Showing papers on "Active vibration control published in 2010"

Nonlinear Vibration with Control: For Flexible and Adaptive Structures

Abstract: to Nonlinear Vibration and Control.- Nonlinear Vibration Phenomena.- Control of Nonlinear Vibrations.- Approximate Methods for Analysing Nonlinear Vibrations.- Modal Analysis for Nonlinear Vibration.- Beams.- Cables.- Plates and Shells.

Experimental Comparison Research on Active Vibration Control for Flexible Piezoelectric Manipulator Using Fuzzy Controller

Abstract: Space manipulators are flexible structures. Vibration problem will be unavoidable due to motion or external disturbance excitation. Model based control methods will not maintain the required accuracy because of the existence of nonlinear factors and parameter uncertainties. To solve these problems, fuzzy logic control laws with different membership function groups are adopted to suppress vibrations of a flexible smart manipulator using collocated piezoelectric sensor/actuator pair. Also, dual-mode controllers combining fuzzy logic and proportional integral control are designed, for suppressing the lower amplitude vibration near the equilibrium point significantly. Experimental comparison research is conducted, using fuzzy control algorithms and the dual-mode controllers with different membership functions. The experimental results show that the adopted fuzzy control algorithms can substantially suppress the larger amplitude vibration; and the dual-mode controllers can also damp out the lower amplitude vibration significantly. The experimental results demonstrate that the proposed fuzzy controllers and dual-mode controllers can suppress vibration effectively, and the optimal placement is feasible.

A low-power circuit for piezoelectric vibration control by synchronized switching on voltage sources

Abstract: In the paper, a vibration damping system powered by harvested energy with implementation of the so-called SSDV (synchronized switch damping on voltage source) technique is designed and investigated. In the semi-passive approach, the piezoelectric element is intermittently switched from open-circuit to specific impedance synchronously with the structural vibration. Due to this switching procedure, a phase difference appears between the strain induced by vibration and the resulting voltage, thus creating energy dissipation. By supplying the energy collected from the piezoelectric materials to the switching circuit, a new low-power device using the SSDV technique is proposed. Compared with the original self-powered SSDI (synchronized switch damping on inductor), such a device can significantly improve its performance of vibration control. Its effectiveness in the single-mode resonant damping of a composite beam is validated by the experimental results.

Active vibration control of piezoelectric laminated beams with electroded actuators and sensors using an efficient finite element involving an electric node

Abstract: This paper presents an efficient finite element (FE) model for the active vibration control response of smart laminated beams integrated with electroded piezoelectric sensors and actuators. The FE model is based on an efficient layerwise theory with a quadratic variation of electric potential across the piezoelectric layers. The beam element has two conventional nodes and one electric node, which has no physical coordinate. The electric potential degrees of freedom (DOF) at the electroded piezoelectric surfaces are attached to the electric node which is connected to multiple elements belonging to the same electroded surface. This models the equipotential surface of the electroded sensors and actuators conveniently, and eliminates the cumbersome task of averaging the electric DOF over the surface. The control system is designed using a reduced-order modal state space model. The constant gain velocity feedback (CGVF) and optimal control strategies are studied for smart composite and sandwich beams with single-input–single-output (SISO) and multi-input–multi-output (MIMO) configurations under step and impulse excitations. The numerical study for CGVF control is performed on cantilever smart beams with both conventionally and 'truly' collocated actuators and sensors. The reasons for experimentally observed instability in CGVF control with conventional collocated sensors and actuators is explained. The effect of multiple segmentation of electrodes on the control performance is investigated.

Piezoelectric Actuators: Control Applications of Smart Materials

Abstract: Introduction Piezoelectric Effect General Requirements for Control Devices Control Strategies PID Control LQ Control Sliding Mode Control H Control QFT Control Inverse Model Control Vibration Control of Flexible Structure Vibration Control of Beam Structures Vibration Control of Hull Structures Vibration Control Using Piezostack Mount Vibration Control Using Active Mount One-Axis Active Mount Three-Axis Active Mount Control of Flexible Robotic Manipulators Two-Link Flexible Manipulator Flexible Gantry Robot Application to Fine Motion Control System Optical Pickup Device Dual-Servo Stage Application to Hydraulic Control System Piezoactuator-Driven Pump Piezoactuator-Driven Jetting Dispenser Piezoelectric Shunt Technology Vibration Control of CD-ROM Devices Vibration Control of the HDD Disk-Spindle System Index

