Nonlinear Circuits Patents (Class 318/620)
  • Patent number: 9729094
    Abstract: In torque pulsation suppressing control in apparatus using battery as main power source, with feedforward table, there arises compensating table error due to voltage fluctuation by battery internal resistance, depending on load power. In system where compensating values for suppressing torque pulsation are collected beforehand in the form of compensating table, and the torque pulsation of each frequency component is suppressed by the torque compensating quantity determined by inputting torque command and sensed rotational speed, the system senses main power source voltage of controlled object, and to perform compensation by outputting the torque compensating quantity dependent on the voltage by inputting into the compensating table corresponding to voltage.
    Type: Grant
    Filed: June 10, 2014
    Date of Patent: August 8, 2017
    Assignee: MEIDENSHA CORPORATION
    Inventors: Takashi Yamaguchi, Yugo Tadano
  • Patent number: 9008843
    Abstract: In a positioning apparatus for an actuator, a sliding mode controller for compensating for nonlinear characteristics of a wave gear device of the actuator generates a control input u to a controlled object, based on a position command ?l* and a state variable x for expressing the controlled object. The controlled object is defined in the following formula. {dot over (x)}=Ax+Bu+E?l* y=Cx The switching surfaces of the sliding mode control system are defined by a variable S expressed in the following formula. S=BTP The control input u is the sum of the linear-state feedback control term ul and the nonlinear control input unl u = u l + u nl = - ( SB ) - 1 ? ( SAx + SE ? ? ? l * ) - k ? ( SB ) - 1 ? ? ? ? ? ? = Sx , where ? is the switching function, and k is the switching gain.
    Type: Grant
    Filed: April 17, 2012
    Date of Patent: April 14, 2015
    Assignees: Harmonic Drive Systems Inc., National University Corporation Nagoya Institute of Technology
    Inventors: Yoshifumi Okitsu, Masafumi Yamamoto, Yuki Kato, Makoto Iwasaki
  • Publication number: 20140203752
    Abstract: A positioning control system for an actuator provided with a strain wave gearing is provided with: a semi-closed feedback controller FB(s) that controls a load shaft position ?l on the basis of a feedback motor shaft position ?m; and a feedforward linearization compensator configured by incorporating a nonlinear plant model for an object to be controlled into a feedback linearization compensator using an exact linearization technique. The feedforward linearization compensator uses a forward-calculated state quantity estimated value x* to calculate a feedforward current instruction i*ref and a feedforward motor position instruction ?*m to be input into the feedback controller FB(s). A positioning error caused by a non-linear element (non-linear spring property, relative rotational synchronization component, and non-linear friction) of the strain wave gearing is compensated for by the feedforward linearization compensator.
    Type: Application
    Filed: October 24, 2011
    Publication date: July 24, 2014
    Applicants: National University Corporation Nagoya Institute of Technology, Harmonic Drive Systems Inc.
    Inventors: Masafumi Yamamoto, Yoshifumi Okitsu, Makoto Iwasaki
  • Patent number: 8080964
    Abstract: A method for collecting operational parameters of a motor may include controlling the energization of a phase winding of the motor to establish an operating point, monitoring operational parameters of the motor that characterize a relationship between the energization control applied to the motor's phase winding and the motor's response to this control, and collecting information of the operational parameters for the operating point that characterizes the relationship between the applied energization control and the motor's response. The collected information characterizing the relationship between the applied energization control and the motor's response may be employed by a neural network to estimate the regions of operation of the motor. And a system for controlling the operation of motor may employ this information, the neural network, or both to regulate the energization of a motor's phase winding during a phase cycle.
    Type: Grant
    Filed: October 31, 2005
    Date of Patent: December 20, 2011
    Assignee: Virginia Tech Intellectual Properties, Inc.
    Inventors: Christopher Allen Hudson, Nimal Lobo, Krishnan Ramu
  • Patent number: 7937166
    Abstract: The invention relates to a method for adjusting a system that changes in a cycle to a nonconstant cyclic target profile by comparing measured actual values with appropriate target values for the target profile and outputting a control value.
    Type: Grant
    Filed: January 25, 2007
    Date of Patent: May 3, 2011
    Assignee: Otto Bock Healthcare IP GmbH & Co. KG
    Inventor: Erik Laatsch
  • Patent number: 5969443
    Abstract: An electromagnetic actuating device comprises a solenoid coil to which a control current can be applied and an armature associated with the solenoid coil which is adapted to carry out movements which are dependent upon a control current flowing through the solenoid coil and a spring arrangement for biassing the armature into opposite directions, with a holding position being defined which is assumed by the armature at a holding current through the solenoid coil, with the holding current flowing through the solenoid coil being variable to a higher value or to a lower value with the armature not leaving the holding position, and both the higher and the lower current value being able to be dimensioned in such a manner that interference influences on the magnetic and spring forces which actuate the armature do not bring the armature from its holding position into an actuated position which is different from the holding position.
