Active Vibration Control Devices Research Articles

Experimental design of an active vibration control device used to protect cultural heritage objects.

While light, temperature and humidity on cultural heritage objects are drastically controlled to assure their better conservation, it is not the case of the vibrations and their impact on the objects have received little consideration. Most of the proposed solutions to protect objects from vibrations suffer from a lack of adaptability and poor performances in the lowest frequency range. To tackle this issue, the development of a new kind of protection devices based on active control is proposed. The main challenge is to respect the cultural heritage ethics: non intrusiveness and reversibility. To adapt to a wide variety of cultural heritage objects, the proposed solution aims to minimize the vibrations of a museum's shelf in real time. A replica of museum's shelf is excited by a vibration exciter and a feedforward control configuration is used to monitor the shelf vibrations, by a reference signal measured on the shelf structure and actuators and error sensors placed on the shelf plate. This bench offers the opportunity to experiment multiple PAA (parameter adaptation algorithms) for which a parameter analysis can be performed. A comparative study based on criterions such as amplitude attenuation and time convergence is performed to find an optimized control configuration.

Applications of Approximate Optimal Control to Nonlinear Systems of Tracked Vehicle Suspensions

Technique of approximate optimal vibration control and simulation for vehicle active suspension systems are developed. Considered the nonlinear damping of springs, mechanical model and a nonlinear dynamic system for a class of tracked vehicle suspension vibration control are established and the corresponding system of state space form is described. To prolong the working life of suspension system and improve ride comfort, based on the active suspension vibration control devices and using optimal control approach, an approximate optimal vibration controller is designed, and an algorithm is presented for the vibration controller. Numerical simulation results illustrate the effectiveness of the proposed technique.

Acceleration Estimation for Linear Oscillatory Actuator with 2 pole and 3 pole movers.

Recently, a linear oscillatory actuator with two movers are developed and are applied as active vibration control devices that can reduce vibration in a wide frequency range. In the system, inertial force is controlled by using acceleration information on movers that obtained from acceleration sensors. In this paper, an acceleration estimation method using extended Kalman filter is suggested for sensorless control. The future of the suggested method is that nonlinear detent characteristics depending positions on two movers are considered in the state model of extended Kalman filter. As a result of online estimation using a controller and prototype, estimation values agreed with measured.

Study on the Vibration Active Control of Three-Support Shafting with Smart Spring While Accelerating over the Critical Speed

Smart Spring is a kind of active vibration control device based on piezoelectric material, which can effectively suppress the vibration of the shaft system in an over-critical state, and the selection of control strategy has great influence on the vibration reduction effect of the Smart Spring. In this paper, the authors investigate the control of the over-critical vibration of the transmission shaft system with Smart Spring, based on the ADAMS and MATLAB joint simulation method. Firstly, the joint simulation model of three-support shafting with Smart Spring is established, and the over-critical speed simulation analysis of the three-support shafting under the fixed control force of the Smart Spring is carried out. The simulation results show that the maximum vibration reduction rate is 71.6%. The accuracy of the joint simulation model is verified by the experiment of the three-support shafting subcritical vibration control. On this basis, a function control force vibration control strategy with time-varying control force is proposed. By analyzing the axis orbit of the shafting, the optimal fixed control force at different speeds is obtained, the control force function is determined by polynomial fitting, and the shafting critical crossing simulation under the function control force is carried out. The simulation results show that the displacement response of the shafting under the function control force is less than that under the fixed control force in the whole speed range.

Optimal vibration control for nonlinear systems of tracked vehicle half-car suspensions

Technique of optimal vibration control and simulation for vehicle active suspension systems is developed. Considered the nonlinear damping of springs, mechanical model and nonlinear dynamic system for a class of tracked vehicle half-car suspensions vibration control are established and the corresponding system of state space form is described. In order to prolong the working life of suspension system and improve ride comfort, based on the active suspension vibration control devices and used optimal control approach, an optimal vibration controller is designed, and an algorithm is presented for the vibration controller. Numerical simulation results illustrate the effectiveness of the proposed technique.

