Abstract: An abnormality detection apparatus for a position detection device is provided which is capable of performing abnormality detection accurately and inexpensively. The position detection device has a primary winding and a secondary winding, and at least one excitation signal each having a predetermined periodic waveform is supplied to the primary winding to thereby generate at least one output signal each in the form of a phase modulated signal corresponding to a rotational position of a rotating member from the secondary winding directly or after having been subjected to phase shifting and appropriate arithmetic operations. The apparatus is provided with an abnormality detection section for determining an abnormality of the position detection device when the phase modulated signal has a peak value which is outside a predetermined range.

Abstract: A digital signal processor for closed loop velocity or position control receives sine winding output signals and cosine winding output signal from a resolver, digitizes the signals and outputs quadrature encoded signals to an excitation circuit. The excitation circuit is connected to an excitation winding in the resolver to provide signals for driving the resolver.

Abstract: A position detecting apparatus includes: a position sensor 10 that inputs an excitation signal having a given period waveform and outputs a first amplitude modified signal induced in accordance with a detected position from a first output winding and outputs a second amplitude modified signal induced in accordance with a detected position from a second output winding; a first phase shifting circuit 23 for electrically shifting a phase of the first amplitude modified signal by a given angle; a second phase shifting circuit 24 for electrically shifting a phase of the second amplitude modified signal by a given angle; converting means 15,16 for converting the signal outputted from the first phase shifting circuit 23 and the signal outputted from the second phase shifting circuit 24 into a phase modulated signal; and calculating means 17-22 for obtaining a detected position on the basis of the phase of the phase modulated signal outputted from the converting means 15,16.

Abstract: A resolver for measuring or detecting the angular positions of a shaft is characterized by the fact that the stator (1,2) carries all windings, i.e. the exciting, winding (3) and the measurement winding (4), whereas the rotor (5) comprises a purely mechanical structure. The rotor carries at its circumference polar surfaces having different polarities that cooperate with the stator windings. The polar surfaces (6,7) are designed in such a way that they have in each angular position of the rotor a reluctance that is specific to that position. This resolver with an extremely simple design allows very precise measurements to be carried out.

Abstract: Disclosed is an electric motor system with reduced torque ripple comprising a sinusoidally magnetized permanent magnet, a sinusoidal inverter, a higher resolution position sensor, a composite iron stator yoke, a composite reinforced plastic rotor core and shaft; and a high gear ratio gear reduction box. The novel combination of magnet, inverter, sensor, plastic rotor core and shaft and high gear ratio gear box substantially reduces the torque ripple on the shaft of said motor system.

Abstract: A resolver (20, 21) is provided with redundant excitation windings in which only a single excitation winding (E1) is energized externally. Cross coupling from the externally energized winding (E1) excites the other excitation winding (E2). A control circuit (27, 28) monitors the excitation of the redundant excitation winding (E2) and switches the excitation to the redundant excitation winding (E2) in the event of a failure of the externally winding (E1).

Abstract: A non-contact linear position center has juxtaposed transmit and receive sections with a coupler or slider section interposed therebetween carrying a symmetrical attenuating conductive pattern. The inductive coupling of coils on the transmitter and receive sections is attenuated in accordance with the linear position of the pattern on the coupler. A unique sinusoidal signal is generated whose phase is indicative of the linear position of the coupler.

Abstract: An improved resolver permits the outer periphery of a ring-shaped stator and the inner periphery of a ring-shaped rotor to be directly exposed by eliminating the use of a case and a hollow rotating shaft to thereby reduce the outside diameter of the resolver as a whole. This arrangement overcomes the difficulty of reducing the outside diameter of a prior art resolver due to a case disposed to the outer periphery of a ring-shaped stator and a hollow rotating shaft disposed to the inner periphery of a ring-shaped rotor.

