In this paper we review essential aspects in- volved in the design of an active vibration control system. We present a generic procedure to the design process and give selective examples from the literature on relevant ma- terial. Together with examples of their applications, various topics are briefly introduced, such as structure modeling, model reduction, feedback control, feedforward control, con- trollability and observability, spillover, eigenstructure assign- ment (pole placement), coordinate coupling control, robust control, optimal control, state observers (estimators), intelli- gent structure and controller, adaptive control, active con- trol effects on the system, time delay, actuator-structure interaction, and optimal placement of actuators.

Active Structural Vibration Control: A Review

A piezohydraulic pump is presented that makes use of the step-and-repeat capability of piezoelectric actuators. This work discusses piezohydraulic pumping theory, pump design, and pump performance....

Piezoelectric hydraulic pump development

On-off nonlinear active control of floor vibrations

The formulation and solution of an optimization problem for the design of a current controlled switching power amplifier to drive a piezoelectric actuator is the subject of this paper. The design is formulated as a continuous optimization problem. A detailed model that includes the anhysteretic nonlinearity between the electric field and polarization is developed and is coupled with a dynamic model of the amplifier. The design specifications are formulated as optimization constraints. The objective function is chosen to be the weight of the inductor. Optimization results are presented to demonstrate the efficiency of the proposed design methodology.

/pdf/optimized-design-of-switching-amplifiers-for-piezoelectric-42d0vr0eyg.pdf

Optimized Design of Switching Amplifiers for Piezoelectric Actuators

The increased use of giant magnetostrictive, Terfenol-D transducers in a wide variety of applications has led to a need for greater understanding of the materials performance. This dissertation attempts to add to the Terfenol-D transducer body of knowledge by providing indepth analysis and modeling of an experimental transducer. A description of the magnetostriction process related to Terfenol-D includes a discussion of material properties, production methods, and the effect of mechanical stress, magnetization, and temperature on the material performance. The understanding of the Terfenol-D material performance provides the basis for an analysis of the performance of a Terfenol-D transducer. Issues related to the design and utilization of the Terfenol-D material in transducers are considered, including the magnetic circuit, application of mechanical prestress, and tuning the mechanical resonance. Experimental results from two broadband, Tonpilz design transducers show the effects of operating conditions (prestress, magnetic bias, AC magnetization amplitude, and frequency) on performance. In an effort to understand and utililize the rich performance space described by the experimental results, a variety of models are considered. An overview of models applicable to Terfenol-D and Terfenol-D transducers is provided, including a discussion of modeling criteria. The Jiles-Atherton model of ferromagnetic hysteresis is employed to describe the quasi-static transducer performance. This model requires the estimation of only six physically-based parameters to accurately simulate performance. The model is shown to be robust with respect to model parameters over a range of mechanical prestress, magnetic biases, and AC magnetic field amplitudes, allowing predictive capability within these ranges. An additional model, based on electroacoustics theory, explains trends in the frequency domain and facilitates an analysis of efficiency based on impedance and admittance analysis. Results and discussion explain the importance of the resonance of the electromechanical system, as distinct from the mechanical resonance.

https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=12831&context=rtd

Design, analysis, and modeling of giant magnetostrictuve transducers

We investigate the relationship between the parameters of a proof-mass actuator and the performance of that actuator within a vibration suppression loop for a flexible structure. We parameterize the model of the actuator in terms of the length of the proof-mass, the mass of the proof-mass, and the saturation force of the electromagnetic subsystem. The performance of the actuator within a vibration suppression control loop is characterized in terms of the relationship between the parameters and the structure's natural frequency. These results can be used to size a proof-mass actuator to maximize the operating region of the actuator and to maximize the ratio of the mass of the proof-mass to the total mass of the actuator .

/pdf/performance-and-control-of-proof-mass-actuators-accounting-282zgyjki4.pdf

Performance And Control Of Proof-Mass Actuators Accounting For Stroke Saturation

In this paper we report on the development of a high frequency switching amplifier for electrostrictive actuators. This amplifier is specifically designed for the capacitive loads that electrostrictive actuator present to them. One of the ultimate goals is to miniaturize these amplifiers so that they could be embedded into the material along with the actuators. Therefore, the configuration was chosen that would allow for miniaturization. The amplifier is also designed for high efficiency for thermal management. An integrated nonlinear model of the actuator and the electronics is also developed. A prototype Smart Material was fabricated consisting of sixty four actuators and sixteen amplifiers. Both experimental and simulation results of the Smart Material are reported.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

