Abstract: An apparatus for generating a virtual effect of an electric vehicle includes: a driving information detector configured to detect vehicle driving information in the electric vehicle; a controller configured to determine a characteristic of the virtual effect based on the vehicle driving information detected by the driving information detector, and configured to generate a virtual effect producing signal for producing the determined characteristic of the virtual effect; and a vibration actuator provided in a seat of the electric vehicle such that when the vibration actuator operates, a driver or a passenger who is in the seat experiences vibration, the vibration actuator being controlled by the virtual effect producing signal generated by the controller, so as to produce the vibration according to the determined characteristic of the virtual effect.

Abstract: Secure device association is generally described. In one example, a secure device association system comprises a first device comprising a mechanical actuator and a second device comprising a microphone, the mechanical actuator of the first device and the microphone of the second device to form an out-of-band (OOB) channel for secure association between the first device and the second device.

Abstract: An electrodynamic shaker apparatus is disclosed for providing shaking and/or vibrational motion. The shaker includes armature and stator assemblies as well as a distributed spring assembly. The shaker apparatus of the present invention is robust, supports increased off-center loads, and has a low profile such that it may be easily placed under an item of furniture in order to impart vibrational motion in response to electrical signals from a variety of sources.

Abstract: A shaker for enabling the testing of gyros and/or other devices for performance under realistic 6DOF motions. The shaker may be implemented as a hexapod, comprising a plate and six individually, simultaneously, and real-time controllable strut assemblies that are capable of extending and contracting linearly. The strut assemblies may comprise high-precision, linear electromagnetic actuators. The strut assemblies may also comprise high-precision non-contact sensors to sense the extension/contraction of the strut assemblies along their stroke length. In addition, the strut assemblies may comprise, at each end thereof, stiff, bendable flexures to attain the repeatable and linear motion required. The controller preferably has a control bandwidth of 1000 Hz or more, so that the motion of the plate can be precisely controlled to realize realistic 6DOF motions.

Abstract: A vibration-type measuring device includes an exciter arrangement which exerts a time-dependent force with at least one sinusoidal component at an adjustable excitation frequency on a measuring tube, through which a medium can flow, and causes the measuring tube to oscillate. The measuring device includes first and second sensors which are fitted to the measuring tube at different locations. The first and second sensors output first and second measurement signals, respectively. The measuring device includes an evaluation unit which determines a first phase shift between the first and second measurement signals and uses the determined phase shift to determine a measurement variable of the medium. The measuring device includes a phase comparator, which determines a second phase shift between the force and the average value of the first and second measurement signals, and a frequency generator which sets the excitation frequency on the basis of the second phase shift.

Abstract: Provided is a non-contact type transducer for performing modal testing or non-destructive diagnosis easily, that is, a non-contact type transducer by which even an inexperienced person may perform modal testing or non-destructive diagnosis without errors. The transducer includes a multi-loop coil including two or more looped coil portions that are connected to each other, wherein the looped coil portions are located on top of a rod member, and the looped coil portions form magnetic fields on the surface of the rod member in a direction parallel to the lengthwise direction of the rod member; and one or more magnets that are arranged to form a static magnetic field on the surface of the rod member, whereon the surface of the rod member a dynamic magnetic field is formed by the multi-loop coils in the direction parallel to the lengthwise direction of the rod member, even partially in a direction parallel to the lengthwise direction of the rod member.

Abstract: The electrostatic sensors of bridge or cantilever type with multiple electrodes, the electrostatic sensors of comb type and piezoelectric sensors are used for the single molecule detection of ligands. The electrical driving of sensors is separated in some cases from the sensing for increased sensitivity. The large arrays of sensors with individual or common sensing circuits are employed to further improve detection sensitivity. The fabrication of the sensors, their functionalization for detection of many chemical and biological species and electrical circuitry, packaging, microfluidic subsystem and the system architecture are also disclosed. The individual, specific sensing of single species or simultaneous detection of multiple species is realized. The freeze drying or critical point drying after exposure of sensors to ligands present in liquids and detection in reduced pressure or vacuum is employed for increased sensitivity, down to the single molecule.

Abstract: An electrodynamic shaker apparatus is disclosed for providing shaking and/or vibrational motion. The shaker includes armature and stator assemblies as well as a distributed spring assembly. The shaker apparatus of the present invention is robust, supports increased off-center loads, and has a low profile such that it may be easily placed under an item of furniture in order to impart vibrational motion in response to electrical signals from a variety of sources.