    Type: Grant
    Filed: January 20, 1998
    Date of Patent: October 19, 1999
    Assignee: Lucas Industries Public Limited Company
    Inventors: Christopher Linden, Stefan Helbing
  • Patent number: 5880567
    Abstract: A servomechanism is controlled to move at a rate below a critical limit by means of a feedback controller (10) which is responsive to the output of a rate measurement device (9). The feedback controller (10) has a non-linear response whose effect only becomes appreciable when the measured rates approach the critical limit. Operation within the critical limits ensures stable and accurate operation of the servomechanism.
    Type: Grant
    Filed: August 27, 1996
    Date of Patent: March 9, 1999
    Assignee: Matra BAe Dynamics (UK) Ltd.
    Inventor: Anthony D Browne
  • Patent number: 5721477
    Abstract: A method and apparatus for controlling a hydraulic manipulator defines a position error signal (.theta..sub.e), defining a first control signal (U.sub.P, U.sub.PD) based on the position error (.theta..sub.e) and generating an improved position error integral signal (.theta..sub.I) based on a product of the position error (.theta..sub.e) integral signal and a velocity factor F.sub.V. The velocity factor F.sub.V is based on a derivative of the position error (.theta..sub.e) and a nonlinear function. An integral control signal (U.sub.I) is produced based on the improved position error integral signal (.theta..sub.I) and is combined with the first signal (U.sub.P, U.sub.PD) to provide an output control signal U to control the manipulator. The invention also preferably includes a system to further reduce overshoot by further modifying the position error signal (.theta..sub.
    Type: Grant
    Filed: February 11, 1997
    Date of Patent: February 24, 1998
    Assignee: The University of Manitoba
    Inventors: Nariman Sepehri, Bradley Edwin Heinrichs, Amir Ali-Akbar Khayyat
  • Patent number: 5694016
    Abstract: A method for controlling a servo system (10) having friction, in which the non-linear characteristic (20) of the position controller (12) is defined such that the magnitude of the variable Ns, Vs supplied to the servo system (10) having friction in the case of a control deviation .DELTA.x lying outside a predeterminable target region (21) produces a torque or a force which is adequate to tear the servo system free of the stiction torque or stiction and such that the movement energy of the servo system (10) can be dissipated in the target region (21). The additional use of an integral component, which is preferably a function of the control deviation .DELTA.x, increases the steady state accuracy.
    Type: Grant
    Filed: October 23, 1996
    Date of Patent: December 2, 1997
    Assignee: Robert Bosch GmbH
    Inventor: Hans-Martin Heinkel
  • Patent number: 5640074
    Abstract: A method and apparatus are disclosed for joining a drive band to the driven element of a servo-controlled precision motion system. A vibration dampening clamp assembly absorbs unwanted vibration energy. The clamp assembly utilizes energy absorbing molded grommets which mechanically isolate the driven element from the band. A threaded fastener passing through an axial bore in each of two energy absorbing grommets is used to join two halves of a clamp assembly. The grommets are preloaded at assembly using threaded fastener and a nut to compress each grommet to a known compression prior to tensioning of the drive band. Upon final tensioning of the band drive assembly, the grommets are brought to a final compression value.
    Type: Grant
    Filed: June 19, 1992
    Date of Patent: June 17, 1997
    Assignee: Agfa Division, Bayer Corporation
    Inventor: Jerry F. Negrotti
  • Patent number: 5627421
    Abstract: A plurality of electromagnetics in an array surround a shaft, with current controlled in the coils of the electromagnets to support the shaft at a desired position approximately centered between the electromagnets. Shaft position sensors provide feedback to a control system for modulating the current to the electromagnet coils, which are arranged in pairs on opposite sides of the shaft. A drive circuit for each coil includes first and second switching transistors which connect the coil to the power supply to transfer a current pulse to the coil. A pair of circulating diodes begin conducting when the transistors turn off, and return power to the supply. A control circuit for the drive circuits interleaves on and off intervals for the coils in the electromagnet pairs so that one coil of the pair is being switched off at about the same time as the other coil of the pair is being switched on.
    Type: Grant
    Filed: October 28, 1994
    Date of Patent: May 6, 1997
    Assignee: Barber-Colman Company
    Inventors: Lance F. Miller, Kenneth J. Eakman
  • Patent number: 5179330
    Abstract: A control circuit includes a microprocessor, a table store and an amplifier stage to control a controlled device which has a non-linear or linear, but discontinuous response curve. To obtain a linear response curve of the controlled device the table store is loaded with a response curve map in operating the controlled device. Thereafter the data loaded in pairs in the table store are inversely read-out and used as a control signal for the controlled device. The table store thus allows to linearize the response curve of the controlled device. In addition the data may be modified. According to the invention any correcting means to obtain an ideal response of the controlled device is eliminated. The invention provides for an optimum performance, smallest possible expenditure of circuitry and shortest possible control time.
