Abstract: Disclosed is a method for suppressing a speed ripple occurring during an operation of an AC motor by using a torque compensator based on an activation function. The method includes the steps of calculating a speed error ?err based on a reference speed ?ref and an actual speed ?act; calculating a controller output Trm by using the speed error ?err as an input of a PI control and an operation of a compensated torque Tcom; and determining a torque variation based on the controller output Trm and a reference torque Tref and operating the torque variation in relation to an anti-windup gain Ka to use torque variation as an input of an integral (I) control. The method suppresses the speed ripple by compensating for the torque ripple through a controller which calculates the compensated torque by taking the signs of the speed error and the differential speed error into consideration.

Abstract: The present invention discloses a brushless dc motor driver circuit capable of reducing vibration or shock noise and a method thereof. The brushless dc motor driver circuit of the present invention comprises a Time-Voltage Digital/Analog Converter. The Time-Voltage Digital/Analog Converter further comprises: at least one magnetic field detecting circuit, at least one counter, and a signal processor. The Time-Voltage Digital/Analog Converter is connected to a driver circuit of a brushless dc motor and detects the periodically varying magnetic field of the brushless dc motor. Based on the rising time and the falling time of the preceding magnetic field variation, the Time-Voltage Digital/Analog Converter calculates the elapsed time from the current phase-change point and generates a linearly rising signal and a linearly falling signal. Then, those two sets of analog signals are used to drive the brushless dc motor. Thereby, the vibration or shock noise of the brushless dc motor is reduced.

Abstract: Systems and methods are provided through which the current to a spindle motor of the recording medium of a mass storage device is modulated to avoid anomalies in the operation of mass storage device and reduce power consumption. In the example of a disc drive, the current is modulated to prevent expected or predicted disturbances in the air bearing between a read/write head and the recording medium, and to reduce the power consumption when no disturbances are predicted or expected.

Abstract: A method of reducing torque ripple and noise for an brushless DC machine comprising: determining a control frequency for the electric machine, the control frequency indicative of an existing current command to and a rotational velocity of the electric machine; multiplying the control frequency by a selected multiple and forming a modulating signal responsive thereto; and formulating a modified command profile. The method also includes: correlating and synchronizing the modified command profile with the existing current command and a rotor position for the electric machine; and generating a modulated current command to the electric machine.

Abstract: A switched reluctance drive is supplied from a voltage source which varies from the voltage at which the control laws for the drive were determined. The control system compensates for this by modifying both the speed and torque values used to determine the correct firing angles for the demanded load. The system works over a very wide range of voltage variation and is independent of the shape of the torque/speed curve of the drive.

Abstract: High resolution and accuracy of the measured values for detection of the position, speed and/or acceleration of a drive is ensured. The tolerances are determined and considered in signal evaluation on a partitioned basis. Measurement errors caused by inaccuracies of the signal generator due to manufacturing difficulties are greatly reduced or eliminated such that use of signal generators without particularly high quality specifications is possible. Thus, use of less exact components in generation and detection is possible.

Abstract: A linear vibration motor which includes a vibration system, an electromagnetic driver, a detection system, and a control system. The vibration system includes a driven member or reciprocator which is mounted to a magnetic member for reciprocating movement. The amplitude of the reciprocating movement varies as an inverse function of load on the motor. The electromagnetic driver includes a coil and drives the vibration system by applying an electromagnetic force to the magnetic member, the electromagnetic force being produced by a driving current flowing through the coil. The detection system detects at least one characteristic of the vibration system that is related to a characteristic frequency of the vibration system, and produces a feedback signal indicative of a value of the at least one characteristic.

Abstract: A time-compensated overcurrent detection circuit shuts off a D.C. motor during large overcurrent conditions caused by actual constraints on the motor. The circuit prevents premature motor shut off by establishing a minimum activation time for shutting off the D.C. motor. An overcurrent time compensator establishes a minimum time period for activating a motor reset signal after sensing an overcurrent condition. The circuitry uses a relatively small capacitor that provides quick response to overcurrent conditions.

Abstract: A motor speed control apparatus is provided in which the controllable frequency band of the control system can be sufficiently enhanced with a comparatively simple structure even if the frequency generator equipped into the motor is low in output frequency and the rotational accuracy can be highly improved even if the disturbance of high frequency components of load torque is applied to the motor. The frequency band of the control system can be improved by using the estimated speed signal as the speed feedback signal. A motor speed control apparatus superior in disturbance control characteristic can be realized through the feed forward compensation of an estimated load torque.

Abstract: The present invention employs digital circuitry to compensate for variations in DC link voltage transmitted to a switched reluctance machine. The digital voltage compensation system of the present invention periodically samples the DC link voltage and actual rotor speed, then supplies the samples in digital form to a microcontroller that derives a compensated speed signal to compensate for changes in DC link voltage.

