Digital Comparison Patents (Class 318/601)
  • Patent number: 6218800
    Abstract: A control system in accordance with the invention comprises error signal generating means for generating an error signal in response to a reference signal and a first and a second position signal. The reference signal is a measure of the desired value of a position of a first part of a drive system with respect to a second part of the drive system. The position signals are a measure of the actual value of said position. The error signal is a measure of the difference between the desired value and the actual value of the position. The control system further comprises energizing means for energizing a motor which is to be controlled by the control system in dependence on the error signal. The control system of the invention is characterized in that the error signal generating means are adapted to generate weighting factors from the reference signal, for weighting the position signals with the weighting factors and determining a sum of the weighted position signals.
    Type: Grant
    Filed: July 20, 1999
    Date of Patent: April 17, 2001
    Assignee: U.S. Philips Corporation
    Inventors: Antonius H. M. Akkermans, Cornelius A. Hezemans
  • Patent number: 6201361
    Abstract: A mail piece handler defines a paper path having a downstream direction. A first motor is mechanically coupled with the mail piece handler, and an encoder is operatively coupled with the mail piece handler. A mail piece sensor is positioned at the paper path, and a print rotor is positioned at the paper path downstream of the mail piece sensor, the print rotor having a print surface. A second motor is mechanically coupled with the print rotor, and an electronic controller is communicatively coupled with the encoder, with the mail piece sensor, and with the second motor, the controller disposed in the event of sensing of a mail piece by the mail piece sensor to control said second motor so as to cause the print surface of the print rotor to move at substantially a speed measured via the encoder.
    Type: Grant
    Filed: August 5, 1999
    Date of Patent: March 13, 2001
    Assignee: Ascom Hasler Mailing Systems AG
    Inventor: Martin Müller
  • Patent number: 6195592
    Abstract: A method and apparatus implementing a user interface device, such as a mouse or trackball, having electronically controllable tactile responsiveness which is flexibly programmable. A user interface device effects positioning of a cursor within a limited area, such as on a display screen, with limits imposed by controllable tactile responsiveness. Programmable force-position characteristics relate the tactile responsiveness of the interface device to the position of the cursor within the limited area or on the display screen. In a described embodiment, the interface device includes at least two sets of wheels that move as the interface device is actuated. The at least two sets of wheels are aligned on mutually orthogonal axes. A servo motor is attached to each of the at least two sets of wheels.
    Type: Grant
    Filed: March 23, 1999
    Date of Patent: February 27, 2001
    Assignee: Immersion Corporation
    Inventors: Chester L. Schuler, Seth M. Haberman
  • Patent number: 6124696
    Abstract: A system and method for controlling a stepper motor wherein the amount of memory space needed to store a phase table is minimized. The stepper motor controller comprises a memory sized to store data representing a plurality of states for current outputs to be supplied to a first winding of a stepper motor and from which are derived current outputs for the first winding and a second winding of the stepper motor. A finite state machine is coupled to the memory. The finite state machine comprises a first address register that stores an address for data in the memory for a present state of the first winding and a second register that stores an address for data in the memory for a present state of the second winding.
    Type: Grant
    Filed: July 14, 1999
    Date of Patent: September 26, 2000
    Assignee: Lexmark International, Inc.
    Inventors: Timothy John Rademacher, Randall David Mayo
  • Patent number: 6118244
    Abstract: A circuit arrangement for powering an electric motor having at least three windings from a direct voltage source via a commutation circuit which, for each winding terminal of the electric motor, comprises a commutation branch including a first and a second switching element by which the relevant winding terminals can be connected selectively to a first terminal of the direct voltage source or, via a measurement impedance, to a second terminal of the direct voltage source. A ring counter device periodically changes over the switching elements of the commutation circuit in accordance with a signal series which is cycled through the ring counter device under control of a clock signal, one period of the ring counter device corresponding to one complete cycle of the signal series through the ring counter device. A clock frequency generating stage supplies the clock signal whose clock frequency is dependent on the measurement voltage.
    Type: Grant
    Filed: June 8, 1999
    Date of Patent: September 12, 2000
    Assignee: U.S. Philips Corporation
    Inventor: Hans Steinbusch
  • Patent number: 6107763
    Abstract: The synchronizing circuit of a digital drive system of an electric motor is configured to function in a closed loop or in an open loop mode by adding a minimum number of elements to the normal scheme of a closed loop synchronizing circuit. In practice, by adding only one programmable register and a pair of two-input de-multiplexers, the system is able to automatically switch from one mode of operation to the other mode. The programmable open loop mode permits compensating for the phase angle between the current flowing through the windings and the drive voltage applied thereto, as in case of a voltage mode driving.
    Type: Grant
    Filed: September 17, 1998
    Date of Patent: August 22, 2000
    Assignee: STMicroelectronics S.r.l.
    Inventor: Annamaria Rossi
  • Patent number: 6107764
    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.
