Abstract: A method and apparatus of driving a motor in a light scanning arrangement. The method includes the following steps: (1) driving a drive coil with a drive signal to oscillate a scan mirror and a light beam reflected from the scan mirror; (2) generating a feedback signal having zero crossings during oscillation of the scan mirror by a feedback coil in proximity to the drive coil; (3) integrating the feedback signal to generate an integrated feedback signal; and (4) processing the integrated feedback signal to generate a periodic drive signal that has the same time period as the feedback signal.

Abstract: A motor drive control unit includes a chip in which everything about a control system is provided and controls a spindle motor which rotates magnetic disks at a constant speed. When a measurement instruction is received from a disturbance generating unit and the upper-level device, sine wave disturbance is generated in the revolution speed of the spindle motor which depends on the motor drive control unit. A speed detecting unit detects the revolution speed of the spindle motor as measured data while the disturbance is being generated by the disturbance generating unit. A measured data transferring unit transfers the detected measured data detected by the speed detecting unit to the upper-level device, wherein control characteristics such as gains and phases with respect to frequencies of the motor control unit are computed.

Abstract: A system for optimizing the power to a movable valve core includes a controller for providing a control signal to the core, which is movable between first and second positions. With the core in the first position, the control signal has a hold voltage, and the controller measures a first self inductance. The control signal is provided with an inrush voltage for forcing the core from the first position to the second position, and then with the hold voltage for retaining the core in the second position. With the core in the second position, the controller measures a second self inductance, and it gradually decreases the hold voltage and measures a third self inductance representing the actual position of the core. The controller determines, by comparing one of the first and second self inductances with the third self inductance, whether the core is in the first or second position.

Abstract: A method for operating a linear compressor including a linear drive with a stator and a rotor configured for displacement by a magnetic field of the stator against a spring force, and a compression chamber which is delimited by a displaceable piston coupled to the rotor during the operation of which an alternating current is applied to the stator in order to drive the rotor in an reciprocatingly, the method including the steps of applying, prior to operation, a direct current with a first polarity to the stator in order to displace the rotor from a rest position, measuring a first end position attained by the rotor under the action of the direct current, and controlling, during operation, the intensity of the alternating current with which the stator is excited in a manner wherein the rotor does not reach the first end position or reaches it at a reduced speed.

Abstract: A power-generating illumination device for the bicycle comprises comprising at least one permanent magnet disposed onto wheel spokes so as to form a rotor, an induction coil assembly mounted onto a fork for forming a stator, such that during the rotation of the rotor, the induction coil assembly may be cut by magnetic lines of force to generate electrical energy for being outputted to a light-emitting unit, characterized in between the induction coil assembly and the light-emitting unit is provided with a control unit at least including a wave detector, a wave filter, and a current limiting resistor so that the wave detector, the wave filter, and the current limiting resistor are connected together to form a loop, thereby detecting and filtering polarity of voltage of the generated electrical energy and lowering the resonating frequency to maintain the service life and illuminative brightness.

Abstract: In a method of automatically setting the vibration suppression filter, when a vibration detection portion detects a vibration A2, a state variable frequency analysis portion analyzes the frequencies of data from a state variable trace portion to calculate a vibration frequency A3, and the frequency characteristics of the vibration suppression filter is set based on vibration frequency A5. A vibration level store portion stores the vibration level before the automatic setting of the vibration suppression filter, a filter setting selection portion compares the vibration level after the automatic setting with the vibration level before the automatic setting A6. When the vibration level after the automatic setting is larger than the vibration level before the automatic setting, restoring of the setting of the vibration suppression filter to the state before the automatic setting A7 and/or reducing the gain of a servo control portion.

Abstract: The present invention relates to an apparatus and method for controlling operation of a reciprocating compressor. The operating efficiency of the compressor can be improved by performing the steps of: detecting a current and a stroke applied a compressor; a calculating a mechanical resonance frequency by using the detected current and stroke; and determining an operating frequency command value by adding or subtracting the present operating frequency so as to be within a predetermined range of the calculated mechanical resonance frequency and then driving the compressor by the operating frequency command value.

