US 6,889,146 B2 · Seat belt tension determination using multiple belt tension sensors

Abstract

A vehicle seat belt is provided with multiple seat belt tension sensors providing output signals that are received and averaged. Signals having values outside a band around the average are dynamically tested against a signal from an occupant weight sensor, vertical seat accelerometer or other sensor indicating expected vertical acceleration of an occupant restrained by the seat belt. This test provides variance values and time-averaged values of each signal, derives a reference value for each signal and compares the variance value for each signal to its reference value. If the comparisons indicate that the dynamic variance of the signals is significantly different, the signal is declared invalid and the average value is recalculated without the invalid signal. The final average signal after removal of all invalid signals determines the belt tension value, which may be used to compensate a weight sensor signal in an occupant characterization system to help control deployment of a vehicle airbag.

Claims36

Dependent claims

A method of determining a belt tension value in a vehicle seat belt exerting a downward force on a seat occupant, comprising the steps:

receiving a plurality of seat belt tension signals from a plurality of belt tension sensors operatively coupled to the vehicle seat belt at different locations, said seat belt tension signals representing tensile forces in said different locations;
and
deriving the belt tension value from the plurality of seat belt tension signals, comprising deriving an average seat belt tension value from the plurality of seat belt tension signals;
and deriving the belt tension value from the average seat belt tension value.

1 more element

Apparatus for determining a belt tension value in a vehicle seat belt exerting a downward force on a seat occupant, comprising:

a plurality of belt tension sensors operatively coupled to a seat belt at different locations thereof;
means for receiving a plurality of seat belt tension signals from said belt tension sensors representing tensile forces in said different locations within a the seat belt;
and
means for deriving the belt tension value from the plurality of seat belt tension signals, comprising means for deriving an average seat belt tension value from the plurality of seat belt tension signals;
and means for deriving the belt tension value from the average seat belt tension value.

2 more elements

Apparatus for characterizing an occupant of a vehicle seat, the apparatus comprising:

a seat belt disposed in association with the vehicle seat for restraint of the occupant;
a plurality of belt tension sensors providing seat belt tension signals at different points of the seat belt;
a weight sensor disposed on the vehicle seat and responsive to the downward force exerted by the seat occupant as well as a downward force exerted by tension in the vehicle seat belt through the vehicle occupant;
and
means for deriving a belt tension value from the plurality of seat belt tension signals;
said means for deriving the belt tension value comprising
means for characterizing the occupant responsive to a signal from the weight sensor and the belt tension value means for deriving an average seat belt tension value from the seat belt tension signals;
and
means for deriving the belt tension value from the average seat belt tension value.

6 more elements

A method of determining tension in a vehicle seat belt comprising the steps:

providing a plurality of seat belt tension sensors distributed at different locations along the seat belt;
reading tension signals from the plurality of seat belt tension sensors;
calculating an average tension signal from ones of the tension signals presumed to be valid;
identifying an outlier one of the tension signals outside a calibrated tolerance band around the average tension signal;
testing the identified outlier one of the tension signals for valid dynamic variance during vehicle motion;
if the outlier one of the tension signals fails the test, recalculating the average tension signal without the identified outlier one of the tension signals;
repeating the identifying, testing and recalculating steps until all outlier ones of the tension signals failing the test are eliminated and a final recalculated average tension signal is obtained;
and
providing the final recalculated average tension signal as the determined tension in the vehicle seat belt.

6 more elements

Dependencies are inferred from the claim text.

Seat belt tension determination using multiple belt tension sensors

Life of this patent

Seat belt tension determination using multiple belt tension sensors

Life of this patent

Abstract

Claims36