    Type: Grant
    Filed: October 30, 1998
    Date of Patent: August 22, 2000
    Assignee: Dana Corporation
    Inventor: Scott Evart Blackburn
  • Patent number: 6084375
    Abstract: An apparatus for controlling operation of a processing machine has a computer preferably with a computer aided design program configurable to model a kinematic velocity profile of a point of interest on a machine to be controlled. A graphical user interface on the computer enables an operator to select desired velocity points for a motor drive controlling motion of the point on the machine. A curve fit is applied to the velocity points to realize a desired velocity profile for the motor drive and the point on the machine. The desired velocity profile is then integrated and scaled in order to obtain a scaled velocity profile that realizes an actual, or target displacement of the point as dictated by operation of the machine. By controlling operation of elements of a machine with velocity profiles, coordination of associated elements and points on the machine can be visualized by an operator selecting the velocity points for each drive of the machine. A method for implementing same is also disclosed.
    Type: Grant
    Filed: May 8, 1998
    Date of Patent: July 4, 2000
    Assignee: The Vision Limited Partnership
    Inventors: Jere F. Irwin, Gary A. Curry, Marian J. Fisk, Andrew Roy, David L. Roberts, Stephanie L. Roberts, Todd W. Rudberg
  • Patent number: 6066929
    Abstract: A brushless direct current motor driving circuit includes a data generator adapted to receive a first signal corresponding to a rotor position and to generate a digital data signal therefrom, a clock signal generator adapted to receive phase voltage signals and back electromotive force (BEMF) signals from a motor and to generate a clocking signal therefrom, and a data output block coupled to the data generator and the clock signal generator and adapted to receive the data signal and the clocking signal such that the digital data is clocked into the data output block as a result of the BEMF signals to produce a frequency signal to be used in controlling the velocity of the rotor. Switching noise present together with the BEMF signals is rejected by the clock signal generator so that the frequency signal is substantially free from switching noise, thereby allowing a velocity controller to provide more precise velocity control of the rotor.
    Type: Grant
    Filed: May 24, 1999
    Date of Patent: May 23, 2000
    Assignee: Fairchild Korea Semiconductor
    Inventor: Nam-Jin Kang
  • Patent number: 6020708
    Abstract: A stop range setting circuit sets a range of permissible positions around where the control object is desired to be stopped on the basis of a target position signal, and a potentio balance resistor (PBR) detects a present position of the control object driven by a motor. The comparison circuit compares the present position of the control object with the set range, and outputs an out-of-stop range signal and a rotating direction indication signal until the control object reaches the range. The out-of-stop range signal is input to a drive start determination circuit, and a drive permission signal is output to a drive circuit when the out-of-stop range signal is continuously output for at least a predetermined period of time. The drive circuit drives the motor in a direction indicated by the rotating direction indication signal while the drive permission signal is continuously output, so that an instantaneous ON/OFF signal is not input to the drive circuit in the presence of external noise.
    Type: Grant
    Filed: November 8, 1996
    Date of Patent: February 1, 2000
    Assignee: Nissan Motor Co., Ltd.
    Inventors: Takashi Matsumoto, Yoshinori Satoh, Hiroyuki Ureshino
  • Patent number: 6011376
    Abstract: A method and apparatus for verification of the linear position of a machine element driven by a motor is provided. The actual position of the element is detected and compared to an expected position. When the two positions differ from each other by more than a predetermined tolerance value for a predetermined amount of time, an error signal is generated which deactivates the motor and generates an alarm for the machine operator. Preferably, the linear position of the axis is detected by a transducer and the expected position is determined by detecting the rotary position of the motor through the use of a resolver, which is then converted to a linear equivalent through the use of the gearing ratio. The method and apparatus can detect faulty machine conditions and thereby prevent machine malfunction and/or machine damage. Preferably, the method and apparatus are used to verify the position of machine elements in an injection molding machine.
    Type: Grant
    Filed: March 13, 1998
    Date of Patent: January 4, 2000
    Assignee: Cincinnati Milacron Inc.
    Inventors: James E. O'Bryan, John C. Catanzaro, David A. Topmiller
  • Patent number: 5992383
    Abstract: A control unit (75) for controlling a first state variable of a system, for example an angle of rotation .phi. of a throttle valve (7) in a throttle device for use in an internal-combustion engine, the system being influenced by a disturbance variable during operation, for example an oscillating loading torque caused by air-flow fluctuations in the throttle device. The control unit includes a disturbance observer (125) for calculating a value of the disturbance variable at a first point in time on the basis of a mathematical model of the system, and a disturbance predictor (128) for predicting a value of the disturbance variable at a second point in time which follows the first point in time by a predetermined time interval. In this manner, a phase shift between the disturbance variable actually influencing the system and the compensation provided by the system for the disturbance variable is prevented at high frequencies of the disturbance variable.