Abstract: Disclosed herein is a power device. The power device has a power source; timing circuitry powered by the power source for producing a current pulse output having a pulse width; a switch for triggering the current pulse output produced by the timing circuitry; an armature motor powered by the power source and in electrical communication with the timing circuitry for receiving the current pulse therefrom, the armature motor comprising: an electro-magnetic core; a first winding for carrying electric current to energize a magnetic field associated with the electro-magnetic core; a second winding for carrying current to reset the magnetic field associated with the electro-magnetic core, the first and second windings wound about the electro-magnetic core; and a swinging armature for providing movement in response to the energizing of the magnetic field about electro-magnetic core. The first winding and the second winding are bifilar wound together about the electro-magnetic core.

Abstract: In a closed loop control method of a linear vibration actuator which vibrates linearly and energized by a switching element driven in a PWM control method, a crest or peak point (Bc, Bp) of the back electromotive force occurring in the linear vibration actuator is detected (S14). The detected crest or peak point (Bc, Bp) is compared with a reference value (Bcr, Bpr) (S15), and adjusting the PWM duty (?) applied to the switching element and controlling the operating frequency of the linear vibration actuator to resonant frequency (S16 to S19), thereby keeping the crest or peak point (Bc, Bp) of the back electromotive force always constant.

Abstract: Disclosed herein is a power device. The power device has a power source; timing circuitry powered by the power source for producing a current pulse output having a pulse width; a switch for triggering the current pulse output produced by the timing circuitry; an armature motor powered by the power source and in electrical communication with the timing circuitry for receiving the current pulse therefrom, the armature motor comprising: an electro-magnetic core; a first winding for carrying electric current to energize a magnetic field associated with the electro-magnetic core; a second winding for carrying current to reset the magnetic field associated with the electro-magnetic core, the first and second windings wound about the electro-magnetic core; and a swinging armature for providing movement in response to the energizing of the magnetic field about electromagnetic core. The first winding and the second winding are bifilar wound together about the electro-magnetic core.

Abstract: A method for balancing vibrations in a rotating machine is provided. The rotating machine has a first and a second plane of imbalance. The method includes determining a first set of solution mass vectors that includes a first solution mass vector for the first plane and a first solution mass vector for the second plane. Each first solution mass vector includes a mass and a phase angle. A first phase difference between a phase angle of the first solution mass vector for the first plane and a phase angle for the first solution mass vector for the second plane is calculated. The first phase difference is compared to a pre-selected value. If the first phase difference is less than the pre-selected value, the first set of solution mass vectors is retained. The first set of solution mass vectors is then incremented to create a second set of solution mass vectors that includes a second solution mass vector for the first plane and a second solution mass vector for the second plane.

Abstract: A method is for controlling a multi-phase electrical ship propulsion motor that is supplied with electric energy via a power converter. The ship propulsion motor is preferably a permanently excited motor with at least three windings. The phase currents flowing in the windings are controlled via the power converter to minimize the body noise emitted by the electrical ship propulsion motor.

Abstract: A method and apparatus for evaluating window regulators of the type having a reversible electric motor connected to a slide/carrier plate by means of cables. The apparatus comprises a first transducer such as a piezoelectric accelerometer or a laser for generating a first signal quantity related to periodic noise produced by the motor during operation thereof, a second transducer such as a piezoelectric accelerometer for producing a second signal quantity representing transient noise produced by irregularities in the slide/carrier plate assembly during travel of the carrier plate along the slide, and a processor for decoding the first and second waveforms and using data derived therefrom as a basis for identifying unacceptably noisy window regulator assemblies. The method comprises placing the window regulators on a test fixture, operating the window regulator with a simulated glass load, and generating and processing the first and second signal quantities as described above.