Abstract: An object of the present invention is to provide a motor control system comprising an R/D converter which is capable of outputting a good phase signal without being affected by the switching noise due to a PWM signal of an inverter and a motor control method. A motor control system comprising a motor 3 having a resolver 8 as a rotary sensor; an inverter 10 for driving the motor; and a control unit 11 for controlling the inverter, the control unit executing phase calculation processing based on a phase signal which is an output of the resolver converted by an R/D converter 15, calculating a voltage reference based on a current reference and a current value of the motor detected by a current sensor 12, generating a PWM signal for controlling the inverter based on the voltage reference, wherein a PWM synchronism signal 212 in synchronism with the PWM signal is generated in the control unit, and the R/D converter 15 is driven using the PWM synchronism signal.

Abstract: A resolver system and method is provided for determining the angle position of a shaft. The resolver system includes a resolver having first and second output windings and an input or reference winding spaced apart from the first and second output windings, where either the input winding or the output windings are connected to the shaft. When a drive signal is introduced into the input winding, it generates first and second output signals on the output windings representing the angle position of the shaft. The resolver system of the present invention further includes a processor connected to the output windings for receiving the first and second data signals from the resolver and determining the angle position of the shaft. For generating the drive signal, the resolver system further includes a drive circuit connected to the input winding of the resolver. The drive circuit generates a pulsed drive signal for input into the resolver.

Abstract: A position sensor, such as a rotary position sensor, includes the signal-conditioning electronics in the housing. The signal-conditioning electronics are disposed on a printed wiring board, which is assembled with another printed wiring board including the sensor windings to provide a sub-assembly. A mu-metal shield is interposed between the printed wiring boards to prevent magnetic interference. The sub-assembly is disposed in the sensor housing adjacent to an inductor board which turns on a shaft. The inductor board emanates an internally or externally generated excitation signal that induces a signal in the sensor windings. The induced signal represents the rotary position of the inductor board relative to the sensor winding board.

Abstract: An image detecting apparatus comprises a rotating disk having pinholes that allow light to pass through, a photosensor for detecting the rotation of the disk, a CCD camera for capturing a confocal image of a specimen passed through the pinholes of the disk, a brushless DC motor for rotating the disk at a given speed, and an FPGA which produces a pulse-like brake signal having two levels for accelerating and decelerating the disk and its pulse width set variable and outputs it to the DC motor, thereby allowing the synchronization of the rotation of the disk with the image capture timing of the CCD camera.

Abstract: An encoder comprises position detecting device for detecting a magnetic pole position and a rotational position of a motor. The encoder also includes a memory portion for storing parameter information particular to the motor or the position detecting device. A transmitting portion of the encoder is provided for externally transmitting parameter information particular to the position detecting device as a differential signal. A transmission suspension request detecting device is provided for detecting that the differential signal is driven by a given signal externally provided such that the differential signal does not exist as a transmission signal and for generating a transmission suspension request signal requesting suspension of transmission of the differential signal.

Abstract: The present invention provides a capacitive resolver (100). The capacitive resolver (100) includes a charge plate (102), a sensing plate (106), and an interrupter plate (400) positioned between the charge plate (102) and the sensing plate (106). The front surface of the sensing plate (500) has a sinusoidal pattern (502). The back surface of the sensing plate (600) includes charge detectors (602), charge collectors (608), and rectifiers (618). The capacitive resolver (100) also includes a signal generator (110) which is electrically connected to the charge plate (102) and a signal analyzer which is electrically connected to the sensing plate (106). The capacitive resolver (100) may additionally include a non-conductive support (112).

Abstract: An electrical machine with a discoidal structure comprising rotor and stator discs disposed coaxially and having at least two axial air gaps between the rotor and stator discs. The widths of the axial air gaps are measured and sent to a control unit for being compared so that an offset signal can be generated based on the difference between the widths of the axial air gaps. The offset signal is supplied to a drive module for driving a balancing means in order to cancel an axial magnetic force exerted on either the rotor or stator discs. The deterioration of the electrical machine can be reduced.

Abstract: A method and an apparatus for driving a stepping motor is provided. Digital desired current values are stored in the form of a sine table and are read from the sine table at a constant sampling frequency. The intervals between the read-out table values can be varied equally and unequally. The digital desired current values are converted into discrete analog signals. A sinusoidal signal is reconstructed from the analog signals. A motor current for exciting a phase of the stepping motor is derived from the sinusoidal signal.