    Type: Grant
    Filed: April 10, 1997
    Date of Patent: November 30, 1999
    Assignee: U.S. Philips Corporation
    Inventors: Lutz Scholten, Rudolf Tracht
  • Patent number: 5977735
    Abstract: The invention relates to a tracking detection system of electrical servomotors with incremental position detection in particular for servomotors in motor vehicles. To determine the position, said tracking detection system is provided with a microcontroller with an autoalarm device. Said microcontroller can be moved from run mode (B1) to sleep mode (B0) to reduce the average current intake, and after a predetermined period of time (e.g. 1 mm) can be automatically moved back to run mode (B1). Said microcontroller samples the position signals (HS) of position transmitter when it is in run mode (B1) at particular sampling points (11, 12), and is move between the required sampling points for a particular, calculated period of time in sleep mode (B0). The particular, calculated period of time is calculated from a detected edge change of the position signal.
    Type: Grant
    Filed: November 19, 1997
    Date of Patent: November 2, 1999
    Assignee: Robert Bosch GmbH
    Inventor: Volker Aab
  • Patent number: 5952807
    Abstract: A tracing control method includes the steps of (a) controlling a movement direction of a move point to a tangential direction of an objective locus at a present position of the move point and (b) moving the move point in the movement direction at a non-controlled speed. A tracing control apparatus includes (a) a direction control actuator for controlling a movement direction of a move point and (b) a drive actuator for driving the move point at a non-controlled speed.
    Type: Grant
    Filed: September 27, 1996
    Date of Patent: September 14, 1999
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventor: Hisanori Nakamura
  • Patent number: 5932986
    Abstract: A brushless AC servo motor control and modified motor to minimize the rotational acceleration and deceleration of a semiconductor wafer during processing steps where fluid is applied in a thin coating on the wafer. The control utilizes sine and cosine encoder outputs of single cycle and multiple cycle per revolution to calculate motor shaft position by an inverse tangent calculation of sine and cosine ratios. Resolution of motor shaft position is greatly improved as is rotational velocity control. In response to a prediction of desired shaft position in comparison with actual position the three field currents are adjusted to change the torque applied to the rotor and shaft. In the semiconductor wafer manufacturing application the motor shaft is modified to permit vacuum attachment of the wafer to the disc that rotates with the shaft.
    Type: Grant
    Filed: March 5, 1997
    Date of Patent: August 3, 1999
    Assignee: Whedco, Inc.
    Inventors: William B. Henry, Paul Firehammer
  • Patent number: 5903941
    Abstract: An automatic control system for controlling the firmness of a fluid supported mattress of a bed assembly. The control system includes a motorized fluid pump, a control unit for operating the pump to adjust the firmness of the air mattress, a hand held remote control unit for actuating the control unit, and a transceiver system for transmitting information signals between the hand held unit and the control unit. The air control system provides for independent control of both bladders in a two bladder air mattress from a single unit, and allows a user to consistently set the firmness of each mattress air bladder to a desired value. The air control system includes an air pump specially designed to minimize transmission of motor noise into the environment.
    Type: Grant
    Filed: March 27, 1997
    Date of Patent: May 18, 1999
    Assignee: Select Comfort Corporation
    Inventors: David C. Shafer, Eugene P. Duval
  • Patent number: 5905350
    Abstract: A position measuring system to determine the absolute angle position of a rotor of a motor during startup. With this absolute angle position, correct commutation for startup of the motor is provided. During later operation a high-precision incremental angle measurement is possible. For this purpose a switching unit is disposed between a rotary transducer and an evaluation unit, which is driven in such a manner that first the analog signals necessary for the determination of the absolute angle position are input to the evaluation unit and thereafter the analog signals required for incremental angle measurement are input to the evaluation unit. In order to avoid unacceptable incorrect positioning in case of incorrect switching between the first and second modes of operation, all the analog signals have an approximately equal spacing period.
    Type: Grant
    Filed: September 25, 1997
    Date of Patent: May 18, 1999
    Assignee: Dr. Johannes Heidenhain GmbH
    Inventors: Hermann Hofbauer, Steffen Bielski, Helmut Huber
  • Patent number: 5889672
    Abstract: A method and apparatus implementing a user interface device, such as a mouse or trackball, having electronically controllable tactile responsiveness which is flexibly programmable. A user interface device effects positioning of a cursor within a limited area, such as on a display screen, with limits imposed by controllable tactile responsiveness. Programmable force-position characteristics relate the tactile responsiveness of the interface device to the position of the cursor within the limited area or on the display screen. In a described embodiment, the interface device includes at least two sets of wheels that move as the interface device is actuated. The at least two sets of wheels are aligned on mutually orthogonal axes. A servo motor is attached to each of the at least two sets of wheels.
    Type: Grant
    Filed: June 3, 1998
    Date of Patent: March 30, 1999
    Assignee: Immersion Corporation
    Inventors: Chester L. Schuler, Seth M. Haberman
  • Patent number: 5883482
    Abstract: A method and apparatus for controlling the output to a drive for moving a workpiece and/or tool along a defined path in a machine tool. The drive output can be modified according to a periodic controlling variable or a periodic disturbance variable. The defined path of the workpiece is divided into equidistant subdivisions and a control deviation corresponding to each subdivision of the defined path is determined and stored. A control variable is derived from the control deviation and utilized to control the drive output.