    Type: Grant
    Filed: September 25, 1990
    Date of Patent: January 12, 1993
    Assignee: Mannesmann Rexroth GmbH
    Inventor: Heinrich Nikolaus
  • Patent number: 5119003
    Abstract: A non-linear dynamic compensation subsystem is added in the feedback loop of a high precision optical mirror positioning control system to smoothly alter the control system response bandwidth from a relatively wide response bandwidth optimized for speed of control system response to a bandwidth sufficiently narrow to reduce position errors resulting from the quantization noise inherent in the inductosyn used to measure mirror position. The non-linear dynamic compensation system includes a limiter for limiting the error signal within preselected limits, a compensator for modifying the limiter output to achieve the reduced bandwidth response, and an adder for combining the modified error signal with the difference between the limited and unlimited error signals.
    Type: Grant
    Filed: October 10, 1990
    Date of Patent: June 2, 1992
    Assignee: California Institute of Technology
    Inventors: Yu-Hwan Lin, Boris J. Lurie
  • Patent number: 4872190
    Abstract: A system and method is disclosed for minimizing residual vibration of a radiographic system due to rapid movement of a radiographic film cassette between a park and expose position. The cassette is moved by a servo system including a servo motor which is responsive to a voltage input waveform to drive the cassette. A waveform is chosen for the voltage input such that no impulse derivatives appear until the waveform has been differentiated at least three times. The primary natural resonant frequency of the system is determined and noted. The duration of the selected input waveform is adjusted such that the frequency spectrum of the adjusted input waveform defines a relative null which approximately coincides with the primary resonant frequency. The amplitude of the voltage input waveform is then further adjusted as a function of the distance to be traveled by the cassette between the park and expose positions.
    Type: Grant
    Filed: January 13, 1989
    Date of Patent: October 3, 1989
    Assignee: Picker International, Inc.
    Inventors: Mark Stojkov, Patrick M. Flanagan, Victor Hrdlicka, John Geither, Dennis Everett
  • Patent number: 4642541
    Abstract: Described is a novel technique and associated arrangement for determining the noise-free value of a system parameter (e.g., head position in a disk drive) which is time variable and (usually) has a noise component as detected. The technique involves processing the (as detected) noise-including value and passing it, plus a "Time-derivative version" thereof, through "Second Order/Summing" filter means.For instance, the technique is described as particularly useful with the "track-following servo" (part of the transducer positioning means) in a high density disk file (where track density is higher than usual) to secure superior head-displacement error values which are more noise-free. Thus, (see FIG. 4), a pair of first values V.sub.a, V.sub.b are secured by detecting motor current sense voltage V.sub.i, integrating it with respect to time and passing the result through a pair of novel "second order filter" means--one band-pass (F.sub.1), the other low-pass (F.sub.2); while also securing a third value V.sub.
    Type: Grant
    Filed: October 20, 1983
    Date of Patent: February 10, 1987
    Assignee: Memorex Corporation
    Inventor: Ashraf I. El-Sadi
  • Patent number: 4636700
    Abstract: A servo system 10 (FIG. 1) for positioning a sighting mirror 11 connected to a pulley 16 comprises a drive motor 13 rigidly connected to a drive pulley 15 in turn coupled by a tensioned drive belt to the pulley 16. Angular position of the motor or pulley 15 is measured by sensor 18 and passed by way of phase advance network 19 and amplifier 21 to produce an error signal for the drive motor. The pulley 16 is outside of the servo loop and any oscillations induced in the tensioned belt at its resonant frequency, possibly originating from electrical noise in the servo loop, will be uncontrollable.
    Type: Grant
    Filed: October 12, 1984
    Date of Patent: January 13, 1987
    Assignee: Ferranti, plc
    Inventors: Peter G. Moore, John D. Davidson
  • Patent number: 4538493
    Abstract: A machine tool for working sheet metal is described. The principal characteristic of the present invention lies in the fact that it comprises electronic apparatus operable to control the adjustment of the stroke of a striker which can strike a pin supporting a tool for punching or nibbling a metal sheet.
    Type: Grant
    Filed: September 15, 1983
    Date of Patent: September 3, 1985
    Assignee: Rainer S.r.l.
    Inventors: Eugenio Perazzolo, Mauro Tomasi
  • Patent number: 4298833
    Abstract: Apparatus for damping operator induced oscillations of a controlled system responding to an operator controlled signal (DEP) utilizing a lag-lead filter (14) for frequency and amplitude estimation of the control input, and a rectification and smoothing filter (16) for producing a signal proportional to the absolute value of the frequency and amplitude estimate for use in suppression of the control system output signal (DEC). In one embodiment, this is accomplished by computing a correction signal in a correction generating section (18). In a second embodiment, a second rectification and smoothing filter (21) produces a signal proportional to the absolute value of the controlled input signal. A ratio of the outputs of the first and second rectification and smoothing filters is then used in a generator (24) to generate a gain factor k.sub.
