Adaptable spatial notch filter
First Claim
1. A method comprising:
- receiving a speed signal representing an angular velocity of a rotating component;
receiving a feedback signal from a sensor coupled to the rotating component;
identifying in the feedback signal at least one frequency of a periodic noise signal that changes linearly with a change in the angular velocity of the rotating component, wherein the periodic noise signal represents periodic errors introduced by imperfections of the sensor; and
attenuating the identified frequency of the feedback signal from the sensor as a function of the angular velocity to remove the periodic errors introduced by the sensor.
1 Assignment
0 Petitions
Accused Products
Abstract
A spatial notch filter is described that adapts in accordance with changes to an angular velocity of a rotating component within a manufacturing system. In a manufacturing system, noise may appear in feedback signals due to spatially distributed physical features in the system, such as imperfections in the components or sensors. This noise may be concentrated in a frequency band that changes as the angular velocity of rotating system components changes. The invention provides techniques for filtering this noise with one or more notch filters, and for adapting the center frequency of the notch filter as a function of angular velocity. The center frequency of the notch filter tracks the noise when the noise frequency changes.
43 Citations
40 Claims
-
1. A method comprising:
-
receiving a speed signal representing an angular velocity of a rotating component;
receiving a feedback signal from a sensor coupled to the rotating component;
identifying in the feedback signal at least one frequency of a periodic noise signal that changes linearly with a change in the angular velocity of the rotating component, wherein the periodic noise signal represents periodic errors introduced by imperfections of the sensor; and
attenuating the identified frequency of the feedback signal from the sensor as a function of the angular velocity to remove the periodic errors introduced by the sensor. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. A medium comprising one or more instructions to cause a processor to:
-
receive a speed signal representing an angular velocity of a rotating component;
receiving a feedback signal from a sensor coupled to the rotating component;
identify in the feedback signal at least one frequency of a periodic noise signal that changes linearly with a change in the angular velocity of the rotating component, wherein the feedback signal includes periodic errors introduced by the sensor; and
attenuate the identified frequency of the feedback signal from the sensor as a function of the angular velocity to remove the periodic errors. - View Dependent Claims (9, 10, 11, 12, 13, 14)
-
-
15. A system comprising:
-
a motor operable to drive a rotating component in response to a motor control signal;
a sensor to generate a feedback signal representing a measurement of the rotating component; and
a filter that receives the feedback signal and attenuates a frequency band of the feedback signal as a function of an angular velocity of the rotating component based on an identified frequency of a periodic noise signal within the feedback signal that changes linearly with a change in the angular velocity of the rotating component. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
-
-
26. A method comprising:
-
rotating a component at an angular velocity;
changing the angular velocity; and
identifying in a feedback signal responsive to the rotation at least one frequency of a periodic signal that changes linearly with the change in angular velocity. - View Dependent Claims (27, 28, 29, 30)
-
-
31. A method comprising:
-
receiving a feedback signal generated by a sensor coupled to a rotating component;
identifying in the feedback signal at least one frequency band of noise generated by one or more spatially distributed physical features on at least one rotating component having an angular velocity, wherein the frequency band changes linearly with a change in the angular velocity of the rotating component;
computing a center frequency for a notch filter as a function of the angular velocity and the identified frequency band of the noise; and
applying the notch filter to the feedback signal to attenuate the frequency baud of noise. - View Dependent Claims (32, 33)
-
-
34. An apparatus comprising:
-
a pre-processing unit that receives and samples a feedback signal provided by a sensor coupled to a rotating component; and
a processor that receives a reference signal indicating a target angular velocity for the rotating component and filters the sampled feedback signal with a notch filter, wherein the processor sets a center frequency of the notch filter as a fiction of the target angular velocity and a periodic noise signal within the feedback signal that changes linearly with a change in the angular velocity of the rotating component. - View Dependent Claims (35, 36)
-
-
37. A method comprising:
-
receiving a feedback signal representing an angular velocity of a rotating component;
identifying a fundamental frequency as a function of an angular velocity of the rotating component;
identifying a harmonic of the fundamental frequency;
setting a sampling frequency for sampling a feedback signal produced by a sensor coupled to the rotating component as a function of the fundamental frequency and the harmonic;
sampling the feedback signal in accordance with the selected sampling frequency to generate a sampled feedback signal;
setting a center frequency of a digital notch filter as a function of the angular velocity of the rotating component and a noise signal within the feedback signal that changes linearly with a change in the angular velocity of the rotating component;
applying the digital notch filter to attenuate a frequency band of the sampled feedback signal to attenuate periodic noise within the feedback signal; and
outputting a control signal to control the rotating component based on the attenuated feedback signal. - View Dependent Claims (38, 39, 40)
-
Specification