Abstract: In a rotation sensor having a resolver attached to a rotor and a signal processing unit for angle detection for supplying a reference signal having a predetermined periodic waveform to the resolver, allowing the resolver to generate a sin signal having a waveform obtained by amplitude-modulating the reference signal by sin &thgr; and a cos signal having a waveform obtained by amplitude-modulating the reference signal by cos &thgr;, and detecting the angle &thgr; on the basis of the sin signal and cos signal, there are provided a signal processing unit for rotation detection for outputting a rotation pulse signal and a reference position signal on the basis of the angle &thgr; and a signal process abnormality detecting unit for detecting the presence or absence of an abnormality in the signal processing unit for angle detection on the basis of the angle &thgr; and an angle &thgr;′ calculated from both of the rotation pulse signal and the reference position signal of the signal processing unit for rotatio

Abstract: A controller for a system has two or more operating modes. The controller operates according to a different control algorithm in each operating mode. A manually operable switch typically used for sending a reset signal to the controller, may also be used to change operating modes. The controller changes operating mode when it detects that the switch is manually operated during a preselected phase of controller operation, typically when power is first applied. The disclosed embodiment allows up to four different operating modes to be selected. A first selection of operating modes can occurs if the switch is held closed during startup and then immediately released. A second selection of operating mode occurs if the switch is pressed within a preselected time interval after power is first applied to the controller. Both selections can be made during a single start-up event.

Abstract: In a VR-type resolver which is used in combination with a motor to detect the rotation position of the motor, the teeth number of a rotor of the resolver is reduced over the teeth number of a rotor of the motor. Also, the shape of the teeth of the resolver rotor is simplified into a curved shape such as a sine wave shape. Further, in another type of VR-type resolver, the number of the magnetic poles of the stator with respect to the number of the teeth of the rotor is set as a number being capable of satisfying not only the condition that it is a multiple of the phase number N and an even number but also the condition that it is a number which can be calculated according to one of the following expressions (1) and (2), that is,stator pole number=rotor teeth number/(M+1/N) (1)stator pole number=rotor teeth number/{M+(N-1)/N} (2),where M is an integral number of one of 1, 2, and 3.

Abstract: For regulating drives, process information is transmitted from a measuring device to a regulating device. In addition to position-measurement signals, acceleration-measurement signals are also transmitted. The acceleration-measurement signals are used as reference signals for position-measurement signals. As a result, no additional connecting leads are required for the additional transmission of acceleration-measurement signals.

Abstract: A control circuit and method for controlling a switched reluctance motor are provided. The control circuit includes a tone wheel and a Hall effect sensor for generating a position feedback signal indicative of the position of the motor. The control circuit also includes a sensing resistor for generating a current feedback signal indicative of a level of current in a phase coil of the motor. Finally, the control circuit includes first and second switches connected to opposite ends of the phase coil for controlling the level of current in the phase coil responsive to the position feedback signal and the current feedback signal.

Abstract: A resolver (10) is excited with a high frequency signal from excitation circuit (16). Outputs of the resolver (10) are transmitted through receiver circuit (24) and input to a DSP signal processing circuit (18), which demodulates the sine and cosine outputs to provide samples of the sine and cosine of the rotor position. The sample values are converted to digital values, which are used to calculate a shaft angular position, which is then used for closed loop position and velocity control of a brushless PM motor (14).

Abstract: The known arrangements have at least one rotor coil (RS) arranged on the rotor and at least one stator coil (SS) arranged on the stator. The rotor coil (RS) and the stator coil (SS) respectively have at least one winding (WI) and there is a magnetic coupling between the rotor coil (RS) and the stator coil (SS). With an arrangement of this sort, it is possible for example to transmit measurement signals of a measurement pickup (MA) arranged on the rotor (RO) for the contactless measurement of torques. The additional acquisition of the respective angular position and/or of the respective angular speed (.omega.

