Patents by Inventor Raymond Y. Liu
Raymond Y. Liu has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 8058826Abstract: In a normal operating mode, a motor controller provides motor drive current to windings of a motor based on sensor signals to drive the windings in a normal commutation sequence, and monitors for occurrence of a motor stall condition. Upon detecting the motor stall condition in a given commutation state, then in a first driving step, the windings are momentarily driven according to an advanced commutation state, and during the first driving step, a reverse transition of the sensor signals to a state corresponding to a preceding commutation state is detected.Type: GrantFiled: June 30, 2008Date of Patent: November 15, 2011Assignee: Woodward HRT, Inc.Inventors: M. Robert Mock, Raymond Y. Liu
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Patent number: 7973503Abstract: A system has a sensor assembly mounted adjacent to a moving magnetic member such as a motor rotor to sense its position. The sensor assembly includes Hall-effect sensors each having a binary output, configured such that distinct positions of the moving magnetic member correspond to distinct digital patterns of the outputs of the Hall-effect sensors. Encoding circuitry is coupled to the outputs of the Hall-effect sensors to generate a multi-valued analog output, distinct values of the multi-valued analog output representing corresponding distinct digital patterns of the outputs of the Hall-effect sensors. The encoding circuitry may employ a ladder network with weighted-value resistors contributing different components of an analog current sensed by the controller. The sensed current can be converted to digital position information using suitable analog-to-digital conversion circuitry.Type: GrantFiled: June 26, 2007Date of Patent: July 5, 2011Assignee: Wooward HRT, Inc.Inventors: Raymond Y. Liu, Estella C. Chung
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Patent number: 7956619Abstract: A device has built-in inductive load testing capabilities. The device includes a device housing, an inductive load disposed within the device housing; and test circuitry disposed within the device housing. The test circuitry is constructed and arranged to effectuate application of a modulated test signal to the inductive load, and obtain a result signal in response to the application of the modulated test signal to the inductive load. The test circuitry is further constructed and arranged to generate an output signal indicating that the inductive load is in one of (i) a shorted inductive load state, (ii) a normal inductive load state, and (iii) an abnormally high inductive load state, based on the result signal. Such test circuitry is well-suited for testing a variety of devices having inductors/coils which are susceptible to defects (e.g., a solenoid, a motor winding, various actuator components, etc.).Type: GrantFiled: May 31, 2007Date of Patent: June 7, 2011Assignee: Woodward HRT, Inc.Inventors: Raymond Y. Liu, Estella C. Chung, Joon Lee
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Publication number: 20100259274Abstract: A device has built-in inductive load testing capabilities. The device includes a device housing, an inductive load disposed within the device housing; and test circuitry disposed within the device housing. The test circuitry is constructed and arranged to effectuate application of a modulated test signal to the inductive load, and obtain a result signal in response to the application of the modulated test signal to the inductive load. The test circuitry is further constructed and arranged to generate an output signal indicating that the inductive load is in one of (i) a shorted inductive load state, (ii) a normal inductive load state, and (iii) an abnormally high inductive load state, based on the result signal. Such test circuitry is well-suited for testing a variety of devices having inductors/coils which are susceptible to defects (e.g., a solenoid, a motor winding, various actuator components, etc.).Type: ApplicationFiled: May 31, 2007Publication date: October 14, 2010Applicant: HR Textron Inc.Inventors: Raymond Y. Liu, Estella C. Chung, Joon Lee
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Patent number: 7808200Abstract: A technique can recover from motor stalls caused by misalignment of motor position sensors such as Hall-effect sensors. In a normal operating mode, a motor controller provides motor drive current to the motor windings based on the sensor signals according to a normal commutation sequence, and monitors for occurrence of a motor stall condition. Upon detecting the motor stall condition, the motor controller first momentarily drives the windings according to one of an advanced commutation state and a delayed commutation state each adjacent to the given commutation state in the normal commutation sequence, and determines whether the motor stall condition persists. If the stall condition persists, then the motor controller next momentarily drives the windings according to the other of the advanced commutation state and the delayed commutation state.Type: GrantFiled: September 6, 2007Date of Patent: October 5, 2010Assignee: Woodward HRT, Inc.Inventors: Raymond Y. Liu, Estella C. Chung, William K. Morita, Jr.