Abstract: An apparatus for driving a linear vibration motor that employs a proper motor thrust constant value corresponding to each linear vibration motor at position calculation for obtaining the position of the mover of the linear vibration motor, thereby increasing the accuracy of the position calculation. This motor driving apparatus includes a motor driver for applying a DC voltage to the linear vibration motor, and a thrust detection unit for detecting a thrust of the mover, which is generated by the application of the DC voltage to the linear vibration motor, and calculates the thrust constant of the linear vibration motor according to an arithmetic operation of dividing the mover thrust detected by the thrust detection unit, by a value of a DC current that is supplied to the linear vibration motor due to the application of the DC voltage to the linear vibration motor.

Abstract: A vibration generator system is capable of generating vibrations of a frequency that can be bodily sensed by humans, notwithstanding a small size, and making setting of a configuration of vibrations easy. When a drive signal composed of a set of an accumulation signal and a damping signal is given as a natural frequency of a movable body, a vibrational waveform of the movable body makes an envelope. Since a frequency of the envelope is in a lower frequency band than the natural frequency of the movable body, humans can surely sense vibrations. When the number of and a current quantity of excitation signals and reverse excitation signals included in the accumulation signal are changed and the number of and a current quantity of inhibition signals and reverse inhibition signals included in the damping signal are changed, the envelope can be changed in frequency and amplitude, so that it becomes possible to generate a variety of vibrations.

Abstract: Disclosed herein is an apparatus and method for controlling a linear compressor. The linear compressor control apparatus has a collision detection unit, a control unit, and a compressor driving unit. The collision detection unit detects a collision of a piston with a valve due to the operations of the linear compressor. The control unit determines whether the collision of the piston occurs on the basis of an output signal from the collision detection unit, and resets maximum amplitude data of the piston of the linear compressor when the collision occurs. The compressor driving unit controls the maximum amplitude of the piston of the linear compressor under the control of the control unit.

Abstract: A motor driving apparatus for driving a linear vibration motor includes an order output determining unit for determining a motor output which is required of the linear vibration motor, and a driving frequency determining unit for determining a driving frequency of the linear vibration motor based on the determined motor output. An amplitude-fixed AC voltage having a frequency which is equal to the determined driving frequency is applied to the linear vibration motor, whereby the output of the linear vibration motor can be controlled without changing the amplitude value of the driving voltage which is applied to the linear vibration motor.

Abstract: A spatial notch filter is described that adapts in accordance with changes to an angular velocity of a rotating component within a manufacturing system. In a manufacturing system, noise may appear in feedback signals due to spatially distributed physical features in the system, such as imperfections in the components or sensors. This noise may be concentrated in a frequency band that changes as the angular velocity of rotating system components changes. The invention provides techniques for filtering this noise with one or more notch filters, and for adapting the center frequency of the notch filter as a function of angular velocity. The center frequency of the notch filter tracks the noise when the noise frequency changes.

Abstract: A motor control device for a flow control device includes an opening part through which an upstream side of a fluid flow passage is in communication with a downstream side of the fluid flow passage, a valve element that controls a flow of a fluid which passes through the opening part, a motor which includes a rotor and a stator that relatively moves the valve element with respect to the opening part and a drive control section by which the motor is rotationally driven and controlled. Drive pulses are outputted from the drive control section for rotationally driving the rotor of the motor and a stop pulse is outputted from the drive control section and set to be a period width longer than that of the drive pulse for stopping the rotor of the motor at a prescribed position. The stop pulse is applied to the motor and the rotor stops at the prescribed position by a magnetic detent torque between the rotor and the stator.

Abstract: A method and apparatus for evaluating window regulators of the type having a reversible electric motor connected to a-slide/carrier plate by means of cables. The apparatus comprises a first transducer such as a piezoelectric accelerometer or a laser for generating a first signal quantity related to periodic noise produced by the motor during operation thereof, a second transducer such as a piezoelectric accelerometer for producing a second signal quantity representing transient noise produced by irregularities in the slide/carrier plate assembly during travel of the carrier plate along the slide, and a processor for decoding the first and second waveforms and using data derived therefrom as a basis for identifying unacceptably noisy window regulator assemblies. The method comprises placing the window regulators on a test fixture, operating the window regulator with a simulated glass load, and generating and processing the first and second signal quantities as described above.