Abstract: A testing apparatus, for subjecting a device-under-test to oscillating acceleration, includes a stage having a mounting surface attachable to the device-under-test. An actuator is coupled to the stage, and also coupled to a reaction mass movable along a linear axis. A first flexure plate has a first flexure plate middle and a first flexure plate periphery, with the first flexure plate middle attached to the stage at a first stage end. A second flexure plate has a second flexure plate middle and a second flexure plate periphery, with the second flexure plate middle attached to the stage at a second stage end that opposes the first stage end. The first flexure plate periphery and the second flexure plate periphery are attached to the frame. The first and second flexure plates define major surfaces that are substantially perpendicular to the linear axis.

Abstract: A shaker for enabling the testing of gyros and/or other devices for performance under realistic 6DOF motions. The shaker may be implemented as a hexapod, comprising a plate and six individually, simultaneously, and real-time controllable strut assemblies that are capable of extending and contracting linearly. The strut assemblies may comprise high-precision, linear electromagnetic actuators. The strut assemblies may also comprise high-precision non-contact sensors to sense the extension/contraction of the strut assemblies along their stroke length. In addition, the strut assemblies may comprise, at each end thereof, stiff, bendable flexures to attain the repeatable and linear motion required. The controller preferably has a control bandwidth of 1000 Hz or more, so that the motion of the plate can be precisely controlled to realize realistic 6DOF motions.

Abstract: An electrodynamic shaker apparatus is disclosed for providing shaking and/or vibrational motion. The shaker includes armature and stator assemblies as well as a distributed spring assembly. The shaker apparatus of the present invention is robust, supports increased off-center loads, and has a low profile such that it may be easily placed under an item of furniture in order to impart vibrational motion in response to electrical signals from a variety of sources.

Abstract: To drive an oscillator always at a stable and constant oscillation even if frequency and amplitude of a power supply voltage differ depending on a delivery destination of the oscillator, an oscillator drive control device (10), which generates a predetermined switching pattern by operating a switching element, and supplies an oscillation generation unit (7) of the oscillator with drive electric power for generating predetermined oscillation frequency and amplitude according to the switching pattern, includes: a voltage detection circuit (11) for detecting a power supply voltage unique to a delivery destination of the oscillator; a memory circuit (12) storing, in advance, a basic switching pattern adapted to an arbitrarily set reference voltage, and used for driving the oscillation generation unit (7) at proper oscillation frequency and amplitude; and an arithmetic processing circuit (13) for calculating a ratio of the detected voltage unique to the delivery destination detected by the voltage detection circui

Abstract: A testing apparatus and method comprising providing a platform for a unit under test, charging a capacitor bank with a charging system, with a switching and power control system generating multiple pulses per cycle from energy from the capacitor bank, and with an electromagnetic force generator receiving pulses from the switching and power control system and directing force at the platform.

Abstract: Provided is a non-contact type transducer for performing modal testing or non-destructive diagnosis easily, that is, a non-contact type transducer by which even an inexperienced person may perform modal testing or non-destructive diagnosis without errors. The transducer includes a multi-loop coil including two or more looped coil portions that are connected to each other, wherein the looped coil portions are located on top of a rod member, and the looped coil portions form magnetic fields on the surface of the rod member in a direction parallel to the lengthwise direction of the rod member; and one or more magnets that are arranged to form a static magnetic field on the surface of the rod member, whereon the surface of the rod member a dynamic magnetic field is formed by the multi-loop coils in the direction parallel to the lengthwise direction of the rod member, even partially in a direction parallel to the lengthwise direction of the rod member.

Abstract: An electrodynamic shaker apparatus is disclosed for providing shaking and/or vibrational motion. The shaker includes armature and stator assemblies as well as a distributed spring assembly. The shaker apparatus of the present invention is robust, supports increased off-center loads, and has a low profile such that it may be easily placed under an item of furniture in order to impart vibrational motion in response to electrical signals from a variety of sources.

Abstract: A method for characterizing one or more properties of a sample using acoustic waveforms is disclosed, and comprises directing a sequence of at least three optical pulses to the sample to generate an acoustic response in the sample at a frequency corresponding to the pulse sequence, varying the timing of one or more of the pulses in the sequence to vary the frequency of the acoustic response in the sample, and measuring the strength of the acoustic response as a function of the varied frequency to determine information about the sample.

