OCCUPANT DETECTION SYSTEM AND CONTROL METHOD OF OCCUPANT DETECTION SYSTEM
First Claim
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1. An occupant detection system, comprising:
- a detection electrode provided in at least one of a seat bottom and a seatback of a vehicle seat;
an oscillator circuit that supplies a reference signal comprising a sinusoidal wave, to the detection electrode, via a resistive element;
a first comparator circuit that produces a binary reference phase signal by comparing the voltage of the reference signal with a first threshold value;
a second comparator circuit that detects the potential of the detection electrode as an electrode signal, and produces a binary electrode phase signal by comparing the electrode signal with a second threshold value, wherein the second threshold value is set so that a phase of the reference signal at a point at which the reference signal passes the first threshold value is substantially the same as that of the electrode signal at a point at which the electrode signal passes the second threshold value; and
a control circuit that includes a measuring unit that measures a delay time of a rise of the electrode phase signal relative to a rise of the reference phase signal as a rise delay time, and measures a delay time of a fall of the electrode phase signal relative to a fall of the reference phase signal as a fall delay time, and a detecting unit that detects an occupant based on the rise delay time and the fall delay time.
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Abstract
An occupant detection system includes an electrode provided in a vehicle seat for detecting the capacitance derived from a human body, an oscillator circuit that supplies a sinusoidal signal S0 to the electrode via a resistive element, a first comparator circuit that digitizes the signal S0 using a threshold corresponding to a given phase so as to produce a phase signal D0, a second comparator circuit that detects the potential of the electrode as an electrode signal S1, and digitizes the electrode signal S1 using a threshold corresponding to a phase that is substantially the same as the given phase of the signal S0 so as to produce an electrode phase signal D1, and a control circuit that measures delay times of the electrode phase signal D1 relative to those of the phase signal D0, so as to determine the presence of a seated occupant based on the delay times.
11 Citations
6 Claims
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1. An occupant detection system, comprising:
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a detection electrode provided in at least one of a seat bottom and a seatback of a vehicle seat; an oscillator circuit that supplies a reference signal comprising a sinusoidal wave, to the detection electrode, via a resistive element; a first comparator circuit that produces a binary reference phase signal by comparing the voltage of the reference signal with a first threshold value; a second comparator circuit that detects the potential of the detection electrode as an electrode signal, and produces a binary electrode phase signal by comparing the electrode signal with a second threshold value, wherein the second threshold value is set so that a phase of the reference signal at a point at which the reference signal passes the first threshold value is substantially the same as that of the electrode signal at a point at which the electrode signal passes the second threshold value; and a control circuit that includes a measuring unit that measures a delay time of a rise of the electrode phase signal relative to a rise of the reference phase signal as a rise delay time, and measures a delay time of a fall of the electrode phase signal relative to a fall of the reference phase signal as a fall delay time, and a detecting unit that detects an occupant based on the rise delay time and the fall delay time. - View Dependent Claims (2, 3, 4, 5)
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6. A control method of an occupant detection system including a detection electrode provided in at least one of a seat bottom and a seatback of a vehicle seat, an oscillator circuit that supplies a reference signal comprising a sinusoidal wave, to the detection electrode, via a resistive element, a first comparator circuit that produces a binary reference phase signal by comparing the voltage of the reference signal with a first threshold value, and a second comparator circuit that detects the potential of the detection electrode as an electrode signal, and produces a binary electrode phase signal by comparing the electrode signal with a second threshold value, wherein the second threshold value is set so that a phase of the reference signal at a point at which the reference signal passes the first threshold value is substantially the same as that of the electrode signal at a point at which the electrode signal passes the second threshold value, comprising:
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measuring a delay time of a rise of the electrode phase signal relative to a rise of the reference phase signal as a rise delay time, and measuring a delay time of a fall of the electrode phase signal relative to a fall of the reference phase signal as a fall delay time; and detecting a wet condition of the seat based on the rise delay time and the fall delay time.
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Specification
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Current AssigneeToyota Boshoku Kabushiki Kaisha
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Original AssigneeToyota Boshoku Kabushiki Kaisha
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InventorsISHIGURO, Yasuhiro, UNO, Hideki
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Application NumberUS13/033,781Publication NumberTime in Patent OfficeDaysField of SearchUS Class Current324/705CPC Class CodesB60N 2/002 Seats provided with an occu...B60R 21/01532 using electric or capacitiv...