Modified acceleration feedback for active vibration control of aerospace structures

Abstract: An acceleration feedback control method suggested in several past studies is modified to include two compensators, one first order and another second order, to separately control the closed-loop system stiffness and damping. The second order compensator has a damping ratio that is as low as that of the flexible structure in order to provide periodic vibration control. The first order compensator is used to provide the necessary damping, simultaneously. Employing two separate compensators allow us to provide stiffness and damping control in a dynamically decoupled manner. The new controller is readily applicable to a strain-based sensing and actuating approach, such as piezoelectrically controlled systems. Control gains are obtained through a stability analysis that is described in detail in the paper. The effectiveness of the controller is verified experimentally using a test setup that includes a flexible plate. The plate includes two small piezoelectric patches that are used as control actuators. Ten miniature size accelerometers are mounted on the plate for measuring plate vibrations. Two piezoelectric actuators in different positions are used for vibration control of the plate and the results are compared with the condition in which only one actuator is used. In addition, the results confirm that the new controller is able to effectively control more than one frequency simultaneously.

Finite element analysis of actively controlled smart plate with patched actuators and sensors

Abstract: The active vibration control of smart plate equipped with patched piezoelectric sensors and actuators is presented in this study. An equivalent single layer third order shear deformation theory is employed to model the kinematics of the plate and to obtain the shear strains. The governing equations of motion are derived using extended Hamilton's principle. Linear variation of electric potential across the piezoelectric layers in thickness direction is considered. The electrical variable is discretized by Lagrange interpolation function considering two-noded line element. Undamped natural frequencies and the corresponding mode shapes are obtained by solving the eigen value problem with and without electromechanical coupling. The finite element model in nodal variables are transformed into modal model and then recast into state space. The dynamic model is reduced for further analysis using Hankel norm for designing the controller. The optimal control technique is used to control the vibration of the plate.

Adaptive Modified Positive Position Feedback for Active Vibration Control of Structures

Abstract: The modified positive position feedback (MPPF) controller, an active vibration control method that uses collocated piezoelectric actuator actuators and sensors, is developed using an adaptive controller. The adaptive mechanism consists of two main parts: (1) frequency adaptation and (2) adaptive controller. Frequency adaptation only tracks the frequency of vibrations using fast Fourier transforms. The obtained frequency is then fed to MPPF compensators and the adaptive controller. This provides a unique feature for MPPF by extending its domain of capabilities from controlling tonal vibrations to broadband disturbances. The adaptive controller mechanism consists of a reference model that is of the same order as the MPPF system and its compensators. The adaptive law provides the additional control force that is needed for controlling frequency changes caused by broadband vibrations. The experimental results show that the frequency adaptation method that is derived has worked quite well. The results also ind...

Experimental Implementation on Vibration Mode Control of a Moving 3-PRR Flexible Parallel Manipulator with Multiple PZT Transducers

Abstract: This paper presents the experimental implementation of active vibration control applied to a moving 3-PRR parallel manipulator with three flexible links. The active vibration control is implemented using three piezoelectric (PZT) transducer pairs applied to one flexible intermediate link based on modal strain rate feedback (MSRF) control. A real-time active vibration control system is developed using two PCs with LabVIEW Real-Time. Modal analyses are conducted, and the results demonstrate that the vibration modes of the intermediate links are dynamically coupled and the vibration frequency components are complicated and closely spaced. Simplified and efficient modal filters are developed to extract modal coordinates in real time, and a second order compensator is used to filter amplified noises and unmodeled high frequency dynamics. A MSRF controller is then designed using an independent mode space control strategy, and is implemented experimentally with the first mode targeted for control. Experimental r...

