Method and apparatus for controlling an operable protection device with enhanced rollover discrimination

Abstract

To provide a method for controlling actuation of an actuatable restraint to assist to protect a vehicle occupant in response to a rollover event, where the method is implemented in a controller of a vehicle safety system that includes the actuatable restraint.SOLUTION: In order to implement a method, a controller is configured to execute a roll discrimination metric that discriminates occurrence of a ramp rollover event or an embankment rollover event in response to a vehicle roll rate (R_RATE) having a magnitude that exceeds a predetermined threshold roll rate (R_RATE). The controller is also configured to execute a switching metric that is operative to reduce the predetermined threshold roll rate (R_RATE) in response to a vehicle pitch rate (P_RATE) having a magnitude that exceeds a predetermined threshold pitch rate (P_RATE).SELECTED DRAWING: Figure 2

Description

Technical Field

[0001]

[0001] The present invention relates to a method and apparatus for controlling an occupant protection device operable in a vehicle, and more particularly to an enhanced discrimination method and apparatus for classifying certain specific types of rollover vehicle collision events.

Background Art

[0002]

[0002] A vehicle safety system includes a central control unit, sometimes referred to as an airbag control unit (“ACU”), which utilizes both sensors local to the ACU and sensors remote to the ACU to detect the occurrence of a collision event involving the vehicle and to determine whether these events are worthy of activation of operable restraint devices such as airbags and seat belt retractors. The sensors utilized by the ACU can include accelerometers and other sensors such as impact sensors, seat belt buckle switches, seat pressure switches, steering angle sensors, and the like. Using data from these sensors, the ACU can determine the occurrence of a vehicle collision event and can implement a discrimination algorithm for classifying the collision event as one of a particular type. The ACU can activate an operable restraint device according to a particular type of collision event.

[0003]

[0003] A vehicle safety system desirably discriminates various collision events in which the vehicle may be involved. "Discriminating" a collision event can mean classifying the collision event as one of a particular type of collision event and distinguishing that collision event from other types of collision events. If the vehicle safety system can discriminate or identify a collision event as one particular type, an operable restraint device can be actuated in a manner tailored to that particular type of collision event. As used herein, "collision event" can be used to encompass the various events that can involve a vehicle. For example, a collision event can be a collision or impact in which the vehicle hits, impacts, or engages a different type of structure. These collision events can be a collision with a deformable obstacle such as another vehicle, or a collision with a non-deformable obstacle such as a tree or a utility pole. As another example, a collision event can further involve an event such as a rollover event where the impact on the vehicle causes a rollover of the vehicle. A rollover event can occur when the vehicle skids laterally and hits a curb, slides or moves downward from the side of the road into an embankment or a ditch, or slides or moves upward from the side of the road onto an incline such as a hill.

[0004]

[0004] A vehicle safety system can be set or configured to discriminate between an event in which deployment of an operable restraint device is desired ("deployment event") and an event in which deployment of an operable restraint device is not desired ("non-deployment event"). Discriminating a collision involves, for example, determining the type of event, such as a deformable obstacle, a non-deformable obstacle, a frontal impact collision, a rear impact collision, a side impact collision, an oblique collision, an offset collision, a rollover, etc. Discriminating a collision further involves determining the severity of the collision and implementing a safety function that acts as a check or allowance to ensure that an operable restraint device is deployed in a safe manner.

[0005] From the above, it will be appreciated that there may be cases where it is desirable to control the operation and timing of restraint devices that can be actuated in a safety system according to the type and / or severity of a collision event in which a vehicle is involved. To determine which occupant protection devices to actuated in response to a sensed collision event, the safety system can implement a collision assessment process to identify the type of the collision event. If the identified collision event meets or exceeds a severity threshold and the safety function agrees, a restraint device that can be actuated in a manner corresponding to the identified event type can be actuated.

[0006]

[0006] For years, with respect to vehicle safety, safety standards have been compiled and updated to "push the limits". As a result, in keeping with the standards, vehicle manufacturers have been forced to constantly improve the safety of their products. As the standards have become stricter, safety systems have adapted and become more complex and capable. Through the evolution of vehicle safety systems, collision classification has been found to be one of the important aspects that helps determine the effectiveness of the system. If a safety system can accurately and robustly identify a collision scenario as defined by safety standards, it can take countermeasures adjusted to produce the best results for the occupants involved in the accidents that the standards are intended for.

[0007]

[0007] While vehicle safety systems have been developed with the function of identifying various collision events, there is a continuing need to further classify and identify collision events so that the vehicle safety system can take appropriate response actions. Among the collision events for which discrimination may be desirable, there can be various types of collision events such as rollover events or events that can lead to rollovers.

[0008]

[0008] A rollover collision event is an event where it may be desirable to activate safety devices such as side airbags (curtain airbags, chest airbags) and / or seat belt pretensioners. Rollover collision events can occur in various scenarios. For example, the vehicle may lose control and slide sideways off the road onto adjacent grass / dirt, down an embankment, into a ditch, or up an incline or hill. As another example, the vehicle may lose control and slide sideways into a low obstacle such as a curb. In any of these scenarios, the resulting magnitude of the rollover collision event may be worthy of activating one or more vehicle safety devices.

SUMMARY OF THE INVENTION

MEANS FOR SOLVING THE PROBLEM

[0009]

[0009] According to one aspect, a vehicle safety system includes an actuatable restraint device for assisting in protecting vehicle occupants and a controller for controlling the actuation of the actuatable restraint device in response to a vehicle rollover event. The controller is configured to execute a roll discrimination metric that discriminates the occurrence of an inclined rollover event or an embankment rollover event in response to the vehicle roll rate (R_RATE) having a magnitude that exceeds a predetermined threshold roll rate (R_RATE). The controller is further configured to execute a switching metric that functions to reduce the predetermined threshold roll rate (R_RATE) in response to the vehicle pitch rate (P_RATE) having a magnitude that exceeds a predetermined threshold pitch rate (P_RATE).

[0010]

[0010] According to another aspect, alone or in combination with other aspects described herein, the roll discrimination metric can evaluate the roll rate (R_RATE) to detect the occurrence of an inclination event in response to the roll rate (R_RATE) having a magnitude that exceeds an inclination event threshold, or an embankment event in response to the roll rate (R_RATE) having a magnitude that exceeds an embankment event threshold.

[0011] According to another aspect, alone or in combination with other aspects described herein, in response to the pitch rate (P_RATE) having a magnitude exceeding a predetermined threshold pitch rate (P_RATE), the roll discrimination metric is an inclination event corresponding to the roll rate (R_RATE) having a magnitude exceeding the switching inclination event threshold, or a build-up event corresponding to the roll rate (R_RATE) having a magnitude exceeding the switching build-up event threshold. The roll rate (R_RATE) can be evaluated to detect the occurrence of the build-up event.

[0012] According to another aspect, alone or in combination with other aspects described herein, the roll discrimination metric can evaluate the roll rate (R_RATE) against the vehicle roll angle (R_ANGLE).

[0013] According to another aspect, alone or in combination with other aspects described herein, the switching metric can evaluate the pitch rate (P_RATE) to detect the occurrence of a switching inclination event threshold condition corresponding to the pitch rate (P_RATE) having a magnitude exceeding the inclination pitch switching threshold, or a switching build-up event threshold condition corresponding to the pitch rate (P_RATE) having a magnitude exceeding the build-up pitch switching threshold.

[0014] According to another aspect, alone or in combination with other aspects described herein, the switching metric can evaluate the pitch rate (P_RATE) against the vehicle roll angle (R_ANGLE).