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Publication number: 20090322267Abstract: In a normal operating mode, a motor controller provides motor drive current to windings of a motor based on sensor signals to drive the windings in a normal commutation sequence, and monitors for occurrence of a motor stall condition. Upon detecting the motor stall condition in a given commutation state, then in a first driving step, the windings are momentarily driven according to an advanced commutation state, and during the first driving step, a reverse transition of the sensor signals to a state corresponding to a preceding commutation state is detected.Type: ApplicationFiled: June 30, 2008Publication date: December 31, 2009Applicant: HR TEXTRON INC.Inventors: M. Robert Mock, Raymond Y. Liu
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Publication number: 20090066274Abstract: A technique can recover from motor stalls caused by misalignment of motor position sensors such as Hall-effect sensors. In a normal operating mode, a motor controller provides motor drive current to the motor windings based on the sensor signals according to a normal commutation sequence, and monitors for occurrence of a motor stall condition. Upon detecting the motor stall condition, the motor controller first momentarily drives the windings according to one of an advanced commutation state and a delayed commutation state each adjacent to the given commutation state in the normal commutation sequence, and determines whether the motor stall condition persists. If the stall condition persists, then the motor controller next momentarily drives the windings according to the other of the advanced commutation state and the delayed commutation state.Type: ApplicationFiled: September 6, 2007Publication date: March 12, 2009Applicant: HR TEXTRON INC.Inventors: Raymond Y. Liu, Estella C. Chung, William K. Morita, JR.
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Publication number: 20090001966Abstract: A system has a sensor assembly mounted adjacent to a moving magnetic member such as a motor rotor to sense its position. The sensor assembly includes Hall-effect sensors each having a binary output, configured such that distinct positions of the moving magnetic member correspond to distinct digital patterns of the outputs of the Hall-effect sensors. Encoding circuitry is coupled to the outputs of the Hall-effect sensors to generate a multi-valued analog output, distinct values of the multi-valued analog output representing corresponding distinct digital patterns of the outputs of the Hall-effect sensors. The encoding circuitry may employ a ladder network with weighted-value resistors contributing different components of an analog current sensed by the controller. The sensed current can be converted to digital position information using suitable analog-to-digital conversion circuitry.Type: ApplicationFiled: June 26, 2007Publication date: January 1, 2009Applicant: HR TEXTRON INC.Inventors: Raymond Y. Liu, Estella C. Chung
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Patent number: 7230422Abstract: Systems, methods, and computer-readable media are disclosed for error-compensated counting of Hall states for motor position feedback and/or commutation. An indicated Hall state is detected by digital Hall state sensors and a duration of the Hall state is compared to a specified time period. When the duration exceeds the specified time period, the indicated Hall state is compared to one or more valid Hall states and a position counter is changed for valid states. When the indicated Hall state is invalid, the position counter is not changed. The Hall state sensors may be connected to logic means and may detect the position of a rotor of a permanent magnet motor relative to a stator. When noise induces a change in an indicated Hall state, corresponding noise-induced effects on the position counter may be may be removed through error-compensated counting.Type: GrantFiled: April 28, 2006Date of Patent: June 12, 2007Assignee: HR Textron, Inc.Inventors: William K. Morita, Jr., Raymond Y. Liu, Estella C. Chung
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Patent number: 7049813Abstract: Systems, methods, and computer-readable media are disclosed for error-compensated counting of Hall states for motor position feedback and/or commutation. An indicated Hall state is detected by digital Hall state sensors and a duration of the Hall state is compared to a specified time period. When the duration exceeds the specified time period, the indicated Hall state is compared to one or more valid Hall states and a position counter is changed for valid states. When the indicated Hall state is invalid, the position counter is not changed. The Hall state sensors may be connected to logic means and may detect the position of a rotor of a permanent magnet motor relative to a stator. When noise induces a change in an indicated Hall state, corresponding noise-induced effects on the position counter may be may be removed through error-compensated counting.Type: GrantFiled: May 19, 2004Date of Patent: May 23, 2006Assignee: HR Textron Inc.Inventors: William K. Morita, Jr., Raymond Y. Liu, Estella C. Chung