Adaptation performance improvements for active control of sound or vibration
First Claim
1. A method for reducing sensed physical variables including the steps of:
- a) generating a plurality of control commands as a function of the sensed physical variables based upon an estimate of a relationship between the sensed physical variables and the control commands;
b) updating the estimate of the relationship based upon a response by the sensed physical variables; and
c) varying a size of the update to the estimate in said step b) based upon a magnitude of change over time by at least one of the plurality of control commands, wherein the estimate of the change in response y=Δ
z due to a chance in control command v=Δ
u at a specific time tk is denoted Tk, where Tk is updated according to the equations
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Abstract
A noise or vibration control system improves the quality of adaptation estimates by filtering the input signals to the adaptation, selectively implementing a “dead-zone” during which adaptation does not occur and by selectively adding a dither signal to the control commands. The dead-zone is based on the magnitude of the changes in the control commands, which are responding to the changes in the sensor signals. The dead-zone can be applied to all actuators simultaneously, or can be applied to the adaptation of each actuator channel independently. To maintain identifiability, a “dither signal” is added to the control commands to “ping” the system to increase the amount of information available to the adaptive algorithm. The dither signal is preferably implemented on only one actuator channel at a time. Also, the dither amplitude for each channel is preferably set to be proportional to the current control amplitude. The quality of the adaptation estimates is also improved by filtering the input signals to the adaptation circuit, yk=Δzk, and vk=Δuk. Among other things, the filter matches the filtering applied by the harmonic estimator.
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Citations
22 Claims
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1. A method for reducing sensed physical variables including the steps of:
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a) generating a plurality of control commands as a function of the sensed physical variables based upon an estimate of a relationship between the sensed physical variables and the control commands;
b) updating the estimate of the relationship based upon a response by the sensed physical variables; and
c) varying a size of the update to the estimate in said step b) based upon a magnitude of change over time by at least one of the plurality of control commands, wherein the estimate of the change in response y=Δ
z due to a chance in control command v=Δ
u at a specific time tk is denoted Tk,where Tk is updated according to the equations - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for reducing sensed physical variables including the steps of:
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a) generating a plurality of control commands as a function of the sensed physical variables based upon an estimate of a relationship between the sensed physical variables and the control commands;
b) updating the estimate of the relationship based upon a response by the sensed physical variables;
c) where the control commands are filtered to match a filter that has been applied to the sensed physical variables to improve the quality of the estimates prior to said step b); and
wherein a change in the sensed physical variables Δ
z is related to a change in the control commands Δ
u by Δ
z=T(Δ
u), the estimate of a sensed physical variable response T is based on Δ
u and Δ
z, said method further including the step of filtering Δ
u to match a known filter on Δ
z.- View Dependent Claims (9)
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10. A system for controlling a plurality of sensed physical variable comprising:
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a plurality of sensors for measuring the physical variables;
a control unit generating an estimate of a relationship between the sensed physical variables and a plurality of control commands, and generating the plurality of control commands over time based upon the sensed physical variables and based upon the relationship; and
a plurality of force generators activated based upon said plurality of command signals;
wherein the control unit sequentially adds a signal to each of the plurality of control commands, measures the response to the signal and updates the estimate of the relationship based upon the response, wherein the signal added by the control unit is a dither signal that initially decreases in order to avoid saturation for that control command. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A system for controlling a plurality of sensed physical variable comprising:
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a plurality of sensors for measuring the physical variables;
a control unit generating an estimate of a relationship between the sensed physical variables and a plurality of control commands, and generating the plurality of control commands over time based upon the sensed physical variables, and based upon the relationship; and
a plurality of force generators activated based upon said plurality of command signals;
wherein the control unit varies a size of the update to the estimate of the relationship based upon a magnitude of change over time by at least one of the plurality of control command and wherein the control unit selects between updating or leaving unchanged the estimate of the relationship based upon a magnitude of change by the plurality of control commands. - View Dependent Claims (18, 19, 20)
the estimate of the change in response y=Δ - z due to a change in control command v=Δ
u at a specific time tk is denoted Tk,
where Tk is updated according to the equations
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20. The system of claim 19 wherein the control unit sets each variable qi to zero or some nominal value at each time step depending on whether |vi|>
- δ
i where |vi| is a magnitude of change in the ith control command and the variables δ
i are a deadzone threshold for channel i.
- δ
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21. A method for reducing sensed physical variables including the steps of:
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a) generating a plurality of control commands as a function of the sensed physical variables based upon an estimate of a relationship between the sensed physical variables and the control commands;
b) updating the estimate of the relationship based upon a response by the sensed physical variables; and
c) varying a size of the update to the estimate in said step b) based upon a magnitude of change over time by at least one of the plurality of control commands, wherein the estimate of the relationship is given by Δ
z=TΔ
u, where Δ
z is a change in the sensed physical variables and Δ
u is a change in the control commands, and wherein the size of the update is varied in said step c) based upon a comparison of ||Δ
u|| to a threshold.- View Dependent Claims (22)
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Specification