[0015] According to another aspect, alone or in combination with other aspects described herein, the controller can be further configured to execute at least one of a roll discrimination algorithm including a roll classification portion configured to classify roll events and an embankment discrimination algorithm including an embankment classification portion configured to classify embankment events. The controller can be configured to deploy an actuatable restraint device in response to the roll discrimination metric having discriminated the occurrence of a rollover event and the roll classification portion having classified the roll event. The controller can be configured to deploy an actuatable restraint device in response to the embankment discrimination metric having discriminated the occurrence of an embankment rollover event and the embankment classification portion having classified the embankment event.

[0016] According to another aspect, alone or in combination with other aspects described herein, the system can further include an accelerometer for sensing a lateral acceleration of the vehicle and providing a signal indicative of the sensed lateral acceleration of the vehicle, an accelerometer for sensing a vertical acceleration of the vehicle and providing a signal indicative of the sensed vertical acceleration of the vehicle, a roll sensor for sensing a roll value of the vehicle and providing a signal indicative of the sensed roll value of the vehicle, and a pitch sensor for sensing a pitch value of the vehicle and providing a signal indicative of the sensed pitch of the vehicle. The controller can be configured to execute a roll discrimination metric and a switching metric using signals provided by the accelerometers, roll rate sensor, and pitch rate sensor.

[0017] According to another aspect, alone or in combination with other aspects described herein, the actuatable restraint device can include at least one of a seat belt anchor pretensioner, a seat belt retractor pretensioner, a curtain airbag, a chest airbag, and a side airbag.

[0018] According to another aspect, a method for controlling the actuation of a restraint device operable in response to a vehicle rollover event includes determining the occurrence of a tip-over event or a ramp-over event in response to the vehicle roll rate (R_RATE) having a magnitude that exceeds a predetermined threshold roll rate (R_RATE). The method further includes reducing the predetermined threshold roll rate (R_RATE) in response to the vehicle pitch rate (P_RATE) having a magnitude that exceeds a predetermined threshold pitch rate (P_RATE).

[0019]

[0019] According to another aspect, determining the occurrence of a tip-over event or a ramp-over event, alone or in combination with other aspects described herein, can include evaluating the roll rate (R_RATE) to detect the occurrence of a tipping event in response to the roll rate (R_RATE) having a magnitude that exceeds a tipping event threshold, and evaluating the roll rate (R_RATE) to detect the occurrence of a ramp event in response to the roll rate (R_RATE) having a magnitude that exceeds a ramp event threshold, including at least one of them.

[0020]

[0020] According to another aspect, alone or in combination with other aspects described herein, the method can include evaluating the roll rate (R_RATE) to detect the occurrence of at least one of a tipping event in response to the roll rate (R_RATE) having a magnitude that exceeds a switching tipping event threshold in response to the pitch rate (P_RATE) having a magnitude that exceeds a predetermined threshold pitch rate (P_RATE), and a ramp event in response to the roll rate (R_RATE) having a magnitude that exceeds a switching ramp event threshold.

[0021]

[0021] According to another aspect, determining the occurrence of a tip-over event or a ramp-over event, alone or in combination with other aspects described herein, can include evaluating the roll rate (R_RATE) versus the vehicle roll angle (R_ANGLE).

[0022] According to another aspect, alone or in combination with other aspects described herein, reducing a predetermined threshold roll rate (R_RATE) in response to a vehicle pitch rate (P_RATE) having a magnitude that exceeds a predetermined threshold pitch rate (P_RATE) can include evaluating the pitch rate (P_RATE) to detect the occurrence of a switching slope event threshold condition in response to the pitch rate (P_RATE) having a magnitude that exceeds a slope pitch switching threshold, or a switching embankment event threshold condition in response to the pitch rate (P_RATE) having a magnitude that exceeds an embankment pitch switching threshold.

[0023] According to another aspect, alone or in combination with other aspects described herein, reducing a predetermined threshold roll rate (R_RATE) in response to a vehicle pitch rate (P_RATE) having a magnitude that exceeds a predetermined threshold pitch rate (P_RATE) can include evaluating the pitch rate (P_RATE) with respect to the vehicle roll angle (R_ANGLE).

[0024] According to another aspect, alone or in combination with other aspects described herein, the method can further include classifying a rollover event as a slope event or an embankment event. The method can further include classifying a rollover event as a slope event and deploying an actuatable restraint device in response to determining the occurrence of a slope rollover event. The method can further include classifying a rollover event as an embankment event and deploying an actuatable restraint device in response to determining the occurrence of an embankment rollover event.

[0025] According to another aspect, alone or in combination with other aspects described herein, a vehicle safety system can include an actuatable restraint device for assisting in protecting vehicle occupants and a controller for controlling the actuation of the actuatable restraint device according to the method described herein.

[0026]

[0026] The foregoing and other features and advantages of the present invention will become apparent to those skilled in the art upon consideration of the following description of the invention and the accompanying drawings.

Brief Description of the Drawings

[0027]

Figure 1

[0027] It is a schematic block diagram illustrating signals obtained from a vehicle and a sensor architecture deployed in the vehicle.

Figure 2

[0028] It is a block diagram showing a vehicle safety system.

Figure 3

[0029] It is a block diagram showing metric calculations implemented in a vehicle safety system.

Figure 4

[0030] It is a diagram showing discrimination and switching metrics for determining the occurrence of a rollover event implemented in a vehicle safety system.

Figure 5

[0031] It is a schematic block diagram showing classification metrics and deployment logic for a rollover event implemented in a vehicle safety system.

Figure 6

[0032] It is a diagram showing discrimination and switching metrics for determining the occurrence of a ditching rollover event implemented in a vehicle safety system.

Figure 7

[0033] It is a schematic block diagram showing classification metrics and deployment logic for a ditching rollover event implemented in a vehicle safety system.

Mode for Carrying Out the Invention

[0028]

[0034] The present invention relates to a vehicle safety system that implements an enhanced discrimination algorithm capable of discriminating and classifying a rollover event and a ditching rollover event. The algorithm switches classification thresholds using pitch rate sensing to more quickly and accurately identify a rollover event and a ditching rollover event.

[0029]

[0035] Since the present invention relates to enhanced discrimination of rollover events due to inclination and rollover events due to embankment, in this specification, a vehicle safety system is shown and described as implementing an algorithm that includes components necessary to implement these specific enhanced discrimination functions. Those skilled in the art will understand that a vehicle safety system can include components in addition to those shown and described in this specification, and can implement discrimination functions in addition to those shown and described in this specification.

[0030]

[0036] Referring to FIG. 1, in accordance with an exemplary configuration, vehicle 12 includes a vehicle safety system 10 that includes a central control unit, herein referred to as an airbag control unit (ACU) 50. ACU 50 functions to activate one or more operable restraint devices 20, such as left / right seat belt pretensioners (anchors and / or retractors), left / right curtain airbags, left / right chest airbags, and left / right side airbags. ACU 50 further functions to control the activation of other protection devices, such as front airbags and knee airbags.

[0031]

[0037] ACU 50 includes one or more sensors that function to provide signals indicative of the linear and / or angular acceleration and / or speed of movement of the vehicle in various directions and with respect to various vehicle axes. The sensors can be mounted locally within or on ACU 50 itself, or can be remote from the ACU, and can be interconnected with the ACU, for example, via wiring. These vehicle axes include the X-axis that extends longitudinally of the vehicle in the forward / rearward direction of the vehicle path. The Y-axis of the vehicle extends laterally of the vehicle and is orthogonal to the X-axis. The Z-axis of the vehicle extends vertically of the vehicle and is orthogonal to both the X-axis and the Y-axis.