Abstract: A mechanical response of an implantable medical device (IMD) to a first static magnetic field and a first gradient magnetic field slew rate is simulated by exposing the IMD to a second static magnetic field having a magnitude greater than the first static magnetic field and generating a second gradient magnetic field at the IMD such that a product of the second static magnetic field and a second gradient magnetic field slew rate is substantially equal to a product of the first static magnetic field and the first gradient magnetic field slew rate.

Abstract: An electrodynamic shaker apparatus is disclosed for providing shaking and/or vibrational motion. The shaker includes armature and stator assemblies as well as a distributed spring assembly. The shaker apparatus of the present invention is robust, supports increased off-center loads, and has a low profile such that it may be easily placed under an item of furniture in order to impart vibrational motion in response to electrical signals from a variety of sources.

Abstract: In order to provide a vibration testing apparatus which can have a large diameter without introducing undesirable rigid vibration modes, the vibration testing apparatus 1 comprises a support 2, at least one electromagnetic vibration generator 12 mounted on the support, the mounting comprising an annular body 5 and a head expander 10, the annular body being supported by bearings located around the periphery of the annular body 5.

Abstract: A testing apparatus for use with a data storage component that includes a base platform and a retaining element coupled to the base platform. The retaining element is sized and configured to retain the data storage component. The retaining element is linearly movable relative to the base platform during a linear acceleration mode without substantial rotational movement. The retaining element is rotationally movable relative to the base platform without substantial linear movement during a rotational acceleration mode. The testing apparatus further includes an actuator disposable in mechanical communication with the retaining element for moving the retaining element relative to the base platform.

Abstract: A cavity vibrates a sample and is combined with the sample to be equivalent to an LC circuit. An insulator electrically insulates the sample from the cavity. The insulator is placed between the sample and the cavity. A first output unit outputs, to the cavity, a first frequency signal including a frequency which causes the cavity combined with the sample to function as an equivalent circuit of an LC circuit. A second output unit outputs, to the sample and the cavity, a second frequency signal including a frequency which vibrates the sample. An amplitude detection unit detects, based on the second frequency signal, the amplitude of a reflected signal reflected from the cavity, the reflected signal being caused by the first frequency signal.

Abstract: A small-sized rotational vibration testing apparatus having a wide band of measuring frequencies and capable of directly driving a rotary table (1) to oscillate or vibrate in a rotational direction under the action of torque generated by a vibration applying mechanism. The rotary table (1) is rotatably mounted on a base (2), and a plurality of coil frames (14) each having a coil (13) attached thereto are mounted on a flange (1c) of the rotary table (1) at an equal circumferential pitch or interval about its axis of rotation. A plurality of magnetic circuits (12) are fixedly secured to the base (2) in such a manner that the center of each coil (13) is positioned at the center of an associated magnetic circuit (12).

Abstract: An anti-vibration member is provided on an inner wall of a cylinder tube of a lift cylinder. The anti-vibration member is formed into a cylindrical form, and an outer circumferential surface thereof is formed along an inner circumferential surface of the cylinder tube. The anti-vibration member is formed by coating resin high in ultrasonic wave attenuating effect (such as polyphenylene sulfide (PPS) resin). It is possible to attenuate or absorb a vibration of a surface wave transmitted from an ultrasonic wave sensor and indirectly transmitted through the inner wall of the cylinder tube.

Abstract: An apparatus for subjecting a disc drive to rotational vibration test profiles includes a mounting base, a disc drive mounting plate, and a rotary vibration motor assembly mounted between the mounting plate and the base in which the disc drive mounting plate may be vibrationally rotated about an axis through the base and plate. The motor assembly preferably includes a plurality of voice coil motors mounted and radially spaced about a tubular shaft supporting the disc drive mounting plate. The voice coil motors are connected and driven in series to impart the rotational vibrational profile to the disc drive mounted on the mounting plate. The method involves providing a support structure, a rotatable shaft carried by the support structure, a voice coil motor connected to the shaft for reciprocally rotating the shaft, mounting a device to be tested on the shaft, and applying a current to the voice coil motor to reciprocally rotate the shaft to vibrate the device.

Abstract: A method and apparatus for testing the durability of a catalytic converter incorporating a catalyst support honeycomb supported by a resilient mounting material within an exterior converter enclosure, the method comprising vibrating the exterior of the converter enclosure while the converter is heated to a predetermined testing temperature and while the force or acceleration applied to the catalyst support honeycomb by the vibrating exterior enclosure and resilient mounting layer is measured.

