Active Vibration Control of a Flexible Plate Structure Using Ant System Algorithm

This paper presents investigations of modeling the flexible plate structures using particle swarm optimization (PSO) and active vibration control (AVC) of such structures. The optimization technique is utilized to obtain a dynamic model of a flexible plate structure based on auto-regressive with exogenous (ARX) input structure. The structure is subjected to two different disturbance signal types, namely random, and finite duration step. The fitness function for the PSO is the mean-squared error (MSE) between the measured and estimated outputs of the plate. The validation of the algorithm is presented in both time and frequency domains. The developed PSO modeling approach is used for AVC system design to suppress the vibration of the flexible plate. The performance of the controller is assessed in terms of level of attenuation achieved in the power spectral density (PSD) of the observed signal.

Active robust vibration control of flexible structures

The study of smart structures with active devices of sensors and actuators for self-monitoring and self-adaption has been of much recent research interest. Active vibration control is a major application focus and there has been tremendous amount of research work on active vibration control of flexible structures using piezoelectric materials. In this paper, the control mechanism for a flexible cantilever plate structure using surface bonded piezoelectric sensors and actuators has been studied through analytical simulations and experiments. The sensor outputs were used to determine the amount of input to the actuators for controlling the response of the structure in a closed loop. The responses under different control mechanisms were analysed by three dimensional finite element model. The effectiveness of different feedback control methods in altering system characteristics and system responses of the structure was investigated. Experimental investigations on active vibration control were also conducted on a cantilever plate with surface bonded piezoelectric sensors and actuators.

Active vibration control of large flexible space structure is a challenging topic in the system dynamics and control of spacecraft. This paper proposes a novel approach for vibration control on a large hoop truss structure, typically used as mesh satellite antenna. First, to suppress the first-order bending modal response of the hoop truss structure with an initial disturbance, a piezoelectric bending actuator with excellent bending actuation performance was carefully designed as a key component of an active vibration control system. Then, the actuating characteristics of the actuator and the dynamic equations of the active structure were analyzed and formulated based on a finite element method. In order to improve the vibration-attenuating effect of the control system, a Mamdani-type fuzzy logic algorithm was employed in a closed-loop control system. Finally, simulations and experiments were implemented to validate the effectiveness of the proposed active control approach and structure. The experimental results showed that the decay time of first-order bending modal response (around 0.34 Hz) of control system reduces by 75% compared with that of the uncontrolled system. The results demonstrate that the proposed active vibration control system has good application potential in controlling the bending modes of a large flexible spacecraft.

The flexible structure offers various advantages such as lightweight, efficient, fast system response and low energy consumption. However, this structure produces too much vibration which lead to system failure. This thesis presents a modelling of the horizontal flexible plate system based on cuckoo search algorithm. The aim of this research is to eliminate vibrations produced by the flexible plate structure in order to preserve the performance and lengthen the life of the system. Initially, the system models are developed based on the vibration data collected experimentally. The dynamic models were developed based on auto-regressive with exogenous (ARX) using system identification technique. The system identification technique applied in this study to develop the mathematical models of the system are the conventional technique known as recursive least squares (RLS) and swarm intelligence algorithm known as cuckoo search algorithm (CS). Then, the developed system models were evaluated and validated by mean squared error (MSE), correlation test and also pole-zero diagram. The performance of developed model was compared between the conventional and swarm intelligence algorithms. The best system model was verified based on lowest MSE, within 95% confidence level of the correlation test and high stability of the pole-zero diagram.KeywordsFlexible plateSystem identificationRecursive least algorithmCuckoo search algorithmSwarm intelligence algorithm

In this paper, we developed an approach for active vibration control of flexible rectangular plate structures using control theory. The flexible rectangular plate system is firstly modelled and simulated via a finite element method; and secondly, a new type of modelling method, and the state-space model are involved in the development of the equation of motion in state-space, which is efficiently used for the analysis of the system and design of control laws with a modern control framework. Then, the validity of the obtained new model is investigated by comparing the plate natural frequencies and forced vibration response analysis predicted by the finite element model with the calculated values obtained from new model. After validating the model, nominal model-based sliding mode robust MIMO controller is applied to the plate dynamics via the MATLAB/Simulink platform. The simulation results clearly demonstrate an effective vibration suppression capability that can be achieved using nominal model-based sliding mode robust MIMO controller.

This work is aimed at the active vibration control of a flexible structures using piezoelectric material. A simple supported plate structure, which is supported at two opposite ends, is taken as the flexible structure with piezoelectric materials as sensors and actuators. Sensors and actuators, which are square in shapes, are embedded to the parent structure. The active controller was designed to control first three modes of vibration of plate. First, the analysis for the transient vibrations in a simple supported plate structure was performed which was followed by the analysis of the same simple supported plate structure when embedded upon with a pair of sensor and actuator. The plate was discretised into several small rectangular elements (6X6, 7X7… 11X11) of identical size in order to assign the different locations to sensors and actuators, which were assumed to be of the exact shape of the discretized plate elements. Further a LQR controller is applied for attenuating the global structural vibration. Settling time for each different location of piezoelectric patch location was observed which was then followed by an interpretation for the optimal location for piezoelectric patch for maximizing the vibration control. The model designed for study was duly verified with the results from past literature and an agreement between the both was observed.

