Method and system for detecting integrity of a control loop of a physical system
First Claim
1. An apparatus for controlling a closed loop control system of a physical system, the apparatus comprising:
- a controller configured to output a command signal to control a state of a plant of the physical system and to receive a feedback signal providing information about the state of the plant; and
an integrity detection system, wherein the integrity detection system is configured to;
output an excitation signal to the plant;
receive the feedback signal;
determine whether a component associated with the excitation signal is present in the feedback signal; and
identify whether or not the closed loop control system is experiencing a failure based the determination;
wherein the excitation signal has energy in a frequency spectrum,wherein the integrity detection system comprises;
a first filter for filtering the feedback signal in a first frequency band encompassing at least a portion of the excitation signal frequency spectrum;
a level detector for measuring the filtered feedback signal level;
a noise level estimator for providing a noise level estimate of the feedback signal in the first frequency band; and
a signal ratio computation block for computing a signal ratio, wherein the signal ratio is the ratio of the filtered feedback signal to the noise estimate.
8 Assignments
0 Petitions
Accused Products
Abstract
In a control loop, a command signal is applied to physical components to cause movement of the physical components. The position of the physical components is detected and used to generate subsequent command signals. In an implementation, an integrity detection system causes an excitation signal to be injected onto the command signal to cause movement of the physical components at an excitation frequency. This movement is detected in the physical system control loop and isolated by the integrity detection system. If the integrity detection system fails to detect energy in the excitation frequency band, a failure of at least one component of the control system is inferred.
24 Citations
14 Claims
-
1. An apparatus for controlling a closed loop control system of a physical system, the apparatus comprising:
-
a controller configured to output a command signal to control a state of a plant of the physical system and to receive a feedback signal providing information about the state of the plant; and an integrity detection system, wherein the integrity detection system is configured to; output an excitation signal to the plant; receive the feedback signal; determine whether a component associated with the excitation signal is present in the feedback signal; and identify whether or not the closed loop control system is experiencing a failure based the determination; wherein the excitation signal has energy in a frequency spectrum, wherein the integrity detection system comprises; a first filter for filtering the feedback signal in a first frequency band encompassing at least a portion of the excitation signal frequency spectrum; a level detector for measuring the filtered feedback signal level; a noise level estimator for providing a noise level estimate of the feedback signal in the first frequency band; and a signal ratio computation block for computing a signal ratio, wherein the signal ratio is the ratio of the filtered feedback signal to the noise estimate. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. A method of detecting integrity of a closed loop control system of a physical system, the method comprising:
-
outputting a command signal by a controller to control a state of a plant of the physical system; receiving, by the controller, a feedback signal providing information about the state of the plant; outputting an excitation signal into the closed loop control system; receiving the feedback signal; determining whether a component associated with the excitation signal is present in the feedback signal; identifying whether or not the closed loop control system is experiencing a failure based the determination; filtering the feedback signal in a first frequency band encompassing at least a portion of an excitation signal frequency spectrum; measuring the filtered feedback signal level; estimating a noise level of the feedback signal in the first band; and computing a signal ratio, wherein the signal ratio is the ratio of the filtered feedback signal to the noise estimate. - View Dependent Claims (9, 10, 11, 12, 13, 14)
-
Specification