Abstract: In order to quickly stop vibration of a vibrator of a vibrator controlling circuit, according to the present invention, an intermittent signal is generated by a spring vibration control integrated circuit, a switching element is turned on/off based on the intermittent signal from the spring vibration control integrated circuit, an intermittent electric current is supplied to a spring vibrator by switching of the switching circuit and the spring vibrator is vibrated. When vibration of the spring vibrator is stopped, a signal opposite to that when the spring vibrator is vibrated is applied from the spring vibration control integrated circuit to the switching element so as to cause the spring vibrator to generate a force to attenuate vibration and to stop the vibrator from vibrating.

Abstract: An antivibration apparatus for a rotary element, including an active mass vibration absorber actuated by a controller which generates a control signal by extracting harmonics of a rotation frequency of the rotary element. The controller determines a phase shift and an amplification as predetermined functions of the rotation frequency, and applies the phase shift and amplification to the harmonics of the input signal for obtaining the control signal.

Abstract: An active balance system is provided for counterbalancing vibrations of an axially reciprocating machine. The balance system includes a support member, a flexure assembly, a counterbalance mass, and a linear motor or an actuator. The support member is configured for attachment to the machine. The flexure assembly includes at least one flat spring having connections along a central portion and an outer peripheral portion. One of the central portion and the outer peripheral portion is fixedly mounted to the support member. The counterbalance mass is fixedly carried by the flexure assembly along another of the central portion and the outer peripheral portion. The linear motor has one of a stator and a mover fixedly mounted to the support member and another of the stator and the mover fixedly mounted to the counterbalance mass. The linear motor is operative to axially reciprocate the counterbalance mass. A method is also provided.

Abstract: A driving device for an oscillatory actuator in which a FLL (Frequency Locked Loop) is employed for detecting an electromotive force generated in a driving coil resulting from mechanical oscillation during a period in which no driving current is supplied to the oscillatory actuator, and for controlling an oscillation frequency on the basis of a relative time ratio between positive and negative polarities of the electromotive force to thereby pull a driving frequency into a neighborhood of a self-resonance frequency of the oscillatory actuator.

Abstract: Disclosed are a magnetic bearing device with a vibration restraining function, a magnetic bearing device with a vibration estimating function, and a pump device with the magnetic bearing devices mounted thereto, in which it is possible to realize a reduction in vibration in the apparatus system as a whole inclusive of the equipment associated with the vacuum pump without newly providing a vibration sensor. In a vibration detector, a multiplication result obtained by multiplying the Laplace transformation of a displacement of a rotor by a predetermined transfer function is added to a multiplication result obtained by multiplying the Laplace transformation of a variation in an unbalance force acting on the rotor by the reciprocal of the mass of the rotor. The result of this calculation is reversed in polarity and is added to the output of a compensator by an adder.

Abstract: Frequency translation of microelectromechanical vibration signals such as a tip vibration signal in a scanning force microscopy system expands the versatility of existing control systems and enables new signal processing techniques. The vibration signal such as the cantilever probe tip vibration signal of a scanning force microscopy is frequency converted to a lower or higher frequency signal that is utilized to provide a control signal.

Abstract: A rocking seat control apparatus for a moveable seat supported and having a magnetic member attached thereto is provided that is capable of maintaining the seat being rocked constant in rocking amplitude. The apparatus includes a solenoid for bi-directionally attracting the magnetic member to cause the seat to move in a positive and a negative direction alternately and thereby to be rocked; an amplitude measuring means for measuring an amplitude of the seat being rocked and a rocking motion of the seat; an amplitude damping factor measuring means responsive to displacements in the positive and negative directions of the seat being rocked for measuring an extent of damping factor of the amplitude caused while the seat is being rocked; and a solenoid energizing means for energizing the solenoid means during a time period in which the seat is being rock traveling a distance that is a product of the measured rocking swing and the measured extent of damping factor of amplitude.

