Roll sensor system for a vehicle

A method of activating a land vehicle safety system, comprising the steps of:

• sensing angular rate around at least one roll axis of the land vehicle;
• integrating said angular rate over a predetermined time to produce an angle;
• analyzing said angular rate and said angle to determine if a safety system activation event has occurred;
• producing a trigger signal if said analyzing step indicates that a safety system activation event has occurred based upon said angular rate and said angle;
• and
• activating the safety system based upon receipt of said trigger signal;
• wherein said analyzing step comprises comparing said angular rate and said angle to a look-up table correlating angular rate and angle to safety system activation events.

A roll sensor system for activating a land vehicle safety system, comprising:

• an angular rate sensor mounted to the land vehicle, said angular rate sensor sensitive around at least one roll axis, for outputting an angular rate signal corresponding to the vehicle's angular rate of change around said at least one roll axis;
• an incline sensor sensitive along at least one axis, perpendicular to and located within the same plane as said at least one roll axis, said incline sensor providing an incline sensor angle output;
• a processor for processing both said angular rate signal and said incline sensor angle output signal to determine whether a vehicle safety system trigger event has occurred, said processor producing a trigger signal output if it is determined that a vehicle safety system trigger event has occurred;
• and
• activation circuitry in communication with said processor, said activation circuitry activating the land vehicle safety system in response to receipt of said trigger signal.

A vehicle roll sensor system for detecting a land vehicle roll condition and for activating a safety system in response thereto, comprising:

• an angular rate sensor aligned to be sensitive around at least one roll axis of the land vehicle, said angular rate sensor producing an angular rate sensor output signal, said angular rate sensor output signal being prone to drift;
• an incline sensor aligned to be sensitive along at least an axis perpendicular to said at least one roll axis, said incline sensor producing an incline sensor output signal;
• a processor connected to said angular rate sensor and to said incline sensor, said processor receiving said angular rate sensor output signal and said incline sensor output signal, wherein said processor processes said angular rate sensor output signal to obtain a signal representative of the angular rate of said angular rate sensor and an angular rate derived angle corresponding to said angular rate sensor output integrated over time;
• wherein said processor additionally processes said incline sensor signal to obtain a signal representative of the angle of incline along the at least one incline axis;
• a comparator for periodically comparing the incline angle with the angular rate sensor angle to obtain a difference angle value;
• drift angle compensation circuitry to produce a vehicle roll angle by adjusting said angular rate sensor angle by said drift angle value, to compensate for said drift component of said angular rate sensor angle;
• activation logic circuitry including comparison circuitry, said activation logic circuitry in communication with said drift angle compensation circuitry to receive at least said vehicle roll angle, wherein said activation logic circuitry activates the safety system if said vehicle roll angle is greater than a threshold roll angle value.

A land vehicle roll sensor system for detecting a vehicle roll condition and for activating a safety system in response thereto, comprising:

• an angular rate sensor sensitive along at least one roll axis of the vehicle, said angular rate sensor producing an output signal representative of an angular rate around said at least one roll axis;
• an integrator, including an input and an output, said integrator receiving said angular rate output at said integrator input and integrating said angular rate output over time to produce an angle output;
• a processor connected to receive said angle and said angular rate and to correlate said angular rate signal and said angle to determine if a safety system activation event has occurred, said processor generating a safety system trigger signal if said detected angular rate output and said determined angle output correlate to a desired safety system activation event;
• at least one safety system deployment control unit operatively connected to receive said trigger signal from said processor and to activate the safety system based upon receipt of a trigger signal.