[0032]

[0038] In FIG. 1, the X, Y, and Z axes are shown as intersecting the ACU 50. This is because the ACU 50 includes sensors for measuring movement with respect to the axes, i.e., the acceleration of the vehicle 12. In FIG. 1, these movements are identified by a display (+ / −) indicating a positive or negative sign that the safety system 10 assigns to the movement.

[0033]

[0039] The vehicle safety system 10 is configured to interpret movement along the X axis as positive forward and backward (acceleration) and negative backward and forward (deceleration). Movement along the Y axis is interpreted as positive right and left and negative left and right. Movement along the Z axis is interpreted as positive downward and negative upward.

[0034]

[0040] The vehicle safety system 10 is configured to interpret movement about the X axis, i.e., roll, as positive left roll and negative right roll. Movement about the Y axis, i.e., pitch, is interpreted as positive downward pitch (nose down) and negative upward pitch (nose up). Movement about the Z axis, i.e., yaw, is interpreted as positive left rotation yaw and negative right rotation yaw.

[0035]

[0041] Referring to FIG. 2, the ACU 50 includes an accelerometer 52 for sensing lateral (Y axis) acceleration (ACU_Y) of the vehicle. The ACU 50 further includes an accelerometer 54 for sensing vertical (Z axis) acceleration (ACU_Z) of the vehicle. Although not utilized in the discrimination algorithms disclosed herein, the ACU 50 can also include an accelerometer 56 for sensing longitudinal (X axis) acceleration (ACU_X) of the vehicle.

[0036]

[0042] The ACU 50 further includes a pitch rate sensor 60 for sensing the vehicle pitch rate value (PITCH), i.e., the pitch rate about the Y axis of the vehicle. The ACU 50 further includes a roll rate sensor 62 for sensing the vehicle roll rate value (ROLL), i.e., the roll rate about the X axis of the vehicle. Although not utilized in the discrimination algorithms disclosed herein, the ACU 50 can also include a yaw rate sensor 64 for sensing the yaw rate about the Z axis of the vehicle.

[0037]

[0043] It may be desirable to position sensors along or around an axis that senses vehicle movement, on or near each axis. Since the sensors can be mounted locally on the ACU50, it may be desirable to mount the ACU on or near the center of gravity of the vehicle through which the X, Y, and Z axes of the vehicle pass. Positioning the ACU50 at or near the center of gravity of the vehicle is not critical, and the ACU50 may be positioned elsewhere on the vehicle.

[0038]

[0044] The hardware and software settings for the ACU implemented in the vehicle safety system are known in the art. Therefore, a detailed description of the hardware settings of the ACU50 is not necessary for those skilled in the art to understand and appreciate the vehicle safety system 10. The ACU50 in FIG. 1 includes a central processing unit (CPU) such as a microcomputer, and the CPU is configured to receive signals ACU_X, ACU_Y, ACU_Z, ROLL, PITCH, and YAW from their respective sensors, perform vehicle metric calculations 70 on these signals, and perform an enhanced discrimination algorithm 80 using the calculated metrics.

[0039]

[0045] Vehicle metrics obtained from the calculations 70 include the following. · Lateral vehicle Y-axis acceleration moving average (AMA_Y). · Vertical vehicle Z-axis acceleration moving average (AMA_Z). · Vehicle roll differential rate, i.e., roll acceleration (D_RATE). · Vehicle pitch rate (P_RATE). · Vehicle pitch angle (P_ANGLE). · Vehicle roll rate (R_RATE). · Vehicle roll rate 2 (R_RATE_2). · Vehicle roll angle (R_ANGLE).

[0040]

[0046] The enhanced discrimination algorithm 80 includes a normal roll discrimination algorithm 82, an inclination discrimination algorithm 84, an embankment discrimination algorithm 86, a hard soil discrimination algorithm 88, an intermediate soil discrimination algorithm 90, and a soft soil discrimination algorithm 92. The ACU 50 is configured to perform vehicle metric calculations 70 and the enhanced discrimination algorithm 80 and to determine which, if any, of the operable restraint devices 20 to activate. For the purposes of the present disclosure, the discrimination algorithms for the inclination event 84 and the embankment event 86 are novel, inventive, and are disclosed in detail.

[0041]

[0047] Figure 3 illustrates the vehicle metric calculations 70 performed by the ACU 50. The elements of the vehicle metric calculations 70 shown in Figure 2 are referred to herein as "functions" that are internally performed by the ACU 50.

[0042]

[0048] Roll rate metric The ACU 50 employs signal conditioning including analog-to-digital conversion (ADC) to convert the ROLL, PITCH, ACU_Y, and ACU_Z signals from various accelerometers into digital signals. The ACU can also employ rail checking and bias adjustment. As shown in FIG. 3, the digitized and biased roll rate ROLL is passed to a high-pass filter (HPF) function 104 that can be selected, for example, to have a certain time constant, and the filter function is reset after a predetermined time, for example, T = 8 seconds. The roll rate ROLL passed through the high-pass filter generated by the HPF function 104 is passed to a low-pass filter (LPF) function 106 that generates a roll rate metric R_RATE. R_RATE has a value indicating the vehicle roll rate (i.e., angular velocity), and this is implemented in an enhanced discrimination algorithm 80 (see FIG. 2). R_RATE is passed to an integrator high-pass filter (IHPF) 110 having an integrator function and a dual time constant high-pass filter function. The IHPF function 110 integrates the R_RATE signal to generate a value indicating the determined relative roll angle of the vehicle. The IHPF function 110 further performs high-pass filtering of the R_RATE signal. The IHPF function 110 generates a metric R_ANGLE, and R_ANGLE is implemented in the enhanced discrimination algorithm 80 (see FIG. 2).

[0043]

[0049] R_ANGLE indicates the normalized roll angle of the vehicle and is a measure of the rotational angular direction of the vehicle relative to the sensed roll rate. The IHPF function 110 can reset R_ANGLE based on the time constant for the high-pass filter function so that R_ANGLE gives an indication of the angular direction of rotation while the detected roll rate is occurring. Thus, R_ANGLE may not indicate the actual angular direction orientation of the vehicle relative to the ground. In this method, determination of the vehicle rollover condition does not need to depend on determination of the initial angular direction orientation of the vehicle relative to the ground or road surface.

[0044]

[0050] The roll rate ROLL passed through the high-pass filter generated by the HPF function 104 is also passed to the moving average function 120 and then to the moving average function 122. Each of the moving average functions 120, 122 can be finely adjusted, for example, to select the number of samples (e.g., 1 to 32 samples). The moving average functions 120, 122 smooth the fluctuations of the roll rate and generate the metric R_RATE_2 implemented in the enhanced discrimination algorithm 80 (see Figure 2).

[0045]

[0051] R_RATE_2 is given to the difference function 124 where the difference between the current sample and the previous sample is compared. This generates the differentiated roll rate metric D_RATE, and D_RATE indicates the rate of change, i.e., the acceleration of the roll rate. This roll acceleration D_RATE is the angular acceleration of the vehicle about the X-axis of the vehicle. The roll acceleration D_RATE is implemented in the enhanced discrimination algorithm 80 (see Figure 2).

[0046]

[0052] Pitch rate metric As shown in Figure 3, the digitized and biased pitch rate PITCH is passed to a high-pass filter (HPF) function 134 that can be selected, for example, to have a certain time constant, and the filter function is reset after a predetermined time, e.g., T = 8 seconds. The pitch rate passed through the high-pass filter generated by the HPF function 134 is passed to a low-pass filter (LPF) function 136. The LPF function 136 generates the pitch rate metric P_RATE, and P_RATE has a value indicating the vehicle pitch rate (i.e., angular velocity), and P_RATE is implemented in the enhanced discrimination algorithm 80 (see Figure 2). The IHPF function 110 integrates the P_RATE signal, similar to the case of the roll angle, to generate a value indicating the relative pitch angle of the determined vehicle. The IHPF function 110 further performs high-pass filtering on the P_RATE signal. The IHPF function 110 generates the metric P_ANGLE, and P_ANGLE is implemented in the enhanced discrimination algorithm 80 (see Figure 2).