Abstract: A controlling apparatus for controlling a linear oscillation motor includes a sensor and a controller. The motor has a movable element and a stator one of which includes an electromagnet with a winding. The sensor is configured to detect movement of the movable element. The controller is configured to intermittently supply electric power to the winding of the electromagnet to move the movable element reciprocally and linearly. The controller is configured to begin each intermittent supply of electric power to the winding at a timing before a dead center of the movable element based on an output of the sensor.

Abstract: An electrical machine includes a rotor, a stator operably coupled with the rotor, at least one phase winding operably coupled with the rotor and stator and arranged to establish flux in a magnetic circuit in the machine, and a flux observer adapted to produce a signal indicative of flux-causing voltage across the at least one phase winding. A flux control system includes a flux controller adapted to receive a flux command as an input and to provide a phase coil energization signal as an output. The system also includes an electromagnetic system adapted to receive the phase coil energization signal, the electromagnetic system including at least one phase coil, and a flux observer adapted to provide a feedback signal to the flux controller. The feedback signal corresponds to flux in the electromagnetic system, and the phase coil energization signal provided by the flux controller energizes the electromagnetic system such that flux in the electromagnetic system follows the flux command.

Abstract: A positioning device and method can position a subject of positioning at a higher speed than conventional ones. A positioning device and method for moving a subject of positioning to a desired position, moves the subject of positioning at a desired speed and acceleration, and adjusts the acceleration/deceleration duration of the subject of positioning and the timing of starting the deceleration so as to cancel the residual vibration, in accordance with the vibration period of the residual vibration that occurs immediately after positioning the subject of positioning.

Abstract: A processing machine, in particular a processing center, with a spindle, a tool clamping device, a converter unit with a spindle motor, at least one oscillation sensor and a balancing apparatus is disclosed. The oscillation sensor(s) and the balancing device are connected for signal transmission with a control device of a converter unit. The control device includes a balancing program. The processing machine with this type of automatic balancing system requires less wiring and less space than conventional systems.

Abstract: A vibration motor obtains a FAST signal when r.p.m. of the motor is faster than reference speed, whereby an output-driving circuit is controlled by the FAST signal to omit parts of the powering periods of respective phases. The motor thus controls the r.p.m. and increases torque ripple generated from the motor. As a result, vibration magnitude increases and insufficient vibration due to downsizing of the motor can be compensated by the control system.

Abstract: An electricity distribution network for a motor vehicle, the network having at least two pieces of equipment connected to a storage battery, at least one of the pieces of equipment operates in a pulse mode likely to create oscillations in the network at a resonant frequency thereof, the network includes at least one resistive element and capacitor that are associated in series and that are of resistance and capacitance determined so that the resistance of the resistive element is equal to a damping resistance for the network.

Abstract: An apparatus for controlling an electromagnetic parts feeder comprises a vibrating unit provided with an electromagnet that vibrates at a predetermined frequency, a bowl adapted to discharge parts accommodated therein by means of the vibrating unit, a driving circuit for driving the electromagnet, and a control unit for outputting a driving signal to the driving circuit to cause a predetermined driving. The control is performed by idling the driving of the electromagnet temporarily at every predetermined driving cycles thereof and controlling the vibration of the electromagnet based on a signal obtained from a coil of the electromagnet by its electromagnetic induction during the idling period, for instance, based on a phase difference between a waveform of this signal and the driving signal of the driving circuit.

Abstract: One preferred embodiment of the invention provides systems and methods for controlling a physical system by generating an input to the physical system that does not excite unwanted dynamics. Briefly described, one embodiment of the system among others, can be broadly summarized by as follows. A control entity generates a desired motion command for a physical system. A command generator then produces a shaped-smooth reference command for the physical system from the desired motion command that will cause the physical system to move in the desired motion without unwanted dynamics. Methods and other systems are also provided.