    Type: Grant
    Filed: March 6, 1996
    Date of Patent: March 16, 1999
    Assignee: The Gleason Works
    Inventors: Johannes Hocht, Bernhard Leicht
  • Patent number: 5877603
    Abstract: An electric current control method for a servomotor in which a reactive current is lowered in a region where a voltage saturation does not occur, to suppress generation of heat caused by the reactive current and achieve a stable rotation up to a high-speed region. In the current control of the servomotor using a DQ conversion, an electric current is not supplied to d-phase and supplied only to q-phase when a rotational speed of the servomotor is not high, and the reactive current is supplied to the d-phase only when the rotational speed of the servomotor is high, to thereby lower the terminal voltage of the servomotor by the reactive current. Thus, the reactive current is reduced in the region where the voltage saturation does not occur, to thereby suppress the generation of heat due to the reactive current, and also achieve the stable rotation even in the high-speed region.
    Type: Grant
    Filed: May 13, 1997
    Date of Patent: March 2, 1999
    Assignee: Fanuc Ltd
    Inventors: Hiroyuki Uchida, Yasusuke Iwashita, Yuichi Endo, Takashi Okamoto
  • Patent number: 5877605
    Abstract: A servo device which simultaneously controls plural servo systems, using a digital signal processor (DSP). The servo device includes plural servo systems, plural control subjects, and plural sensors which determine control quantities of the respective control subjects. The servo device also includes a calculation processing device which finds operating amounts of the respective control subjects from the control quantities which have been detected. The calculation processing device measures the gain of each servo system, and during the gain measurement of a given servo system, drops the control band of other servo systems, or sets the other servo systems to OFF or HOLD.
    Type: Grant
    Filed: February 5, 1997
    Date of Patent: March 2, 1999
    Assignee: Nikon Corporation
    Inventor: Hiroshi Arai
  • Patent number: 5852996
    Abstract: An apparatus for controlling the positioning of a throttle valve situated to control the amount of air permitted to enter an internal combustion engine operable in a plurality of control modes. The apparatus includes a driver responsive to a drive signal indicating a target throttle valve position for moving the throttle valve to the target throttle valve position, a sensor sensitive to the movement of the throttle valve for producing a digital sensor signal indicative of a sensed throttle valve position, and a control unit for producing the drive signal to bring the sensed throttle valve position into coincidence with the target throttle valve position. The disturbances introduced onto the driver and the sensor are estimated based on the target and sensed throttle valve positions. The target throttle valve position is corrected based on the estimated disturbances.
    Type: Grant
    Filed: December 6, 1996
    Date of Patent: December 29, 1998
    Assignee: Nissan Motor Co., Ltd.
    Inventors: Hideo Nakamura, Masashi Matsuyama
  • Patent number: 5854545
    Abstract: An acknowledgement-free method for the positioning of an actuator by means of an electric motor which is controlled as a function of time by a microprocessor, wherein there are proportionality constants K.sub.1, K.sub.2 of a formulaAdjustment Path=K.multidot.Adjustment Timeas well as the corresponding times T.sub.1, T.sub.2 for the braking of the rotor, after disconnection of the electric motor, from a first speed of rotation N.sub.a to a second speed of rotation N.sub.b. The constant K.sub.1 and K.sub.2 are the times T.sub.1 and T.sub.2 are determined and stored for the structural unit consisting of actuator and electric motor at at least two different loads B.sub.1, B.sub.2. Upon operation of the actuator, the time T.sub.x for the braking of the rotor from N.sub.a to N.sub.b is measured and, with the use of the stored times T.sub.1, T.sub.2, the proportionality constant K.sub.x corresponding to the time T.sub.x is calculated by linear interpolation and used for the control.
    Type: Grant
    Filed: March 27, 1997
    Date of Patent: December 29, 1998
    Assignee: VDO Adolf Schindling AG
    Inventor: Michael Eibel
  • Patent number: 5847524
    Abstract: A motor having a power switching circuit adapted to be connected between a power source and its winding for selectively energizing the winding to generate a magnetic field which causes a rotating assembly to rotate. A position sensing circuit provides a position signal representative of the position of the rotating assembly and a commutating circuit controls the power switching circuit to commutate the power switching circuit at a commutating angle to achieve a desired rotating speed of the rotating assembly. The commutating circuit varies the commutating angle in response to the position signal to maintain the substantially constant rotating speed of the rotating assembly. As result, the efficiency of the motor is varied to maintain the substantially constant rotating speed.
