Abstract:
An energy-absorbing member is mounted within a vehicle door outboard of an interior panel adjacent to a seating position. The member is rotatable between a first position wherein a maximum-stiffness axis of the member is relatively more aligned with an impact vector of an occupant of the seating position during a crash, and a second position wherein the maximum-stiffness axis is relatively less aligned with the impact vector. A controller receives signals from safety-related systems and operates an actuator to move the member between the first and second positions. Selection between the first and second position may be made at the start of a driving cycle based upon signals from an occupant sensor, stored biometric data, and/or a command from the occupant. The selection may be updated after the start of the driving cycle based upon signals from an impact sensor, a vehicle dynamics sensor, and/or a pre-crash sensor.

Description:
TECHNICAL FIELD 
     The present invention relates to an occupant safety system for a motor vehicle, and to an energy-absorbing component having a stiffness that may be varied in response to occupant and/or vehicle conditions. 
     BACKGROUND 
     To minimize the possible severity of injury to a vehicle occupant during a crash or similar event, the rigidity or stiffness of any vehicle interior components that the occupant may strike during such an event should be of the correct level to absorb the maximum amount of kinetic energy without applying force to the occupant in a manner or degree that is likely to cause injury. The optimum or desired level of stiffness of the interior component may depend, at least in part, upon the size and weight of the occupant. Recent advances in the fields of computer modeling, vehicle dynamics sensing, crash prediction, and occupant sensing (size, condition, and/or position) provide a wealth of information that may be used to determine the optimal level of stiffness of a vehicle interior component. 
     SUMMARY 
     According to an embodiment, occupant protection apparatus comprises an energy-absorbing member mounted to a portion of a vehicle for rotation between a first position wherein a maximum-stiffness axis is relatively more aligned with an impact vector of a vehicle occupant during a crash event, and a second position wherein the maximum-stiffness axis is relatively less aligned with the vector. An actuator moves the member between the first and second positions based upon conditions detected by one or more safety-related sensors. 
     According to another embodiment, apparatus for a vehicle comprises a door having an interior panel located outboard of a seating position, and at least one member mounted within the door and adjacent to an exterior surface of the panel. The member is rotatable between a first position wherein a maximum-stiffness axis is relatively more aligned with an impact vector of an occupant seated in the seating position during a crash event, and a second position wherein the maximum-stiffness axis is relatively less aligned with the impact vector. A controller receives signals from a safety-related system and operates an actuator to move the member between the first and second positions. 
     According to another embodiment, a method of improving protection of an occupant of a vehicle during a crash comprises moving a member disposed adjacent to a cabin of the vehicle between a first position wherein a maximum-stiffness axis of the member is relatively more aligned with an impact vector of an occupant during the crash, and a second position wherein the axis is relatively less aligned with the impact vector. The movement between the two positions is in in response to a signal from one or more occupant safety systems. 
     The signal(s) from the safety-related sensor(s) may indicate an occupant condition, such as physical size or position. The signals may indicate a vehicle dynamic condition, such as whether the vehicle is currently involved in a crash and/or is about to strike another object. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partial schematic view of a motor vehicle with a variable-stiffness component installed in a lower portion of a driver-side door; 
         FIG. 2  is a simplified schematic view of a variable-stiffness component in a maximum stiffness condition; 
         FIG. 3  is the variable-stiffness component of  FIG. 2  in a reduced stiffness condition; 
         FIG. 4  is a schematic vertical cross section through a vehicle door showing a variable-stiffness component in a maximum stiffness condition; and 
         FIG. 5  is a view similar to  FIG. 4  showing the variable-stiffness component in a reduced stiffness condition. 
         FIG. 6  is a schematic system block diagram of a control system for a variable-stiffness component; and 
         FIG. 7  is a schematic view of a second possible installation of a variable-stiffness component in a vehicle door. 
     
    
    
     DETAILED DESCRIPTION 
     As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention. 
