Abstract Active Vibration Control Research Articles

Active vibration control of a shaft bracket-plate coupled system

Active vibration control of a shaft bracket-plate coupled system is investigated. The vibration of the plate is controlled with electromagnetic vibration absorbers (EVAs), which are mounted around the feet of the shaft bracket to impede the transmission of vibration from the bracket apex to the plate. A dynamic model is established on the Timoshenko beam theory and the Kirchhoff thin plate theory to reveal the mechanism of vibration transmission. It is exhibited that all the induced forces and moments at the coupling points contribute much to the transverse responses of the plate. The feasibility of active control with the EVAs is evaluated numerically based on the controllability of the plate vibration. It is demonstrated that the two-point in-plane control is able to attenuate the plate vibration under the excitation of in-plane disturbance forces, while the multi-point control is effective in reducing the plate vibration regardless of the directions of disturbance forces. An experimental system is built to verify the performance of the two-point in-plane control. The results have shown that with the help of adaptive control, the two-point in-plane control is capable of suppressing the vibration of the foundation induced by the in-plane forces acting on the shaft bracket.

A Novel Active Control Strategy with Decentralized Decoupling and Wavelet Packet Transformation: Design and Verification

Active vibration control (AVC) can solve many vibration problems. However, structural vibration in underwater vehicles often involves other factors such as complex excitation and path coupling, etc. At present, the traditional algorithm (e.g., multi Filtered-x Least Mean Square, M-FxLMS) usually cannot effectively process the multi-frequency excitation and the coupling effects of the multi-secondary path, which will affect its convergence and stability to a certain extent. Consequently, a novel strategy is presented in this paper, namely, the wavelet packet transformation decentralized decoupling M-FxLMS algorithm (WPTDDM-FxLMS), which can solve the structural vibration problems mentioned above. The multi-frequency control is converted into a single-frequency line spectrum control, and the feedback compensation factor is introduced in the identification of the secondary path, both of which can simplify the multi-path control system to the parallel single-path systems. Furthermore, the WPTDDM-FxLMS algorithm is applied to the AVC in a multi-input and multi-output system (MIMO) vibration platform. Finally, the simulation and experiments show that the wavelet packet can decompose the multi-frequency excitation into a line spectrum signal, and the improvement of the decentralized decoupling and the variable step-size can effectively reduce the computation amount and increase the convergence speed and accuracy. Overall, the novel algorithm is significant for multi-path coupling vibration control. It will have certain engineering application value in underwater vehicles.

Active Vibration Control of a Fluid-Conveying Functionally Graded Cylindrical Shell using Piezoelectric Material

Active vibration control of a smart FG (functionally graded) cylindrical shell conveying fluid in thermal environment is studied theoretically by using a laminated piezoelectric actuator. Velocity feedback control law is implemented to activate the piezoelectric actuator. Considering the electric-thermo-fluid-structure interaction effect, a nonlinear dynamic model of the smart fluid-conveying FG cylindrical shell is developed based on Hamilton’s principle and von-Karman type geometrical nonlinear relationship. The inviscid, incompressible, isentropic and irrotational fluid is coupled into governing equations using the linearized potential theory. The Galerkin’s method is used to obtain the nonlinear governing equations of motion of the coupled system. The multiple time scales approach is applied to solve the resulting governing equations for analysing the nonlinear dynamic characteristics of the coupled system. The influence of fluid flow velocity, feedback control gains of piezoelectric voltage, external excitation and material properties of FGM on the frequency-response curves of system are investigated. The results indicate that the piezoelectric voltage is an effective controlling parameter for vibration control of the system, and the flow velocity can effect significantly the vibration amplitude and nonlinearity of the coupled system.

Teaching Learning Based Optimization (TLBO) for Optimal Placement of Piezo-Patches

Active vibration control using piezopatches has been active field for the past few years. Various methods like Genetic Algorithm (GA), Particle Swarm Optimization (PSO) etc. had been used for optimal placement of piezopatches to control vibration of a cantilever beam. In the present study an attempt is made to find optimal location for placement of both single and multiple (i.e. 5 patches) piezo-patches on the cantilever beam. An advanced optimization technique known as Teaching Learning Based Optimization (TLBO) algorithm is used. The objective function used in this study is based on the strain equation of the cantilever beam. It is found that both the advanced optimization techniques i.e. TLBO and GA has given the maximum strain value at the root of the cantilever beam for the first six modes in case of single patch. Also for multiple patches the optimal locations obtained by TLBO is almost the same as that obtained by GA.

Active Vibration Control of an Axially Translating Robot Arm with Rotating-Prismatic Joint Using Self-Sensing Actuator

Active vibration control of an axially translating robot arm with rotating-prismatic joint using self-sensing actuator is investigated. The equations of the system are derived by Lagrange’s equation with the assumed mode method. The displacement and velocity control law is used to configure the self-sensing actuator, which provides the active damping and stiffness effect to the structure. The numerical simulations reveal that the tip deflection of the arm can be effectively reduced by the self-sensing actuator. The amplitude of sensor voltage is inversely proportional to the length of axially translating arm. And higher feedback control gain results in lower sensor voltages and vibration amplitudes.

