With Particular Compensation (e.g., Gain, Offset, Etc.) Patents (Class 318/568.22)
  • Patent number: 6507165
    Abstract: A controller for a machine such as a robot and a machine tool having an electric motor as a driving source of the machine, capable of suppressing a natural vibration of the machine and/or an attachment attached to the machine. A frequency or a cycle of the natural vibration of an end effector of the robot as the attachment or the machine itself is determined and a coefficient of a filter for suppressing an amplitude of the natural vibration is altered in accordance with the measured frequency or cycle of the natural vibration. In the case of suppressing a natural vibration of the end effector attached to the robot, frequencies or cycles of natural vibrations of various end effectors in accordance with an operation status of the end effector are determined and stored, and the coefficient of the filter is set in accordance with the stored frequency or cycle of the natural vibration in accordance with the end effector attached to the robot and the operation status.
    Type: Grant
    Filed: February 9, 2001
    Date of Patent: January 14, 2003
    Assignee: Fanuc Ltd.
    Inventors: Tetsuaki Kato, Toru Shirahata, Kaname Matsumoto, Hiroyuki Kawamura
  • Patent number: 6487458
    Abstract: A closed-loop control of a servo motor in which multiple closed-loop terms of a motor command are adaptively tuned and selectively activated to achieve both stable operation and improved performance. The motor command includes a first term proportional to an error signal, a second term based on the integral of the error signal, and a third term based on the rate of change of the measured feedback signal, and representing the kinetic energy of the system. The first term is continuously active, whereas the second term is only activated when the rate of change of the measured feedback signal is below a threshold, and the third term is only activated when the error signal is within a reference window, thereby allowing relatively high gains while ensuring stable operation.
    Type: Grant
    Filed: August 31, 1999
    Date of Patent: November 26, 2002
    Assignee: Delphi Technologies, Inc.
    Inventor: David James Trapasso
  • Patent number: 6479960
    Abstract: A machine tool includes a tool (a drill or the like having a diameter of 2 mm or less), a camera (artificial retina chip or the like) which acquires an image of the tool, and an image processor which determines whether the tool is faulty based on the image acquired by the camera.
    Type: Grant
    Filed: February 14, 2001
    Date of Patent: November 12, 2002
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Satoru Nakai, Takashi Iwasaki, Peter Loennqvist
  • Patent number: 6476575
    Abstract: An adaptive control system for adaptively controlling a turning operation performed at a work piece by a turning tool adjusts a controlled input operation parameter F to maintain an output operation parameter &Dgr;M substantially at a predetermined value &Dgr;Mo to compensate variation of the output operation paramemeter &Dgr;M caused by the variation of at least one operation condition B=B (t). The system comprises a sensor (8) of the output operation parameter &Dgr;M for providing a signal Uc proportional to a current value &Dgr;Mc and an adaptive controller (10) for determining a value Fc to which the input operation parameter F should be adjusted, as a function of kUc, where k is a signal transmission coefficient which comprises an invariant signal transmission coefficient component ko inversely proportional to &Dgr;Mo.
    Type: Grant
    Filed: June 11, 2001
    Date of Patent: November 5, 2002
    Assignee: Omat Ltd.
    Inventors: Boris Fainstein, Mark Zuckekrman, Igor Rubashkin, Eduard Takachnik
  • Patent number: 6472839
    Abstract: Based on a control object, a result of the detection of driving of an actuator and a response from a standard mathematical model of the actuator, the actuator is controlled, or in a servo system that controls the angle of a joint, etc., the control value is corrected so that the response from the thing to be driven and the response from the model of the thing to be driven are set to coincide with each other, and also based on a result of the correction of the control value, at least the moment of inertia of the thing to be driven is detected. Thereby, the moment of inertia of the driver and the like can be detected in real-time without providing a special sensor.
    Type: Grant
    Filed: January 19, 2001
    Date of Patent: October 29, 2002
    Assignee: Sony Corporation
    Inventors: Shinji Ishii, Yoshihiro Kuroki
  • Patent number: 6430473
    Abstract: A power assist apparatus includes an autonomously mobile base on which a manipulator for holding a load is mounted. The movement of the mobile base is controlled such that when the manipulator tip is within a prescribed operating region relative to the mobile base, the mobile base is maintained stationary, but when the manipulator tip moves outside the operating region, the mobile base is moved to decrease the distance between the mobile base and the manipulator tip. The power assist apparatus assists with the carrying of loads by amplifying an operational force applied to the manipulator.
