Patents by Inventor Farhad Aghili

Farhad Aghili 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).

  • Publication number: 20170244344
    Abstract: An energy-efficient and accurate torque control system and method for multiphase nonsinusoidal PMSM with or without open-circuited phase(s) under time-varying torque and speed conditions is based on orthogonally decomposing a phase voltage vector into two components, which become primary and secondary control inputs for torque control and energy minimizer control. The primary control system includes nonlinear feedback from measured phase currents, motor angle, motor speed, and instantaneous value of reference torque and a signature vector indicating which phase(s) is/are open-circuited to establish a first-order linear relationship between reference and generated torques.
    Type: Application
    Filed: February 23, 2017
    Publication date: August 24, 2017
    Inventor: Farhad AGHILI
  • Patent number: 8994308
    Abstract: A technique for controlling drive currents to respective windings of a multi-winding brushless motor comprises monitoring an output of the motor and a demand of the motor, determining whether a failure mode has occurred, the failure mode being an instantaneous complete or partial failure to generate demanded output; and, upon detection of a failure mode on a first winding, distributing a demand contribution that is not being produced by the first winding to one or more of the windings that are not in a failure mode. The demand may be torque demand, and the failure modes may include winding failure, and voltage and/or current saturation. Improved torque output is generated by the redistribution of demand among phases in the event of a failure mode.
    Type: Grant
    Filed: September 21, 2012
    Date of Patent: March 31, 2015
    Assignee: Canadian Space Agency
    Inventor: Farhad Aghili
  • Patent number: 8766578
    Abstract: A method and apparatus are provided for ripple suppression of brushless DC motors at any given velocity irrespective of the limited bandwidth of the driver/amplifier supplying the excitation currents to the stator. In a preferred embodiment, Fourier coefficients of the current waveform are calculated as a function of rotor velocity by taking into account the driver/amplifier's finite bandwidth dynamics. For a given velocity, Fourier coefficients of the series approximating the waveform (control signal) are calculated as a function of the rotor velocity and the amplifier dynamics, to generate a waveform that results in no torque or velocity pulsations. When changing the motor speed, the coefficients are updated (recalculated) based on the new desired velocity (and amplifier dynamics), resulting in generation of an updated waveform that results in no torque or velocity pulsations at the new motor speed.
    Type: Grant
    Filed: February 27, 2012
    Date of Patent: July 1, 2014
    Assignee: Canadian Space Agency
    Inventor: Farhad Aghili
  • Publication number: 20140084833
    Abstract: A technique for controlling drive currents to respective windings of a multi-winding brushless motor comprises monitoring an output of the motor and a demand of the motor, determining whether a failure mode has occurred, the failure mode being an instantaneous complete or partial failure to generate demanded output; and, upon detection of a failure mode on a first winding, distributing a demand contribution that is not being produced by the first winding to one or more of the windings that are not in a failure mode. The demand may be torque demand, and the failure modes may include winding failure, and voltage and/or current saturation. Improved torque output is generated by the redistribution of demand among phases in the event of a failure mode.
    Type: Application
    Filed: September 21, 2012
    Publication date: March 27, 2014
    Inventor: Farhad AGHILI
  • Publication number: 20130221887
    Abstract: A method and apparatus are provided for ripple suppression of brushless DC motors at any given velocity irrespective of the limited bandwidth of the driver/amplifier supplying the excitation currents to the stator. In a preferred embodiment, Fourier coefficients of the current waveform are calculated as a function of rotor velocity by taking into account the driver/amplifier's finite bandwidth dynamics. For a given velocity, Fourier coefficients of the series approximating the waveform (control signal) are calculated as a function of the rotor velocity and the amplifier dynamics, to generate a waveform that results in no torque or velocity pulsations. When changing the motor speed, the coefficients are updated (recalculated) based on the new desired velocity (and amplifier dynamics), resulting in generation of an updated waveform that results in no torque or velocity pulsations at the new motor speed.
    Type: Application
    Filed: February 27, 2012
    Publication date: August 29, 2013
    Inventor: Farhad AGHILI
  • Publication number: 20120086598
    Abstract: In order to determine positional information, about a mobile robot, Real Time Kinematic (RTK) Global Satellite Navigation System (GNSS) measurement data are obtained by at least two GNSS receivers mounted on the mobile robot. Estimates of the covariance matrices of the measurement data are computed. The RTK GNSS measurement data are combined according to the covariance matrices to obtain enhanced positional information. The results may be fused with data from an IMU to obtain driftless attitude and/or localization information.