Active vibration control of lightweight floor systems

Long-span and lightweight floors are often prone to structural vibrations due to their low resonance frequency and inherent damping. They are easily excited by human walking or running and present a serviceability problem for persons working or living in these buildings. Tuned mass dampers can be used to improve the dynamic behaviour of such structures. The drawback of these passive damping systems is that they require high inertial damper masses and that the damping efficiency in transient phase is low. Especially for systems with resonance frequencies that change over time (due to an addition mass or a change of the structure or temperature dependant phenomena) the damping efficiency drops rapidly.Active controlled tuned mass damper can be used to reduce the inertial mass and improve the damping efficiency for a broad band of frequencies in transient phase. Several constraints, like the stability in closed loop, robustness and performance criteria and the maximum stroke and saturation of the actuator have to be considered when designing a controller for an active vibration control device. Different control strategies are analysed in this work and simulated using a 2nd and a 4th order system in order to analyse advantages and drawbacks.

Real-Time Performance of Mechatronic PZT Module Using Active Vibration Feedback Control.

This paper proposes an innovative mechatronic piezo-actuated module to control vibrations in modern machine tools. Vibrations represent one of the main issues that seriously compromise the quality of the workpiece. The active vibration control (AVC) device is composed of a host part integrated with sensors and actuators synchronized by a regulator; it is able to make a self-assessment and adjust to alterations in the environment. In particular, an innovative smart actuator has been designed and developed to satisfy machining requirements during active vibration control. This study presents the mechatronic model based on the kinematic and dynamic analysis of the AVC device. To ensure a real time performance, a H2-LQG controller has been developed and validated by simulations involving a machine tool, PZT actuator and controller models. The Hardware in the Loop (HIL) architecture is adopted to control and attenuate the vibrations. A set of experimental tests has been performed to validate the AVC module on a commercial machine tool. The feasibility of the real time vibration damping is demonstrated and the simulation accuracy is evaluated.

G1000203 動的量子化器による柔軟構造物用回転型アクティブ除振装置AWDの低コスト高性能化

This study develops a rotary active vibration control device (AWD) using a flywheel to control vibrations in flexible structures. The AWD achieves lightweight and higher inertia by the flywheel and can be mounted on the flexible structure easily. In addition, the AWD can construct sky-hook control easily because it can measure the absolute angular velocity of the flexible structure by the gyro sensor. Therefore, The AWD use Sky-hook With Adaptive Disturbance Cancellation (SWADC) control which is combined control system of sky-hook control and adaptive disturbance cancellation control. This paper investigates a method for cost-performance improvement of the AWD by using the dynamic quantizer for practical use. In general, performance deteriorates according to using low cost instruments. So this study uses the dynamic quantizer to prevent performance deteriorates of the AWD. In addition, the parameters of the dynamic quantizer is optimized by Genetic Algorithm (GA). Cost-performance improvement of the AWD is shown by simulation.

Optimal Vibration Control for Tracked Vehicle Suspension Systems

Technique of optimal vibration control with exponential decay rate and simulation for vehicle active suspension systems is developed. Mechanical model and dynamic system for a class of tracked vehicle suspension vibration control is established and the corresponding system of state space form is described. In order to prolong the working life of suspension system and improve ride comfort, based on the active suspension vibration control devices and using optimal control approach, an optimal vibration controller with exponential decay rate is designed. Numerical simulations are carried out, and the control effects of the ordinary optimal controller and the proposed controller are compared. Numerical simulation results illustrate the effectiveness of the proposed technique.