Abstract: A method, apparatus, for subjecting a test object to vibrational energy testing is disclosed. The apparatus comprises a rotatable joint such as a hydrostatic ball joint for transmitting energy from a force generator to the test object, and a support structure, coupled to the test object and the rotatable joint, for flexibly restraining the test object from rotating about the center of rotation of the rotatable joint. In one embodiment of the invention, the support structure comprises a support member and at least one suspension device disposed between the support member and a ground datum. In another embodiment, the suspension device applies a suspension force to the support member in a direction substantially perpendicular to a vector from the center of rotation to the suspending force. In this embodiment the suspension devices are subjected primarily to compression and tension forces.

Abstract: Three or more frequency components are used as deformation waveforms to perturb a sample during spectroscopic measurement. Simultaneously measuring more than one frequency allows for multiplexing. Further, many frequencies insure that the optimal perturbation frequencies for a particular measurement are present. The multiplex advantage of a particular spectroscopic instrument may accrue simultaneously with a multiplex advantage in the characterization of the time dependence of the sample response.

Abstract: An electromagnetic acoustic transducer for inducing and sensing vibrations in a cylindrical object and methods of using an electromagnetic acoustic transducer to determine resonant frequencies and physical properties of cylindrical objects. The electromagnetic acoustic transducers produce specific modes of vibration in cylindrical objects including axial shear vibrations, torsional vibrations, radial vibrations and plane strain vibrations. The methods of determining physical properties of a cylindrical objects include comparing sensed resonant frequencies of the cylindrical object to known relationships between resonant frequency and the physical properties of interest. The methods can be used to determine the temperature, dimensions, elastic constants, and damping coefficients of cylindrical objects, the magnitude of a load applied to a cylindrical object, or the texture or grain orientation of the material forming a cylindrical object.

Abstract: An electromagnetic acoustic transducer for inducing and sensing vibrations n a cylindrical object and methods of using an electromagnetic acoustic transducer to determine resonant frequencies and physical properties of cylindrical objects. The electromagnetic acoustic transducers produce specific modes of vibration in cylindrical objects including axial shear vibrations. The electromagnetic acoustic transducers are used to determine the temperature, dimensions, elastic constants, and damping coefficients of cylindrical objects, the magnitude of a load applied to a cylindrical object, or the texture or grain orientation of the material forming a cylindrical object.

Abstract: An absolute amplitude sensor device for measuring absolute vibrations comprising a non-contact displacement sensor, in particular, an eddy-current sensor and a vibrator. Said vibrator is comprised of a number of inertial mass pieces, springs, a damper and a housing. The inertial mass piece is levitated in said housing by means of said springs and damper. The output signal of said device is directly proportional to the amplitude of the object to be measured. The number of said inertial mass pieces is N. It is a single-vibrator when N equals 1 and a multi-vibrator when N equals 2 to 20.

Abstract: An electromagnetic acoustic transducer for inducing and sensing vibrations in a cylindrical object and methods of using an electromagnetic acoustic transducer to determine resonant frequencies and physical properties of cylindrical objects. The electromagnetic acoustic transducers produce specific modes of vibration in cylindrical objects including axial shear vibrations, torsional vibrations, radial vibrations and plane strain vibrations. The methods of determining physical properties of a cylindrical objects include comparing sensed resonant frequencies of the cylindrical object to known relationships between resonant frequency and the physical properties of interest. The methods can be used to determine the temperature, dimensions, elastic constants, and damping coefficients of cylindrical objects, the magnitude of a load applied to a cylindrical object, or the texture or grain orientation of the material forming a cylindrical object.

Abstract: In a vibratory apparatus including vibratory speed detector for detecting a vibratory speed of a vibratory machine, a self-excited oscillation controller for amplifying the output of the vibratory speed detector at a feed-back gain K, receiving the output of the vibratory speed detector as a positive feed-back signal, a power amplifier for power-amplifying the output of the self-excited oscillation controller and a vibratory exciter receiving the output of the power amplifier for vibrating the vibratory machine, the feed back gain K is changed in accordance with the equation; K=K.sub.1 .DELTA.r+K.sub.3 (.DELTA.r).sup.3 +Kcr, where .DELTA.r represents the amplitude difference between a predetermined amplitude and the present amplitude, K.sub.1, K.sub.3 constants, and Kcr critical stability gain.