Abstract: A speed control for controlling the speed of a DC motor provides improved speed regulation during transient loading conditions. The control includes a regulating circuit having an output for controlling the armature voltage to the motor, An input speed reference signal corresponding to the desired speed is provided to the regulating circuit. A feedback signal proportional to armature voltage is also provided to the regulating circuit to establish an error signal for operating the control to regulate the voltage to the motor and therefore the motor speed, An IR compensating circuit provides increased motor voltage when the load increases. The voltage drop due to the armature circuit inductance is measured directly and also utilized to alter the output of the regulator to compensate for the inductive voltage drop occurring under transient loading conditions in a manner tending to establish the speed at the desired speed corresponding to the speed reference signal, during such conditions.

Abstract: A speed control circuit for a DC motor includes a digital-to-analog (D/A) converter, a regulator/controller, and a control circuit which applies a compensating current to the DC motor that compensates for variations in loading applied to the motor. The regulator/controller compares a reference voltage provided by the D/A converter with a feedback signal provided by the motor to generate a signal to activate the control circuit, thus to supply a compensating current to the motor.

Abstract: A position controller includes: a compensation torque control circuit which outputs a second torque signal T.sub.2 * and an initial value of an integration torque T.sub.iset on the basis of a real speed signal .omega..sub.M, a rotation angle instruction signal .theta..sub.M *, a real rotation angle signal .theta..sub.M, an integration torque signal T.sub.i of a speed control circuit, and a reference .theta..sub.drp *; a speed control circuit which outputs a first torque signal T.sub.1 * and the integration output T.sub.i on the basis of a speed instruction signal .omega..sub.M * and the real speed signal .omega..sub.M ; an adder which adds the first torque signal T.sub.1 * to the second torque signal T.sub.2 * and outputs a torque instruction signal; and a torque control circuit which controls the torque of the motor in accordance with the torque instruction signal.

Abstract: A speed controller includes a drive source, an input device for inputting the driving speed information of the drive source, a driver for driving the drive source on the basis of the driving speed information input by the input device, a detector for linearly detecting the amount of movement of the drive source an output device for outputting movement amount information obtained by the detector, and a corrector for correcting the driving speed information by the use of the movement amount information obtained by the detector, the corrector imparting new driving speed information as the corrected value to the driver.

Abstract: A method for thermal modeling and updating of bias errors in inertial navigation instrument outputs relies upon piecewise cubic spline encoding of data. The temperature range of the thermal model is divided into contiguous intervals of equal length. Instrument bias-versus-temperature data is encoded on an interval-by-interval basis with all intervals normalized so that cubic polynomials of identical form may be fitted between boundary intervals defined by function values and slopes. Instrument bias error at a measured temperature is estimated in the field and an update point (bias, temperature) established. The particular interval is located and the thermal model is re-fit accordingly in the region of the relevant interval. The spline parameters are then adjusted to accommodate the estimated bias error thereby updating the instrument thermal model of bias.

Abstract: A method for controlling the speed of a motor for a tape drive in a mailing machine includes providing an optical sensor for signaling the appearance of slots in a slotted wheel connected to the motor shaft. The time intervals between slots are used to make a prediction in respect of expected future time intervals and the motor speed is adjusted in accordance with the predicted value to obtain the desired value. For best results, the data is received at the microprocessor using the "capture" mode of operation in order to avoid excessive errors due to a "busy" processor. The invention enables the small motor of a tape drive to avoid over and undershoot even when operating under highly variable load conditions.

Abstract: A speed estimation observer for a motor control system outputs a motor speed estimate in a motor speed control system upon receiving a torque command and an averaged motor speed value. The speed estimation observer includes a time lag correction value calculating block for implementing a correction of a model output speed estimate. Therefore, the accuracy and stability of the speed estimation are improved, and the control system keeps the stability in a speed range of low to high speed and ensures the disturbance suppressing effect in a high speed range.

Abstract: An electric motor control system compensates torque ripples to control the rotation of an electric motor more accurately. Compensated current amplitudes corresponding to the torques, speeds and rotational positions in the electric motor are stored in a memory 61. Address setting unit 91 prepares a read address AD.sub.1 in the memory 61 from the torque command T, speed information VL and rotational motor position P. The prepared read address AD.sub.1 is then used to read a torque error compensation data MD.sub.1 from the memory 61. An adder 12 adds the torque error compensation data MD.sub.1 thus prepared to the torque command T to determine current amplitudes AM in the electric motor. Three-phase current setting unit 10 sets three-phase AC current commands CU, CV and CW based on the current amplitudes AM and rotational motor position P. Thus, the rotation of the electric motor can be accurately controlled.