[0047]

[0053] Lateral acceleration metric As shown in FIG. 3, the digitized and biased lateral acceleration ACU_Y is passed to a high-pass filter (HPF) function 144 that can be selected to have a certain time constant, and as a result, the filter function is reset after a predetermined time, for example, T = 8 seconds. The lateral acceleration ACU_Y passed through the high-pass filter generated by the HPF function 144 is passed to a low-pass filter (LPF) function 146. The lateral acceleration ACU_Y value passed through the low-pass filter generated by the LPF function 146 is passed to moving average blocks 148 and 150, and these blocks generate a lateral acceleration metric ACU_Y_AMA metric and an ACU_Y_AMA_SAFE metric, respectively. The number of samples included in each of the moving average functions 148 and 150 can be finely adjusted within a predetermined range such as 1 to 32 samples. ACU_Y_AMA and ACU_Y_AMA_SAFE are the lateral acceleration moving average values implemented in the enhanced discrimination algorithm 80 (see FIG. 2).

[0048]

[0054] Vertical acceleration metric As shown in FIG. 3, the digitized and biased vertical acceleration ACU_Z is passed to a high-pass filter (HPF) function 164 that can be selected to have a certain time constant, and as a result, the filter function is reset after a predetermined time, for example, T = 8 seconds. The lateral acceleration ACU_Z passed through the high-pass filter generated by the HPF function 164 is passed to a low-pass filter (LPF) function 166. The lateral acceleration ACU_Z value passed through the low-pass filter generated by the LPF function 166 is passed to moving average blocks 168 and 170, and these blocks generate a lateral acceleration metric ACU_Z_AMA metric and an ACU_Z_AMA_SAFE metric, respectively. The number of samples included in each of the moving average functions 168 and 150 can be finely adjusted within a predetermined range such as 1 to 32 samples. ACU_Z_AMA and ACU_Z_AMA_SAFE are the lateral acceleration moving average values implemented in the enhanced discrimination algorithm 80 (see FIG. 2).

[0049]

[0055] Roll discrimination The enhanced discrimination algorithm 80 implements the ability to discriminate various types of rollover events, thereby enabling adjustment of the threshold that triggers the deployment of the operable restraint device 20. Some examples of these thresholds are illustrated in FIG. 4. As shown in FIG. 4, the enhanced discrimination algorithm 80 includes a discrimination metric 200 that employs various thresholds to determine whether the sensed vehicle roll characteristics indicate various different rollover event classifications. As shown in FIG. 4, the deployment threshold metric is based on the comparison of R_RATE and R_ANGLE. The threshold determination in FIG. 4 illustrates a left roll (i.e., a roll towards the driver side) as indicated by positive direction R_RATE and R_ANGLE values. The right roll (i.e., a roll towards the passenger seat) is also illustrated as indicated by values for R_RATE and R_ANGLE in the opposite direction, i.e., the negative direction.

[0050]

[0056] As shown in FIG. 4, the soft soil rollover event classification has the lowest threshold for triggering the deployment of the operable restraint device. The hard soil condition has the next lowest rollover event classification threshold for triggering the deployment of the operable restraint device, followed by medium soil, embankment, slope, and then normal rollover. These deployment threshold triggers may be latched, in which case the latch can be reset if the roll angle is equal to zero or if the metric enters the reset frame shown in FIG. 4.

[0051]

[0057] The normal condition, i.e., the condition where no other threshold is classified, has the highest deployment trigger threshold. The normal condition may also be latched, in which case the latch can be reset if the roll rate is equal to zero or if the metric enters the reset frame shown in FIG. 4. It should be understood that the thresholds are shown in FIG. 4 in order of a particular magnitude, but the magnitudes associated with the thresholds can vary. For example, the hard soil threshold may be lower than the soft soil, etc. Nevertheless, the normal threshold is typically the highest threshold.

[0052]

[0058] Enhanced Incline Discrimination Using Pitch Rate Switching As further shown in FIG. 4, discrimination metric 200 includes an incline switching threshold, which is illustrated by the dashed line. Advantageously, the incline switching threshold has a lower magnitude than the corresponding non-switching reference, i.e., the incline threshold. Using a switching incline threshold with a low threshold magnitude, an incline event can be discriminated at an early stage, thereby improving the speed and responsiveness of vehicle safety system 10 in response to an incline rollover event.

[0053]

[0059] As shown in FIG. 4, enhanced discrimination algorithm 80 further includes a switching metric 202 that is used to enable or “switch” discrimination metric 200 to implement the incline switching threshold. As shown in FIG. 4, switching metric 202 is based on a comparison of P_RATE and R_ANGLE. Looking at switching metric 202, the incline switching threshold is satisfied in response to a negative P_RATE, i.e., the vehicle pitch going up (nose up), which is consistent with the vehicle moving up an incline, such as a hill or road obstacle / median.

[0054]

[0060] As shown in FIG. 4, enhanced discrimination algorithm 80 implements a boolean type discrimination logic based on the results or outputs of discrimination metric 200 and switching metric 202. The boolean type logic forms part of an incline discrimination algorithm 84 implemented by enhanced discrimination algorithm 80. In relation to incline discrimination, discrimination metric 200 can output an incline threshold ON indication (block 206) and / or an incline switching threshold ON indication (block 208). These indications 206, 208 are output by discrimination metric 200 in response to the metric exceeding its respective threshold, as indicated by the asterisk symbols at 210 and 212, respectively. Switching metric 202 outputs an incline pitch threshold ON indication (block 214) in response to the metric exceeding the incline pitch switching threshold, as indicated by the asterisk symbol at 216.

[0055]

[0061] This tilt discrimination algorithm 84 discriminates the occurrence of a tilt rollover collision event and functions to output a tilt discrimination ON indication (block 222) in the OR block 220 in response to either of two conditions being satisfied. The tilt discrimination ON indication 222 occurs as a result of the tilt threshold ON indication 206 or, as shown by the AND block 218, as a result of both the tilt switching threshold ON indication 208 and the tilt pitch threshold ON indication 214. Advantageously, by implementing the switching metric 202, the enhanced discrimination algorithm 80 can utilize vehicle pitch rate sensing to lower the tilt discrimination threshold so that the tilt rollover collision event is identified earlier in time, i.e., earlier than discrimination using only the vehicle roll rate.

[0056]

[0062] Tilt Classification FIG. 5 illustrates the tilt classification portion of the tilt discrimination algorithm 84 implemented by the enhanced discrimination algorithm 80. The tilt classification portion of the tilt discrimination algorithm 84 classifies a rollover collision event as a tilt event using vehicle metrics. If confirmed through tilt discrimination (see FIG. 4), the tilt discrimination algorithm 84 issues a command (see block 246) to deploy the vehicle safety device in a predetermined manner commensurate with the identified tilt event.

[0057]

[0063] The tilt classification portion of the tilt discrimination algorithm 84 of FIG. 5 is shown for a rollover event to the left, i.e., a tilt event in which the vehicle rolls to the left, i.e., the driver's side. However, it should be understood that the algorithm shown in FIG. 5 also applies to a rollover event to the right, the only difference being that the signs (+ / −) of the values used in the classification metrics are opposite. In other words, the classification metric for a rollover event to the right is identical to the metric shown in FIG. 5 except that the signs of each axis for different metric values in the classification metric are opposite, e.g., positive becomes negative and vice versa.