    Type: Grant
    Filed: October 13, 2000
    Date of Patent: August 6, 2002
    Assignee: Agency of Industrial Science & Technology, Ministry of International Trade & Industry
    Inventors: Hyoung-Ki Lee, Hirohiko Arai, Kazuo Tanie
  • Patent number: 6400114
    Abstract: A numerical control apparatus for the numerical control of a roll grinding machine comprises a flaw detecting means for scanning the entire surface of a roll (11), provided with an ultrasonic detecting head (23) for detecting flaws formed in the surface of the roll (11), a command generating means for generating cross-feed commands to repair detected flaws on the basis of flaw information about the positions and levels of the detected flaws, a control means for executing a first shaft position control operation on the basis of the cross-feed command to position the grinding wheel at a position with respect to a Z-axis corresponding to the position of the flaw by moving the wheel spindle stock in parallel to the axis of the roll and a second shaft positioning control operation to cross-feed the grinding wheel in parallel to an X-axis, and a decision means for deciding whether or not the flaw has been completely repaired and invoking the next cross-feed command if the flaw has been completely repaired.
    Type: Grant
    Filed: March 16, 2001
    Date of Patent: June 4, 2002
    Assignee: Toshiba Kikai Kabushiki Kaisha
    Inventors: Takashi Kunugi, Hiroshi Uchimura
  • Patent number: 6384562
    Abstract: A scanner motor acceleration method that uses a software driver and a flexible process method to enable a scanner to perform fast scanning operation without increasing motor cost or complex hardware design. Motor acceleration and deceleration may be done through software control on existing scanner hardware which do not support acceleration and deceleration function. Through positioning and speeding mechanisms of existing scanner hardware, and software which may be changed flexibly, scanner positioning function may be accurately performed without deviations.
    Type: Grant
    Filed: September 8, 2000
    Date of Patent: May 7, 2002
    Assignee: UMAX Data Systems Inc.
    Inventor: Chen-Ho Lee
  • Patent number: 6377014
    Abstract: In a biped walking robot having a body and two articulated legs each connected to the body and each having a foot at its free end such that the robot is controlled to walk by landing a heel of the foot first on a floor. The heel of the foot has projections and packings charged in gaps. The projections are constituted to have high rigidity against forces acting in the direction of the gravity axis and low rigidity, which is lower than the first rigidity, against forces acting in other directions, when the heel is landed, thereby enabling to achieve an optimum balance between absorption/mitigation of shock at footfall and attitude stabilization after footfall.
    Type: Grant
    Filed: August 11, 2000
    Date of Patent: April 23, 2002
    Assignee: Honda Giken Kogyo Kabushiki Kaisha
    Inventors: Hiroshi Gomi, Kazushi Hamaya
  • Patent number: 6377012
    Abstract: A servo system controller which has a sequence controlling section 2 and a servo controlling section 3, employs not only a current position of a servo motor but also other servo control data or a sequencer device as comparison data, and executes a comparing process for compares whether or not respective comparison data are in respective detection ranges to then output respective comparison results, increase and variation of a response time can be prevented until the comparison results are output from the change of the comparison data. A comparing process table memory 14 is provided in the servo controlling section 3, and the comparing process is executed in synchronism with a calculation period of the servo controlling section 3, and a detection signal is output while the comparison data is within a detection range. In a machining apparatus utilizing the servo system controller, a tact time can be reduced without large increase of a cost.
    Type: Grant
    Filed: January 29, 2001
    Date of Patent: April 23, 2002
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Nobuyasu Takaki
  • Patent number: 6374156
    Abstract: A key input section which permits the execution of output controls is provided on a teach pendant. A control unit of a robot control system ignores all input movement requests to move the robot if a key of the key input section is depressed and if an output of the key is an output set for prohibiting the movement of the robot and is in an output state that is set.