Vibration attenuation and shape control of surface mounted, embedded smart beam

Active Vibration Control (AVC) using smart structure is used to reduce the vibration of a system by automatic modification of the system structural response. AVC is widely used, because of its wide and broad frequency response range, low additional mass, high adaptability and good efficiency. A lot of research has been done on Finite Element (FE) models for AVC based on Euler Bernoulli Beam Theory (EBT). In the present work Timoshenko Beam Theory (TBT) is used to model a smart cantilever beam with surface mounted sensors / actuators. A Periodic Output Feedback (POF) Controller has been designed and applied to control the first three modes of vibration of a flexible smart cantilever beam. The difficulties encountered in the usage of surface mounted piezoelectric patches in practical situations can be overcome by the use of embedded shear sensors / actuators. A mathematical model of a smart cantilever beam with embedded shear sensors and actuators is developed. A POF Controller has been designed and applied to control of vibration of a flexible smart cantilever beam and effect of actuator location on the performance of the controller is investigated. The mathematical modeling and control of a Multiple Input multiple Output (MIMO) systems with two sensors and two actuators have also been considered.

Implementation of FxLMS Algorithm Based on Level-2 S-Function and Behavior Analysis

Active vibration control use an active force from secondary path to suppress or attenuate periodic or quasi-periodic vibration and noises, one of the popular control algorithms is filtered-x least mean square (FxLMS) adaptive method. Based on structure of FxLMS algorithm, the paper uses Level-2 S-fun to create a new FxLMS blocks in Matlab/Simulink and apply it on vibration active control system simulator. Results of computer simulation showed the custom FxLMS block’s feasibility and control algorithm’s efficiency. On the condition of stabilization, behavior analysis was also taken out by adjusting the interior parameters, including the number of Weights and the Step size.

Intelligent Control and Simulation of Piezoelectric Smart Plate

Active vibration control based on fuzzy algorithm for piezoelectric smart plate is studied. After the characteristic of piezoelectric ceramic (PZT) is analyzed, modal and transient analysis are developed in this paper with finite element model of the piezoelectric smart plate constructed in ANSYS. Fuzzy logic control rules are established by the analysis of the deformation of the plate. With mode shape and displacement response curve obtained, active vibration suppression for the smart plate system is achieved by using commercial finite element programs. The simulation results illustrate that analysis of piezoelectric smart plate using ANSYS is practicable and the intelligent control method is effective.

COMPENSATED INVERSE PID CONTROLLER FOR ACTIVE VIBRATION CONTROL WITH PIEZOELECTRIC PATCHES: MODELING, SIMULATION AND IMPLEMENTATION

Active vibration control of the first three modes of a vibrating cantilever beam using collocated piezoelectric sensor and actuator is examined in this paper. To achieve this, a model based on Euler-Bernoulli beam equation is adopted and extended to the case of three bonded piezoelectric patches that act as sensor, actuator and exciter respectively. A compensated inverse PID controller has been designed and developed to damp first three modes of vibration. Controllers have been designed for each mode and these are later combined in parallel to damp any of the three modes. Individual controller gives better reduction in sensor output for the second and third modes while the combined controller performs better for the first mode. Simulation studies are carried out using MATLAB. These results are compared and verified experimentally and the real-time implementation is carried out with xPC-target toolbox in MATLAB

Modal control of smart shells by optimized discretely distributed piezoelectric transducers

Active vibration control of the shell structures with discretely distributed piezoelectric sensor and actuator patches is investigated. The quasi-modal sensor is developed to estimate the dominant mode coordinates of the shell from the outputs of the sensor patches, and a criterion for finding the optimal locations and sizes of the sensor elements is given by minimizing the observation spillover. The quasi-modal actuator is also designed to actuate the designated modes by means of modulating the voltage distribution of the piezoelectric actuator patches, and a criterion for optimal placement of the actuator patches is presented based on the energy and control spillover consideration. Furthermore, the compensators are employed to filter out the residual components with high frequencies from the estimated modal coordinates. Based on the quasi-modal sensor and quasi-modal actuator, the independent modal control is performed approximately to control the vibration of smart shells. The simulation examples show that the vibration of the shells can be controlled effectively by using the presented method.

Self-Powered Active Vibration Control Using Regenerated Vibration Energy

Active vibration control using regenerated vibration energy, i.e., self-powered active vibration control is proposed in which energy absorbed by a damper is stored in a condenser. An actuator produces control input using this stored energy. This requires no external energy. Energy used by the actuator is restricted to be less than energy regenerated. It is important to reduce energy consumption in the actuator. The control we developed requires less external energy than typical active control. A linear DC motor operating as an energy regenerative damper with high efficiency is used in experiments realizing self-powered active control and showing better isolation than passive control.

Retrofitting Active Control into Well Designed Passive Vibration Isolation Systems

Active vibration control uses sensing and power actuators to attenuate vibrational energy due to external disturbances. Many of these systems are retrofitted into already existing passive ones. As a result allowable relative motions are prescribed, and this influences the performance of the active system. This paper exposes these limitations and shows realistic expectations for two excellent control strategies.

Retrofitting Active Control into Passive Vibration Isolation Systems

Active vibration control uses sensing and power actuators to attenuate vibrational energy due to external disturbances. Many of these systems are retrofitted into already existing passive ones. As a result allowable relative motions are prescribed, and this influences the performance of the active system. This paper exposes these limitations and shows realistic expectations for two excellent control strategies.