[0058]

[0064] The tilt classification part of the tilt discrimination algorithm 84 implements four different classification metrics to classify tilt events. The four tilt classification metrics are as follows. · AMA_Y vs. R_ANGLE (metric 232) · AMA_Z vs. R_ANGLE (metric 234) · R_RATE vs. R_ANGLE (metric 236) · D_RATE vs. R_ANGLE (metric 238)

[0059]

[0065] The lateral acceleration vs. roll angle classification metric 232 uses AMA_Y and R_ANGLE to generate an output, and the output is provided to the AND block 240. As shown, the lateral acceleration vs. roll angle classification metric 232 is triggered when the metric exceeds the threshold shown as a dashed line and enters the shaded trigger region. This trigger is generally indicated by a star. The metric 232 remains ON while the metric is in the trigger region. The solid line of the lateral acceleration vs. roll angle classification metric 232 represents the metric when the vehicle is experiencing a tilt rollover event. The lateral acceleration vs. roll angle classification metric 200 is a non-latching metric, that is, the metric is ON only when the metric is within the trigger region.

[0060]

[0066] The vertical acceleration versus roll angle classification metric 234 generates an output using AMA_Z and R_ANGLE, and the output is provided to the AND block 240. As shown, the vertical acceleration versus roll angle classification metric 234 is triggered when the metric exceeds a threshold shown in its entirety by the dashed line and enters the shaded trigger region. This trigger is generally indicated by a star. The metric 234 remains ON while the metric is within the shaded trigger region bounded by the dashed line. Here, note that there is no limit to the magnitude of AMA_Z with respect to the trigger region of the metric 234, which is shown by the absence of a dashed-line threshold for the trigger region. The solid line of the vertical acceleration versus roll angle classification metric 234 represents the metric when the vehicle is experiencing a rollover event. The vertical acceleration versus roll angle classification metric 234 is a non-latching metric, i.e., the metric is ON only when the metric is within the trigger region.

[0061]

[0067] The roll rate versus roll angle classification metric 236 generates an output using R_RATE and R_ANGLE, and the output is provided to the AND block 240. As shown, the roll rate versus roll angle classification metric 236 is triggered when the metric exceeds a threshold shown in its entirety by the dashed line and enters the shaded trigger region. This trigger is generally indicated by a star. The metric 236 remains ON while the metric is within the shaded trigger region bounded by the dashed line. Here, note that there is no limit to the magnitude of R_RATE with respect to the trigger region of the metric 236, which is shown by the absence of a dashed-line threshold for the trigger region. The solid line of the roll rate versus roll angle classification metric 236 represents the metric when the vehicle is experiencing a rollover event. The roll rate versus roll angle classification metric 236 is a non-latching metric, i.e., the metric is ON only when the metric is within the trigger region.

[0062]

[0068] The angle or roll acceleration versus roll angle classification metric 238 generates an output using D_RATE and R_ANGLE, and the output is provided to the AND block 240. As shown, the roll acceleration versus roll angle classification metric 238 goes ON when the metric exceeds a threshold value shown generally by the dashed line and enters the shaded trigger region. This trigger is generally indicated by a star. The metric 238 remains ON while the metric is in the shaded trigger region bounded by the dashed line. The solid line of the roll acceleration versus roll angle classification metric 238 represents the metric when the vehicle is experiencing a rollover event. The roll acceleration versus roll angle classification metric 238 is a non-latching metric, i.e., the metric is ON only when the metric is within the trigger region.

[0063]

[0069] The tilt classification part of the tilt discrimination algorithm 84 implements boolean logic to determine whether to issue the safety device tilt deployment command 246. As shown in FIG. 5, the safety device tilt deployment command 246 is issued when the AND block 244 is ON. The AND block 244 turns ON in response to the tilt discrimination ON (see block 222, FIG. 4) and the tilt classification being ON (block 242). The tilt classification block 242 turns ON in response to the AND block 240, and the AND block 240 turns ON when all four of the tilt classification metrics 232, 234, 236, and 238 are ON. The tilt classification block 242 can latch until the roll angle becomes equal to zero or enters a reset frame (see FIG. 4).

[0064]

[0070] Therefore, it should be understood that the tilt discrimination algorithm 84 implemented in the enhanced discrimination algorithm 80 functions to issue the safety device tilt deployment command 246 in response to both the rollover event being classified as a tilt event (FIG. 5) and being discriminated as a tilt event (FIG. 4). As described above, since the discrimination is implemented by pitch rate switching, the rollover event can be identified earlier in time, and thus the safety device tilt deployment command 246 can also be issued earlier in time.

[0065]

[0071] Enhanced Embankment Discrimination Using Pitch Rate Switching The enhanced discrimination algorithm 80 implemented by the vehicle safety system 10 also performs enhanced embankment discrimination using pitch rate sensing. This is shown in FIG. 6. The enhanced embankment discrimination using pitch rate switching is similar to the enhanced slope discrimination using pitch rate switching described above with reference to FIG. 4. In fact, the discrimination metric and switching metric used to perform the enhanced embankment discrimination can be the same as the metrics implemented in FIG. 4, with the addition of an embankment switching threshold to the discrimination metric and an embankment pitch switching threshold added to the switching metric. For this reason, for simplicity, the discrimination metric and switching metric in FIG. 6 are shown as being the same as those shown in FIG. 4. However, those skilled in the art will appreciate that the metrics used for enhanced embankment discrimination and the metrics used for pitch rate sensing may be separate and / or different from the metrics used for slope discrimination / switching.

[0066]

[0072] Referring to FIG. 6, the enhanced discrimination algorithm 80 implements a discrimination metric 300 that includes an embankment switching threshold shown by the dashed line. Advantageously, the embankment switching threshold has a magnitude that is lower than the corresponding non-switching reference, i.e., the embankment threshold. Using a switching embankment threshold with a low threshold magnitude, an embankment event can be discriminated at an early stage, thereby improving the speed and responsiveness of the vehicle safety system 10 in responding to an embankment rollover collision event.

[0067]

[0073] As shown in FIG. 6, the enhanced discrimination algorithm 80 further includes a switching metric 302 that is used to enable or “switch” the discrimination metric 300 to implement the fill cut-off threshold. As shown in FIG. 6, the switching metric 302 is based on a comparison of P_RATE and R_ANGLE. Looking at the switching metric 302, the fill cut-off threshold is satisfied in response to a positive P_RATE, i.e., the vehicle pitch pointing downwards (nose down), which is consistent with the vehicle moving the fill downwards, such as down a hill or into a trench.

[0068]

[0074] As shown in FIG. 6, the enhanced discrimination algorithm 80 implements boolean type discrimination logic based on the results or outputs of the discrimination metric 300 and the switching metric 302. In relation to fill discrimination, the discrimination metric 300 can output a fill threshold ON indication (block 306) and / or a fill cut-off threshold ON indication (block 308). These indications 306, 308 are output by the discrimination metric 300 in response to the metric exceeding its respective threshold, as indicated by the asterisks at 310 and 312, respectively. The switching metric 302 outputs a fill pitch threshold ON indication (block 314) in response to the metric exceeding the fill pitch cut-off threshold, as indicated by the asterisk at 316.

[0069]

[0075] This embankment discrimination algorithm 86 functions to discriminate the occurrence of an embankment rollover collision event and outputs an embankment discrimination ON indication (block 322) in response to either of two conditions being satisfied in the OR block 320. The embankment discrimination ON indication 322 occurs as a result of the embankment threshold ON indication 306 or, as shown by the AND block 318, as a result of both the embankment switching threshold ON indication 308 and the embankment pitch threshold ON indication 314. Advantageously, implementing the switching metric 302 allows the enhanced discrimination algorithm 80 to utilize vehicle pitch rate sensing to lower the embankment discrimination threshold so that an embankment rollover collision event is identified earlier in time, i.e., earlier than discrimination using only the vehicle roll rate.

