Devices and method for detecting the position and the weight of a person

• US 20050056467A1
• Filed: 09/10/2004
• Published: 03/17/2005
• Est. Priority Date: 09/15/2003
• Status: Active Grant

• Current Assignee: Continental Automotive GmbH (Continental AG)
• Original Assignee: Siemens AG
• Inventors: Stielow, Arnd, Klement, Thomas, Hofbeck, Klaus, Rosel, Birgit
• Granted Patent: US 7,315,002 B2
• Time in Patent Office: Days
• US Class Current: 177/2
• CPC Class Codes: B60R 21/01534 using electromagneticwaves, e.g. infrared
• CPC Class Codes: G01G 19/4142 for controlling activation of safety devices, e.g. airbag systems electrical circuits for triggering safety arrangements in case of vehicle accidents B60R21/015

Abstract

The position and the weight of a person, in particular a person on a motor vehicle seat, is determined. Reflectors are used to reflect electromagnetic radiation from a transceiver. The attenuation of the sensor reflector radiation enables a report on the seat position of a person in the radiation path. An antenna of each sensor reflector is connected to an electrical load assigned thereto, which is dependent on the weight of the person acting upon it. Depending on this weight, weight information about the person is superimposed by the load onto the reflected sensor reflector signal. The reflected sensor reflector signal is received by the transceiver and fed to the evaluation unit after a signal pre-processing, which enables the weight information of the person to be evaluated.

Claims

1. A device for detecting the position and the weight of a person, comprising:

at least one transceiver for electromagnetic signals;

a weight-dependent changeable electrical load device disposed to detect weight information about the person;

at least one sensor reflector with an antenna for reflecting a transmitting signal from said transceiver as a sensor reflector signal, said antenna of said sensor reflector being linked to said electrical load device and the sensor reflector signal including weight information about the person, superimposed by said load device;

an evaluation unit connected to said transceiver and being configured to evaluate the weight information of the person.

2. The device according to claim 1, wherein said sensor reflector is one of a plurality of sensor reflectors each connected to a respective said antenna.

3. The device according to claim 1, which comprises an oscillator oscillating at a weight-dependent oscillating frequency, thereby changing the load depending on the weight acting thereon.

4. The device according to claim 3, wherein said load device comprises a switch having:

a first connection linked to said antenna;

a control connection linked to a signal output of said oscillator; and

a second connection linked to a reference potential.

5. The device according to claim 3, wherein said oscillator comprises an oscillation frequency-influenced element with a weight-dependent value characteristic for said element.

6. The device according to claim 4, wherein said oscillation frequency-influenced element is a capacitor.

7. The device according to claim 1, wherein said load device is an oscillation circuit, and:

a resonance frequency of said oscillation circuit is weight-dependent, and

an amplitude of the sensor reflector signal is at a maximum value at the resonance frequency.

8. The device according to claim 7, wherein said oscillation circuit has a resonance frequency-influenced element with a weight-dependent value characteristic for the element.

9. The device according to claim 8, wherein said load device comprises a series or parallel oscillation circuit each with a capacitor and a coil.

10. The device according to claim 8, wherein said resonance frequency-influenced element is a capacitor.

11. The device according to claim 1, wherein said at least one sensor reflector is one of a plurality of sensor reflectors strategically disposed on a motor vehicle seat.

12. The device according to claim 1, wherein said at least one sensor reflector is one of a plurality of sensor reflectors disposed at a seating surface and/or a backrest and/or at a head support of a motor vehicle seat.

15. A method for detecting a position and a weight of a person, which comprises:

providing the device according to claim 1;

transmitting a transmitting signal with said transceiver;

receiving the transmitting signal with said sensor reflector;

superimposing weight information of a person on the signal with said sensor reflector;

reflecting the receiving signal provided with the weight information as a sensor reflector signal;

receiving the sensor reflector signal with said transceiver; and

determining the weight information of the person from the sensor reflector signal received by said transceiver.

13. A sensor reflector for detecting a weight of a person, comprising:

an antenna configured to reflect a transmitting signal of a transceiver as a sensor reflector signal;

an electrical load device connected to said antenna, said load device having a weight-dependent changeable load value; and

the sensor reflector signal containing weight information about the person superimposed by said load device.

14. A method for detecting a position and a weight of a person, which comprises:

providing a sensor reflector according to claim 13;

transmitting a transmitting signal with a transceiver;

receiving the transmitting signal with said sensor reflector;

superimposing weight information of a person on the receiving signal with said sensor reflector, and reflecting the signal with the superimposed weight information as a sensor reflector signal;

receiving the sensor reflector signal with the transceiver; and

determining the weight information of the person from the sensor reflector signal received by the transceiver.