High-frequency switching amplifiers for electrostrictive actuators

A proof-mass actuator is an actuator for structural control that accelerates a proof-mass in linear motion, imparting an equal and opposite force to thestructure. Acontinuousmotion of theproof-mass in onedirection will eventuallylead toa collisionoftheproof-masswith itsstops,impartingshockstothestructureand possiblycausing damagetotheactuator.Weproposenonlinearcontrollawsforpreventing collisionsoftheproof-masswithitsstops. Thelinearcontrol-loop gainsaresizedso thattheproof-masswill nothit itsstopsundercommandedmotions.Then a nonlinear control loop is added to increase the restoring force to the proof-mass when the proof-mass is close to its stops. It is shown that the nonlinear control law increases the operating region over an actuator with only linear control loops. It is also shown that the nonlinear control law allows the mass of the actuator to be decreased while the same performance is maintained. Nomenclature b = modal ine uence coefe cient d = stroke length of the proof-mass Fmax = maximum force attainable from the electromagnetic subsystem fmaxstroke(x ) = maximum force available from sinusoidal motion of the proof-mass fpm(t) = electromagnetic force applied to the proof-mass fst(t) = force applied to the structure by the proof-mass Kn = gain of the nonlinear control loop Kpa = gain of the actuator’ s position loop Kps = gain of the structure’ s position loop Kva = gain of the actuator’ s velocity loop Kvs = gain of the structure’ s velocity loop m = mass of the proof-mass rmax = value of the saturation function for command limiter rpm(t) = reference input signal to the actuator control loops rst(t) = reference input signal to the outer control loops ts(x0) = 1% settling time due to the initial conditionx0 vn(t) D f (yr, P yr) = nonlinear restoring force dee ned in Eq. (16) vpm(t) = voltage input signal to the actuator ypm(t), P ypm(t) = position and velocity of the proof-mass yst(t), P yst(t) = position and velocity of the structure f ed(x0) = equivalent damping, dee ned in Eq. (9) f PM(x0) = performance function dee ned in Eq. (12) f st, x st = damping and modal frequency of the structure g (t) = modal amplitude x b = saturation break frequency

/pdf/nonlinear-control-of-a-proof-mass-actuator-15jrw666ct.pdf

Nonlinear Control of a Proof-Mass Actuator

In this paper we report on the development of a high frequency switching amplifier for electrostrictive actuators. This amplifier is specifically designed for the capacitive loads that electrostrictive actuator present to them. An integrated nonlinear model of the actuator and the electronics is also developed. It is shown that one source of distortion in the actuator velocity is the nonlinear field to polarization relationship. The amplifier reduces the impact of this nonlinearity by controlling the current entering the actuator instead of the voltage across the actuator. Another major source of the distortion is caused by the quadratic relationship between polarization and strain in the electrostrictive material. The paper develops a new control scheme for the amplifier which significantly improves the linearity of the overall amplifier/actuator combination. Both experimental and simulation results of the Smart Material are reported.

Nonlinear electronic control of an electrostrictive actuator

In this paper we analyze the power flow between stacked electrostrictor actuators and a pulse-width-modulated switching amplifier. The amplifier and actuator are analyzed as components of a smart skin whose function is underwater acoustic echo cancellation. An integrated model is developed which includes a dynamic structural model of the actuator, a dynamic model ofthe power electronics and a nonlinear electromechanical coupling mechanism of the electrostrictor actuation material. Using a linearized version of this model, the mechanical admittance of the actuator as seen by an external force is analyzed. It is shown that an outer acoustic control loop can modify this mechanical admittance and optimize the power coupling between the actuator and an external fluid medium by impedance matching. With the nonlinear model, the power flow between the electrical and mechanical systems is analyzed through simulation. The flow of power is traced from the power injected by the external force, through the amplifier and into the electrical bus. It is shown that effective power flow occurs only when the frequency ofthe external force is within the bandwidth ofthe amplifier. This analysis also reveals that the electrical power flow through the actuator is two orders of magnitude larger than the external mechanical power extracted by the actuator. This analysis shows that one main requirement on the amplifier design is to manage the charge flow through the actuator.

/pdf/power-flow-analysis-of-electrostrictive-actuators-driven-by-2bnd221uqq.pdf

Gregory A. Zvonar

Papers

Performance And Control Of Proof-Mass Actuators Accounting For Stroke Saturation

High-frequency switching amplifiers for electrostrictive actuators

Nonlinear Control of a Proof-Mass Actuator

Nonlinear electronic control of an electrostrictive actuator

Power Flow Analysis of Electrostrictive Actuators Driven by Switchmode Amplifiers