[0070]

[0076] Embankment Classification FIG. 7 illustrates the embankment classification portion of the embankment discrimination algorithm 86 implemented by the enhanced discrimination algorithm 80. The embankment classification portion of the embankment discrimination algorithm 86 classifies a rollover collision event as an embankment event using vehicle metrics. If confirmed through embankment discrimination (see FIG. 6), the embankment discrimination algorithm 86 issues a command (see block 346) to deploy the vehicle safety device in a predetermined manner appropriate for the identified embankment event.

[0071]

[0077] The embankment classification portion of the embankment discrimination algorithm 86 in FIG. 7 is shown for a rollover event to the left, i.e., an embankment event where the vehicle rolls to the left, i.e., the driver's side. However, it should be understood that the algorithm shown in FIG. 7 also applies to a rollover event to the right, the only difference being that the signs (+ / -) of the values used in the classification metrics are opposite. In other words, the classification metric for a rollover event to the right is the same as the metric shown in FIG. 7 except that the signs of each axis for the different metric values in the classification metric are opposite, e.g., positive becomes negative and vice versa.

[0072]

[0078] The fill classification part of the fill discrimination algorithm 86 implements four different classification metrics to classify fill events. The four fill classification metrics are as follows. ·AMA_Y vs R_ANGLE (Metric 332) ·AMA_Z vs R_ANGLE (Metric 334) ·R_RATE vs R_ANGLE (Metric 336) ·D_RATE vs R_ANGLE (Metric 338)

[0073]

[0079] The lateral acceleration vs roll angle classification metric 332 uses AMA_Y and R_ANGLE to generate an output, and the output is given to the AND block 340. As shown, the lateral acceleration vs roll angle classification metric 332 is triggered when the metric exceeds the threshold shown as a dashed line as a whole and enters the shaded trigger region. This trigger is generally indicated by a star. The metric 332 remains ON while the metric is in the shaded trigger region bounded by the dashed line. The solid line of the lateral acceleration vs roll angle classification metric 332 represents the metric when the vehicle is experiencing a fill rollover event. The lateral acceleration vs roll angle classification metric 300 is a non-latching metric, that is, the metric is ON only when the metric is within the trigger region.

[0074]

[0080] The vertical acceleration vs. roll angle classification metric 334 generates an output using AMA_Z and R_ANGLE, and the output is provided to the AND block 340. As shown, the vertical acceleration vs. roll angle classification metric 334 is triggered when the metric exceeds the threshold shown as a dashed line in its entirety and enters the shaded trigger region. This trigger is generally indicated by a star. The metric 334 remains ON while the metric is in the shaded trigger region bounded by the dashed line. Here, note that there is no limit to the magnitude of AMA_Z for the trigger region of the metric 334, which is shown by the absence of a dashed line threshold for the trigger region. The solid line of the vertical acceleration vs. roll angle classification metric 334 represents the metric when the vehicle is experiencing a crest rollover event. The vertical acceleration vs. roll angle classification metric 334 is a non-latching metric, i.e., the metric is ON only when the metric is within the trigger region.

[0075]

[0081] The roll rate vs. roll angle classification metric 336 generates an output using R_RATE and R_ANGLE, and the output is provided to the AND block 340. As shown, the roll rate vs. roll angle classification metric 336 is triggered when the metric exceeds the threshold shown as a dashed line in its entirety and enters the shaded trigger region. This trigger is generally indicated by a star. The metric 336 remains ON while the metric is in the shaded trigger region bounded by the dashed line. Here, note that there is no limit to the magnitude of R_RATE for the trigger region of the metric 336, which is shown by the absence of a dashed line threshold for the trigger region. The solid line of the roll rate vs. roll angle classification metric 336 represents the metric when the vehicle is experiencing a crest rollover event. The roll rate vs. roll angle classification metric 336 is a non-latching metric, i.e., the metric is ON only when the metric is within the trigger region.

[0076]

[0082] The angle direction or roll acceleration versus roll angle classification metric 338 utilizes D_RATE and R_ANGLE to generate an output, which is provided to the AND block 340. As shown, the roll acceleration versus roll angle classification metric 338 goes ON when the metric exceeds the threshold shown as a dashed line in its entirety and enters the shaded trigger region. This trigger is shown in its entirety by a star. The metric 338 remains ON while the metric is in the shaded trigger region bounded by the dashed line. The solid line of the roll acceleration versus roll angle classification metric 338 represents the metric when the vehicle is experiencing a rollover event on a slope. The roll acceleration versus roll angle classification metric 338 is a non-latching metric, that is, the metric is ON only when the metric is within the trigger region.

[0077]

[0083] The slope classification portion of the slope discrimination algorithm 86 implements boolean logic to determine whether to issue the safety device slope deployment command 346. As shown in FIG. 7, the safety device slope deployment command 346 is issued when the AND block 344 is ON. The AND block 344 turns ON in response to slope discrimination ON (block 322, see FIG. 6) and slope classification being ON (block 342). The slope classification block 342 turns ON in response to the AND block 340, and the AND block 340 turns ON when all four of the slope classification metrics 332, 334, 336, and 338 are ON. The slope classification block 342 can latch until the roll angle equals zero or enters a reset frame (see FIG. 6).

[0078]

[0084] Therefore, it should be understood that the embankment discrimination algorithm 86 implemented by the enhanced discrimination algorithm 80 functions to issue a safety device embankment deployment command 346 in response to both the rollover collision event being classified as an embankment event (Figure 7) and being discriminated as an embankment event (Figure 6). As described above, since the discrimination is implemented by pitch rate switching, the embankment rollover event can be identified earlier in time, and thus the safety device embankment deployment command 346 can also be issued earlier in time.

[0079]