Abstract: The device for the generation of vibrations comprises an external casing provided with means of connection to a support structure and at least one mobile internal mass housed in the casing. The device is also provided with magnetic means of guidance of the mobile internal mass with respect to the casing; means of establishing the position and/or the motion of the same mobile mass with respect to the casing, and means of automatic control of the magnetic means of guidance. Furthermore, the mobile internal mass comprises at least one magnetically active element.

Abstract: A dual sided self-oscillation circuit for driving an oscillatory actuator with high efficiency and high response speed. The actuator has a winding to receive a periodical supply current from a power source and oscillates in a predetermined resonant frequency. The self-oscillation circuit includes a bandpass filter for receiving a back electromotive force voltage (Vbemf) developed across the winding and producing a sine wave output signal, a comparator for comparing the sine wave output signal with a threshold voltage and producing two drive pulses per cycle of the resonant frequency, and a switch connected in series with the winding to connect or disconnect the power source to the winding in response to the drive pulses, thereby flowing electric current in two directions at each cycle.

Abstract: An improved self-oscillation system for a linear oscillatory actuator composed of a stator and a reciprocator. The stator carries a winding to which an electric current is periodically supplied for making a resonant oscillation of the reciprocator. The system includes a self-oscillation circuit for continuing the resonant oscillation of the actuator by a positive feedback manner based upon a back electromotive force (Vbemf) appearing across the winding. The system further includes a PWM control for increasing the electric current in response to a decreasing oscillation amplitude due to an increasing load applied to the reciprocator. A detector circuit is included to monitor the oscillation amplitude of the reciprocator and provides a corresponding detector output in response to which the self-oscillation circuit provides a drive pulse of varying pulse width for making the PWM control.

Abstract: The present invention discloses a system for non-contact measurement of vibrational motion in a vibratory compacting machine. The system includes a vibrating element such as a roller drum adapted for vibrational motion and a non-contact sensor positioned a distance from the vibrating element and adapted for sensing the vibrational motion of the vibrating element. The present invention also discloses a method for non-contact measurement of vibrational motion of a vibrating element in a vibrating element that includes sensing position information of the roller drum with a non-contact sensor positioned a distance from the vibrating element and determining at least one vibration characteristic based on the position information sensed with the non-contact sensor.

Abstract: A reference pulse signal P is produced which is synchronized in frequency with a pulse signal S derived from a vibration source and has a predetermined duty ratio. Then, a control signal C is produced by providing at least one or more off intervals &agr;, &bgr; . . . at a random timing and random width predetermined for the reference pulse signal P to have the control amplitude correlated with the amplitude of the vibrations at the vibration source. This control signal C is used for controlling the switching action of the electromagnetic valve to have a desired level of pressure change in an air chamber 35 of a pneumatic vibrator which in turn develops a vibrating force on a mass member 20. The vibrations of the mass member can thus offset the vibrations of the chassis of a vehicle. Also, an electromagnetic vibrator can produce a similar control signal for eliminating the vibrations of the chassis.

Abstract: Vibrating linear actuator and method of operating same. The actuator of the invention includes a stator, a spring vibration system having a moving portion with a magnet and further having a spring configured to support the moving portion. The actuator further includes an electromagnetic coil configured to receive an electrical current, whereupon the coil moves the moving portion against a load supplied by the spring to reciprocally move the moving portion, a frequency detector configured to detect a natural frequency of the spring vibration system, and a frequency controller configured to determine a frequency of an electrical current pulse, the pulse to be received by the coil, in accordance with a detection result of the detector.

Abstract: A waveform control unit of a vibrating table comprises: an off-line compensation wave generator which generates an off-line compensation wave on the basis of the inverse characteristic of the vibrating table determined before performing an excitation and a target wave; and an on-line compensation wave generator which generates an on-line compensation wave on the basis of the inverse characteristic of the vibrating table during the excitation determined on the basis of the data of an excitation wave and a reproduced wave during the excitation and the target wave, and it switches the excitation wave to a mixed compensation wave based on the on-line compensation wave from the off-line compensation wave, during the excitation.