     Referring to  FIG. 1 , a motor vehicle  10  has a side door  12  shown in an open position to expose an interior panel  14  of the door. A variable-stiffness component  16  is mounted inside the door  12 , behind interior panel  14 . Variable-stiffness component  16  is shown located below an arm rest  18  where, when door  12  is closed, it will be directly outboard of the pelvis of an occupant (not shown) seated in a seat  20  of the vehicle. 
     As seen in  FIGS. 2-5 , an embodiment of a variable-stiffness component  16  comprises a plurality of energy-absorbing members  22  mounted to rotate or pivot relative to the structure of door  12 . For example, variable-stiffness component  16  may comprise an outboard wall  24  that is fixed relative to door  12 , and outboard edges  26  of members  22  may be attached to the outboard wall by hinge-like features such that the members may rotate about their outboard edges. Inboard edges  28  of members  22  are secured to an inboard frame  30  that is moveable relative to the structure of door  12  and to outboard wall  24  in a generally vertical plane. Vertical movement of frame  30  and inboard edges  28  relative to the fixed outboard wall  24  and outboard edges  26  thereby changes the angle at which members  22  are oriented relative to horizontal. 
     An actuator  32  is operatively connected with frame  30  to move the frame and thereby change the angular alignment of members  22 . Actuator  32  may, for example, be an electromagnetic, electromechanical, pneumatic, pyrotechnic, or similar high speed device. 
     Referring now to  FIGS. 4 and 5 , variable-stiffness component  16  is shown mounted within an interior cavity of the door  12  adjacent to an outboard or exterior surface of interior panel  14 . In this context, the terms “interior” and “exterior” refer to directions relative to vehicle overall and to the interior of the vehicle cabin. That is, the interior or inboard direction is towards the right in  FIGS. 4 and 5 , and the exterior or outboard direction is toward the left. Actuator  32  is shown located below members  22  such that it pulls downward on frame  30 , but it may be located at any location relative to door  12  as necessary for packaging considerations. 
       FIG. 4  shows the variable-stiffness component  16  in a maximum stiffness condition in which members  22  are oriented such that their respective axes of maximum stiffness are in close angular alignment (parallel or nearly parallel) with the vector F of an occupant impact (relative to the vehicle) on the interior surface of the door that is expected to occur during a side impact crash event. In the disclosed embodiment in which energy absorbing members  22  are flat, the maximum-stiffness axis lies in the plane of the flat members. When the maximum-stiffness axes of members  22  are in angular alignment (parallel) with the impact vector F, variable-stiffness component  16  provides the largest possible amount of resistance to an occupant impact, and thereby serves as a relatively stiff pelvis pusher. Such a maximum stiffness condition may be appropriate for a vehicle occupant that is relatively large and/or heavy. 
       FIG. 5  depicts variable-stiffness component  16  in a reduced stiffness condition. Actuator  32  has been activated to move frame  30  downward such that members  22  are rotated in a clockwise direction (as viewed in  FIGS. 4 and 5 ) about their outboard edges  26 . This rotation causes the maximum-stiffness axes of members  22  to form an angle θ with impact vector F. As angle θ increases, the effective stiffness of each of the members  22  and therefore the resulting overall stiffness of component  16  is reduced. Such a reduction from the maximum stiffness condition may be appropriate, for example, when the occupant is lighter and/or smaller. 
     Variable-stiffness component  16  is depicted as comprising five energy-absorbing members  22 , but any number of members may be used as required to achieve the desired amount of stiffness/energy absorption. The amount of energy absorbed by the deforming members  22  (and, conversely, the amount of energy transferred to an occupant) will depend on many variables that are considered and balanced during the engineering design process. Among these variables are the materials from which the members  22  are fabricated and the geometry (length, thickness, taper, holes, ridges, etc.) of the members. Members  22 , while schematically shown herein as being generally flat, may be of any shape having an axis of maximum stiffness that may be rotated through an angle relative to an impact vector in order to achieve a variation in the effective stiffness of the member under an impact. Members  22  may have exterior and/or interior features such that they will deform or “crumple” in a predictable manner. 