    Type: Grant
    Filed: March 30, 2000
    Date of Patent: April 16, 2002
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Shigeru Shimogama, Hiroshi Nakajima
  • Patent number: 6356808
    Abstract: A method for cell alignment, identification and calibration of part of a robot tool, preferably a part of the robot tool, is positioned close to a detector, whereupon it is moved repeatedly past the limit of the area of detection of the detector. During the movement, the pose of the robot is registered each time the surface of said robot tool comes into tangential contact with the area of detection, and an over determined system of equations is formed, consisting of a correlation between the registered poses and unknown parameters regarding the detection area of the detector and the location of the robot part in space. An error vector is introduced into the system of equations, which is then solved while minimizing the error vector, preferably in the least square sense, in order to thus identify said unknown parameters and the error vector.
    Type: Grant
    Filed: June 4, 2001
    Date of Patent: March 12, 2002
    Assignee: Robotkonsult AB
    Inventor: Björn Stenberg
  • Patent number: 6356807
    Abstract: A method of determining contact positions of a robot relative to a workpiece in a workspace of the robot. The method utilizes the contact positions to determine a location of the workpiece in the robot workspace. The method also monitors an integral operating parameter within the robot, such as motor torque, to determine the contact positions of the robot relative to the workpiece and to locate the workpiece.
    Type: Grant
    Filed: August 12, 2000
    Date of Patent: March 12, 2002
    Assignee: FANUC Robotics North America, Inc.
    Inventors: H. Dean McGee, Eric C. Lee
  • Patent number: 6341246
    Abstract: An object oriented motion system for controlling the movement of a robotic manipulator is presented. The motion system includes a trajectory generator object for producing a stream of machine joint commands. A kinematics object is operable to provide a set of robotic arm specific functions for the trajectory generator object. A servo object provides an interface to the servo system. The stream of machine motor commands are converted by the servo object to a stream of signals that drive the servo system, thereby controlling the trajectory of the robot arm.
    Type: Grant
    Filed: March 26, 1999
    Date of Patent: January 22, 2002
    Assignee: KUKA Development Laboratories, Inc.
    Inventors: Michael D. Gerstenberger, Scott D. Greig, David M. Martin, Khalid Mirza, El-Houssaine Waled
  • Patent number: 6329773
    Abstract: A transmission voltage of a power transmission system in a transmission voltage control depends on a product of a voltage drooping factor and a difference between a reactive current of a synchronous generator and a reference value. The voltage drooping factor depends on a gain and a voltage-up ratio of a transformer arranged between the power transmission system and the synchronous generator. The voltage-up ratio changes with a tap position of the transformer. The tap position of the transformer is always detected to update the voltage-up ratio, the gain is determined according to the updated voltage-up ratio to maintain the voltage drooping factor at a constant value, and the transmission voltage is regulated by using the gain. Therefore, even though the tap position of the transformer is changed, the voltage drooping factor is maintained at a constant value, and the stability of the transmission voltage of the power transmission system is maintained.
    Type: Grant
    Filed: June 19, 2000
    Date of Patent: December 11, 2001
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Yuou Xia, Masaru Shimomura
  • Publication number: 20010045809
    Abstract: The number of operation keys is decreased, realizing cost reduction and miniaturization of a teaching device. Further, the working efficiency and operational safety are considerably improved. Also, the operations of the robot ranging from delicate positioning and high-speed continuous operation can be readily controlled by serial manipulations. The present invention includes (a) a plurality of operation keys to designate one out of a plurality of operation coordinates of the robot arm, and (b) a controller which controls the operation of the robot arm. The controller has a function to control the robot arm so that the robot arm is positioned on the designated operation coordinates and also a function to control the operation speed of the robot arm. The controller includes a jog dial disposed in a manner such that the jog dial can be rotated and pushed.
    Type: Application
    Filed: March 28, 2001
    Publication date: November 29, 2001
    Inventor: Yasushi Mukai
  • Patent number: 6310456
    Abstract: A control system for determining a control function for a control device on the basis of a transfer function of an object to be controlled and for adjusting an operation quantity of an object to be controlled in accordance with the determined control operation function, wherein an control function of a first control device is determined so that a closed-loop transfer function of a control system including the object to be controlled and the first control device coincides with a predetermined first transfer function, an control function of a second control device is determined, in a closed loop control system including the control system and the first control device, so that a transfer function from a disturbance applied to the object to be controlled to a state variable of a point at which the disturbance is applied to the object to be controlled, and a sum signal indicative of a sum of outputs of the first and second control devices is used as an operation quantity of the object to be controlled.
