Abstract:
A crash control system for vehicles employs pre-crash surrogate signals to predict a potential crash. The predictive signals may be generated by activation of the vehicle&#39;s anti-lock brakes, or by a sensor that detects rate of brake pedal travel indicating panic braking or by advanced radar systems. The pre-crash signals may be used to ready various safety systems on the vehicle, such as chassis and suspension systems, dynamic body systems, interior occupant protection systems and other systems that function to improve vehicle&#39;s crash worthiness or assist in improving vehicle stability or control. The pre-crash signals may also be used to modify the normal trigger points of safety systems to improve the timing of their response.

Description:
TECHNICAL FIELD 
     The present invention generally relates to vehicles safety systems that are deployed at the time of a crash or pre-crash avoidance action and deals more particularly with a system that uses predictive pre-crash signals to pre-arm or precondition the vehicle&#39;s safety systems. 
     BACKGROUND OF THE INVENTION 
     Safety systems for passenger vehicles have become more prevalent and increasingly sophisticated in recent years as newly enabling technologies evolve. For example, energy absorbing systems such as air bags, anti-lock brakes, and skid control systems have become commonplace on newer vehicles. These safety systems are normally activated immediately before an actual crash, or by loss of control of the vehicle, by means of sensors that detect the onset of the crash or loss of vehicle control. For example, chassis or body-mounted accelerometers are commonly employed to actuate air bags that protect the vehicle&#39;s occupants upon crash impact. In order for existing safety systems to operate effectively, it is critical that the system be fully activated within a very short time frame preceding the crash or other emergency condition. Because of limitations on the amount of time available for crash detection and deployment of the safety systems, there is limited opportunity to utilize those types of safety systems that require longer periods for arming or deployment. An opportunity exists to further enhance safety outcomes through these systems with improved prediction capabilities. 
     The concept of providing early warning of a vehicle emergency is generally known. For example, U.S. Pat. No. 5,158,343 to Reichelt et al discloses a system that reduces braking distance by sensing the rate of movement of a brake pedal and actuating a pre-braking sequence that reduces the time required to activate a vehicle&#39;s brakes. Similarly, U.S. Pat. No. 5,860,674 to Corrado discloses a system in which sensed brake pressure indicating an emergency condition is used to actuate an air bag system. None of these prior art systems are used in connection with safety systems that require time periods for deployment that exceed the time period for advanced warning provided by typical sensors. The present invention is directed toward overcoming the deficiencies of the prior art discussed above, thereby creating new opportunities to utilize a variety of advanced safety systems. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the invention, a crash control system for a vehicle is provided, comprising a first sub-system on the vehicle for controlling a first operating function of the vehicle and generating a signal predicting of an imminent potential crash of the vehicle, a second sub-system on the vehicle for controlling a second operating function of the vehicle, and a controller on the vehicle for receiving the predictive signal and for altering the operation of the second sub-system, in order to ready the vehicle for a crash. The first sub-system may include a sensor for sensing the rate which a brake pedal on the vehicle is actuated. Alternatively, the vehicle&#39;s anti-lock braking system or adaptive cruise control system may be employed to generate the predictive pre-crash signal. The second sub-system may include any of a variety of safety systems carried on the chassis, body or interior of the vehicle. For example, the second sub-system may comprise a steering wheel and means for automatically adjusting the position of the steering wheel before a crash, an improved air suspension system for quickly lowering the vehicle&#39;s center of gravity, continuously variable semi-active damping, interactive vehicle dynamics, seat adjustment mechanisms, and similar safety systems. 
     According to another aspect of the invention, a method is provided for readying a vehicle for a potential crash, comprising the steps of sensing a first parameter relating to the operation of a braking system on a vehicle; using the sensed parameter to generate a signal that is predictive of the crash; and, readying a safety system on the vehicle when the predictive signal has been generated. 
     Accordingly, it is a primary object of the present invention to provide a crash control system for vehicles using predictive pre-crash signals that enable the use of new safety systems and crash control countermeasures. 
     Another object of the invention is to provide a system as described above which provides earlier warning of a potential vehicle crash so as to allow arming or deployment of safety systems that require additional time to make ready prior to a crash. 
     Another object of the invention is to provide a system of the type mentioned above which uses existing vehicle systems to generate the predictive pre-crash signals. 