[0085] From the above of the present invention, those skilled in the art should understand that the described vehicle safety system and method implement an algorithm that can determine rollover events of slope and embankment using a threshold determined by pitch rate switching to improve the responsiveness of the system. Those skilled in the art will further recognize improvements, changes, and modifications within the spirit and scope of the present invention for the disclosed system and method. These improvements, changes, and / or modifications are intended to be covered by the appended claims. <Appendix> [Form 1] A vehicle safety system, comprising: An operable restraint device for assisting in protecting vehicle occupants; A controller for controlling the operation of the operable restraint device in response to a vehicle rollover event; And comprising: The controller is configured to execute a roll discrimination metric for discriminating the occurrence of a slope rollover event or an embankment rollover event in response to the vehicle roll rate (R_RATE) having a magnitude exceeding a predetermined threshold roll rate (R_RATE); The controller is further configured to execute a switching metric that functions to reduce the predetermined threshold roll rate (R_RATE) in response to the vehicle pitch rate (P_RATE) having a magnitude exceeding a predetermined threshold pitch rate (P_RATE). [Form 2] In the vehicle safety system according to form 1, the roll discrimination metric is a tilt event corresponding to the roll rate (R_RATE) having a magnitude exceeding a tilt event threshold, or a ramp event corresponding to the roll rate (R_RATE) having a magnitude exceeding a ramp event threshold A vehicle safety system that evaluates the roll rate (R_RATE) to detect the occurrence of the above. [Form 3] In the vehicle safety system according to form 2, the roll discrimination metric is a tilt event corresponding to the roll rate (R_RATE) having a magnitude exceeding a switching tilt event threshold, or a ramp event corresponding to the roll rate (R_RATE) having a magnitude exceeding a switching ramp event threshold A vehicle safety system that evaluates the roll rate (R_RATE) to detect the occurrence of the above. [Form 4] In the vehicle safety system according to form 1, the roll discrimination metric evaluates the roll rate (R_RATE) against the vehicle roll angle (R_ANGLE). A vehicle safety system. [Form 5] In the vehicle safety system according to form 1, the switching metric is a switching tilt event threshold condition corresponding to the pitch rate (P_RATE) having a magnitude exceeding a tilt pitch switching threshold, or a switching ramp event threshold condition corresponding to the pitch rate (P_RATE) having a magnitude exceeding a ramp pitch switching threshold A vehicle safety system that evaluates the pitch rate (P_RATE) to detect the occurrence of the above. [Form 6] In the vehicle safety system according to form 1, the switching metric evaluates the pitch rate (P_RATE) against the vehicle roll angle (R_ANGLE). A vehicle safety system. [Aspect 7] In the vehicle safety system according to Aspect 1, the controller is further configured to execute at least one of a roll discrimination algorithm including a roll classification part configured to classify a roll event and an embankment discrimination algorithm including an embankment classification part configured to classify an embankment event. The controller is configured to deploy the operable restraint device in response to the roll discrimination metric determining the occurrence of a rollover event and the roll classification part classifying the roll event. A vehicle safety system, wherein the controller is configured to deploy the operable restraint device in response to the embankment discrimination metric determining the occurrence of an embankment rollover event and the embankment classification part classifying the embankment event. [Aspect 8] In the vehicle safety system according to Aspect 1, an accelerometer for sensing a lateral acceleration of the vehicle and providing a signal indicative of the sensed lateral acceleration of the vehicle; an accelerometer for sensing a vertical acceleration of the vehicle and providing a signal indicative of the sensed vertical acceleration of the vehicle; a roll sensor for sensing a roll value of the vehicle and providing a signal indicative of the sensed roll value of the vehicle; a pitch sensor for sensing a pitch value of the vehicle and providing a signal indicative of the sensed pitch of the vehicle are further provided, A vehicle safety system, wherein the controller is configured to execute the roll discrimination metric and the switching metric using the signals provided by the accelerometer, the roll rate sensor, and the pitch rate sensor. [Aspect 9] In the vehicle safety system according to Aspect 1, the operable restraint device includes at least one of a seat belt anchor pretensioner, a seat belt retractor pretensioner, a curtain airbag, a chest airbag, and a side airbag. [Aspect 10] A method for controlling the operation of a restraint device operable in response to a vehicle rollover event, comprising: determining the occurrence of a tipping rollover event or an embankment rollover event in response to the vehicle roll rate (R_RATE) having a magnitude exceeding a predetermined threshold roll rate (R_RATE); reducing the predetermined threshold roll rate (R_RATE) in response to the vehicle pitch rate (P_RATE) having a magnitude exceeding a predetermined threshold pitch rate (P_RATE); and a method comprising the steps of: [Form 11] In the method according to Form 10, the step of determining the occurrence of a tipping rollover event or an embankment rollover event comprises: evaluating the roll rate (R_RATE) to detect the occurrence of a tipping event in response to the roll rate (R_RATE) having a magnitude exceeding a tipping event threshold; and evaluating the roll rate (R_RATE) to detect the occurrence of an embankment event in response to the roll rate (R_RATE) having a magnitude exceeding an embankment event threshold; and a method comprising at least one of: [Form 12] In the method according to Form 11, in response to the pitch rate (P_RATE) having a magnitude exceeding the predetermined threshold pitch rate (P_RATE), evaluating the roll rate (R_RATE) to detect the occurrence of at least one of a tipping event in response to the roll rate (R_RATE) having a magnitude exceeding a switching tipping event threshold; and an embankment event in response to the roll rate (R_RATE) having a magnitude exceeding a switching embankment event threshold; and a method further comprising evaluating the roll rate (R_RATE) to detect the occurrence of at least one of: [Form 13] In the method according to Form 10, the step of determining the occurrence of a tipping rollover event or an embankment rollover event comprises evaluating the roll rate (R_RATE) against the vehicle roll angle (R_ANGLE). [Form 14] In the method according to form 10, the step of reducing the predetermined threshold roll rate (R_RATE) in response to the vehicle pitch rate (P_RATE) having a magnitude exceeding a predetermined threshold pitch rate (P_RATE) is a switching slope event threshold condition in response to the pitch rate (P_RATE) having a magnitude exceeding a slope pitch switching threshold, or a switching embankment event threshold condition in response to the pitch rate (P_RATE) having a magnitude exceeding an embankment pitch switching threshold including the step of evaluating the pitch rate (P_RATE) to detect the occurrence of the above. [Form 15] In the method according to form 10, the step of reducing the predetermined threshold roll rate (R_RATE) in response to the vehicle pitch rate (P_RATE) having a magnitude exceeding a predetermined threshold pitch rate (P_RATE) includes the step of evaluating the pitch rate (P_RATE) with respect to the vehicle roll angle (R_ANGLE). [Form 16] In the method according to form 10, the step of classifying a rollover event as a slope event or an embankment event, and the step of deploying the operable restraint device in response to the step of classifying the rollover event as a slope event and the step of determining the occurrence of the slope rollover event, and the step of deploying the operable restraint device in response to the step of classifying the rollover event as an embankment event and the step of determining the occurrence of the embankment rollover event further including. [Form 17] A vehicle safety system, an operable restraint device for assisting in protecting vehicle occupants, and a controller for controlling the operation of the operable restraint device according to the method according to form 10 comprising a vehicle safety system. [Form 18] In the vehicle safety system according to form 17, An accelerometer for sensing a lateral acceleration of a vehicle and providing a signal indicative of the sensed lateral acceleration of the vehicle, an accelerometer for sensing a vertical acceleration of the vehicle and providing a signal indicative of the sensed vertical acceleration of the vehicle, a roll sensor for sensing a roll value of the vehicle and providing a signal indicative of the sensed roll value of the vehicle, a pitch sensor for sensing a pitch value of the vehicle and providing a signal indicative of the sensed pitch of the vehicle, further comprising, a vehicle safety system configured such that the controller uses the signals provided by the accelerometer, the roll rate sensor, and the pitch rate sensor to execute the roll discrimination metric and the switching metric. [Embodiment 19] In the vehicle safety system according to Embodiment 18, the operable restraint device includes at least one of a seat belt anchor pretensioner, a seat belt retractor pretensioner, a curtain airbag, a chest airbag, and a side airbag. A vehicle safety system.

Description of Signs

[0080] 10 Vehicle safety system 12 Vehicle 20 Operable restraint device 50 ACU 54 Accelerometer 56 Accelerometer 60 Pitch rate sensor 62 Roll rate sensor 64 Yaw rate sensor 70 Vehicle metric calculation 80 Enhanced discrimination algorithm 82 Normal rollover discrimination algorithm 84 Tilt discrimination algorithm 86 Embankment event, embankment discrimination algorithm 88 Hard soil discrimination algorithm 90 Medium soil discrimination algorithm 92 Soft soil discrimination algorithm 104 High-pass filter (HPF) function 106 Low-pass filter (LPF) function 110 Integral high-pass filter (IHPF) 120 Moving average function 122 Moving average function 124 Difference function 134 High-pass filter (HPF) function 136 Low-pass filter (LPF) function 144 High-pass filter (HPF) function 146 Low-pass filter (LPF) function 148 Moving average block 150 Moving average block 164 High-pass filter (HPF) function 166 Low-pass filter (LPF) function 168 Moving average block 170 Moving average block 200 Discrimination metric

Claims

1. A vehicle safety system, comprising: An operable restraint device for assisting in protecting vehicle occupants; A controller for controlling the operation of the operable restraint device in response to a vehicle rollover event; The controller is configured to execute a roll discrimination metric for discriminating the occurrence of a tilt rollover event or an embankment rollover event in response to the vehicle roll rate (R_RATE) having a magnitude exceeding a predetermined threshold roll rate (R_RATE); The controller is further configured to execute a switching metric that functions to reduce the predetermined threshold roll rate (R_RATE) in response to the vehicle pitch rate (P_RATE) having a magnitude exceeding a predetermined threshold pitch rate (P_RATE); The roll discrimination metric evaluates the roll rate (R_RATE) to detect the occurrence of a tilt event in response to the roll rate (R_RATE) having a magnitude exceeding a tilt event threshold, or an embankment event in response to the roll rate (R_RATE) having a magnitude exceeding an embankment event threshold. A vehicle safety system.