    Type: Grant
    Filed: March 20, 1997
    Date of Patent: December 8, 1998
    Assignee: General Electric Company
    Inventors: David M. Erdman, James R. Kiefer, Robert K. Hollenbeck
  • Patent number: 5834918
    Abstract: A self-tuning tracking controller for permanent-magnet synchronous motors is disclosed, providing for velocity or position trajectory tracking even when both the electrical and mechanical parameters of the motor, amplifier, and load are initially unknown. A time-scale simplification of a full-order mathematical model of the motor leads to a discrete-time design model that is reduced-order and that evolves in a mechanical time-scale which is substantially slower than the electrical time-scale, permitting implementation of the self-tuning tracking controller with a lower sampling frequency (and at a lower cost) than is typically expected. A piecewise-linear parameterization of the motor torque-angle characteristic functions allows for identification of higher-order harmonics with a degree of accuracy which is selectable by the user, without requiring more computation than traditional single-term sinusoidal descriptions. Excellent performance is achieved, even with very poor initial motor parameter knowledge.
    Type: Grant
    Filed: April 1, 1996
    Date of Patent: November 10, 1998
    Assignee: Georgia Tech Research Corporation
    Inventors: David G. Taylor, Kenneth R. Shouse
  • Patent number: 5783924
    Abstract: The drive system (210) comprises an electronically commutated motor (220) having three windings (225, 226 and 227). The motor (220) is energized by an energizing circuit (270). The energizing means (270) is controlled by three Hall elements (241, 242 and 243) which supply sensor signals (H.sub.1, H.sub.2 and H.sub.3). The motor comprises a permanent-magnetic part whose position is measured by means of the Hall elements. The drive system (210) comprises a status generator (280) which generates status signals (Q.sub.1, Q.sub.2, Q.sub.3 and Q.sub.4) which are dependent upon the ratio between the actual values of the sensor signals (H.sub.1, H.sub.2 and H.sub.3). The drive system (210) further comprises a multiplexer (290) and an inverter (295) which are controlled by the status signals (Q.sub.1, and Q.sub.2, respectively) in order to generate a position signal (P). A corrected position signal (P') is applied to a comparator (260) to generate an error signal (E).
    Type: Grant
    Filed: December 6, 1996
    Date of Patent: July 21, 1998
    Assignee: U.S. Philips Corporation
    Inventor: Josephus A. H. M. Kahlman
  • Patent number: 5783923
    Abstract: In a feedback control system with multivariable inputs and outputs, a network of plant actuators, each controlled by self-adaptive feedback control loops with pole-tracking zeroes, is provided as a plant or output load for a network of generally-conventional controllers. Each of the controllers sees a constant load, so the controller network can be viewed as having a constant gain-bandwidth characteristic transmission. The network of plant actuators cancels the effects the load inertias and its variations.
    Type: Grant
    Filed: December 6, 1995
    Date of Patent: July 21, 1998
    Assignee: William L. Wise
    Inventor: William L. Wise
  • Patent number: 5780988
    Abstract: The present invention provides a method for detecting the position, direction of rotation and rotational speed of a rotatably seated part, which are employed, for example, in particular in externally-operated locking parts of motor vehicles (e.g., with an electric window opener with protection against jamming). The method allows a reduction in the number of components and installation space. The method of the present invention has the feature that control commands and the state of the motor are provided to a logical evaluation device. Either the high and low edges of the digitized signal, or one of the high or low edges, together with the signal level at the time of motor start or reversal of the direction of rotation of the motor are assigned to the one or the other direction of movement (direction of rotation).
    Type: Grant
    Filed: March 25, 1996
    Date of Patent: July 14, 1998
    Assignee: Brose Fahrzeugteile GmbH & Co. KG
    Inventors: Roland Kalb, Jurgen Seeberger
  • Patent number: 5742144
    Abstract: A method for properly compensating for a backlash between a servomotor and a machine moving part, such as a table, driven by the servomotor in a semi-closed-loop type control. In the semi-closed-loop type servo control, the force of a motor-driven table which acts on a motor is estimated by means of a disturbance observer, the side of the groove of a ball nut directly connected to the table, with which the ridge of the ball thread directly connected to the motor is in contact, is detected by the sign of the value of the estimated force, and the direction of backlash compensation is changed in accordance with the detected result.
    Type: Grant
    Filed: January 29, 1996
    Date of Patent: April 21, 1998
    Assignee: Fanuc Ltd.
    Inventors: Tetsuaki Kato, Kokoro Hatanaka
  • Patent number: 5739654
    Abstract: A servo controlled tool and stage positioning system. A circuit in the tool positioning servo control circuit removes unwanted glitches. Glitches are generated by servo control DACs when the servo is at rest. The circuit selectively blocks these glitches from being passed to the tool positioning circuit only when the stage is at rest.
    Type: Grant
    Filed: September 19, 1996
    Date of Patent: April 14, 1998
    Assignee: International Business Machines Corporation
    Inventors: Samuel Kay Doran, Erwin Ernst Weissmann
  • Patent number: 5734242
    Abstract: A disturbance estimation observer estimates a disturbance load torque applied to a motor. The estimated disturbance load torque is fed back so that the feedback control is carried out by making the torque corresponds to a commanded force value which is a target value. According to the feedback control, the estimated disturbance load torque is controlled to correspond to the target value, and when the estimated disturbance load torque approximates to an actual load torque, the actual load torque is controlled to the target value. Thus, force control by the motor can readily be carried out on the basis of the disturbance load estimated without using force sensors.
