Active Vibration Suppression Research Articles

Avoiding defects in manufacturing processes: A review for automated CFRP production

Linear robots, numerically controlled machines and articulated robots are some of the major components in automation. In various applications, these single systems are linked together to become advanced mechatronic systems since they can realize special and general tasks. Unfortunately, the degree of automation in carbon fiber reinforced plastic (CFRP) manufacturing is currently rather low. A lot of research still needs to be done in order to achieve the knowledge necessary to gain a consistent, robust and reliable production chain for CFRP. The most decisive criterion in automation is the tradeoff between speed in production and the attainable layup accuracy. One aspect that affects accuracy is vibration caused by rapid movement and interaction forces. In the case of advanced mechatronic systems, the effect of the dynamic coupling is one key factor in accuracy. Over the last few decades, the field of active vibration suppression has made use of its excellent capability to improve the accuracy of machines. Therefore, the paper presents a comprehensive review of active vibration suppression technology for the improvement of precision in manufacturing. The work is mainly focused on, but not limited to, the production of components made of CFRP. The paper concludes with a discussion of promising approaches to identify a trend for future work.

Active vibration suppression of membrane structures and evaluation with a non-contact laser excitation vibration test

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 structure is composed of a vibration control system using a flexible Polyvinylidene fluoride (PVDF) film as an actuator. A non-contact vibration test system, which uses a high power Nd: YAG pulse laser for producing an ideal impulse excitation and laser Doppler vibrometers for measuring the response on the membrane, is employed to evaluate the vibration characteristics of the smart membrane structure. To confirm the effectiveness of the proposed method, using a flexible PVDF actuator installed on the membrane structure, control experiments with H ∞ control for reducing single mode and multiple modes vibration are conducted. In the results of the control experiments for single mode vibration suppression, a corresponding resonance peak is reduced by around 20 dB. In case of multiple modes vibration suppression, the first and second resonance peaks are reduced by 14 dB and 24 dB, respectively. This study demonstrates that the present control method using a flexible piezoelectric element and a non-contact vibration test system effectively suppress and evaluate the vibration responses of smart membrane structures.

Hybrid Positive Feedback Control for Active Vibration Attenuation of Flexible Structures

A new controller is introduced in this paper as a novel method for active vibration suppression in flexible structures. The hybrid positive feedback (HPF) uses a second- and a first-order compensator that are fed by the displacement and velocity feedbacks, respectively. Parallel pairs of the HPF controller are implemented when suppression in multimode condition is issued. Since the controller uses two gains for each pair of the actuator/sensor patch for each mode, a suitable gain optimization method has to be used to ensure the optimum performance. To this end, ${\cal H}_2$ and ${\cal H}_{\infty}$ optimization approaches are utilized. For validation purposes, the controller is verified numerically and experimentally for vibration control of a cantilever beam. System identification is performed, then closed-loop system responses to simultaneous multimode and swept frequency excitations are obtained. According to the results, the HPF controller has a superior performance compared to the conventional method of positive position feedback. Vibration displacement amplitudes were reduced by more than 85% relative to the uncontrolled state. The best performance was achieved by the ${\cal H}_2$ -optimized HPF, as the net value for vibration displacement amplitude reduction in the multimode condition was 90% of the uncontrolled amplitude.

Active Vibration Suppression of an elastic piezoelectric sensor and actuator fitted cantilevered beam configurations as a generic smart composite structure

An efficient analytical method for vibration analysis of a Euler–Bernoulli beam with Spring Loading at the Tip has been developed as a baseline for treating flexible beam attached to central-body space structure, followed by the development of MATLAB© finite element method computational routine. Extension of this work is carried out for the generic problem of Active Vibration Suppression of a cantilevered Euler–Bernoulli beam with piezoelectric sensor and actuator attached as appropriate along the beam. Such generic example can be further extended for tackling light-weight structures in space applications, such as antennas, robot’s arms and solar panels. For comparative study, three generic configurations of the combined beam and piezoelectric elements are solved. The equation of motion of the beam is expressed using Hamilton’s principle, and the baseline problem is solved using Galerkin based finite element method. The robustness of the approach is assessed.

Active vibration-suppression platforms based on magnetorheological elastomers

A damper and platform for active vibration suppression based on magnetorheological elastomers are studied experimentally.

