System and method for detecting occupant

• US 7,460,939 B2
• Filed: 09/08/2005
• Issued: 12/02/2008
• Est. Priority Date: 09/28/2004
• Status: Expired due to Fees

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Wanami, Shingo
• Primary Examiner(s): Zanelli; Michael J.
• Application Number:
  US11/220,528
• Publication Number:
  US 20060075834A1
• Time in Patent Office: 1,181 Days
• Field of Search: None
• US Class Current: 701/45
• CPC Class Codes: B60N 2/002 Seats provided with an occupancy detection means mounted therein or thereon detection means responsive to presence or absence of children B60N2/266
• CPC Class Codes: B60N 3/004 of foldable trays mounted on the back-rest
• CPC Class Codes: B60R 21/01516 using force or pressure sensing means
• CPC Class Codes: B60R 21/0152 using strain gauges
• 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

An occupant detecting system includes a temperature sensor that sequentially detects temperatures at a fixed position, a plurality of weight sensors disposed at predetermined positions of a seat to respectively provide weight signals, an occupant ECU. The ECU estimates temperatures of the weight sensors based on the temperatures sequentially detected by the temperature sensor and temperature characteristic data of the weight sensors relative to temperatures detected by the temperature sensor and corrects the weight signals based on the estimated temperatures.

Claims

1. An occupant detecting system comprising:

a temperature sensor that sequentially detects temperatures at a fixed position;

a plurality of weight sensors, disposed at predetermined positions of a seat, for respectively providing weight signals;

storing means for storing temperature characteristic data of said weight sensors relative to temperatures;

estimating means for estimating temperatures of said weight sensors based on the temperatures sequentially detected by said temperature sensor and said temperature characteristic data of said weight sensors relative to temperatures detected by said temperature sensor;

correcting means for correcting the weight signals based on the temperatures estimated by said estimating means; and

an occupant detecting ECU that carries out an occupant detection according to the corrected weight signals corrected by said correcting means,

wherein said estimating means comprises;

first means for calculating a speed of changing temperature based on a temperature difference between two points of times; and

second means for calculating temperatures of said weight sensors based on the temperatures detected by said temperature sensor and the temperature characteristic data if the temperature difference is larger than a predetermined temperature, and the speed of changing temperature is higher than a predetermined speed.

2. The occupant detecting system as claimed in claim 1,

wherein said estimating means and said correcting means are included in said occupant detecting ECU.

3. The occupant detecting system as claimed in claim 2,

wherein said temperature sensor is included in said occupant detecting ECU.

4. The occupant detecting system as claimed in claim 1,

wherein said weight sensors are disposed at four corners of a seat.

5. The occupant detecting system as claimed in claim 4,

wherein said estimating means estimates a common temperature of said weight sensors disposed at two front corners of the seat and a common temperature of said weight sensors disposed at two rear corners of the seat.

6. A seat occupant detecting system comprising:

a temperature sensor for sequentially detecting temperatures of a fixed position;

a plurality of weight sensors, disposed at predetermined positions of a seat, for respectively providing weight signals; and

an occupant detecting ECU including said temperature sensor, a ROM that stores temperature characteristic data of said weight sensors relative to temperatures detected by said temperature sensor, estimating means for estimating temperatures of said weight sensors based on the temperatures sequentially detected by said temperature sensor and the temperature characteristic data, and correcting means for correcting the weight signals based on the temperatures estimated by said estimating means,

wherein;

said occupant detecting ECU carries out an occupant detection according to the corrected weight signals corrected by said correcting means; and

said estimating means comprises first means for calculating a speed of changing temperature based on a temperature difference between two points of times; and

second means for calculating temperatures of said weight sensors based on the temperatures detected by said temperature sensor and the temperature characteristic data if the temperature difference is larger than a predetermined temperature, and the speed of changing temperature is higher than a predetermined speed.

7. A method of detecting an occupant of a seat comprising the steps of:

sequentially detecting temperature of a fixed position;

detecting weight of the seat at a plurality of positions of the seat by weight sensors respectively disposed at the plurality of positions;

estimating temperatures of said weight sensors based on the temperatures sequentially detected by said temperature sensor and temperature characteristic data of said weight sensors relative to temperatures of said temperature sensor;

correcting the weight signals based on the estimated temperature; and

carrying out an occupant detection according to the corrected weight signals,

wherein said estimating temperatures comprises;

calculating a speed of changing temperature based on a temperature difference between to points of times; and

calculating temperatures of said weight sensors based on the temperatures detected by said temperature sensor and the temperature characteristic data if the temperature difference is larger than a predetermined temperature, and the speed of changing temperature is higher than a predetermined speed.