Acoustic proximity sensing
First Claim
1. An acoustic proximity sensor comprising:
- a housing defining a cavity having a cavity opening;
a first microphone disposed in the cavity;
a second microphone disposed outside of the cavity; and
a processing system configured to receive a first signal from the first microphone and a second signal from the second microphone, and is further configured to analyze the first and second signals to estimate an acoustic resonant frequency of the cavity, wherein the analysis includes estimating a first signal power spectrum for the first signal;
wherein the processing system is further configured to use the acoustic resonant frequency of the cavity to calculate a distance from the cavity opening to an external surface near the cavity opening.
1 Assignment
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Accused Products
Abstract
An acoustic pretouch sensor or proximity sensor (110) includes a cavity (104) with a first microphone (106) disposed therein, and optionally a second microphone (108) disposed outside of the cavity. A processing system (110) receives the signals generated by the first microphone and analyzes the spectrum to produce a result representing the resonant frequency of the cavity. The processing system may optionally subtract the second microphone signal spectrum from the first to automatically compensate for changes in ambient noise. The processing system uses the resonant frequency to estimate the distance from the cavity opening to a surface (90). For example, the pretouch sensors may be incorporated into a stand alone device (100), into a robotic end effector (204), or into a device such as a phone (300).
20 Citations
33 Claims
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1. An acoustic proximity sensor comprising:
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a housing defining a cavity having a cavity opening; a first microphone disposed in the cavity; a second microphone disposed outside of the cavity; and a processing system configured to receive a first signal from the first microphone and a second signal from the second microphone, and is further configured to analyze the first and second signals to estimate an acoustic resonant frequency of the cavity, wherein the analysis includes estimating a first signal power spectrum for the first signal; wherein the processing system is further configured to use the acoustic resonant frequency of the cavity to calculate a distance from the cavity opening to an external surface near the cavity opening. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An acoustic proximity sensor comprising:
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a substrate having a cavity with a cavity opening; a first microphone disposed inside the cavity; and a processing system configured to receive a first signal from the first microphone and to analyze the first signal to estimate an acoustic resonant frequency of the cavity, wherein the analysis of the first signal includes calculating a first signal power spectrum for the first signal; wherein the processing system is further configured to use the acoustic resonant frequency to calculate a distance from the cavity opening to an external surface near the cavity opening. - View Dependent Claims (14, 15, 16)
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17. A robot comprising:
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a base; a finger operably connected to the base; an end effector attached to the finger and incorporating an acoustic pretouch sensor, wherein the pretouch sensor comprises; a first microphone disposed in a cavity having a cavity opening; a second microphone disposed outside of the cavity; and a processing system configured to receive a first signal from the first microphone and a second signal from the second microphone, to calculate a cavity power spectrum for the first signal, and to use the first and second signals to estimate an acoustic resonant frequency of the cavity; wherein the processing system is further configured to use the acoustic resonant frequency to calculate a distance from the cavity opening to an external surface near the cavity opening. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. A method for acoustic pretouch sensing comprising:
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providing an end effector with a first pretouch sensor comprising a cavity having a cavity opening, a first microphone disposed inside the cavity, and a second microphone disposed outside of the cavity; comparing a cavity acoustic signal generated by the first microphone with a simultaneous reference acoustic signal generated by the second microphone to calculate an acoustic resonant frequency of the cavity, wherein the calculation includes estimating the power spectrum for the cavity acoustic signal; and estimating from the calculated resonant frequency of the cavity a distance from the cavity opening to an external surface near the cavity opening. - View Dependent Claims (29, 30, 31, 32, 33)
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Specification