    Type: Grant
    Filed: December 28, 1999
    Date of Patent: October 30, 2001
    Assignee: Hitachi, Ltd.
    Inventors: Yasuo Morooka, Hiromi Inaba, Takashi Nakahara, Takashi Okada, Masahiro Tobise, Yoshitaka Iwaji
  • Patent number: 6310457
    Abstract: When contents of a program for machining to be executed by a servomotor indicate a cutting mode, a current command is generated by performing speed loop processing by using a speed loop gain for cutting mode, and moreover, a voltage command to a servo amplifier is generated by performing proportional-plus-integral (PI) current loop processing in accordance with the generated current command. On the other hand, when the contents of the machining program indicate a positioning mode, a current command is generated by performing speed loop processing by using a speed loop gain for positioning mode, and moreover, a voltage command to the servo amplifier is generated by performing integral-plus-proportional (I-P) current loop processing in accordance with the generated current command.
    Type: Grant
    Filed: January 20, 2000
    Date of Patent: October 30, 2001
    Assignee: Fanuc Ltd.
    Inventors: Yasusuke Iwashita, Tadashi Okita
  • Publication number: 20010033146
    Abstract: A controller for a machine such as a robot and a machine tool having an electric motor as a driving source of the machine, capable of suppressing a natural vibration of the machine and/or an attachment attached to the machine. A frequency or a cycle of the natural vibration of an end effector of the robot as the attachment or the machine itself is determined and a coefficient of a filter for suppressing an amplitude of the natural vibration is altered in accordance with the measured frequency or cycle of the natural vibration. In the case of suppressing a natural vibration of the end effector attached to the robot, frequencies or cycles of natural vibrations of various end effectors in accordance with an operation status of the end effector are determined and stored, and the coefficient of the filter is set in accordance with the stored frequency or cycle of the natural vibration in accordance with the end effector attached to the robot and the operation status.
    Type: Application
    Filed: February 9, 2001
    Publication date: October 25, 2001
    Inventors: Tetsuaki Kato, Toru Shirahata, Kaname Matsumoto, Hiroyuki Kawamura
  • Patent number: 6300738
    Abstract: A method of controlling a motor comprises providing a motion control system and causing the shaft of the motor to move from an initial state to a new state, such as from an initial position or velocity to a new position or velocity. Coefficients for each of a plurality of polynomial segments of a motion profile are determined. The plurality of polynomial segments and the corresponding coefficients for each respective segment characterize planned movement of the shaft through each respective segment. In a particularly preferred aspect, each segment is defined by a plurality of polynomials, which include a first polynomial that describes shaft position with respect to time, a second polynomial that describes shaft velocity with respect to time, and a third polynomial that describes shaft acceleration with respect to time.
    Type: Grant
    Filed: September 30, 1999
    Date of Patent: October 9, 2001
    Assignee: Rockwell Automation Technologies, Inc.
    Inventor: Juergen K. Weinhofer
  • Patent number: 6301511
    Abstract: A numeric control device of a turning mechanism which turns a turning body from a driving source which circularly moves through a non-linear transmitting mechanism has a coordinate transformation device outputting a signal which converts an inputted turning angular signal into a position of the driving source, and a compensator outputting a signal which is derived from computing a positional error of the driving source in accordance with the turning angular signal, and the control of the driving source is carried out by a servo-input signal which is derived from the sum of a conversion signal outputted from the coordinate transformation device and a compensation signal outputted from the compensator. Since the numerical control mechanism of the present invention controls the driving source with addition of the compensation signal, it becomes possible to stabilize the turning velocity of the turning body with high accuracy.
    Type: Grant
    Filed: April 27, 1998
    Date of Patent: October 9, 2001
    Assignee: Toshiba Kikai Kabushiki Kaisha
    Inventors: Jun Fujita, Kiyoshi Inoue, Hideki Hayashi
  • Patent number: 6291962
    Abstract: When a playback signal of recorded data which is a DC free code has non-linearity, the playback signal is equalized by a waveform equalization unit, and sampled by an analog-to-digital converter. The sample data is binarized, and an offset amount is detected by utilizing the feature of the DC free code, and then the reference level of the analog-to-digital converter is controlled so that the output of a first integrator becomes 0. Thereafter, the output of a level shift circuit is input to a second integrator, and the level shift amount is controlled so that the output becomes 0. The converged value is retained. After this learning, by using the retained level shift amount, the reference level is controlled so that the output of the second integrator becomes 0, thereby performing speedy and accurate DC offset control.