     These, and further objects and advantages of the present invention will be made clear or will become apparent during the course of the following description of a preferred embodiment of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings, which form an integral part of the specification and are to be read in conjunction therewith, and in which like reference numerals are employed to designate identical components in the various views: 
     FIG. 1 is a broad block diagram of the crash control system for vehicles that forms the preferred embodiment of the present invention; and, 
     FIG. 2 is a combined block and diagrammatic view of the system shown in FIG.  1 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring first to FIG. 1, the present invention relates to a crash control system for vehicles that employs predictive pre-crash surrogate signals that are generated by any of a plurality of existing sub-systems  10  on a vehicle. The sub-systems  10  may comprise an ABS (Antilock Brake System)  16 , a brake pedal velocity sensor  18 , an adaptive cruise control system  20 , or any other appropriate sensor  22  on the vehicle that provides early warning that the driver may lose vehicle control or that a potential crash may be imminent. The signal produced by the ABS system  16  may be either that signal which activates the system  16 , or another system signal that is generated immediately upon activation of the system  16 . The brake pedal velocity sensor  18  is a of a known type, typically mounted on nor near the vehicle&#39;s brake pedal and functions to sense the rate of downward travel of the brake pedal during a braking sequence. The rate of pedal travel is compared against a reference value to determine whether the rate of travel indicates a panic-braking mode. 
     The adaptive cruise control system  20  is of the type employing a distance measuring system which may comprise radar for example, that measures the distance between the radar carrying vehicle, and a second vehicle ahead or behind of the radar carrying vehicle. The distance measuring system determines the rate of closure of the leading or trailing vehicle, and when the measured distance is less than a threshold value, the cruise control system is disabled, and in some cases the vehicle&#39;s brakes are actuated to avoid a collision. Typically, adaptive cruise control systems produce signals indicative of the rate of closure, and according to the present invention, these signals can be used to produce a surrogate signal indicative of a potential crash. A number of other sensors  22  carried on the vehicle may also be used to produce a surrogate signal. In any event, the signals produced by the sub-systems  10  are delivered to a controller  12  which typically includes a microcomputer provided with memory and a pre-programmed set of instructions. 
     The controller  12  may be a dedicated system, or may be incorporated into an existing body or chassis electronic control module. In some cases, where the surrogate signals are generated by the ABS system  16 , the controller  12  essentially acts to receive the signal and uses it as a trigger to arm or activate any of a plurality of second sub-systems  14  which comprise safety systems that either prepare the vehicle for a crash impact or carry out countermeasures aimed at reestablishing control of the vehicle. In other cases, however, the controller uses the values or states of the input signals to calculate values that are compared to reference values in order to generate signals that are delivered to the sub-systems  14 . For example, the signal delivered to the controller  12  by the brake pedal velocity sensor  18  represents the rate at which the brake pedal is depressed. The controller  12  compares this rate value with a reference value associated with an emergency condition, and when the value of the received signal exceeds that of the reference value, controller  12  delivers an arming or actuation signal to one of the sub-systems  14 . In a similar manner, the signal delivered by the adaptive cruise control system  20  to the controller  12  consists of rate of closure information. The controller  12  compares the closure rate with a reference value, and depending upon the results of that comparison, issues an arming or actuation signal to one or more of the sub-systems  14 . 
     As previously discussed, the second sub-systems  14  may comprise any of a variety of safety systems whose purpose is to protect the vehicle&#39;s occupants, mitigate the effects of a crash, or reestablish control of the vehicle either directly or through assisting the driver indirectly. These systems can be broadly categorized as the vehicle&#39;s chassis systems  26 , body systems  28 , interior systems  30  and other crash sensing systems  32 . Generally, the pre-crash predictive signals issued by the controller  12  can be used by the suspension system  24  and chassis systems  26  to lower the air suspension of a vehicle in order to improve the compatibility of energy absorbing systems and lower the vehicle&#39;s center of gravity to enhance vehicle stability, as well as to provide information that is used to potentially engage active countermeasure systems. Such countermeasures can be made available through advanced chassis systems, such as continuously variable semi-active damping and interactive vehicle dynamics that can assist in maintaining vehicle stability or control. Body systems  28  may employ the predictive systems to lower the threshold for crash sensing, thereby reducing the “gray zone” for restraint firing decisions, and to provide an interrupt signal to occupant sensors in order to provide a status check immediately preceding the crash impact. Thus, for example, seat weight sensors or occupant spatial sensors could be checked immediately before the deployment of air bags. 