    Type: Application
    Filed: October 8, 2010
    Publication date: April 12, 2012
    Applicant: CANADIAN SPACE AGENCY
    Inventor: Farhad Aghili
  • Patent number: 7688016
    Abstract: A system for replicating the behavior of a target robotic manipulator with respect to a payload and worksite, has a real-time simulator capturing the dynamics of the target robot manipulator; a mock-up of the payload and worksite; and an emulating robotic manipulator for interacting with said payload and worksite. The emulating robotic manipulator is controlled by the real-time simulator in a control loop to replicate the dynamical behavior of said target robotic manipulator in its environment by matching the impedance of the emulating robotic manipulator with that of the target robotic manipulator.
    Type: Grant
    Filed: September 28, 2005
    Date of Patent: March 30, 2010
    Assignee: Canadian Space Agency
    Inventor: Farhad Aghili
  • Patent number: 7403826
    Abstract: A combined scheme of identification and torque control is provided for rotary hydraulic actuators. The composite controller consists of a dynamic feedback linearizing inner loop cascaded with a robust linear feedback outer loop. The proposed controller allows the actuator to generate desired torque irrespective of the actuator motion. In fact, the controller reduces significantly the impedance of the actuator as seen by its external load, making the system an ideal source of torque suitable for many robotics and automation applications. An identification method to extract the parameters of non-linear model of actuator dynamics and to estimate a bound for modeling uncertainty, used for synthesis of the outer optimal controller, is also presented. Results are illustrated experimentally on a pitch actuator of a Schilling industrial robot.
    Type: Grant
    Filed: November 30, 2005
    Date of Patent: July 22, 2008
    Assignee: Canadian Space Agency
    Inventors: Farhad Aghili, Mehrzad Namvar
  • Publication number: 20070073442
    Abstract: A system for replicating the behavior of a target robotic manipulator with respect to a payload and worksite, has a real-time simulator capturing the dynamics of the target robot manipulator; a mock-up of the payload and worksite; and an emulating robotic manipulator for interacting with said payload and worksite. The emulating robotic manipulator is controlled by the real-time simulator in a control loop to replicate the dynamical behavior of said target robotic manipulator in its environment by matching the impedance of the emulating robotic manipulator with that of the target robotic manipulator.
    Type: Application
    Filed: September 28, 2005
    Publication date: March 29, 2007
    Applicant: Canadian Space Agency
    Inventor: Farhad Aghili
  • Publication number: 20060116783
    Abstract: A combined scheme of identification and torque control is provided for rotary hydraulic actuators. The composite controller consists of a dynamic feedback linearizing inner loop cascaded with a robust linear feedback outer loop. The proposed controller allows the actuator to generate desired torque irrespective of the actuator motion. In fact, the controller reduces significantly the impedance of the actuator as seen by its external load, making the system an ideal source of torque suitable for many robotics and automation applications. An identification method to extract the parameters of non-linear model of actuator dynamics and to estimate a bound for modeling uncertainty, used for synthesis of the outer optimal controller, is also presented. Results are illustrated experimentally on a pitch actuator of a Schilling industrial robot.
    Type: Application
    Filed: November 30, 2005
    Publication date: June 1, 2006
    Inventors: Farhad Aghili, Mehrzad Namvar
  • Publication number: 20050230557
    Abstract: The present invention provides an emulation system having a control system that allows the testing of a satellite control system with all of its hardware in place, i.e. fully integrated. The emulation methodology is applicable to the case of either a rigid spacecraft or a flexible spacecraft, provided that the spacecraft's sensors and actuators are stowed to the rigid part of spacecraft in the case of a flexible spacecraft. Practically, the latter condition is not restrictive, as the actuators and sensors are usually placed rigidly in the satellite bus, while the satellite solar panels constitute the flexible elements. The control system is used to tune the mass properties and dynamic behaviour of a rigid ground-spacecraft in a 1-G environment to those of a flight-spacecraft in 0-G. A six-axis force/moment sensor is placed at an interface of the ground-spacecraft and a manipulator.
    Type: Application
    Filed: December 23, 2004
    Publication date: October 20, 2005
    Inventor: Farhad Aghili