Abstract: A predictor (20) and a learning device (20) are newly provided to a conventional speed controlling system for a rotating body, according to the present invention. The predictor predicts an instantaneous speed error on the basis of a plurality of speed errors to enable elimination of a phase delay due to sampling. The learning device is effective to remove torque ripple components of a motor on the basis of the speed errors. As a result, it is possible to expand a speed controlling region of the motor and to decrease irregularlity in rotation of the motor to a great extent. The predictor solely makes it possible to obtain a present accurate rate of change of data previously sampled from a plurality of sampled data, whereby a phase delay due to digital processes may be prevented.

Abstract: Disclosed is a speed controller of a motor which comprises a rotation sensor for generating an A.C. signal having a period in accordance with a rotating speed of a motor; speed detection device for effecting detection operations a plurality of times per round of the motor by the A.C.

Abstract: A motor control for a treadmill has an improved, inexpensive, and simple set of power supplies, derived from the bus voltages of the DC busses with simple voltage dividers, to supply operational amplifiers connected to the positive DC voltage bus with a dual voltage supply and a common or neutral, and to provide a single voltage power supply connected to the negative bus for the driving circuitry of a motor energization switching controlling element. The dual power supply for the operational amplifiers comprises a voltage divider containing two, series connected zener diodes in series with a resistor. The one of the series connected zener diodes is connected to the positive DC voltage bus, and the resistor is connected to the negative DC voltage bus. A common connection between the two zener diodes becomes the neutral or common voltage for the operational amplifiers, and the zener diode voltages become the positive and negative supply voltages for the amplifiers.

Abstract: A control for energizing a DC motor to provide improved speed regulation to the motor under transient conditions. The control includes a regulating circuit having an output signal controlling the armature voltage applied to the motor. An input speed reference signal corresponding to the desired speed of said motor is provided to the regulating circuit. An input armature voltage feedback signal is also provided to the regulating circuit to produce an error signal for operating said regulating circuit to establish the armature voltage, and hence the speed of said motor. The armature current of the motor is sensed and a signal corresponding to the voltage drop resulting from the inductance of the armature circuit provided to the regulating circuit for altering the output of the regulating circuit in a manner tending to establish the speed of said motor at that established by said speed reference signal. An IR compensating circuit provides an IR compensating signal to the regulating circuit.

Abstract: A servomotor control device including a drive pulse generating circuit for generating a pulse signal having a frequency corresponding to an actual frequency of a servomotor, and arithmetic operation unit for outputting a control signal on the basis of the pulse signal for control of the servomotor. The arithmetic operation unit generates the control signal by implementing an extrapolation correction on the basis of preestimated variation of a frequency of the servomotor due to a time delay between a moment when the pulse signal is generated and a moment when the control signal is applied to the servomotor.

Abstract: For operating a plurality of mechanisms with a single motor, a motor control device is provided which is capable of stably operating one of the mechanisms while reducing influence of load imparted on the motor and attributed by an operation of remaining one of the mechanisms. A CPU suitably controls or selects electrical current level provisionally ranked and stored in a ROM to a printing motor which drives a print hammer for obtaining predetermined velocity of the hammer. If the print hammer reaches its decelerating position, the CPU determines offset electrical current level and current applying period to be applied to the printing motor on a basis of the rank of the electrical current at that phase.

Abstract: An input control current command signal is modified in accordance with a number of compensation factors stored in a memory and corresponding to each of a number of angular shaft positions to provide a control signal to cause an inverter to drive each of the number of phases of a permanent magnet axial-field motor to cause the motor to produce a ripple-free torque output. The compensation values stored in the memory are identified and determined in accordance with the source of the torque ripple such as vibration, load operation, noise and variations within the motor construction.

Abstract: A motor speed controlling device controls the rotational speed of a motor by feeding back an actual rotational speed detected by a photocoupler. An encoder disk formed with equi-pitch slits in the periphery thereof is attached to the drive shaft of the motor, and a photocoupler is provided in association with the encoder disk. CPU computes ON duration Ton and OFF duration Toff of pulse trains produced from the photocoupler when the motor is rotating at a constant speed. If the ON duration Ton and OFF duration Toff are unequal, ON correction factor and OFF correction factor are computed based on the measured ON and OFF durations, whereas if the ON duration and OFF duration are equal to each other, the ON and OFF correction factors are set to one (1). The CPU corrects the ON and OFF durations Ton and Toff based on the ON and OFF correction factors.

Abstract: An apparatus and method for reducing synchronous speed variations in an electric motor having a rotating shaft, comprises a speed transducer for generating a continuous analog speed signal corresponding to the speed of the motor shaft including its synchronous and asynchronous speed variations. A trigger signal is generated each time the shaft rotates through a reference position and is used in conjunction with the speed signal in a fast Fourier transform analyzer to resolve the analog signal into a synchronous time averaged signal which varies with the synchronous speed variations but which eliminates the asynchronous speed variations. An arbitrary function generator is connected to the analyzer for generating an antiwave pattern having a frequency phase and amplitude relative to the waveform from the analyzer. The function generator is connected to a motor controller and superimposes the antiwave pattern onto a control signal internal to the controller which is thereafter applied to the motor.