Abstract: A rotary resolver having a stator housing with electromagnetic coils and a permanent magnetic rotor rotatable therein is improved to provide a resolver system with more precise angular rotor position readings. Interacting system features include a ring of soft magnetic material interposed between north and south magnetic pole structure on the rotor, which is enhanced in performance by a particular one of the soft magnetic materials RSi 24, RNi 8 and RNi 5. Adjustable compensation coil structure in the stator housing interacting with the rotor flux pattern obtains more precise angular readings in different working locations. A digital control system dynamically processes flux compensation information. Resolver units may be positioned at an end of a rotating shaft in a working position for detecting the angular rotation position of the shaft.

Abstract: A method and apparatus for detecting an aberrant velocity of a motor used to drive an element in a plastics processing machine, such as an injection molding machine, for example. The velocity of the motor is detected by a first sensor and a machine parameter associated with the machine operation is provided. A velocity limit is determined based upon the machine parameter and an error signal is generated when the motor velocity exceeds the velocity limit by more than a predetermined tolerance value. Preferably, the machine parameter comprises the position of the element driven by the motor, which is sensed by a sensor, such as a linear displacement transducer. The velocity limit can be based upon this measured element position as well as data entered for the particular machine, such as a minimum element position, a maximum element position, and a maximum motor velocity, such that a desired motor operating envelope is defined.

Abstract: A slip controlled induction motor using a variable frequency feedback transducer comprises a motor stator, a motor rotor and a variable frequency feedback transducer (VFFT). The VFFT includes an input winding transformer coupled to an output winding by a VFFT rotor. The VFFT rotor is operably connected to the motor rotor so as to rotate with the motor rotor at the same angular velocity. The input winding is excited with an input AC voltage of predetermine frequency. The transformer coupling combines the predetermined frequency AC input with the signal produced by the VFFT rotor to produce a variable frequency signal in the output winding which is fed as an input to the motor stator. Since the stator input is tied to the motor rotor angular velocity, the stator input will always have a constant absolute frequency difference with the motor rotor.

Abstract: A resonance circuit includes a capacitor, a coil element and a primary coil of a transformer. A connection between the resonance circuit and a vehicle-mounted battery is connected and disconnected by a switching transistor at a predetermined duty cycle. Output voltage of a secondary coil of the transformer is supplied to an exciting winding of a resolver.

Abstract: The present invention provides for a press feed apparatus for use in feeding stock material to a high speed automatic press. The feed roller is driven by a servo motor integral with the shaft of the roller, the feed roller release mechanism is infinitely adjustable, and a feedback system is used to accurately determine the position of various shafts. The apparatus is controlled electronically, by a microprocessor or the like, which permits the press feed to be electronically geared to the press and accurately operate at high speeds.

Abstract: A method of controlling a rotary magnet multi-phase synchronous motor and a control system based on this method increases the permissible range of accuracy in installing a position detector on the synchronous motor and automatically calculates a phase correction to improve controllability. Using a position detector for detecting a magnet position of a rotary magnet multi-phase synchronous motor and a drive unit, the synchronous motor having the position detector is driven by a drive unit. After the synchronous motor reaches a constant speed, current and drive voltage of the synchronous motor are measured to calculate a phase correction value between a biaxial coordinate axis based upon the installation error of the position detector and a biaxial coordinate system from conversion of a polyphase AC coordinate system based on the measured current and drive voltage, constants of the synchronous motor, and the constant speed.

Abstract: The period Tn needed to count a lowermost bit of a signal of which an absolute value of difference between a last real data .theta.(k) and a present real data .theta.(k+1) is assumed to be quantized in a data block period To is obtained. One digital quantity is successively accumulated on the present real data .theta.(k+1) every period Tn to obtain interpolation data C, D . . . . At the point t1 a final interpolation data G is adapted to be added or subtracted, the total of added or subtracted digital quantity exceeds the absolute value of difference. Accordingly, a final interpolation data G is held until a next real data .theta.(k+2) is output.