A review of active vibration and noise suppression of plate-like structures with piezoelectric transducers

Structural vibrations are the major causes of noise problems, passenger discomforts, and mechanical failures in aerospace, automotive, and marine systems, which are mainly composed of lightweight and flexible plate-like structures. In order to reduce structural vibrations and noise radiations of lightweight structures, passive and active treatments have been used and investigated over the last three decades. Our aim of this article is to review current state-of-the-art of active vibration and noise suppression systems for plate and plate-like structures with various kinds of boundary conditions. The reviewed articles use numerical methods and experimental tools to study different aspects of controller architectures. In particular, the focus is placed on the active vibration and noise control systems utilizing piezoelectric patches as sensors and actuators since their popularity in vibration-based applications has increased significantly during the last two decades. We first classify the controllers according to their architectures, then compare their performance in vibration and noise attenuation, and finally provide suggestions for further progress. The categorization of the information regarding the controller strategies and sensor/actuator configurations for different host structures can be used by the controller designers as a starting point for their specific configuration.

Multi-Objective Robust Active Vibration Control of an Arbitrary Thick Piezolaminated Beam

A multi-objective mixed / robust output feedback control synthesis with additional regional pole placement constraints in a linear matrix inequalities (LMI) framework is adopted for active vibration suppression of a simply supported, arbitrary thick, piezolaminated beam with continuously integrated sensor and actuator layers, in the face of high frequency unmodeled dynamics (residual uncertainties) and external disturbance. The structural formulation is based on a spatial state-space approach using the exact linear two-dimensional piezoelasticity theory and involving local/global transfer matrices. To assist control system design, subspace-based multivariable system identification is carried out by using the first four modes in the frequency range of 0–4000 rad/sec for control purpose, while the remaining high frequency (residual) modes in the control bandwidth are left as the uncertainty of modeling. The dynamic performance of vibration control system is demonstrated in both frequency and time domains for a three-layered sandwich beam including three pairs of piezoelectric actuator/sensor (Ba2NaNb5O15/PZT4) segments asymmetrically collocated on both sides of an orthotropic core for two different types of loading (i.e., impulsive load and random disturbance). The accuracy of dynamic analysis is established with the aid of a commercial finite element package and the data available in the literature.

Active vibration control of an arbitrary thick smart cylindrical panel with optimally placed piezoelectric sensor/actuator pairs

Active vibration suppression of a simply supported, arbitrarily thick, transversely isotropic circular cylindrical host panel, integrated with spatially distributed piezoelectric actuator and sensor layers, is investigated based on the linear three dimensional exact piezo-elasticity theory. To assist control system design, system identification is conducted by applying a frequency domain subspace approximation method based on N4SID algorithm using the first few structural modes of the system. The state space model is constructed from system identification and used for state estimation and development of control algorithm. The optimal electrode configuration for the collocated piezoelectric actuator–sensor pair is found by applying a genetic optimization procedure based on maximization of a quantifiable objective function considering the controllability, observability and spillover prevention of the identified system. A linear quadratic Gaussian (LQG) optimal controller is subsequently designed and simulated based on the identified model of optimally configured smart structure in order to actively control the system response in both frequency and time domains. The dynamic performance and effectiveness of the optimized vibration control system is demonstrated for two different types of external mechanical excitations (i.e., impulsive load and white noise disturbance). The accuracy of dynamic analysis is established with the aid of a commercial finite element package and the data available in the literature.

Vibration suppression of cantilever laminated composite plate with nonlinear giant magnetostrictive material layers

In this paper, a nonlinear and coupled constitutive model for giant magnetostrictive materials (GMM) is employed to predict the active vibration suppression process of cantilever laminated composite plate with GMM layers. The nonlinear and coupled constitutive model has great advantages in demonstrating the inherent and complicated nonlinearities of GMM in response to applied magnetic field under variable bias conditions (pre-stress and bias magnetic field). The Hamilton principle is used to derive the nonlinear and coupled governing differential equation for a cantilever laminated composite plate with GMM layers. The derived equation is handled by the finite element method (FEM) in space domain, and solved with Newmark method and an iteration process in time domain. The numerical simulation results indicate that the proposed active control system by embedding GMM layers in cantilever laminated composite plate can efficiently suppress vibrations under variable bias conditions. The effects of embedded placement of GMM layers and control gain on vibration suppression are discussed respectively in detail.

Active suppression of structural chatter vibrations using machine drives and accelerometers

Chatter vibrations coming from the machine tool structure are a major limitation for heavy duty milling operations. Passive and active dampers can be added to increase the productivity. However, the price and required space of these absorbers are important drawbacks for their use in the industry. In this work, the machine tool's own drives are used to suppress chatter with the help of an external accelerometer located close to the tool centre point. The measured acceleration is fed back as an additional control loop. A significant increase in the chatter stability limit is demonstrated experimentally on a large milling machine.