    Type: Grant
    Filed: February 29, 1980
    Date of Patent: November 3, 1981
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: John W. Edwards, John W. Smith
  • Patent number: 4284942
    Abstract: Load actuating servomechanism apparatus includes dynamic regeneration and a mechanically damped motor-load coupling to equalize and overcome a frequency-varying load/load drive train mechanical resonance. The drive circuitry comprises a per se conventional primary motor speed controlling rate feedback loop including a cascaded rate signal command source, summing error-signal producing node, and loop frequency response shaping filter and driver amplifier for exciting a load driving motor, and a rate tachometer signal feedback element connecting a measure of the motor output speed to a subtractive input of the summing node.To broaden the response band of the primary feedback circuit and accommodate a mechanical resonance otherwise interfering therewith, a secondary, positive feedback path supplements the input rate command with a signal dependent upon motor current, and thus upon motor load.
    Type: Grant
    Filed: June 16, 1978
    Date of Patent: August 18, 1981
    Assignee: Lockheed Electronics Co., Inc.
    Inventors: William J. Bigley, Vincent J. Rizzo
  • Patent number: 4268785
    Abstract: A compensation circuit for overshoot, undershoot and delay occurring in response to sudden D. C. level changes in signals received by reactive filters. A D. C. level change, represented by an input signal step applied to the reactive filter is detected by the compensation circuit. The compensation circuit responsively provides a compensation D. C. signal step of a predetermined magnitude and polarity with respect to the input signal step. The compensation step is applied by the circuit to the signal return line of the reactive filter, simultaneously with the input signal step received by the filter to maintain a substantially constant D. C. signal level with respect to the reactive filter elements. The reactive filter elements are thus prevented from charging and discharging in response to the input signal step and filter delay is eliminated.
    Type: Grant
    Filed: September 13, 1979
    Date of Patent: May 19, 1981
    Assignee: Ampex Corporation
    Inventor: Gordon D. Svendsen
  • Patent number: 4207506
    Abstract: A servo system wherein an actuating signal obtained by the subtraction of a controlled variable delivered from a controlled system from a secondary command variable is applied to the controlled system, the actuating signal is added to the command to provide a secondary command variable, and the command is compared with the controlled variable in such a manner that when they are coincident with each other, the control is effected so as to change the secondary command variable to a predetermined value, thereby reducing both the transient error and the transient or settling time to a minimum and consequently decreasing the steady state error to a minimum.
    Type: Grant
    Filed: January 18, 1979
    Date of Patent: June 10, 1980
    Assignee: Nippon Telegraph and Telephone Public Corporation
    Inventors: Hisashi Sasaoka, Akira Nagayama
  • Patent number: 4197577
    Abstract: A control system of the non-linear type which behaves in a substantially `proportional` manner. The system comprises an error detector which compares the input and output of a plant to obtain an error value, and a control unit which derives from the error value a continuous control signal for the plant. The control signal comprises a linear term which is a linear function of the error signal and a nonlinear damping term which is a continuously variable function comprising the ratio of the rate of change of the error signal and the error itself.
    Type: Grant
    Filed: July 10, 1978
    Date of Patent: April 8, 1980
    Assignee: Rolls-Royce Limited
    Inventors: Christopher L. Johnson, Peter J. Stratton
  • Patent number: 4051423
    Abstract: A signal compensator for a position servo loop system to attenuate the position error signal and provide stability at a larger band width by limiting the position actuator current in selected frequency ranges.
    Type: Grant
    Filed: February 10, 1976
    Date of Patent: September 27, 1977
    Assignee: Sperry Rand Corporation
    Inventors: James J. Touchton, John Cuda, Frank J. Sordello
  • Patent number: 4042868
    Abstract: A control system using a duty cycle converter to convert an analog input into both a second order or velocity squared feedback as well as a set of clockwise and counterclockwise pulse trains the frequency of which is dependent upon the amplitude of the input signal. The velocity squared feedback is augmented by a position feedback from a stepper motor to provide optimum operation. To obtain optimum performance from a stepper motor, the rate of change of input pulses must not exceed a predetermined value for starting or stopping or the motor will react improperly to some of the pulses. The present system provides a linear increase in the step rate to a maximum and then a linear decrease in the step rate such that there is no overshoot beyond the requested analog input signal.
    Type: Grant
    Filed: September 22, 1975
    Date of Patent: August 16, 1977
    Assignee: Rockwell International Corporation
    Inventor: Melvin H. Rhodes