    Type: Grant
    Filed: February 16, 2000
    Date of Patent: September 18, 2001
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Yoichi Ogura, Shoji Marukawa
  • Patent number: 6289265
    Abstract: The posture inclination of the robot is detected, a moment of compensating total floor reaction force about a desired total floor reaction force central point is determined therefrom to be distributed to each foot such that the position/posture of the feet are rotated by predetermined amounts about the desired total floor reaction force central point and a desired foot floor reaction force central points respectively. And by parallel-translating the feet in phase, the force component of the actual total floor reaction force is also controlled. In addition, the internal force components (which do not influence on the actual total floor reaction force) generated by the actual foot floor reaction force are controlled independently.
    Type: Grant
    Filed: October 19, 2000
    Date of Patent: September 11, 2001
    Assignee: Honda Giken Kogyo Kabushiki Kaisha
    Inventors: Toru Takenaka, Tadaaki Hasegawa, Takashi Matsumoto
  • Patent number: 6285972
    Abstract: A method and system for generating an improved nonlinear system model includes generating a linear system model and using a response therefrom to generate the nonlinear system model. A method and system for generating drive signals for a test system uses the improved nonlinear system model or a conventional nonlinear system model.
    Type: Grant
    Filed: October 18, 1999
    Date of Patent: September 4, 2001
    Assignee: MTS Systems Corporation
    Inventor: Andrew J. Barber
  • Patent number: 6274994
    Abstract: In a servo control apparatus in which a machine system is driven by a servo motor, a phase compensation device is provided. The phase compensating device calculates a speed component (phase delay compensation signal) corresponding to a phase delay caused by a mechanical resonance suppressing filter which is provided so as to suppress resonance and mechanical vibrations, produced by a characteristic frequency owned by the machine system. While such a signal obtained by adding this speed component (phase delay compensation signal) to an actual motor speed is used as a speed feedback signal for a control operation, unstable conditions of a servo system, which are caused by the phase delay caused when the mechanical resonance filter is applied, are suppressed, and a high gain of the servo control apparatus is realized.
    Type: Grant
    Filed: January 12, 2001
    Date of Patent: August 14, 2001
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Kazuhiko Tsutsui
  • Patent number: 6252368
    Abstract: A backlash compensation device for use with a numerically controlled system compensates for a position command signal used to drive and control an object to be controlled. The device includes a reversal detecting unit for detecting a reversal of a direction of driving the object to be controlled based on a reversal of an upward or downward trend in the level of an applied position command signal. A maximum backlash signal generating unit generates a maximum backlash signal corresponding to a maximum value of backlash error every time a reversal of a direction of driving the object is detected. A filter then reduces the level of the maximum backlash signal according to how much time has elapsed since the detected reversal of the driving direction. An adder adds the reduced maximum backlash signal from the filter to the position command signal.
    Type: Grant
    Filed: December 28, 1999
    Date of Patent: June 26, 2001
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Hiroshi Sugie
  • Patent number: 6246203
    Abstract: Systems and methods are described for direct skew control and interlock of a gantry. An apparatus includes a gantry that includes a first member defining a gantry primary axis Z, a cross member defining a secondary axis X that is coupled to the first member via a trunnion, and a second member defining a gantry primary axis Z′ coupled to the cross member via an elastic hinge. A method for controlling skew on a cross member moved by a first and second driver includes moving the first and second drivers to a first position, measuring a resulting skew value, and correcting the skew on the cross member by moving the first driver and/or the second driver.
    Type: Grant
    Filed: February 5, 1999
    Date of Patent: June 12, 2001
    Assignee: Silicon Valley Group, Inc.