Approach for a smart device for active vibration suppression as an add-on for robot-based systems

Robot-based systems are defined by the capabilities of links and joints that form the robot arm, the control including drive engines and the endeffector. In particular, articulated robots have a serial structure. They have to carry the drive engine of each ongoing axis, which results in higher susceptibility to vibration. To compensate weak precision the German Aerospace Center (DLR) integrates a quality improving sensor system on the robot platform. A vibration monitoring system detects vibrations that affect the precision during motion tasks. Currently, higher precision is achieved by slowing down the speed in production. Therefore, a compromise is given between speed and precision. To push the limits for these two conflicting process properties, we propose an approach for an additional smart device to decouple the process-sensitive unit from disturbances arising through motion of the kinematic structure. The smart device enables active vibration suppression by use of a piezo-based actuator with a lever mechanism connected to a motion platform. The lever mechanism provides the required force and displacement adaption. The platform provides mounting and steering of the process-sensitive components. First, an insight into the automation task is given within this paper. Secondly, the system design is illustrated. Based on simulation results the characteristic of the proposed mechanism is shown. Besides the mechanical properties like stiffness and lever amplification, dynamical issues like the smallest eigenfrequency are discussed. To verify simulation results initial measurements are presented and discussed. The paper sums up with the discussion of an implementation of a closed-loop control system to achieve vibration-free and fast motion.

Wireless sensing and vibration control with increased redundancy and robustness design.

Control systems with long distance sensor and actuator wiring have the problem of high system cost and increased sensor noise. Wireless sensor network (WSN)-based control systems are an alternative solution involving lower setup and maintenance costs and reduced sensor noise. However, WSN-based control systems also encounter problems such as possible data loss, irregular sampling periods (due to the uncertainty of the wireless channel), and the possibility of sensor breakdown (due to the increased complexity of the overall control system). In this paper, a wireless microcontroller-based control system is designed and implemented to wirelessly perform vibration control. The wireless microcontroller-based system is quite different from regular control systems due to its limited speed and computational power. Hardware, software, and control algorithm design are described in detail to demonstrate this prototype. Model and system state compensation is used in the wireless control system to solve the problems of data loss and sensor breakdown. A positive position feedback controller is used as the control law for the task of active vibration suppression. Both wired and wireless controllers are implemented. The results show that the WSN-based control system can be successfully used to suppress the vibration and produces resilient results in the presence of sensor failure.

Potential Applications of Magnetorheological Elastomers

Magnetorheological elastomer still becomes interested topics among researchers since the rheological properties can be controlled by applying external magnetic field by means of adjustable modulus of elasticity. In this paper, the current application of MRE and related patents will be discussed. Potential application of MRE focused on three main areas. The first is explanation on MRE implementation in vibration cancellation mainly in vehicle system such as active vibration suppression and variable impedance sound absorber. The second explanationfocuses on its potential application on medical devices such as prosthetic device. The third section describes future possible application of MRE based on its tunable properties.Finally, the concluding remarks can be generally stated that MRE still has wide range smart device development and promising more valuable product.

Digital Feedback Control of the Flow-Induced Vibrations on the Head Gimbals Assembly in Hard Disk Drives: Design and Implementation

In this paper, a digital feedback control closed-loop is presented for active suppression of flow-induced vibrations on a head gimbals assembly (HGA) in a working hard disk drive (HDD). In this closed loop, a laser Doppler vibrometer was used to detect the flow-induced HGA off-plate vibration as feedback error signals, a digital controller was implemented to filter the feedback signals, and a piezoelectric disk stuck on the HDD cover inner surface was employed to actuate feedback acoustic pressure around the HGA to exert control on the HGA flow-induced vibrations. The digital controller was designed to enable the closed loop with capabilities of single or simultaneous multiple narrowband control on the HGA flow-induced vibrations. Experiments have been carried out for single- or multi-narrowband active suppression of five principal peaks in the HGA off-plate vibration spectrum, around 1256, 1432, 2144, 2524, and 3474 Hz, respectively. Results show that, with the digital closed loop, distinct vibration suppression of up to 15 dB was achieved on those single principal peaks in single-narrowband active controls, or simultaneous distinct suppression of up to 17 dB can be achieved on all those principal peaks in one multi-narrowband active control.

DOB-based piezoelectric vibration control for stiffened plate considering accelerometer measurement noise

This paper presents a composite control strategy for the active suppression of vibration due to the unknown disturbances, such as external excitation, harmonic effects and control spillover, as well as high-frequency accelerometer measurement noise in the all-clamped stiffened plate. The proposed composite control action based on the modal approach, consists of two contributions including feedback part and feedforward part. The feedback part is the well-known PID controller, which is widely used to increase the structure damping and improve its dynamic performance close to the resonance frequencies. In order to get better performance for vibration suppression, the weight matrixes is optimized by chaos sequence. Then an improved disturbance observer (IDOB) as the feedforward compensation part is developed to enhance the vibration suppression performance of PID under various disturbances and uncertainties. The proposed IDOB can simultaneously estimate the various disturbances dynamically as well as measurement noise acting on the system and suppress them by feedforward compensation design. A rigorous analysis is also given to show why the IDOB can effectively suppress the unknown disturbances and measurement noise. In order to verify the proposed composite control algorithm (IDOB-PID), the dSPACE real-time simulation platform is used and an experimental platform for the all-clamped stiffened plate active vibration control system is set up. The experimental results demonstrate the effectiveness, practicality and strong anti-disturbances ability of the proposed control strategy.