    Type: Grant
    Filed: December 1, 1994
    Date of Patent: March 31, 1998
    Assignee: Fanuc Ltd.
    Inventor: Yasusuke Iwashita
  • Patent number: 5723965
    Abstract: A velocity control method for use in a servo motor having a disturbance eliminator is described. The velocity control method includes the steps of calculating a control torque input value based on a desired target velocity input value and an output velocity value of an actual mechanical model, adding a disturbance torque value to the control torque input value to input the added result to the mechanical model, inputting the control torque input value to a virtual model to calculate an estimation velocity according to the control torque input value, calculating a corrected torque based on a velocity value difference between the output velocity value of the mechanical model and the estimation velocity value of the virtual model, and reflecting the corrected torque on the control torque input value. Accordingly, although unknown disturbances are input to the control system, a velocity error can be conversed into zero as closely as possible to enable an accurate velocity control.
    Type: Grant
    Filed: April 9, 1996
    Date of Patent: March 3, 1998
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Chung Hyuk Yim
  • Patent number: 5684972
    Abstract: An integrated circuit includes a programmable servo burst sequencer that includes an instruction memory, an instruction register, and an address control circuit. The instruction register drives a plurality of output lines of the programmable servo burst sequencer. The programmable servo burst sequencer can process a plurality of fields in any one of a plurality of servo sectors. The programmable servo burst sequencer eliminates the need for a specific servo burst sequencer for each possible configuration of the plurality of fields in a servo sector. The user simply uses a plurality of instructions to configure the programmable servo burst sequencer so that the programmed servo burst sequencer can process the plurality of fields in the servo sector information on the user's disk drive.
    Type: Grant
    Filed: August 22, 1994
    Date of Patent: November 4, 1997
    Assignee: Adaptec, Inc.
    Inventors: John P. Hill, David L. Dyer, Nicolas C. Assoud
  • Patent number: 5654840
    Abstract: A disk drive for operating in an environment in which the drive is subject to physical shock includes a circuit which senses movement of a transducer head support arm which result from a shock's rotational component. The rotational shock is detected as a residual BEMF signal in the drive's VCM coil winding. The residual signal is extracted from much larger position control signals that are applied to the VCM winding during normal system operation by providing circuits that simulate the VCM winding voltage caused by the position control signal and subtracting the outputs of the simulation circuits from the actual VCM coil winding voltage. This eliminates the normal operating components and leaves a residual signal that represents only the small portion of the VCM BEMF signal that results from the rotational shock. A threshold circuit compares the shock BEMF signal to a predetermined threshold. If the BEMF signal exceeds the threshold, disk drive write operations are aborted.
    Type: Grant
    Filed: June 30, 1994
    Date of Patent: August 5, 1997
    Assignee: Western Digital Corporation
    Inventors: Charles R. Patton, John R. Edwards, Anil Sareen
  • Patent number: 5600221
    Abstract: A control apparatus for a servo system uses a servo motor to perform operations equivalent to those of a cam mechanism. A motion command section has two data tables which are used to calculate and output a position command and a velocity compensation command equivalent to a cam stroke. A servo drive section makes velocity compensation and current compensation on the basis of position and velocity compensation commands. The motion command section, alternatively, may have three data tables for the calculation of the compensation commands. In addition, multipliers are used to adjust the weight of the compensation commands. Rather than the data tables being present in the motion command section, they may be placed in the servo drive section. Formulae representing the mechanical characteristics of the cam system may be used in place of the data tables.
    Type: Grant
    Filed: May 5, 1995
    Date of Patent: February 4, 1997
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Kazuhiko Tomatsuri, Misako Okada, Yusuke Ushio, Yuko Tomita, Satoshi Mizogami
  • Patent number: 5574349
    Abstract: A servo motor control circuit for a video signal playback apparatus including a wave-shaping circuit, a speed error detector, a first filtering circuit for filtering torque ripple components of servo motor speed error signals characterized in that the gain in much higher in a low frequency band than in any other frequency band, a second filtering circuit for attenuating the low frequency gain of signals output from the first filtering circuit, a phase error detector, an adder, and a motor controller, resulting in a decrease in low frequency band phase distortion and a decrease in the time required for servo motor stabilization.
    Type: Grant
    Filed: December 30, 1994
    Date of Patent: November 12, 1996
    Assignee: Goldstar Co., Ltd.