A system for correcting drift in the output of an angular rate sensor used in a vehicle roll sensor system for detecting a land vehicle roll condition, for activating a safety system in response thereto, comprising:

• an angular rate sensor sensitive around a roll axis of the land vehicle;
• an incline sensor sensitive along an incline axis, said incline axis perpendicular to said roll axis of the land vehicle
• a processor for obtaining an output signal from the angular rate sensor and for subtracting an angular rate sensor offset amount to obtain a signal representative of the angular rate of change detected by said angular rate sensor around said roll axis, said processor additionally receiving a signal from said incline sensor representative of said incline angle along said incline axis, and averaging said signal with previous incline angle signals to obtain an average incline angle signal;
• integrating means for integrating said angular rate sensor angular rate signal over time to obtain an output signal representative of a angular rate sensor angle;
• wherein said processor compares said angular rate sensor angle to said average incline angle signal to obtain a difference angle;
• said processor additionally adjusting said angular rate sensor angle by said difference angle to compensate for drift;
• and
• said processor generating a safety system trigger signal if at least said drift compensated angular rate sensor angle corresponds to a safety system trigger event on a lookup table stored by said processor.

A method of activating a land vehicle safety system, comprising the steps of:

• providing an angular rate sensor sensitive around at least one roll axis of the land vehicle, said angular rate sensor producing an angular rate sensor output signal, said angular rate sensor output signal being prone to drift;
• providing an incline sensor aligned to be sensitive along at least an axis perpendicular to said at least one roll axis, said incline sensor producing an incline sensor output signal;
• processing said angular rate sensor output signal to obtain a signal representative of the angular rate from said angular rate sensor;
• processing said incline sensor output signal to obtain a signal representative of the angle of incline of said incline sensor;
• integrating said signal representative of the angular rate to obtain an angular rate derived angle;
• comparing said angle of incline to said angular rate derived angle to obtain a difference angle value;
• comparing said difference angle value to a predetermined threshold difference angle value to determine if said angle of incline is valid;
• generating and outputting a trigger signal if said angle of incline is valid and if it is determined that said angle of incline indicates a safety system trigger event has occurred;
• and
• activating the vehicle safety system in response to the generation of a trigger signal.

A vehicle roll sensor system for detecting a land vehicle roll condition and for activating a safety system in response thereto, comprising:

• an angular rate sensor sensitive around at least one roll axis of the land vehicle, said angular rate sensor producing an angular rate sensor output signal, said angular rate sensor output signal being prone to drift;
• an incline sensor sensitive along at least an axis perpendicular to said at least one roll axis, said incline sensor producing an incline sensor output signal;
• a processor connected to said angular rate sensor and to said incline sensor, said processor receiving said angular rate sensor output signal and said incline sensor output signal, wherein said processor processes said angular rate sensor output signal to obtain a signal representative of the angular rate of said angular rate sensor and an angular rate derived angle;
• wherein said processor additionally processes said incline sensor signal to obtain a signal representative of the angle of incline along the at least one incline axis;
• difference circuitry to compare said angle of incline to said angular rate derived angle to determine a difference angle value;
• comparison circuitry to compare said difference angle value to a predetermined threshold difference angle value to determine if said angle of incline is valid;
• trigger signal generation circuitry for generating and outputting a trigger signal if said angle of incline is valid and if it is determined that said angle of incline indicates a safety system trigger event has occurred;
• and
• activation circuitry in communication with said trigger signal generation circuitry to activate the vehicle safety system if a trigger signal is generated.

A method of correcting drift in the output of an angular rate sensor used in a vehicle roll sensor system for detecting a land vehicle roll condition, for activating a safety system in response thereto, comprising the steps of:

• (a) providing an angular rate sensor sensitive to motion around at least one roll axis of the land vehicle;
• (b) providing an incline sensor sensitive along at least one incline axis, said incline axis perpendicular to said at least one roll axis of the land vehicle
• (c) obtaining an output signal from the angular rate sensor representative of the angular rate of change around said roll axis;
• (d) integrating said output signal representative of said angular rate over time to obtain an output signal representative of angular rate sensor angle;
• (e) obtaining from said incline sensor a signal representative of an incline angle along said at least one incline axis;
• (f) comparing said angular rate sensor angle to said incline angle to obtain a difference angle;
• (g) adjusting said angular rate sensor angle by said difference angle to compensate for drift;
• (h) determining if at least said drift compensated angular rate sensor angle corresponds to a safety system trigger event;
• and
• (i) generating a safety system trigger signal if it is determined in said determining step that a safety system trigger event has occurred.