Abstract: A stator wound resolver comprising: a stator and a rotor aligned on an axis; the stator having a plurality of teeth with input and output windings disposed on some or all of the teeth, the input and output windings exhibiting a mutual inductance characteristic that varies as a function of position of the rotor about the axis; the input winding being connectable to a drive signal and the output windings being disposed on the teeth such that output signals induced in the output windings correspond to position of the rotor; the rotor being attachable to a position changing means, the rotor comprising at least two axially spaced rotor pieces that are offset from each other by a stagger angle such that a portion of harmonic distortion produced by one of the rotor pieces is reduced by complementary harmonic distortion produced by another of the rotor pieces.

Abstract: Excitation signals having a phase difference of 120.degree. are generated based on a count of a ring counter and they are supplied to a phase detection type resolver. An output of the resolver is compared with zero level by a comparator to generate uncorrected position data .theta..sub.F which is supplied to a digital delay circuit to delay it in accordance with a position correction value .DELTA..theta. from a position correction ROM to generate corrected position data .theta..sub.B. The corrected position data is supplied to a latch circuit which latches a count of a ring counter and a velocity detection circuit to produce resolver position data .theta..sub.P and velocity data .DELTA.T, which are added and the sum is supplied to the position correction ROM as address data. The velocity data .DELTA.T is converted to a pulse by a pulse generator and it is accumulated by an accumulation counter to detect a position of a moving part.

Abstract: Two A.C. output signals amplitude-modulated in accordance with two function values (sine and cosine) differing from each other in correspondence to a position-to-be-detected are received from a position sensor such as a resolver. By performing an addition or subtraction between a signal derived by shifting the electric phase of one of the received A.C. output signals by a predetermined angle, and the other received signal, two electric A.C. signals (sin(.omega.t .+-.d.+-..theta.), sin(.omega.t.+-.d-.theta.)) are electrically synthesized which have electric phase angles (.theta.) corresponding to the position-to-be-detected and are phase-shifted in opposite directions. ".+-.d" here represents phase variation error caused by factors, other than the position-to-be-detected, such as temperature change. In the synthesized two signals, the phase variation errors (.+-.d) appear in the same direction, while the phase differences (.theta.

Abstract: A pulse excitation circuit applies a constant voltage to windings, each of which is wound around a respective one of four magnetic poles of a resolver stator. In each of the respective windings, a voltage is generated corresponding to the rotation of the resolver rotor. From the generated voltage, it is possible to detect two flows of electrical currents which have different phases from each other. Values of the electrical currents after a lapse of time 2*Lav/r from the start of pulse excitation (Lay is an average inductance of the windings, while r is a DC resistance of a winding, including an electrical current detection resistance) are converted into two digital values. A micro computer calculates a rotation angle signal .theta. on the basis of the two digital values.

Abstract: A software-based resolver-to-digital converter (RDC) (80) for computing an angle of rotation .THETA. of gimbal-mounted instrumentation (16) in a gimbal system. The RDC (80) computes the angle of rotation of the instrumentation using parameter signals received from a resolver (32) in the system. The parameter signals, along with a resolver reference signal are input into a multiplexor (60) and are multiplexed. The signals are then fed to an analog to digital converter (38) and converted to digital form. The digital signals are then input into a processor (36) associated with the system. This processor, in addition to performing numerous system computations, is programmed through appropriate software to filter the digital signals received, compute the value for the angle of rotation .THETA. and output the computed value to system circuitry (31) for processing to enhance system operation.

Abstract: An electrical drive system for angular positioning of one or several rotating and/or tilting machine components and equipment components, particularly of printing machines, including at least one electric motor having a rotor designed for rigid and direct coupling to the component, further including by one or several angle encoders for registering the angular motion of the rotor of the electric motor and/or the component, a signal processing module which receives the actual angle position signals from the angle encoder or encoders and which also receives the setpoint data for comparison with the actual data, and a power amplifier controlled by the signal processor and used for driving the electric motor.