     The angle θ and thus the stiffness of component  16  may be adjusted based on any number of factors and by various automatic or manual means.  FIG. 6  is a schematic system block diagram of a control system whereby actuator  32  may be controlled to set the stiffness to a desired appropriate level. The control system may include various sensors such as: one or more occupant condition sensor(s)  40  detecting the size and/or position of an occupant relative to the vehicle interior; one or more impact sensor(s)  42  detecting crush or intrusion into the vehicle structure; one or more remote (pre-crash) sensors  44  such as radar, LIDAR, or vision systems detecting other objects in proximity to the vehicle and may be used to predict a collision; and one or more accelerometer(s)  46  detecting a dynamic state of the vehicle (including crash and roll-over condition). 
     Input devices  50  may include one or more means by which the size and/or identity of a vehicle occupant may be input to allow the stiffness of component  16  to be adjusted to an optimum condition for that occupant. For example, an occupant may enter his/her personal identity and/or physical size using a keypad  58   a , a voice recognition system  50   b , and/or a wireless device  50   c . Wireless device  50   c  may, for example, be a keyless entry fob, a “smart phone”, or some other communication device including a storage device containing biometric data related to the occupant to whom the device is assigned. For use in the present system, such information may include or relate to the occupant&#39;s physical stature, weight, age, or health condition. 
     A restraints control module (RCM)  48  receives inputs from the various available safety-related systems (this term broadly including sensors such as  40 - 46  and input devices such as  50   a - c ) and controls operation of the actuator  32 . RCM  48  may also control activation/actuation of other occupant safety devices such as air bags, side curtain, etc. (not shown). The system illustrated in  FIG. 6  utilizes a data bus  52  to enable communication between the various components. However, other system architectures are well known in the art and may also be used. 
     In a first possible implementation of the disclosed system, the stiffness of variable-stiffness component  16  may be adjusted to match the physical characteristics of the vehicle occupant at the beginning of a drive cycle by means of input device(s)  50 . The stiffness condition of the component  16  may also be adjusted based on the seating position of the occupant as detected by occupant sensor(s)  40 , such as a seat position indicator and/or more advanced sensors using vision, ultrasonic, or capacitive sensing. For example, if a wireless device  50  assigned to and carried by an occupant contains information identifying that occupant as being a 95 th  percentile male, the variable-stiffness component may be set to a relatively high stiffness condition. If the wireless device  50   c  identifies the occupant as a 5 th  percentile female, and this is confirmed by the seat position sensor indicating that the seat  20  has been adjusted to a relatively far-forward position, the variable-stiffness component  16  will be adjusted to a relatively low stiffness condition. 
     The initial stiffness setting selected at the beginning of a drive cycle, as described in the above paragraph, may be maintained throughout that drive cycle or may be altered if other vehicle sensors provide information to RCM  48  indicating that the stiffness should be changed to improve occupant safety. In such a case, RCM  48  may consider signals or inputs from, for example, remote sensors  44  that detect an imminent collision with another vehicle or object; and/or accelerometer  46  and/or impact sensors  42  that detect an actual collision. Based upon signals from such sensors and upon programmed logic (algorithms, look up tables, etc.), RCM  48  may determine that occupant protection in the particular impending or actual collision may be maximized by changing the level of stiffness of variable-stiffness component  16  from that set at the beginning of the drive cycle. If such a determination is made, RCM  48  operates actuator  32  to adjust the angle θ of component  22  in a manner to provide the desired level of stiffness. 
       FIG. 7  shows another embodiment of a variable stiffness component  116  in which members  122  are mounted for rotation about generally vertical axes. In this embodiment, the angle θ between the axes of maximum stiffness and an impact vector is measured in a generally horizontal plane rather than the generally vertical plane as with the first embodiment described herein. The axes about which members  16 / 116  are rotated preferably lies in a plane that is normal to the expected direction of the impact vector, or as close to normal as is permitted for a given vehicle installation. 
     While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.