ACTIVE VIBRATION CONTROL FOR SUBTERRANEAN DRILLING OPERATIONS

An active vibration control device improves drilling by actively applying a dampening profile and/or a controlled vibration to a drill string and/or bottomhole assembly (BHA). Embodiments of the present invention control the behavior of a drill string and/or BHA in order to prevent or minimize the occurrence of harmful drill string/BHA motion and/or to apply a vibration to the drill string/BHA that improves one or more aspects of the drilling process. Measurements of one or more selected parameters of interest are processed to determine whether the undesirable vibration or motion is present in the drill string or BHA and/or whether the drill string and/or BHA operation can be improved by the application of a controlled vibration. If either or both conditions are detected, corrective action is formulated and appropriate control signals are transmitted to one or more devices in the drill string and/or BHA.

On physical realization of the wireless semi active real time vibration control based on signal statistical behavior

Non-linear semi active vibration control devices have experienced a significant development in recent years, due to their performance and advantages compared with the passive and active approaches. Pulse switching techniques, which were developed in the field of piezoelectric damping, lead to effective tradeoffs between performance, simplicity and the required power supply. The control law in this method is based on triggering an inverting switch on each extremum of the produced voltage (or displacement); however, in the case of random excitation, false switching on the local maxima can reduce the efficiency overwhelmingly. A successful approach, to overcome this limitation is based on windowed statistical examination of the vibration signal to determine the optimum triggering voltage level. According to this approach, this paper presents a modified method and for the first time presents a novel circuit structure to predict the optimum trigger time of the damping switch. This circuit structure is implementable using compact analog devices which can be embedded in the vibration energy extraction system. The proposed circuit calculates statistical parameters of the displacement sensor signal then estimates the value of the threshold. Results for a cantilever beam excited by different excitation forces, such as harmonic, random samples and pulse forces are presented and compared with the numerical simulations.

Vibration Damping and Isolation Systems Using Direct Inertia Force Control

Recently, active vibration control devices are widely used in many industrial fields. These are categorized into the following two types with their mechanisms. (A) Vibration is controlled by actuators whose one ends are connected to the controlled object and the other ends are connected to “the fixed floor or reaction walls”. (B) Vibration is controlled by actuators whose one ends are connected to the controlled object and the other ends are connected to “the movable mass”. Typical devices of (A) are active vibration isolation devices. The advantage of type (A) is excellent vibration control performance. However, it is difficult to downsize the devices, because the actuator has to support the controlled object. Meanwhile, typical devices of (B) are active mass dampers (AMD). In type (B), since the actuator doesn't need to support the controlled object, it is possible to realize compact systems. However, the control system design of type (B) tends to be complicated, especially for multi-axis plants. In this paper, we propose a new vibration control system design concept called “Direct Inertia Force Control (DIFC)”. By using the DIFC, we can achieve the advantage of the type (A) and (B) simultaneously. Also the DIFC is able to cover the disadvantage of (A) and (B) cited above. Furthermore, the effectiveness of the DIFC is verified by using a newly designed one-degree of freedom active vibration control device, in experiment.

Active Switching Vibration Control Based on the Frequency for Double-layered Structure

An active vibration control device of a multistory structure is usually set up at the top of the structure; The device has aimed to suppress the primary vibration mode chiefly. However, a variety of frequency modes are included in the earthquake wave. Therefore, when a lot of frequency modes to make the secondary mode excited are included, the secondary mode is excited compared with the first mode. In this paper, it is considered to improve the control performance of the primary mode and the secondary mode with one active vibration control device set up at the top of the structure according to the vibration frequency of double-layered structure by the simulation and the experiment.

444 周波数に基づく二層構造物のアクティブ切換え振動制御

An active vibration control device of a multistory structure is usually set up at the top of the structure. The device has aimed to suppress the primary vibration mode chiefly. However, a variety of frequency modes are included in the earthquake wave. Therefore, when a lot of frequency modes to make the secondary mode excited are included, the secondary mode is excited compared with the first mode. In this paper, it is considered to improve the control performance of the primary mode and the secondary mode with one active vibration control device set up at the top of the structure according to the vibration frequency of double-layered structure by the simulation and the experiment.