Modeling and Control of Vibration in Mechanical Systems

Abstract: Many chapters have introductions, conclusions, and references Symbols and Acronyms 1 Mechanical Systems and Vibration Magnetic recording system Stewart platform Vibration sources and descriptions Types of vibration Random vibration Vibration analysis 2 Modeling of Disk Drive System and Its Vibration Introduction System description System modeling Vibration modeling Modeling of Stewart Platform System description and governing equations Modeling using adaptive filtering approach Classical Vibration Control Passive control Self-adapting systems Active vibration control Introduction to Optimal and Robust Control H2 and H norms H2 optimal control H control Robust control Controller parametrization Performance limitation Mixed H2/H Control Design for Vibration Rejection Mixed H2/H control problem Method 1: slack variable approach Method 2: an improved slack variable approach Application in servo loop design for hard disk drives Low-Hump Sensitivity Control Design for Hard Disk Drive Systems Problem statement Design in continuous-time domain Design in discrete-time domain Generalized KYP Lemma-Based Loop Shaping Control Design Problem description Generalized KYP lemma-based control design method Peak filter Application in high frequency vibration rejection Application in mid-frequency vibration rejection Combined H2 and KYP Lemma-Based Control Design Problem formulation Controller design for specific disturbance rejection and overall error minimization Simulation and implementation results Blending Control forMulti-Frequency Disturbance Rejection Control blending Control blending application in multi-frequency disturbance rejection Simulation and experimental results H -Based Design for Disturbance Observer Conventional disturbance observer A general form of disturbance observer Application results Two-DimensionalH2 Control for Error Minimization 2-D stabilization control 2-D H2 control SSTW process and modeling Feedforward compensation method 2-D control formulation for SSTW 2-D stabilization control for error propagation containment 2-D H2 control for error minimization Nonlinearity Compensation and Nonlinear Control Nonlinearity compensation Nonlinear control Quantization Effect on Vibration Rejection and Its Compensation Description of control system with quantizer Quantization effect on error rejection Compensation of quantization effect on error rejectioAdaptive Filtering Algorithms for Active Vibration Control Adaptive feedforward algorithm Adaptive feedback algorithm Comparison between feedforward and feedback controls Application in Stewart platform

Elimination of Unstable Ranges of Rotors Utilizing Discontinuous Spring Characteristics: An Asymmetrical Shaft System, an Asymmetrical Rotor System, and a Rotor System With Liquid

Abstract: Unstable vibration occurs in the vicinities of the major critical speeds of asymmetrical shaft and rotor systems. It occurs also in a wide rotational speed range higher than the major critical speed of a shaft with a hollow disk partially filled with liquid. The occurrence of the unstable vibrations is a serious problem because the amplitude increases exponentially, and finally, the system is destroyed. The active vibration control can suppress unstable vibrations but the method is generally complicated and costly. No simple effective method to suppress unstable vibrations has been developed yet. In the previous paper, the authors proposed a simple method by utilizing discontinuous spring characteristics, which can suppress steady-state resonances. This paper shows that this method is also effective to suppress unstable vibrations. By using this method, the unstable vibrations can be changed into almost periodic motions, and the amplitudes are suppressed to the desired small level even in an unstable range. The validity of the proposed method is also verified by experiments.

Active vibration control of a flexible cantilever beam using shape memory alloy actuators

Abstract: This paper demonstrates the feasibility of using shape memory alloys (SMAs) as actuators to control the vibration of a flexible cantilever beam In a tendon mechanism, SMAs are controlled in a push–pull fashion based on H-infinity theory and taking into account the uncertainty in the actuator performance Using this mechanism, the four vibrational modes (three bending and one torsional) of the cantilever beam can be simultaneously damped To control bending and torsional vibrational modes of a flexible beam, we install SMAs obliquely in a beam–SMA structure, then measure and theoretically model the properties of an actuator consisting of an SMA and a spring Using the properties of the actuator, we introduce the state equations based on the dynamic model of the proposed beam–SMA structure and design the active control system according to H-infinity theory Finally, we experimentally verify the functioning of the system

Vibration Suppression in Cutting Tools Using a Collocated Piezoelectric Sensor/Actuator With an Adaptive Control Algorithm

