Enhanced occupant spring mass model for use with an actuatable restraint system including compensating for monotonicity of misuse conditions

An actuatable occupant restraint system comprising:

• a crash sensor mountable to a vehicle and providing a crash signal in response to a vehicle crash event;
• crash velocity determining means for determining a crash velocity value from said crash signal;
• and,
• crash determining means for determining the occurrence of a vehicle crash event in response to said determined crash velocity value, said crash determining means including a spring mass model for use in said crash determination, said spring mass model including a switchable spring constant switchable to a value responsive to said determined crash velocity value.

An actuatable restraint system comprising:

• accelerometer mounted to a vehicle for providing an electric signal indicative of crash acceleration;
• spring mass model coupled to said crash acceleration signal for providing a modified crash acceleration signal indicative of the virtual acceleration of a vehicle occupant;
• crash velocity determining means for determining a virtual crash velocity value from said virtual crash acceleration signal;
• crash displacement determining means for determining virtual crash displacement value from said virtual crash acceleration signal;
• crash determining means for monitoring said virtual crash velocity value and said virtual crash displacement value and determining the occurrence of a crash event in response thereto;
• first quadrant switch boundary defined by a predetermined crash velocity value and a predetermined crash displacement value;
• first determining means for determining when the value of said virtual crash velocity value and said virtual crash displacement value is within said first quadrant switch boundary;
• second quadrant switch boundary defined by a predetermined crash velocity value and a predetermined crash displacement value;
• second determining means for determining when the value of said virtual crash velocity value and said virtual crash displacement value is within said second quadrant switch boundary;
• and,
• means for controlling said spring value in response to said value of said virtual crash velocity value and said virtual crash displacement value being within said first and second quadrant switch boundaries.

A method for controlling an actuatable occupant restraint system comprising the steps of:

• mounting a crash sensor to a vehicle and providing a crash signal in response to a vehicle crash event;
• determining a crash velocity value from said crash signal;
• and,
• determining the occurrence of a vehicle crash event in response to said determined crash velocity value, said step of determining including using a spring mass model and selecting a spring constant value responsive to said determined crash velocity value.

A method for controlling an actuatable restraint system comprising the steps of:

• mounting an accelerometer to the vehicle for providing an electric signal indicative of crash acceleration;
• determining a spring mass model of said restraint system for providing a modified crash acceleration signal indicative of the virtual acceleration of a vehicle occupant;
• determining a virtual crash velocity value from said virtual crash acceleration signal;
• determining a virtual crash displacement value from said virtual crash acceleration signal;
• determining the occurrence of a crash event in response to the determined virtual crash velocity value and said determined virtual crash displacement value;
• determining when the value of said virtual crash velocity value and said virtual crash displacement value is within a first quadrant switch boundary defined by a predetermined crash velocity value and a predetermined crash displacement value;
• determining when the value of said virtual crash velocity value and said virtual crash displacement value is within a second quadrant switch boundary defined by a predetermined crash velocity value and a predetermined crash displacement value;
• and,
• controlling said spring value in response to said value of said virtual crash velocity value and said virtual crash displacement value being within said first and second quadrant switch boundaries.