new Shinkansen and MAGLEV vehicle. However, this causes the deterioration of riding comfort. Bending vibration control method using piezoelectric actuators were proposed and good control performances were obtained through simulations and experiments. In this paper, active vibration control by combined use of piezoelectric actuators and linear actuators is investigated. Elastic vibrations are suppressed by piezoelectric actuators and rigid-body vibrations are reduced by linear actuators. Simulation studies and experiments using scale model were conducted and the effectiveness of the proposed control was confirmed.