Abstract: The machining process is very important in many engineering applications. In high precision machining, surface finish is strongly correlated with vibrations and the dynamic interactions between the part and the cutting tool. Parameters affecting these vibrations and dynamic interactions, such as spindle speed, cut depth, feed rate, and the part's material properties can vary in real-time, resulting in unexpected or undesirable effects on the surface finish of the machining product. The focus of this research is the development of an improved machining process through the use of active vibration damping. The tool holder employs a high bandwidth piezoelectric actuator with an adaptive positive position feedback control algorithm for vibration and chatter suppression. In addition, instead of using external sensors, the proposed approach investigates the use of a collocated piezoelectric sensor for measuring the dynamic responses from machining processes. The performance of this method is evaluated by comparing the surface finishes obtained with active vibration control versus baseline uncontrolled cuts. Considerable improvement in surface finish (up to 50%) was observed for applications in modern day machining.

Vibration Suppression in Structures Using Cable Actuators

Abstract: We investigate the use of cable tension for active vibration control in frame structures. A general formulation for this class of systems is developed using finite elements, which includes the dynamics of the structure and the effects of cable-structure interactions. It is found that the cable tension has two distinct effects on the structure. The first is a parametric effect in which the cable tension changes the stiffness of the structure, and the second is a direct effect that provides an external force on the structure. Based on this model, a general control scheme is developed that uses cable actuation to take advantage of these effects, both separately and together. The control scheme for all cases is based on modal amplitudes, and it applies and releases tension in such a manner that vibration energy is removed from the modes of the structure over a prescribed frequency range that depends on the bandwidth(s) of the actuator(s). The stability of the controlled systems is proven using nonlinear control theory. In addition, a method is developed for determining the optimal placement of cables for parametric stiffness control, which is verified via simulations. Finally, an experimental realization of the direct force control is tested on a frame structure and compared with simulations, demonstrating its effectiveness.

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

Abstract: 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.

Vibration piece, sensor unit, electronic apparatus, method for manufacturing vibration piece, and method for manufacturing sensor unit

Abstract: PROBLEM TO BE SOLVED: To provide a vibration piece which can suppress and adjust leakage output, a sensor unit using the same, and method for manufacturing the same, and an electronic apparatus on which the vibration piece or the sensor unit is loaded.SOLUTION: A vibration gyro element 11 has: a base part 21; a pair of vibration arms 22a, 22b for driving extended, respectively from both ends of the Y-axis direction of the base part 21; and a pair of vibration arms 23a, 23b for detection. In addition, vibration arms 125a, 125b for adjustment extended by being made in parallel with the vibration arms 22a, 22b for driving from the respective tip parts of connection parts 24a, 24b extended, respectively from both ends of the X-axis direction of the base part 21. The vibration gyro element 11 has weight parts 127a, 127b as wide parts on the tip sides of the respective vibration arms 125a, 125b for adjustment. Electrodes 145a, 145b for adjustment as film bodies for adjusting leakage output of the vibration gyro element 11 are provided on the main surfaces of the respective vibration arms 125a, 125b.

Piezoelectric vibration device having structure including self-amplification function of vibration and electric/electronic device using same as vibrating means

Abstract: Disclosed is a piezoelectric vibration device. A piezoelectric vibration member vibrates with a maximum displacement of an edge or both ends thereof in a vertical direction on the basis of a central part as a point of action of vibration or a maximum displacement of a central part thereof in the vertical direction on the basis of both ends or a plurality of edge parts as the point of action of vibration by changing polarity of an applied voltage. A weight is formed with a material having high specific gravity and is coupled with a maximum displacement point of the piezoelectric vibration member as one body. The weight interlocks and vibrates with the vibration of the piezoelectric vibration member to amplify vibration at a specific frequency of a driving voltage. One side of a vibration supporting member is fixed on a vibration force transferring target and the other side of the vibration supporting member is coupled with a predetermined part of a piezoelectric vibration member so that the vibration supporting member supports the piezoelectric vibration member to vibrate the piezoelectric vibration member in the vertical direction on the basis of the predetermined part as the point of action of vibration. A coupling member is used for coupling the weight and the piezoelectric member as one body so as to apply the full weight of the weight to the piezoelectric vibration member. A vibration displacement is amplified at a particular frequency using the coupling member having elasticity or the vibration supporting member. The power consumption of the piezoelectric vibration device is remarkably reduced in comparison with a vibration motor using electromagnetic induction.