Abstract: A motor speed control system takes one approach to establish dummy load models having characteristics equivalent to an electric motor to be controlled. One of the dummy load models is established for feedback controlling the electric motor on the basis of the speed of the dummy model. The dummy model is divided into first and second models. The first model is designed to have equivalent characteristics to output a first motor speed representative data. The current to supply to the first model is so adjusted as to reduce a difference between the motor speed representative data and a desired motor speed data to zero. A frequency signal is added to the current applied to the first model and supplied to the electric motor to drive the latter. The second model receives the frequency signal to output a frequency signal dependent second motor speed representative value.

Abstract: A motor torque control assembly is provided which can automatically adjust the motor torque so that its reaction torque remains substantially constant, and so that the reaction torque is not changed by changes in motor internal variables, such as bearing drag, current loop tolerances, motor drag, speed change, and temperature change. Such assembly includes a motor subassembly and a feedback subassembly. The motor subassembly has torque input signal means, a summer unit, a compensator unit, a current loop unit, a motor unit, and a torque output means. The feedback subassembly has torque output sensing means connected to the torque output means for measuring the reaction torque value and connected to the summer unit for measuring the difference of the reaction torque value from a motor torque value of the torque input signal means.

Abstract: A method for the detection and regulation of a spring moment and a difference speed in rotationally driven systems in which a drive unit can be viewed as an elastically coupled two-mass system. The spring moment and the difference speed are determined without direct measurement of the actual load speed or the load position. This is done by comparison of the actual motor speed influenced by the spring moment and a simulated actual motor speed. The resulting difference speed and spring moment are directly proportional to the actual difference speed and the actual spring moment and can be supplied to the regulating system of the motor for regulating the intrinsic oscillations of the system.

Abstract: A current limiting control circuit for a d.c. motor, wherein compensation is provided for the inherent voltage drop across the armature of the d.c. motor with a first dedicated amplifier, while a second dedicated amplifier provides current limit control. In providing a separate and dedicated amplifier for the current limiting function, the limitations inherent in the current/resistance compensation circuit, such as lag in response time, are avoided.

Abstract: The speed of a DC motor is stabilized to correspond to a reference speed by a motor driving control that is instantaneously responsive to the interval between reference pulses corresponding to the reference speed and actual observed pulses corresponding to the actual motor speed.

Abstract: An offset current which is 180.degree. out of phase with the leakage current for a motorized bed circuit is created through the use of an additional transformer winding and series resistor which is connected between the neutral conductor and ground conductor. As the circuit is connected in the reverse polarity condition for testing to UL standards, the offset current is injected into the ground conductor which cancels out a portion of the leakage current from the motors to thereby bring it within testing standards. In the normal connection condition, the injected offset current is additive to the leakage current, although the normal leakage current is much less than the reverse polarity connection leakage current so that the overall leakage current in the normal connection condition remains within test standards.

Abstract: A speed control device for d-c motors includes an IC control circuit having such a construction that a reference voltage is generated across two of its terminals C and D. Additionally, a current proportional to the armature current of the d-c motor is kept flowing in the terminal D at all times. A transistor is connected across the terminals C and D of the control circuit so that motor revolution can be changed linearly by means of a variable resistor connected in parallel across the base and collector of the transistor. With this arrangement, the revolution of d-c motors can be accurately controlled.

Abstract: A slow start motor control circuit for applications wherein extremely accurate speed control is required, such as, in a centrifugal blood separator application is disclosed. In a blood separator, the degree of separation of cellular components, such as red blood cells and platelets, from the blood plasma is a function of the rotational speed of the centrifuge and the spin time. The control circuit controls the spin time and the rotational speed of the drive motor by controlling the voltage applied to the motor. The control circuit allows the drive motor to start relatively slowly to avoid cell breakage which can contaminate the plasma. After the centrifuge attains its desired operational speed, the speed of the motor is regulated and is relatively uninfluenced by ambient temperature variations.

Abstract: In a control loop for automatically adjusting variable-gain amplification, a sinusoidal signal with a frequency f.sub.o that is critical for the control loop is superimposed over a positioning parameter W. Two synchronous rectifiers S1 and S2 filter out the oscillation components of a control parameter x and of a control difference x.sub.d that contain frequency f.sub.o, and the components are compared in a comparator VL. A control and regulating circuit C continues to vary the variable-gain amplification at controls RG until the amplitudes of the oscillation components being compared in the comparator are equal. The variable-gain amplification is correct at that point. The variable-gain amplification can even be adjusted in a compact-disk player while the player is in operation.