Abstract: A resolver rate sensor is disclosed in which dual brushless resolvers are mechanically coupled to the same output shaft. Diverse inputs are provided to each resolver by providing the first resolver with a DC input and the second resolver with an AC sinusoidal input. A trigonometric identity in which the sum of the squares of the sin and cosine components equal one is used to advantage in providing a sensor of increased accuracy. The first resolver may have a fixed or variable DC input to permit dynamic adjustment of resolver sensitivity thus permitting a wide range of coverage. In one embodiment of the invention the outputs of the first resolver are directly inputted into two separate multipliers and the outputs of the second resolver are inputted into the two separate multipliers, after being demodulated in a pair of demodulator circuits. The multiplied signals are then added in an adder circuit to provide a directional sensitive output.

Abstract: An apparatus for detecting and controlling the rotational position of a motor without using a high-priced component and without requiring special software processing. The apparatus includes a motor rotation control section for selectively connecting a power source to the motor to rotate the motor into a predetermined position, a potentiometer mechanically linked to a shaft of the motor to read the absolute rotational position of the motor, an astable multivibrator for generating output pulses having a duty ratio corresponding to the position read by the potentiometer, and a control signal generation section for supplying a control signal corresponding to the duty ratio of the output pulses to the motor rotation control section to control the rotational position of the motor.

Abstract: An encoder for indicating a position of a movable member and for generating at least two signals which are offset in phase from one another in accordance with movement of the movable member. The encoder includes a position detector and a presettable counter. The position detector generates a position reference signal indicating at least one reference position during movement of the movable member, and the presettable counter is preset for an absolute position of the encoder during movement of the movable member when the position reference signal is generated. The encoder can be constructed in a small size enabling use in servo systems and in industrial robots.

Abstract: A binary locally-initializing incremental position encoder (112) for determining the position of an object, i.e. a robot arm (102). The inventive position encoder (112) is adapted to be coupled to the object (102) and includes first, second, third and fourth gears (129, 130, 131 and 132, respectively). The gears are such that the positions thereof, representing the positions or states of the object, repeat at binary intervals. That is, the first gear (129) has a first number of teeth N.sub.1 and the second gear (130) has a second number of teeth N.sub.2. The second gear (130) is driven by the first gear (129) from a first position to a second position. The third gear (131) is mechanically coupled to and coaxial with the second gear (130). The third gear (131) has a third number of teeth N.sub.3 and is adapted for rotation in direct angular proportion to any rotation of the second gear (130). The fourth gear (132) has a fourth number of teeth N.sub.4 and is driven by the third gear (131).

Abstract: An angle of rotation detector has a drive unit which supplies 90 degree phase shifted signals to a pair of stator coils and measures an analog output from a rotor coil in a resolver. A calculating device calculates the rotational angle of the resolver using the output of an analog to digital converter receiving the analog output of the rotor. In one embodiment, the calculating device performs a Fourier transform to compute the phase of a fixed frequency component contained in the output of the rotor coil. In another embodiment, the drive unit supplies signals wherein f(T/2+t)=-f(t) and the calculating device performs a Fourier transform using data from successive half periods of the drive waveform. In another embodiment, the output of the rotor is sampled at 1/4 period of an excitation signal from the drive unit and the calculating device determines the phase difference between the excitation signal and the rotor output.

Abstract: A multiphase converter circuit generates a plurality of sinusoidal outputs of displaced phase and given speed value from the output of an angular resolver system attachable to a motor excited by these multi-phase outputs, the resolver system having a lower speed value than that of the motor. The angular resolver system provides in parallel format sequential digital numbers indicative of the amount of rotation of the shaft of an angular position sensor associated with the angular resolver system. These numbers are used to excite simultaneously identical addresses of a plurality of addressable memory systems, each memory system having stored therein at sequential addresses sequential values of a sinusoidal wavetrain of a given number of sinusoids. The stored wavetrain values represent sinusoids displaced from each other in phase according to the number of output phases desired.

Abstract: A media transport system for controlling the position and velocity of media in a document production apparatus marking engine having a media positioning system driven by a motor, includes a motion control loop to control the motor; a sensor adapted to detect the position of the media and to create a trigonometric signal characteristic of the position of the media, the trigonometric signal comprising frequency and phase components; a resolver electronics subsystem adapted to trigonometrically process the trigonometric signal to create a resolved signal; and means for comparing the resolved signal to a reference clock signal of predetermined frequency and phase to provide an error signal used to control the motor that drives the media positioning system. The trigonometric signal may include a sine portion and a cosine portion. The sine portion of the trigonometric signal is sin(.omega..sub.e *t+.phi..sub.e) and the cosine portion of the trigonometric signal is cos(.omega..sub.e *t+.phi..sub.e); where .omega..