    Inventors: Rexford Abbott, Son Phi
  • Patent number: 6239572
    Abstract: A servo control apparatus for performing a feedback control to an analog controlled system, includes an error generating device that generates a digital error corresponding to a difference between a desired value and a feedback value corresponding to a controlled variable of the analog controlled system, a control device that generates a digital manipulated variable, and a digital-to-analog converting device that converts the digital manipulated variable into an analog manipulated variable for driving the analog controlled system. The control device includes a disturbance estimating device that estimates a disturbance applied to the analog controlled system by carrying out a digital estimating process by using the digital manipulated variable and the digital error and generates a digital compensated variable corresponding to the estimated disturbance, and a manipulated variable generating device that generates the digital manipulated variable by using the digital error and the digital compensated variable.
    Type: Grant
    Filed: February 14, 2000
    Date of Patent: May 29, 2001
    Assignee: Pioneer Corporation
    Inventor: Kiyoshi Tateishi
  • Patent number: 6232737
    Abstract: According to the present invention, in a first acceleration after power is turned ON, currents flowing through U-phase and V-phase of a servo motor output terminal are detected, and misconnection of the motor output terminal is detected by monitoring a pattern of the current wave form.
    Type: Grant
    Filed: June 8, 2000
    Date of Patent: May 15, 2001
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Mitsuyasu Kachi, Kazuhiko Tsutsui
  • Patent number: 6225771
    Abstract: Probe chord error compensation is provided in a machine tool including a rotary member for supporting a work piece and a probe having a path of travel. The compensation is accomplished by using the probe to measure an observed diameter of the work piece and then determining the crossover error of the machine tool. The observed diameter and the crossover error are then used to compute the work piece's actual diameter, thereby compensating for any probe chord error.
    Type: Grant
    Filed: December 1, 1999
    Date of Patent: May 1, 2001
    Assignee: General Electric Company
    Inventor: R. David Hammerle
  • Patent number: 6218801
    Abstract: A method for supervision of the movement control of a manipulator. The manipulator comprises at least one movement axis, a servo (9) for controlling the axis in accordance with supplied reference values for position, speed and acceleration (&psgr;ref, {dot over (&psgr;)}ref, {umlaut over (&psgr;)}ref). A plurality of dynamic parameters (dyn-par) are calculated in dependence on reference values for the position and speed of the axis and a dynamic model (7) which describes the static and dynamic properties of the robot. A torque signal (&tgr;mr) is generated by the servo in dependence on the control error torque (&tgr;err) of the servo.
    Type: Grant
    Filed: March 7, 2000
    Date of Patent: April 17, 2001
    Assignee: ABB AB
    Inventors: Torgny Brogårdh, Staffan Elfving, Ingvar Jonsson, Stig Moberg, Fredrik Skantze
  • Patent number: 6205839
    Abstract: An equipment for calibration of an industrial robot which has a plurality of axes of rotation and wherein, the equipment comprises a measuring device is adapted for rotatable connection to a reference point the position of which is known, is adapted to be in contact with the robot, or a tool carried by the robot, during the calibration process, and has an axis of rotation which intersects the reference point when the measuring device is connected to the reference point. The measuring device further comprises a gravity sensor which is so mounted so that the axis of the gravity sensor is substantially parallel to the axis of rotation of the measuring device, whereby the gravity sensor measures the angle between the gravity vector and axis of rotation.
    Type: Grant
    Filed: September 25, 1997
    Date of Patent: March 27, 2001
    Assignee: Asea Brown Bovreri AB
    Inventors: Torgny Brogårdh, John-Erik Snell
  • Patent number: 6185467
    Abstract: An adaptive, discrete-time sliding mode controller (SMC) is disclosed which detects and adapts to gain variations in the controlled plant. The overall control effort is generated by combining a linear control effort with a discrete-time sliding mode control effort generated by switching between gains in order to drive the system's phase states toward a sliding line trajectory. A sliding mode variable &sgr;k defines the position of the system phase states relative to the sliding line. The SMC controller is designed such that the sliding mode variable &sgr;k crosses the sliding line and changes sign at every sample interval. For the nominal plant gain, the SMC controller is also designed such that the magnitude of the sliding mode variable &sgr;k+1=−&sgr;k will remain constant (&sgr;k+1=−&sgr;k) and substantially constrained to |&sgr;k|=&Dgr;/(1+&lgr;) where &Dgr; and &lgr; are predetermined design constants.
    Type: Grant
    Filed: September 2, 1998
    Date of Patent: February 6, 2001
    Assignee: Cirrus Logic, Inc.
    Inventors: Paul M. Romano, Louis Supino, Christopher T. Settje