Full-scale measurements of wind-induced responses on the Hamamatsu ACT Tower

Abstract In Japan, most high-rise buildings are equipped with vibration control devices in order to improve their habitability by reducing wind-induced vibration. The Hamamatsu ACT Tower is also equipped with active type vibration control devices. For the purpose of confirming the vibration control effects of these devices, observations of winds and vibrations have been carried out. This paper reports on the vibration control effects of the devices on wind-induced vibration, as well as the results obtained from observations of vibration responses of the building during strong seasonal winds and a typhoon.

Development of CMG Active Vibration Control Device for Gondola

For reduction of the low-cycle vibration of vehicles such as gondolas which are suspended flexibly, the authors studied the utilization of the control moment gyro (CMG) as an active vibration control device. The CMG is a moment generator using the gyroscopic moment effect and it is applied to attitude control of spacecraft. Particularly in the very-low-frequency region (less than 1 Hz), it is effective and requires no reaction support.

Disturbance Cancellation Control for Vibration of Multi-Degree-of-Freedom Systems : Case of Using Active Vibration Absorber and Active Dynamic Vibration Absorber

This paper describes a control system design method concerning feedback and feedforward control to cancel disturbance forces, for two kinds of active vibration control devices. One is the active vibration absorber (AVA) utilizing a fixed point for a civil structure such as a bridge, and the other is the active dynamic vibration absorber (ADVA) utilizing an auxiliary mass for a buildinglike structure. We have built two test rigs to simulate large structures with an AVA or an ADVA. In order to carry out fast computation, including the estimation of disturbances, we have used a digital signal processor (DSP). In conclusion, we found that the disturbance forces are perfectly cancelled and the output zeroing is actually realized when the disturbance frequency is exactly equivalent to the design frequency of the observer. We have confirmed that the proposed disturbance cancellation control is very useful for active vibration control.

Active vibration control device

An active vibration control device for controlling vibration in a cantilevered member (12) and a method for the same are disclosed. The device is comprised of a cantilevered member (12) having a longitudinal axis (13) comprising a sensor (92) mounted near the free end of the member (12) to measure motion of the member (12) in a transverse direction and to produce a corresponding signal. A force generating assembly (64) is mounted to the member (12) near the free end to oppose the measured motion with a force thereby minimizing subsequent motion along the transverse axis caused by vibration.

Disturbance Cancellation Control for Vibration of Multi-Degree-of Freedom Systems. Case of Using Active Vibration Absorber and Active Dynamic Vibration Absorber.

This paper describes a control system design method concerning feedback and feedforward control to cancel disturbance forces, for two kinds of active vibration control devices. One is the active vibration absorber (AVA) utilizing a fixed point for a civil structure such as a bridge, and the other is the active dynamic vibration absorber (ADVA) utilizing an auxiliary mass for a buildinglike structure. We have built two test rigs to simulate large structures with an AVA or an ADVA. In order to carry out fast computation, including the estimation of disturbances, we have used a digital signal processor (DSP). In conclusion, we found that the disturbance forces are perfectly cancelled and the output zeroing is actually realized when the disturbance frequency is exactly equivalent to the design frequency of the observer. We have confirmed that the proposed disturbance cancellation control is very useful for active vibration control.

Vibration control of a plate structure by an active control device for reducing noise.

This paper proposes a method of noise reduction by controlling the vibration of a wall between two rooms by an active control device. This is done by using an additional sensor to measure the wall vibration and feed it back to the controller. The board speaker is used primarily to generate sound by exciting the board. However, in this study, it is used as an active vibration control device. The performance of the device is tested on a panel made from a veneer board 1200 x 900 x 5 mm in size which is exposed to sound vibration from the other speaker. The evaluation of this method is performed experimentally by comparison of the dynamic deflection of the panel with and without the device. The experimental results show a significant reduction level to 1/10 of the panel dynamic deflection at frequencies below 100 Hz. The effectiveness of the method is confirmed theofetically by simulation studies. Also, the stability of the control system using the active control device is examined through the root locus method.