Abstract: A force control system for an electromagnetic actuator includes an observer that outputs signals representing the instantaneous position and velocity of a movable member, and a position controller that receives the output of the observer and signals representing a desired position and a desired velocity. The position controller compares the output of the observer with the desired position and velocity signals to generate position and velocity error signals. The position controller further generates force command signals required to position the movable member at the desired position with the desired velocity based on the position and velocity error signals. The position component may be eliminated from the force command signals, resulting in controlling only the velocity of the movable member.

Abstract: A control system for a linear vibration motor capable of eliminating necessity of a separate sensor of detecting the motion of the motor. The linear vibration motor includes a stator provided with a winding, and a vibrator provided with a permanent magnet. The winding is fed with a drive current to generate a magnetic field which interacts with the permanent magnet to cause the vibrator to reciprocate linearly relative to the stator for producing a vibration. The control system includes a controller which detects an ongoing amplitude, i.e., the motion represented by the displacement, speed, or acceleration of the vibrator and provides ON-periods of feeding the driving current to the winding in a varying amount based upon the ongoing amplitude detected in order to keep a vibration amplitude of the vibrator constant.

Abstract: A vibration control device of a vibration type motor stops motor driving when the actual driving speed, does not come close to a target speed though the frequency of a driving periodic signal is feedback-controlled to the target speed, to prevent an error when the driving circuit fails.

Abstract: A system for measuring and controlling solenoid armature position. The system determines inductive voltage in the drive winding of the solenoid, integrates that voltage to obtain flux, and uses the current/flux ratio to measure armature position. To overcome integration drift, the current/flux position measure is compared to an independent position measure, this comparison leading to a drift correction. In an embodiment maintaining a servo-controlled position, flux drift causes position drift and current drift, the latter providing an independent measure of position drift and flux drift, permitting drift correction. In a second embodiment, a high frequency component of the drive voltage (possibly from pulse width modulation) and a high frequency current measurement provide the independent measure of position.

Abstract: An active attenuation system for a DC motor which yields global vibration reduction of slot or other motor induced tonals at the plate on which the motor is mounted without modifying the construction of the motor. The system comprises one or more vibration sensors, a signal synchronized to the slot rate or other motor induced tonal rate, an electronic adaptive controller and the means to supply the control signal into the motor field and/or armature current.

Abstract: A system for controlling the movement of a movable member with respect to a stationary member, such as is found in a vibration welding apparatus. The system may include a force controller that converts desired force command signals into desired flux command signals and a flux controller that controls the flux in a magnetic core of the stationary assembly to effect the desired movement of the movable member. The stationary assembly may include a plurality of magnetically uncoupled E-cores of paramagnetic material.

Abstract: A method for driving a linear oscillating motor and a linear oscillating motor are provided. The motor includes a fixed magnetic member, a movable member having a magnet and being supported to oscillate relative to the fixed magnetic member, a detector that detects displacement of the movable member, and a control that oscillates the movable member by sending drive current to a coil of the fixed magnetic member. The method includes controlling, during a first half-period that occurs within a full amplitude period of the movable member, the drive current based upon the output of the detector. The method also includes controlling, during a second half-period that occurs within a fill amplitude period of the movable member, the drive current based upon a fixed drive current waveform.

Abstract: Disclosed are a magnetic bearing device with a vibration restraining function, a magnetic bearing device with a vibration estimating function, and a pump device with the magnetic bearing devices mounted thereto, in which it is possible to realize a reduction in vibration in the apparatus system as a whole inclusive of the equipment associated with the vacuum pump without newly providing a vibration sensor. In a vibration detector, a multiplication result obtained by multiplying the Laplace transformation of a displacement of a rotor by a predetermined transfer function is added to a multiplication result obtained by multiplying the Laplace transformation of a variation in an unbalance force acting on the rotor by the reciprocal of the mass of the rotor. The result of this calculation is reversed in polarity and is added to the output of a compensator by an adder.