In this work, control system design and implementation for active vibration control (AVC) of flexible structures with piezoelectric actuators is studied. The goal is to reduce the effect of harmonic disturbances with known time-varying frequencies acting on a system. As a test bed, a thin flexible aluminum cantilevered beam with two symmetrically bonded piezoelectric actuators is used. The harmonic excitation is generated by two DC motors each of them with an unbalanced mass. A discrete-time model is obtained through black-box system identification methods. The control algorithm design is based on a plant description with a disturbance model as a linear parameter varying (LPV) system in linear fractional transformation (LFT) form. This results in a gain-scheduled controller where the harmonic disturbance frequencies are the scheduling variables. The experimental real-time results show the effectiveness of the controller and its capability to suppress time-varying harmonic disturbances, whose frequencies are measured directly from the DC motors. The design method leads to a controller that stabilizes the closed-loop system even for arbitrarily fast changes in the disturbance frequencies. In the real-time experiment, the controller suppresses a disturbance consisting of two independent harmonics with frequencies that vary over a range of 15 Hz.

Active control of structural vibrations requires sensors for control feedback. Strain rate sensing for vibration control is important for implementing effective control schemes. Here, an advanced strain rate sensor for active control of structural vibrations is presented. This rate sensor is based on electromagnetic principles. Technology development for this strain rate sensing method is complete; desirable resolution, noise rejection, fidelity, frequency response, and mass for control of structures applications are demonstrated. A structurally integral application of this technology to the NASA CSI Evolutionary Model is presented.

This paper presents the development of an interactive learning environment for dynamic simulation and active vibration control of flexible plate structures. The work is aimed to facilitate the learning process of the subject area through the development of an interactive environment that can help users to simulate and visualise behaviour of flexible structures with given physical characteristics, to test and validate controller designs. Simulation algorithms based on finite difference scheme in characterizing the dynamic behaviour of a two-dimensional such as plate structures are incorporated. Controller design strategies are integrated within this framework. The design and implementation of the interactive learning system incorporating the simulation algorithms, modelling and control strategies, are developed using Matlab. The result of the simulation is further utilized in the modelling and control of the specified flexible plate structure.

Active vibration control of thin-plate structures with partial SCLD treatment

The objective of this study is to describe the design and the implementation of an experimental set-up used to study the dynamics, the experimental identification, and the active vibration control of a flexible structure mounted manipulator system. The system consists of a three-degree-of-freedom cylindrical manipulator system with a flexible link on its tip. A two-degree-of-freedom polar rigid manipulator is mounted on the flexible macromanipulator. The dynamic modelling and experimental modal analysis identification in the frequency domain are being applied to design active digital control strategies for the micro-manipulator system to damp the mechanical vibrations of the flexible structure on the tip of the macro-manipulator system.

Macro fiber composite (MFC) has been widely investigated in the active vibration control. Yet, the actuation performance of MFC is a function of temperature. For the active vibration control system using MFC based on the linear piezoelectric equation, if the actuation parameters of MFC are variable, it is easy to cause insufficient control force or control spillover, which degrades the performance of control system. Therefore, an adaptive gain adjustment approach for the active vibration control system is developed, which ensures that the active control system can maintain the expected performance of vibration suppression under the time-varying ambient temperatures. The variation of actuation performance of MFC with temperature is measured by the experiment. The polynomial fitting method is utilized to obtain the functional relationship between the regulator parameters and ambient temperature. The performance of the proposed adaptive gain regulator is verified by the experiment in the temperature environment chamber. In the experiment, a scaled vertical tail model attaching the MFC actuator is as an example, and the fractional order positive position feedback control system is as a representative of the control system without temperature adaptability. When the temperature is −60°C, compared with the control system without regulator, the reduction ratio of response RMS of the control system with adaptive gain regulator is increased by 17.26%.The results indicate that the proposed adaptive gain regulator can avoid the adverse influence of the time.varying ambient temperature on the performance of the control system.

This paper presents design, implementation and experimental results of active vibration control of adaptive truss structure using fuzzy neural method. An adaptive truss structure with self-learning active vibration control system is developed. A fuzzy neural network (FNN) controller with adaptive membership functions is presented. The experimental setup of a two-bay truss structure with active members is constructed, and the FNN controller is applied to vibration suppression of the truss. The controller first senses the output of the accelerometer as an error to activate the adaptation of the weights of the controller, and then a control command signal is calculated based on the FNN inference mechanism to drive the active members. Experimental results demonstrate that the active FNN controller can effective reduce the truss vibration.

The interest of this paper is to develop a general and systematic robust control methodology for active vibration control of flexible structures. For this purpose, first phase and gain control policies are proposed to impose qualitative frequency-dependent requirements on the controller to consider a complete set of control objectives. Then the proposed control methodology is developed by employing phase and gain control policies in the dynamic output feedback H∞ control: according to the set of control objectives, phase and gain control policies incorporate necessary weighting functions and determine them in a rational and systematic way; on the other hand, with the appropriate weighting functions efficient H∞ control algorithms can automatically realize phase and gain control policies and generate a satisfactory H∞ controller. The proposed control methodology can be used for both SISO and MIMO systems with collocated or non-collocated sensors and actuators. In this paper, it is validated on a non-collocated piezoelectric cantilever beam. Both numerical simulations and experimental results demonstrate the effectiveness of the proposed control methodology.