Abstract: A self-exciting vibratory device for producing vibration signals in a housing includes actuator means (12) attached to housing (16), sensor means (14) attached to housing (16) and electronics module (18) connecting actuator means (12) and sensor means (14). Actuator means (12) creates vibration signals within housing (16). Sensor means (14) senses the vibration signals created by actuator means (12). Electronics module (18) amplifies and phase shifts the vibration signals sensed by sensor means (14) and containing resonant modes of vibration of housing (16). Electronics module (18) then supplies these amplified, phase shifted signals to actuator means (12) to enhance the vibration of housing (16) at the dominant mode of vibration of housing (16).

Abstract: A vibrator or shaker comprises an audio speaker and a mounting for attaching a payload to be vibrated. One end of the mounting is adhesively bonded to the outside of the speaker cone. The other end of the mounting has a threaded spindle for attaching the payload. A suspension member or spider may be attached at its edges to the speaker frame and at its center to the mounting. The suspension member increases the maximum payload weight that can be accommodated by relieving the speaker cone of a portion of the combined weight of the payload, the mounting, and the moving speaker armature.

Abstract: A second torsional vibrator having an outer frame and a second torsional spring is formed on the outer side of a first torsional vibrator having a pair of torsional springs and a plate member (reflection mirror), with a second torsional vibrator being fixed by the fixed part. The resonant frequency for the first torsional vibrator is set higher than that for the second torsional vibrator. The outer frame in the second torsional vibrator is driven substantially at the resonant frequency of the first torsional vibrator by an electromagnetic or electrostatic force. As a result, it becomes possible to obtain a stable and large scanning angle by using only a small driving force.

Abstract: A device and method are provided which non-destructively detect crack length and crack geometry in thin metallic plates. A non-contacting vibration apparatus produces resonant vibrations without introducing extraneous noise. Resulting resonant vibration shifts in cracked plates are correlated to known crack length in plates with similar resonant vibration shifts. In addition, acoustic emissions of cracks at resonance frequencies are correlated to acoustic emissions from known crack geometries.

Abstract: In an inertial mass measurement instrument, an active force compensator compensates for inertial forces transmitted by an oscillating elastic element to a primary support of the instrument. The compensator applies equal and opposite compensating forces to the primary support along an effective line of action of the oscillating element. Application of the compensating forces result in a substantially zero net acceleration of the primary support and avoids measurement inaccuracies attributable to changes in properties of secondary support elements.

Abstract: The invention relates to an elastic clamping device for at least one body with magnetostrictive properties, wherein a pressure force presses the clamping device against the inner magnetostrictive body with a predetermined force. The pressure force extends in the direction of contraction and perpendicular to the direction of expansion both caused by the influence of a magnetic field on the magnetostrictive body and results in a prestress acting in the direction of contraction in the magnetostrictive body. The predetermined pressure from the pressure force exerted on the clamping device and thus on the magnetostrictive body is adjustable by means of a resilient force or mechanical setting device.

Abstract: Apparatus is disclosed for subjecting a test object to a vibration test. A preferred embodiment of the apparatus uses a flat coil assembly with an arrangement of permanent magnets. The vibrator is small and light weight. Hinge structures are disclosed which permit the vibrator to be used in conjunction with a shock testing machine or with other vibrators. This vibrator design is easily adapted for use for cross-axis testing of airbag crash sensors and for one, two or three axis screening applications.

Abstract: A vibration test fixture includes a reciprocating slip plate carrying an article subjected to vibration and shock testing. A pair of opposed, spaced apart low oil pressure hydrostatic linear bearings support the slip plate during reciprocating single-axis linear travel on the bearings. The slip plate is mounted to each bearing by a single-axis bearing guide system confining the slip plate to reciprocating longitudinal travel on generally planar, two-dimensional bearing surfaces that support the load of the slip plate. The slip plate is reciprocated by a voice coil-driven hydraulic servo valve and double-acting piston actuator integrated into the vibration table between the bearings that support the slip plate. The voice coil connects directly to a pilot valve in the servo valve assembly.

Abstract: Arrays of actuators are affixed to structural elements to impede the transmission of vibrational energy. A single pair is used to provide control of bending and extensional waves and two pairs are used to control torsional motion in addition to these two types of wave motion. The arrays are applied to a wide variety of structural elements such as a beam structure that is part of larger framework that may or may not support a rigid or non-rigid skin. Electrical excitation is applied to the actuators that generate forces on the structure. These electrical inputs may be adjusted in their amplitude and phase by a controller in communication with appropriate vibrational wave sensors to impede the flow of vibrational power in all of the above mentioned wave forms beyond the actuator location. Additional sensor elements can be used to monitor the performance and adjust the electrical inputs to maximize the attenuation of vibrational energy.