    Inventor: Yong G. Oh
  • Patent number: 5569993
    Abstract: An electric vehicle having a computer for controlling the charging of its battery includes a probe adapted to connect with a receptacle on a charging station which has a computer for controlling the charging voltage provided over the connection to the vehicle. In response to the vehicle announcing its presence with a broadcast signal, the charge station receptacle may be raised until it senses a laser signal presented by the vehicle to indicate alignment of the receptacle with the vehicle probe. The vehicle and station communicate over a current loop to establish battery type and voltage, method of payment and credit card number, as well as the cost basis for the power. When communications are complete, the system switches over to utilize the same connections for the charging current. The computers include stop modes which they rest in, and to which they return if performance of vehicle and station diagnostics (respectively) indicate inoperability or if other faults occur.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: October 29, 1996
    Inventor: Arlie L. Keith
  • Patent number: 5559412
    Abstract: An actuator having electronically controllable tactile responsiveness which is flexibly programmable to facilitate provision in a single actuator of torque-position characteristics, such as a selectable number of detents per actuation through its full operative path. A rotary actuator facilitates provision in a single actuator, of torque versus angular position characteristics, such as a selectable number of detents per revolution. The actuator is in communication with a servo motor having a position encoder which outputs position information to a controller that has access to torque-position relation information. The controller outputs a digital torque signal, in accordance with the torque-position relation information, which is converted to an analog current signal applied to the servo motor to generate torque in the servo motor. The torque, presenting a tactile response to a human interacting with the actuator, is sensed as a detent or a plurality of detents.
    Type: Grant
    Filed: May 3, 1995
    Date of Patent: September 24, 1996
    Assignee: Lex Computer and Management Corporation
    Inventor: Chester L. Schuler
  • Patent number: 5552689
    Abstract: A servo motor includes a motor, a motor driver for driving the motor by outputting pulses to the motor, and a speed detector for calculating speed information. The servo motor further includes a comparator for comparing the speed information with command speed information and calculating deviation information therebetween, a memory for storing pulse correction information for modifying a duty factor of the pulses in accordance with a rotational state of the motor, and a pulse updater for reading the pulse correction information stored in the memory based on the deviation information, modifying the duty factor of the pulses, and outputting the duty factor modified pulses to the motor driver.
    Type: Grant
    Filed: December 27, 1994
    Date of Patent: September 3, 1996
    Assignee: Laurel Bank Machines Co., Ltd.
    Inventor: Yasuhiko Matoba
  • Patent number: 5525874
    Abstract: Stable current control to an inductive load uses a digital driver having registers loaded with load control parameters from a microprocessor. The parameters, along with a counter responsive to clock pulses, control a pulse period and a pulse width which are used to operate an FET in series with the load to control load current. Current mode control develops a decreasing current limit voltage in each pulse period by decrementing a down counter at a rate and from an initial value commanded by the microprocessor, and converting the value to an analog current limit signal. The signal is compared to a load current feedback signal and the pulse width is truncated if the load current reaches the current limit signal.
    Type: Grant
    Filed: January 30, 1995
    Date of Patent: June 11, 1996
    Assignee: Delco Electronics Corp.
    Inventors: Shobha R. Mallarapu, Sanmukh M. Patel, Brian W. Schousek
  • Patent number: 5521481
    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.
    Type: Grant
    Filed: October 21, 1994
    Date of Patent: May 28, 1996
    Assignee: Kabushiki Kaisha Meidensha
    Inventor: Tetsuo Yamada
  • Patent number: 5519298
    Abstract: The value of a variable reflecting the operating condition of mechanical equipment is continuously detected as operation condition data. A long period average value of the operating condition data detected in long reference period, and a short period average value of data detected in a short analysis period ending in the present time are calculated. Just how much the short period average value differs from the long period average value is adopted as an index of abnormality and using this index, it is possible to ascertain abnormal operating conditions regardless of the absolute value of the variable detected. The above short period average value, long period average value and standard deviation thereof are applied to a first fuzzy membership function for calculating the degree of stability of the mechanical equipment therefrom.
    Type: Grant
    Filed: December 16, 1994
    Date of Patent: May 21, 1996
    Assignee: Kabushiki Kaisha Kobe Seiko Sho
    Inventors: Norio Fukuhara, Toshiyuki Ueda, Masaki Hamaguchi
  • Patent number: 5514941
    Abstract: A reference machining speed and an offset value for each machining cycle are specified with reference to a machining condition table of a nonvolatile memory in accordance with a set workpiece material, workpiece thickness, wire electrode diameter, and machining frequency. An overall machining path length for each machining cycle is obtained in accordance with a machining movement command given by a machining program, the wire electrode diameter, and the offset value. A machining time required for executing an entire machining operation is obtained by integrating all the required machining times for the individual machining cycles that is obtained by dividing the overall machining path lengths for the individual machining cycles by the reference machining speed for the individual machining cycles, and an operator is informed of an expected machining termination time as the sum of a current time read from a clock device and the required machining time that is displayed on a CRT screen of a CRT/MDI.
    Type: Grant
    Filed: June 21, 1994
    Date of Patent: May 7, 1996
    Assignee: Fanuc Ltd.
