Limit cycle detection and cessation system and method
AssigneeGM Global Technology Operations LLC
InventorsKenneth L. Oblizajek, John D. Sopoci
Life of this patent
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Abstract
Systems and methods are provided for limit cycle detection and cessation. A control system generates a drive signal with at least one drive component. An actuator effects a response to the drive signal and a sensor measures the response. Characteristics of the drive signal and of the drive components are accessed by a controller. The characteristics are compared to a predetermined set of characteristics. When the characteristics fall within the predetermined set of characteristics, a magnitude of at least one of the characteristics is evaluated. When the magnitude exceeds a predetermined value indicative of the limit cycle, an action is undertaken to stop the limit cycle.
Claims20
A system for detecting a limit cycle, comprising:
- a control system configured to generate a drive signal that comprises at least one drive component;
- an actuator configured to effect a response to the drive signal;
- at least one sensor configured to measure the response;
- and
- at least one controller configured to:
- access characteristics of at least one of the drive signal and the at least one drive component;
- compare at least one of the characteristics of the drive signal to a predetermined set of characteristics;
- determine whether the characteristics of the drive signal fall within the predetermined set of characteristics;
- evaluate, when the characteristics of the drive signal fall within the predetermined set of characteristics, a magnitude of at least one of the characteristics;
- undertake, when the magnitude exceeds a predetermined value indicative of the limit cycle, an action to stop the limit cycle;
- and
- modify the drive signal when the characteristics of the drive signal are within a predetermined range and the magnitude does not exceed the predetermined value.
A method for detecting a limit cycle, comprising:
- generating, by a control system, a drive signal;
- effecting, by an actuator, a response to the drive signal;
- accessing, by at least one controller, characteristics of the drive signal and/or characteristics of at least one component of the drive signal;
- measuring, by at least one sensor, the response;
- comparing, by the controller, the characteristics of the drive signal to a predetermined set of characteristics and/or the characteristics of the at least one component to the drive signal in its entirety;
- determining, by the controller, whether the characteristics of the drive signal fall within the predetermined set of characteristics and/or whether a magnitude of the at least one component is disproportionate to the drive signal in the drive signal's entirety;
- triggering, by the controller and when the characteristics of the drive signal fall within the predetermined set of characteristics indicative of the limit cycle, an action to stop the limit cycle;
- and
- modifying, by the controller, the drive signal when an amplitude in the characteristics of the drive signal does not exceed a predetermined value.
A method for detecting a limit cycle, comprising:
- generating, by a control system of a steering system, a drive signal comprising multiple drive components;
- effecting, by a motor, a torque on the steering system in response to the drive signal;
- accessing, by at least one controller, frequency and amplitude of the drive signal;
- measuring, by a torque sensor, the torque on the steering system;
- comparing, by the controller, the frequency of the drive signal to a predetermined range of frequencies;
- determining, by the controller, whether the frequency falls within the predetermined range of frequencies;
- evaluating, by the controller and when the frequency falls within the predetermined range of frequencies, whether the amplitude indicates saturation of the drive signal;
- triggering, by the controller and when the saturation is determined to exist indicative of the limit cycle, an action to stop the limit cycle;
- when the amplitude does not indicate the saturation, effecting a variation of the drive signal by the controller;
- receiving, by the controller and from the torque sensor, an actual value of the torque following the variation;
- comparing, by the controller, the actual value to an expected value;
- and
- triggering, by the controller and when the actual value is different than the expected value indicative of the limit cycle, the action to stop the limit cycle,
- wherein the action comprises at least one of (a) suspending one or more of the multiple drive components;
- and (b) suspending the drive signal.
Dependencies are inferred from the claim text.