Abstract: A rotary sensing device for indicating the angular displacement of a shaft is disclosed which comprises a magnetic core member formed of ferromagnetic material, a first winding wound within the core member for producing a first magnetic field in a closed path throughout the core, a second winding wound around the core member for producing a second magnetic field in a closed path throughout the core, the first and second magnetic fields being orthogonal to each other, and a pick-up coil assembly associated with the magnetic core member, the magnetic fields, and the shaft for sensing angular displacement of the shaft. A proximity sensor for sensing the passage of an object and the direction of passage of the object is also disclosed.

Abstract: Positioning errors of a moveable machine member are reduced by compensation for cyclic errors attributable to anomalies of a position transducer. Compensation values are produced which are unique only within the pitch of transducer measurement and are applied to correct the representation of measured position produced by the transducer. Positioning errors not attributable to the position transducer are corrected by compensation of position commands using compensation values associated with fixed calibration points. Use of both compensations is effective to eliminate residual errors in position correction which arise from use of calibration data created without correction of transducer cyclic errors.

Abstract: According to the present invention, multiple output signals of rotary displacement sensors are processed to detect a displacement different from a radial displacement in a moving direction. This results in a reduced number of displacement sensors. The present invention is a multi-displacement detecting apparatus, comprising: a moving section whose surface is continuously irregular in the moving direction; a stationary section including a plurality of sensors each outputting a signal that contains an output component whose level is proportional to a sine-wave value of a displacement in the moving direction and has an amplitude modulated in proportion to a variation in the gap from the irregular surface; and an arithmetic logic means for inputting the output signals of a plurality of sensors and outputting a displacement in the moving direction and other at least another displacement of the moving section.

Abstract: A position measurement system includes position error circuitry (PEC) that responds to periodically provided actual position information and a computed position to provide correction information, and a position synthesizer which responds to the correction information to provide the computed position. The computed position information is fed back to the PEC. The position synthesizer establishes a rate of change of the computed position based on the correction information in a manner tending to make the computed position track the actual position. The position synthesizer updates the computed position many times for each time that the actual position information is provided to the PEC, and thus provides much more continuous position information.

Abstract: The present invention relates to a resolver excitation signal generating apparatus for supplying a reference excitation signal to a resolver attached to a motor for driving a robot or a computer numerical control machine. When a sine-wave signal is transferred from a signal generator to the resolver, the signal is filtered by a low pass filter, amplified up to the rated voltage by means of a line driver and supplied to the resolver, thereby allowing the position of the motor to be controlled exactly.

Abstract: A motor control apparatus for rotating a motor smoothly. A sine wave form which is an ideal wave form of a signal is stored, and the motor is driven by a signal having the ideal wave form obtained by correcting the period and the phase of the stored sine wave form. A comparator receives a detection signal which indicates the rotating state of the motor through an A/D converter, and obtains the correction values of the current period and phase. A wave form setting means corrects the set period and phase, generates a sine wave having the corrected period and phase on the basis of the sine wave data stored in a sine wave data region, and outputs a driving signal having the sine wave form through a D/A converter.

Abstract: A software-based resolver-to-digital converter (RDC) (80) for computing an angle of rotation &THgr; of gimbal-mounted instrumentation (16) in a gimbal system. The RDC (80) computes the angle of rotation of the instrumentation using parameter signals received from a resolver (32) in the system. The parameter signals, along with a resolver reference signal are input into a multiplexor (60) and are multiplexed. The signals are then fed to an analog to digital converter (38) and converted to digital form. The digital signals are then input into a processor (36) associated with the system. This processor, in addition to performing numerous system computations, is programmed through appropriate software to filter the digital signals received, compute the value for the angle of rotation &THgr; and output the computed value to system circuitry (31) for processing to enhance system operation.