Delayed resonator with acceleration feedback – Complete stability analysis by spectral methods and vibration absorber design

This paper deals with the problem of active vibration suppression using the concept of delayed resonator (DR) absorber with acceleration feedback. A complete dynamic analysis of DR and its coupling with a single degree of freedom mechanical system are performed. Due to the presence of a delay in the acceleration feedback, the dynamics of the resonator itself, as well as the dynamics of combined system are of ‘neutral’ character. On this system, spectral methods are applied to perform a complete stability analysis. Particularly, the method of cluster treatment of characteristic roots is used to determine stability boundaries in the space of the resonator parameters. Based on this analysis, a methodology to select the resonator parameters is proposed in order to guarantee desirable suppression characteristics and to provide safe stability margins. An example case study is included to demonstrate these analytical results.

Modeling and active vibration suppression of a single-walled carbon nanotube subjected to a moving harmonic load based on a nonlocal elasticity theory

This paper investigates active vibration suppression of a single-walled carbon nanotube (SWCNT) under the action of a moving harmonic load using Eringen’s nonlocal elasticity theory. The SWCNT is modeled according to the nonlocal Euler–Bernoulli beam theory. A Dirac-delta function is used to describe the position of the moving load along the SWCNT. Next, a linear classical optimal control algorithm with displacement-velocity feedback is used to suppress vibration in the SWCNT with control forces acting as actuators. The effects of a small-scale parameter, slenderness ratio, moving load velocity, and the excitation frequency of a moving load on the dynamic deflection of the SWCNT are examined. Finally, the ability of the control algorithm to suppress the response of the SWCNT under the effects of a moving load with a number of controlled modes and control forces is surveyed.

Finite element based model predictive control for active vibration suppression of a one-link flexible manipulator

This paper presents a unique approach for active vibration control of a one-link flexible manipulator. The method combines a finite element model of the manipulator and an advanced model predictive controller to suppress vibration at its tip. This hybrid methodology improves significantly over the standard application of a predictive controller for vibration control. The finite element model used in place of standard modelling in the control algorithm provides a more accurate prediction of dynamic behavior, resulting in enhanced control. Closed loop control experiments were performed using the flexible manipulator, instrumented with strain gauges and piezoelectric actuators. In all instances, experimental and simulation results demonstrate that the finite element based predictive controller provides improved active vibration suppression in comparison with using a standard predictive control strategy.

Active vibration suppression of payloads with a conical isolator

This article focuses on active vibration isolation of a rigid payload using a conical shell isolator laminated with piezoelectric sensors and actuators. The payload is mounted on the top (minor end) of the conical shell isolator. The piezoelectric sensor is laminated on the inner surface, and the piezoelectric actuator is laminated on the outer surface of the conical shell. The macro-fiber composite piezoelectric material is utilized as the actuator to enhance control performance, and polyvinylidene fluoride actuators are used as a comparison. The mathematical model of the conical isolator and the payload is derived in terms of the sensing signal equation and the actuation equation. Then, the modal equations are transformed into the state-space form with sensing signal as the system output and modal control force as the system input. Linear quadratic controllers are designed for each independent mode. In case studies, axial vibration isolation of the payload is performed to characterize the performance of the conical isolator and the optimal controller.

Rejecting multiple-period disturbances: active vibration control of a two degree-of-freedom piezoelectric flexible structure system

In this study, an active vibration suppression control is presented for use in a two degree-of-freedom piezoelectric flexible structure system containing a rectangular plate driven by dc motors. A mathematical model involving a clamped-free-free-free cantilever flexible plate, piezoelectric transducer, and motor dynamics is derived for modal analysis and control design. To simplify the control design of this multivariable system, a two-stage design strategy is proposed because the plate motion exerts a comparatively small effect on the dc motors. Both the plate vibration and coupling effect in the motors are considered when designing a centralized motor tracking controller. Given a well-designed two-axis motor control system, piezoelectric actuators are used on the plate to perform efficient active vibration suppression control. Hybrid proportional-derivative and repetitive control methods are extended to manage the multiple-period disturbances and resonant excitation. Three sets of simulation experiments were conducted, focusing on suppressing the plate vibration response and demonstrating the effectiveness of the proposed method.