CAPACITIVE SEAT OCCUPANCY DETECTION AND CLASSIFICATION SYSTEM
First Claim
1. A capacitive seat occupancy detection and classification system, includingan impedance measurement circuit, comprising:
- a signal voltage source that is configured for providing periodic electrical measurement signals at an output port, wherein a capacitive sensor is electrically connectable to the output port for receiving the electrical measurement signals, and wherein the signal voltage source is configured to generate periodic measurement signals of N different fundamental frequencies, wherein N is a natural number of at least 3,a sense current measurement circuit that is configured to determine complex sense currents that are being generated in the capacitive sensor by the provided periodic measurement signals of the at least N different fundamental frequencies,a signal processing unit that is configured to;
determine a complex impedance from each of the determined sense currents with reference to a complex reference potential, and toprovide output signals that are representative of the complex impedances determined at the at least N different fundamental frequencies,anda control and evaluation unit that is configured to;
receive the output signals provided by the signal processing unit,compare each of the complex impedances determined at the at least N different fundamental frequencies to predetermined threshold values,based on the result of the comparing, determine a seat occupancy class for each one of the complex impedances determined at the at least N different fundamental frequencies, and todetermine a final seat occupancy class derived by a majority decision among the seat occupancy classes determined for each one of the complex impedances determined at one of the at least N different fundamental frequencies,wherein N equals [(2×
n)+1], with n being a natural number larger than 1 representing the number of potential resonances or electromagnetic (EM) narrowband interferences.
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Accused Products
Abstract
A capacitive vehicle seat occupancy detection and classification system includes an impedance measurement circuit and a control and evaluation unit. The impedance measurement circuit is configured for providing periodic electrical measurement signals to a capacitive sensor of N different fundamental frequencies, wherein N is a natural number of at least 3, and to determine a complex impedance from each of determined sense currents in the capacitive sensor. The control and evaluation unit is configured to determine a seat occupancy class for each one of the complex impedances determined at the at least N different fundamental frequencies, and to determine a final seat occupancy class derived by a majority decision among the determined seat occupancy classes.
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Citations
10 Claims
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1. A capacitive seat occupancy detection and classification system, including
an impedance measurement circuit, comprising: -
a signal voltage source that is configured for providing periodic electrical measurement signals at an output port, wherein a capacitive sensor is electrically connectable to the output port for receiving the electrical measurement signals, and wherein the signal voltage source is configured to generate periodic measurement signals of N different fundamental frequencies, wherein N is a natural number of at least 3, a sense current measurement circuit that is configured to determine complex sense currents that are being generated in the capacitive sensor by the provided periodic measurement signals of the at least N different fundamental frequencies, a signal processing unit that is configured to; determine a complex impedance from each of the determined sense currents with reference to a complex reference potential, and to provide output signals that are representative of the complex impedances determined at the at least N different fundamental frequencies, and a control and evaluation unit that is configured to; receive the output signals provided by the signal processing unit, compare each of the complex impedances determined at the at least N different fundamental frequencies to predetermined threshold values, based on the result of the comparing, determine a seat occupancy class for each one of the complex impedances determined at the at least N different fundamental frequencies, and to determine a final seat occupancy class derived by a majority decision among the seat occupancy classes determined for each one of the complex impedances determined at one of the at least N different fundamental frequencies, wherein N equals [(2×
n)+1], with n being a natural number larger than 1 representing the number of potential resonances or electromagnetic (EM) narrowband interferences. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification