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AssigneeAutoliv Development AB
InventorPierre SABOURIN
Estimating the term…
A capacitive detection device comprising at least one electrode of a capacitive sensor of said component, an alternating voltage source, a device for measuring a complex value of impedance or admittance between the detection electrode and an electrical circuit reference point and a calibration resistor, and a switching device arranged so as to connect the voltage source to the electrode, in the measurement mode, and to connect the voltage source to the calibration resistor and disconnect the voltage source from the electrode in the calibration mode. The measuring device is arranged so as to measure a first complex value of the calibration resistor, during operation in the calibration mode; to measure a second complex value between the electrode and the electrical circuit reference point during operation in measurement mode, and to correct the second measured complex value according to the first measured complex value.
(canceled)
The device according to claim 17, characterized in that it comprises two calibration resistors.
The device according to claim 17, characterized in that the measuring device is arranged to apply an offset correction to the second measured complex value, said offset correction corresponding to a translation according to a vector {right arrow over (SOCO)} in a complex plane, the point SOC being a point of the complex plane corresponding to an open-circuit complex value of admittance or impedance of the capacitive detection device and the point O corresponding to the origin of the complex plane.
The device according to claim 17, characterized in that it comprises a pair of protective capacitors in series, said pair of capacitors being mounted in parallel with the one or more calibration resistors and in that one of the two capacitors is connected at its terminals to the voltage source via two respective switches and the other capacitor is connected to a frame ground of the vehicle.
The device according to claim 17, characterized in that the measuring device is arranged to calculate a capacitance value between said electrode and the electrical circuit reference point, from said second complex value measured and then corrected, by applying a scaling gain G to the imaginary portion of said second value measured and then corrected, the gain G being provided by the equation
The device according to claim 17, characterized in that the measuring device comprises a current measurement circuit.
A motor vehicle steering wheel provided with the capacitive detection device according to claim 17.
A motor vehicle seat provided with the capacitive detection device according to claim 17.
A capacitive detection device for detecting the presence of a person close to or in contact with a component of a motor vehicle, provided with a capacitive sensor, said device comprising
Dependencies are inferred from the claim text.