Abstract: An electromagnetic vibrating motor requires certain criteria to perform its functions. Such criteria include: achieving high amplitudes from the driven motor when compared with the relatively restricted active gap of a simple electromagnet, the amplitude of the driven member should be unaffected by weight variations or changes in resiliently constraining forces, it should have a stationary member for suspending the system without imparting substantial vibrations to the vicinity, and it should be easily connected to driven member of the system. The present invention includes three masses. The first mass is a driven mass, the second mass is an electromagnetic member and the third mass is a magnetic member. These masses are connected together through springs in order to perform its necessary functions while meeting the required criteria.

Abstract: A vibrator acting in a low frequency vibration domain, for fixing to and applying low frequency vibrations on a frame in a first predetermined direction along an axis X'X.

Abstract: An electromagnetic source or sources in a sonde in a well bore is caused to emit electromagnetic forces into the well casing. The electromagnetic forces cause displacement of the casing, inducing acoustic waves. The acoustic waves may be either P-waves or S-waves, depending on the type of electromagnetic source used. The response of earth formations to the acoustic waves, once detected, is used to detect fractures in the formations.

Abstract: A combination vibration generator and dampener having magnetic suspension and servo-control along three axes includes a hollow outer body fixed to a structure whose vibration is to be controlled, and an inner body which is essentially spherical in shape and which is inside the hollow outer body. Six active magnetic bearing elements are diametrically disposed in pairs along three orthogonal axes and serve to hold the inner spherical body inside the hollow outer body without direct contact between the inner and outer body. At least three position detectors detect the position of the inner body relative to the hollow outer body while at least one vibration detector device detects vibration forces on the structure whose vibration is to be controlled.

Abstract: A vibration control system for damping vibration of an body to be isolated against vibration. The body is supported on a movable base through the medium of vibration-damping supporting structure. The control system comprises a vibration sensor for detecting vibration of the movable base. An inverse vibration signal generating circuit includes a digital sensor and in supplied with a detection signal outputted from the vibration sensor for generating a signal with a waveform to cancel out the vibration of the body through interference therewith. An actuator is connected operatively to the movable base and the inverse vibration signal generating circuit for converting the signal derived from the latter into a mechanical vibration to be applied to the body.

Abstract: A stray magnetic field control system compensates for the generation of stray magnetic flux by the magnetic structure (body) of a load support shaker apparatus. The circuit includes a Hall effect magnetic field sensor for measuring the stray magnetic field, an amplifier/filter connected to the sensor output, and an A/D converter connected to the output of the amplifier filter. A degauss coil for compensating for the stray flux is energized by an SCR phase controlled power supply which is in turn controlled as to its triggering time by a microprocessor.

Abstract: A linkage in an electro-mechanical shaker. The linkage has link arms which have two end members coupled to a center member. The three members provide three pivoting points in an axial direction and prevent lateral movement between the relatively movable structures to which they are attached.

Abstract: The damping of vibrations in a mechanical structure is accomplished while minimizing the impact on the design and operation of the structure through the use of a plurality of attachable vibration damping elements. Each vibration damping element contains: an accelerometer, an integrator, mixer, power amplifier, and a force actuator. The accelerometer measures the motion of the vibration in the structure at its attachment point and produces an acceleration measurement signal. The integrator integrates the acceleration measurement signal to produce a velocity measurement signal. The mixer produces a composite motion signal by mixing the acceleration measurement signal with the velocity measurement signal. The power amplifier adjusts the phase and amplitude of the composite motion signal to drive the force actuator to damp the sensed vibration along one dimension at the attachment point of the force actuator.

Abstract: Apparatus and method for vibrating a specimen in multiple directions. Exciters for vibration in the X and Y orthogonal directions are coupled to shafts extending through orifices in the hollow vibrator to X and Y control plates on the inside of the vibrator in contact with the interior walls thereof to move the vibrator in X and Y directions. A Z-axis exciter is coupled to the base of the vibrator for moving it in the Z-axis direction. The orifices for the X and Y-axis exciter shafts are sufficiently large to allow Z-axis movement of the vibrator without affecting the motions of the X and Y shafts.