Vehicle occupant position and velocity sensor

Abstract

An occupant position sensor utilizing either ultrasonic, microwave or optical technologies, or seatbelt spool out and seat position sensors, are used as inputs to the primary vehicle crash sensor circuit to permit the longest possible sensing time before the occupant gets proximate to the airbag and is in danger of being injured by the deploying airbag. The sensor further disables the inflatable restraint system if the occupant is in danger of being injured by the system deployment. Separate systems are used for the driver and passenger to permit the optimum decision to be made for each occupant.

What is claimed is:  
     
       1. In a motor vehicle containing an inflatable passive restraint system and a seat, a human occupant presence sensor comprising: 
       (a) wave generator means;  
       (b) means for mounting said wave generator to direct said waves toward said vehicle seat;  
       (c) receptor means for receiving said waves which have been reflected from multiple points from the direction of said seat; and  
       (d) pattern recognition means utilizing said received reflected waves at said receptor means to determine the presence of a human occupant in said seat.  
     
     
       2. In a motor vehicle having a human occupant, a vehicle human occupant chest position sensor comprising: at least one transmitter for transmitting waves toward said occupant; means for varying the direction of transmission of said transmitted waves over time whereby the center of the cross-section of said transmitted wave strikes said occupant at different points over time; at least one receiver for receiving waves from said transmitter and reflected off of said occupant; pattern recognition means for analyzing the signal waves received by said receiver to determine the position of said chest. 
     
     
       3. The invention in accordance with  claim 2  wherein said transmitted waves are radar waves and said receiver comprises a single axis antenna. 
     
     
       4. In a motor vehicle having a human occupant, a passive restraint in front of said occupant, an instrument panel, a windshield header, and a rear view mirror, said occupant having ahead and a chest, a vehicle human occupant position sensor comprising: 
       a) at least one transmitter for transmitting waves toward said occupant, said waves illuminating said chest of said occupant;  
       b) at least one receiver for receiving said transmitted waves which have been reflected off of said chest of said occupant, each said receiver producing a signal characteristic of waves received at said receiver;  
       c) means to mount at least one of said transmitters and at least one of said receivers onto said vehicle above the top surface of said instrument panel of said vehicle;  
       d) analysis means connected to said at least one receiver, said means analyzing said at least one signal to determine the distance from said chest of said occupant to said passive restraint; and  
       e) means to respond to said determined distance from said chest of said occupant to said passive restraint to affect the deployment of said passive restraint.  
     
     
       5. The invention in accordance with  claim 4  wherein said mounting location above the top surface of said instrument panel of said vehicle comprises said rear view mirror. 
     
     
       6. The invention in accordance with  claim 4  wherein said mounting location above the top surface of said instrument panel of said vehicle comprises said windshield header. 
     
     
       7. The apparatus of  claim 4 , said analysis means further comprising pattern recognition means. 
     
     
       8. The apparatus of  claim 4  wherein said waves are ultrasonic waves. 
     
     
       9. The apparatus of  claim 4  wherein said waves are electromagnetic waves. 
     
     
       10. The occupant position sensor of  claim 4  comprising at least two of said transmitters and at least two said receivers. 
     
     
       11. The apparatus of  claim 4  wherein at least one of said receivers comprises a charge coupled device. 
     
     
       12. The apparatus of  claim 4  wherein said means to respond further comprises circuitry to disable the deployment of said passive restraint. 
     
     
       13. The apparatus of  claim 4  wherein said restraint is inflatable. 
     
     
       14. The apparatus of  claim 8  wherein the rate at which distance measurements are made using ultrasonic waves is such that said rate exceeds: two times the minimum distance to the occupant divided by the velocity of sound, said transmissions occurring such that associated receptions are known and distinguishable. 
     
     
       15. The apparatus of  claim 4  wherein said responsive means further comprises an alarm. 
     
     
       16. The apparatus of  claim 4  further comprising means to modulate the waves transmitted by said at least one transmitter. 
     
     
       17. The apparatus of  claim 16  wherein said modulations is frequency modulation. 
     
     
       18. The apparatus of  claim 16  wherein said modulation is amplitude modulation. 
     
     
       19. The apparatus of  claim 7  wherein at least one said transmitter transmits infrared waves toward said chest and head of said occupant, said transmitter further comprising 
       a) means to modulate said transmitted waves with a first signal at a first frequency;  
       b) means to generate a second signal, said second signal having a second frequency slightly different from said first signal;  
       c) at least one infrared receiver for receiving said waves transmitted from said transmitter and reflected off of said occupant, said receiver providing a third signal corresponding to said first frequency but shifted in phase;  
       said apparatus further comprising 
       i) means to combine said first signal with said second signal to produce a first beat signal;  
       ii) means to combine said third signal with said second signal to produce a second beat signal; and  
       iii) means to detect a phase shift between said first beat signal and said second beat signal, said phase shift being a measure of the distance of the occupant from said transmitter.  
     
     
       20. The apparatus of  claim 11  wherein there are two spaced apart receivers, each said receiver comprising a charge coupled device. 
     
     
       21. In a motor vehicle having both driver and front seated passenger inflatable restraint systems, a driver having a chest and head and a front seated passenger, a dual deployment system comprising: crash sensor means for determining that a vehicle is experiencing a crash; deployment means for deploying the driver inflatable restraint system; deployment means for deploying the passenger inflatable restraint system; means for determining the position and velocity of the head of said driver relative to said driver inflatable restraint; means for preventing or delaying the deployment of said driver restraint system based on the position and velocity of said driver's head; means for determining the position and velocity of said front seated passenger relative to said passenger inflatable restraint; and means independent of said driver position and velocity, for preventing or delaying the deployment of said passenger restraint system based on the position and velocity of said passenger.