     Interior systems  30  may employ the predictive signals to control systems that adjust seat positions (either track position or seat back angle), active seat energy absorbing systems, or systems for adjusting the position of the steering wheel or the steering column in order to enhance safety outcomes of a crash. 
     Attention is now also directed to FIG. 2 which shows in more detail, certain components of the sub-systems  10 ,  14 . A brake pedal assembly  58  comprises a pedal arm  60  which is displaced in the direction of arrow  61  to activate the vehicle&#39;s brakes. The rate of travel of the brake arm  60  is detected by a conventional position sensor  62 , that may comprise, for example, a rotary position potentiometer that outputs a signal indicative of brake position or rate of travel of the brake arm  60 , which forms a pre-crash predictive or surrogate signal that is delivered to the controller  12  as part of one of the sub-systems  10 . Where the signal delivered to the controller  12  from the sensor  62  is merely indicative of pedal position, then the controller  12  functions to calculate the rate of pedal travel and compares this rate to a reference value representative of a panic braking situation. 
     In response to receipt of one of the surrogate signals, the controller  12  issues any number of signals to body, chassis and interior safety systems, several of which will now be described by way of illustration. For example, controller  12  may issue a control signal to a vehicle seat controller mechanism  28  which moves the position of a seat  24  mounted on a track assembly  26  for bi-directional movement indicated by the arrow  34 . When a pre-crash predictive signal is generated by one of the sub-systems  10 , the seat adjustment mechanism  28  may move the seat  24  rearwardly to create more space between the vehicle&#39;s steering wheel/steering column and the driver. In a similar manner, the controller  12  may issue a control signal to a powered mechanism  30  that moves the steering column  22  bi-directionally as shown by the arrow  32 , which in turn moves the steering wheel  20  away from the driver. When a pre-crash predictive signal is issued, the controller  12  may cause the mechanism  30  to move the steering column  22  away from the driver, thereby mitigating potential driver injury on impact. 
     A suspension system is shown as comprising a pneumatic cylinder  40  supported by an axle  42 . The air suspension cylinder  40  includes a piston  44  that supports a vehicle frame member  14 . A change in air pressure in cylinder  40  moves piston  44  either upwardly or downwardly in the direction of arrow  56 , thereby changing the height of the frame  14 , and thus the height of the vehicle&#39;s body and energy absorbing structures. In response to the receipt of a pre-crash surrogate signal, the controller  12  issues a signal that reduces the air pressure in cylinder  14 , thereby causing the chassis member  14  to move downwardly to the position shown in the phantom and indicated by the numeral  14   a.  This reduction in chassis height in turn lowers the center of gravity of the vehicle, thereby providing additional stability and control, which is especially important in larger vehicles having a high center of gravity. In a similar manner, a signal issued by controller  12  can be used to better align an energy-absorbing member such as the bumper  18  for impact. For example, in response to a signal issued by the controller  12 , a pneumatic cylinder  36  drives a piston rod  38  outwardly to displace the bumper  18  in the direction of the arrow  54  to a position indicated in the phantom and designated by the numeral  18   a.  With the bumper  18  thusly extended, the vehicle is armed to absorbed additional energy upon impact with another vehicle or an object. Alternatively, adjustment of ride height could be performed via air suspension to better align energy absorbing members of impacting vehicles, especially vehicles like trucks. 
     As mentioned earlier, a range of interactive vehicle dynamics can be used to mitigate crashes or maintain/regain vehicle control. For example, yaw-sensing systems typically are desensitized to prevent false activation due to normal driving situations. In cooperation of a signal predicting a crash event may be used to reduce the activation threshold, allowing such systems a broader scope of operation. A range of other safety systems can be operated by the controller  12  to increase their available response time, such as a conventional seat belt tensioner and air bag  62 . 
     From the foregoing, it is apparent that the crash control system of the present invention not only provides for the reliable accomplishment of the objects of the invention, but does so in an effective and economical manner. It is recognized, of course, that those skilled in the art may make various modifications or additions chosen to illustrate the preferred embodiment without departing from the spirit and scope of the present contribution to the art. Accordingly, it is to be understood that the protection sought and to be afforded hereby should be deemed to extend to the subject matter claimed and all equivalents thereof fairly within the scope of the present invention.