    Inventor: Yuki Kita
  • Patent number: 5498943
    Abstract: A feedback control device at a certain control time, predicts a feedback quantity at the next control time on the basis of a feedback quantity fed back from a controlled object and then performs a control operation based on the predicted feedback quantity. The feedback control device includes a predictive control unit for producing such an actuating signal as to decrease a deviation between the predicted feedback quantity and a desired value. The actuating signal is used to control the controlled object. This eliminates the detrimental effects of time delays associated with the controlled object or the control device, thus ensuring good control. The use of the predictive control unit permits the controlled quantity from the controlled object to converge to the desired value monotonically and quickly.
    Type: Grant
    Filed: August 30, 1993
    Date of Patent: March 12, 1996
    Assignee: Fujitsu Limited
    Inventors: Takashi Kimoto, Daiki Masumoto, Hiroshi Yamakawa, Shigemi Nagata
  • Patent number: 5477103
    Abstract: A servo system controller for a disk drive device which includes a rotating mass storage disk incorporates a timing error determining circuit for determining rotational speed variations in the disk from information contained in a servo field recorded in a track. A timing error signal is supplied when the speed variation exceeds a threshold, thus indicating an unacceptable level of speed variation. A digital synchronizer responds to asynchronous servo data signals from the disk to establish a cell clock signal occurring about a normal frequency, a cell during which only one servo data signal will occur, and a cell data signal which occurs during the cell. The cell clock signal clocks logical operations on a synchronous basis, and servo data signals are reliably captured.
    Type: Grant
    Filed: June 4, 1993
    Date of Patent: December 19, 1995
    Assignee: Cirrus Logic, Inc.
    Inventors: Paul M. Romano, Larry D. King, Mike Machado, Petro Estakhri, Son Ho, Phuc Tran, Maryam Imam
  • Patent number: 5444345
    Abstract: A speed control apparatus for a motor has a driver for the motor. The motor's rotational speed is detected, and a signal from the detector is counted. Signals from the counter received as the input by another circuit, which outputs data representing irregularities in the detection signal once the motor has reached its constant speed. Correction information is supplied to the motor driver on the basis of the irregularity data.
    Type: Grant
    Filed: September 27, 1993
    Date of Patent: August 22, 1995
    Assignee: Canon Kabushiki Kaisha
    Inventor: Shigeru Jinnai
  • Patent number: 5414337
    Abstract: An actuator having electronically controllable tactile responsiveness which is flexibly programmable to facilitate provision in a single actuator of torque-position characteristics, such as a selectable number of detents per actuation through its full operative path. A rotary actuator facilitates provision in a single actuator, of torque versus angular position characteristics, such as a selectable number of detents per revolution. The actuator is in communication with a servo motor having a position encoder which outputs position information to a controller that has access to torque-position relation information. The controller outputs a digital torque signal, in accordance with the torque-position relation information, which is converted to an analog current signal applied to the servo motor to generate torque in the servo motor. The torque, presenting a tactile response to a human interacting with the actuator, is sensed as a detent or a plurality of detents.
    Type: Grant
    Filed: June 11, 1993
    Date of Patent: May 9, 1995
    Assignee: Lex Computer and Management Corporation
    Inventor: Chester L. Schuler
  • Patent number: 5389867
    Abstract: In a control system for an actuator applicable to a servo system in which a low resolution sensor and/or an actuator having a play in a speed-reduction gear mechanism, a control gain for the actuator is adjusted according to a result of comparison between an output signal of a control target and output signal of a controlled object. The control gain for the actuator is a cut-off frequency of a low pass filter installed in a disturbance compensator.
    Type: Grant
    Filed: December 30, 1992
    Date of Patent: February 14, 1995
    Assignee: Nissan Motor Co., Ltd.
    Inventors: Kazutaka Adachi, Yoshinori Yamamura
  • Patent number: 5361025
    Abstract: The interface circuit has a single input terminal for receiving an analog or digital control signal indicative of the required speed of rotation of the motor. The type of input signal is recognised by means of comparator circuits. The input signal is processed differently according to its nature in order, in any case, to output an analog signal acceptable by the regulation and control circuit which pilots the motor.
    Type: Grant
    Filed: March 26, 1993
    Date of Patent: November 1, 1994
    Assignee: Industrie Magneti Marelli SpA
    Inventors: Pietro De Filippis, Franco Salerno, Paolo Mastella
  • Patent number: 5355065
    Abstract: A control system for a physical plant has a state output detector for detecting operating conditions of the physical plant. A trajectory production unit produces desired operating conditions of the physical plant, and an error production unit produces error signals based on the detected operating conditions and the desired operating conditions. A control signal generator generates a control signal based on the detected operating conditions, the error signals, a control signal generated a predetermined time period ago, an error dynamics adjustment signal, and a control input signal. The control signal generator includes a control input signal generator and an error dynamics signal generator. The control input signal generator generates the control input signal based on a predetermined control relationship. The error dynamics adjustment signal generator generates the error dynamics adjustment signal and the predetermined time period based on a plurality of predetermined error dynamics relationships.
    Type: Grant
    Filed: May 11, 1993
    Date of Patent: October 11, 1994
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Kazushige Narazaki, Osamu Ito