Method and device for detecting the contact of hands on a steering wheel

• US 7,109,862 B2
• Filed: 05/06/2002
• Issued: 09/19/2006
• Est. Priority Date: 05/04/2001
• Status: Expired due to Fees

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Heinebrodt, Martin, Braeuchle, Goetz, Boecker, Juergen
• Primary Examiner(s): Evans, Robin
• Assistant Examiner(s): FASTOVSKY, LEONID M
• Application Number:
  US10/139,479
• Publication Number:
  US 20020170900A1
• Time in Patent Office: 1,597 Days
• Field of Search: 219/204, 219/544, 219/545, 219/202, 180/142, 340/576, 340/426, 340/562, 340/575, 340/870.37, 340/686.6, 340/552, 340/553, 340/561, 340/563, 755/52, 345/156, 345/174, 364/424.01, 364/425, 701/1
• US Class Current: 340/562
• CPC Class Codes: B60L 2200/26 Rail vehicles
• CPC Class Codes: B60W 2040/0881 Seat occupation; Driver or passenger presence
• CPC Class Codes: B62D 1/06 Rims, e.g. with heating means; Rim covers B62D1/11 takes precedence
• CPC Class Codes: B62D 1/065 Steering wheels with heating and ventilating means heating and ventilation of steering wheel when connected to vehicle HVAC B60H1/00292
• CPC Class Codes: B62D 51/002 comprising safety arrangements safety devices for vehicle propulsion unit control B60K28/00
• CPC Class Codes: G08B 21/06 indicating a condition of sleep, e.g. anti-dozing alarms

Abstract

A method and a device are described for detecting the contact between hands and a steering wheel, which assures that the driver of a vehicle has his hands on the steering wheel.

Claims

1. A method for detecting a contact between hands of a vehicle driver and a steering wheel, comprising:

generating a first signal having a first frequency, the first frequency being a function of whether the hands are in contact with the steering wheel;

generating a second signal having a second frequency;

generating an output signal as a function of the first frequency and the second frequency;

feeding a frequency into a first resonant circuit having a capacitance, the capacitance of the first resonant circuit being changed by the contact between the hands and the steering wheel; and

compensating for a change in the first frequency due to an external disturbance variable.

2. The method as recited in claim 1, wherein the output signal is generated as a function of a difference between the first frequency and the second frequency.

3. The method as recited in claim 1, wherein the output signal is generated as a function of an absolute value of a difference between the first frequency and the second frequency.

4. The method as recited in claim 1, further comprising:

causing a frequency-voltage converter to generate an output voltage as a function of the first frequency and the second frequency.

5. The method as recited in claim 1, further comprising:

detecting the contact between the hands and the steering wheel if the output signal is greater than a first threshold value.