2. A vehicle safety system, comprising: An operable restraint device for assisting in protecting vehicle occupants; A controller for controlling the operation of the operable restraint device in response to a vehicle rollover event; The controller is configured to execute a roll discrimination metric for discriminating the occurrence of a tilt rollover event or an embankment rollover event in response to the vehicle roll rate (R_RATE) having a magnitude exceeding a predetermined threshold roll rate (R_RATE); The controller is further configured to execute a switching metric that functions to reduce the predetermined threshold roll rate (R_RATE) in response to the vehicle pitch rate (P_RATE) having a magnitude exceeding a predetermined threshold pitch rate (P_RATE); The roll discrimination metric evaluates the roll rate (R_RATE) against the vehicle roll angle (R_ANGLE). A vehicle safety system.

3. In the vehicle safety system according to Claim 1, in response to the pitch rate (P_RATE) having a magnitude exceeding the predetermined threshold pitch rate (P_RATE), the roll discrimination metric is ​ ​ ​ ​ ​ An inclination event corresponding to the roll rate (R_RATE) having a magnitude exceeding a switching inclination event threshold, or a banking event corresponding to the roll rate (R_RATE) having a magnitude exceeding a switching embankment event threshold A vehicle safety system that evaluates the roll rate (R_RATE) to detect the occurrence of the above.

4. The vehicle safety system according to claim 1, wherein the roll discrimination metric evaluates the roll rate (R_RATE) against the vehicle roll angle (R_ANGLE).

5. In the vehicle safety system according to claim 1, the switching metric is a switching inclination event threshold condition corresponding to the pitch rate (P_RATE) having a magnitude exceeding an inclination pitch switching threshold, or a switching embankment event threshold condition corresponding to the pitch rate (P_RATE) having a magnitude exceeding an embankment pitch switching threshold A vehicle safety system that evaluates the pitch rate (P_RATE) to detect the occurrence of the above.

6. The vehicle safety system according to claim 1, wherein the switching metric evaluates the pitch rate (P_RATE) against the vehicle roll angle (R_ANGLE).

7. In the vehicle safety system according to claim 1, the controller further includes at least one of a tilt discrimination algorithm including a tilt classification part configured to classify tilt events and a banking discrimination algorithm including a banking classification part configured to classify banking events. Configured to execute, The controller is configured to deploy the operable restraint device in response to the roll discrimination metric determining the occurrence of a rollover event due to inclination and the tilt classification part classifying the tilt event. The controller is configured to deploy the operable restraint device in response to the embankment discrimination metric determining the occurrence of an embankment rollover event and the embankment classification part classifying the embankment event. A vehicle safety system.

8. In the vehicle safety system according to claim 1, an accelerometer for sensing the lateral acceleration of the vehicle and providing a signal indicative of the sensed lateral acceleration of the vehicle; an accelerometer for sensing the vertical acceleration of the vehicle and providing a signal indicative of the sensed vertical acceleration of the vehicle; A roll sensor for sensing a roll value of a vehicle and providing a signal indicative of the sensed roll value of the vehicle, a pitch sensor for sensing a pitch value of the vehicle and providing a signal indicative of the sensed pitch of the vehicle and further comprising, a vehicle safety system, wherein the controller is configured to execute the roll discrimination metric and the switching metric using the signals provided by the accelerometer, the roll sensor, and the pitch sensor.

9. The vehicle safety system according to claim 1, wherein the operable restraint device comprises at least one of a seat belt anchor pretensioner, a seat belt retractor pretensioner, a curtain airbag, a chest airbag, and a side airbag.

10. A method for controlling the actuation of an operable restraint device in response to a vehicle rollover event, comprising: determining the occurrence of a tilt rollover event or a bank rollover event in response to the vehicle roll rate (R_RATE) having a magnitude exceeding a predetermined threshold roll rate (R_RATE); reducing the predetermined threshold roll rate (R_RATE) in response to the vehicle pitch rate (P_RATE) having a magnitude exceeding a predetermined threshold pitch rate (P_RATE); and including, the step of determining the occurrence of the tilt rollover event or the bank rollover event evaluating the roll rate (R_RATE) to detect the occurrence of the tilt event in response to the roll rate (R_RATE) having a magnitude exceeding a tilt event threshold; evaluating the roll rate (R_RATE) to detect the occurrence of the bank event in response to the roll rate (R_RATE) having a magnitude exceeding a bank event threshold; and including at least one of the above.

11. In the method according to claim 10, in response to the pitch rate (P_RATE) having a magnitude exceeding the predetermined threshold pitch rate (P_RATE), a tilt event in response to the roll rate (R_RATE) having a magnitude exceeding a switching tilt event threshold, and a bank event in response to the roll rate (R_RATE) having a magnitude exceeding a switching bank event threshold further comprising evaluating the roll rate (R_RATE) to detect the occurrence of at least one of the above.

12. The method according to claim 10, wherein the step of determining the occurrence of a rollover event or an embankment rollover event includes the step of evaluating the roll rate (R_RATE) against the vehicle roll angle (R_ANGLE).

13. The method according to claim 10, wherein the step of reducing the predetermined threshold roll rate (R_RATE) in response to the vehicle pitch rate (P_RATE) having a magnitude exceeding a predetermined threshold pitch rate (P_RATE) is a switching bank slope event threshold condition in response to the pitch rate (P_RATE) having a magnitude exceeding a bank slope pitch switching threshold, or a switching embankment event threshold condition in response to the pitch rate (P_RATE) having a magnitude exceeding an embankment pitch switching threshold and includes the step of evaluating the pitch rate (P_RATE) to detect the occurrence of the above.

14. The method according to claim 10, wherein the step of reducing the predetermined threshold roll rate (R_RATE) in response to the vehicle pitch rate (P_RATE) having a magnitude exceeding a predetermined threshold pitch rate (P_RATE) includes the step of evaluating the pitch rate (P_RATE) against the vehicle roll angle (R_ANGLE).

15. The method according to claim 10, the step of classifying a rollover event as a bank slope event or an embankment event, and the step of classifying the rollover event as a bank slope event, and the step of deploying the operable restraint device according to the step of determining the occurrence of the bank slope rollover event, and the step of classifying the rollover event as an embankment event, and the step of deploying the operable restraint device according to the step of determining the occurrence of the embankment rollover event and further includes the method.

16. A vehicle safety system, an operable restraint device for assisting in protecting vehicle occupants, and a controller for controlling the operation of the operable restraint device according to the method according to claim 10 comprising a vehicle safety system.

17. In the vehicle safety system according to claim 16, an accelerometer for sensing the lateral acceleration of the vehicle and providing a signal indicative of the sensed lateral acceleration of the vehicle, and an accelerometer for sensing the vertical acceleration of the vehicle and providing a signal indicative of the sensed vertical acceleration of the vehicle, A roll sensor for sensing a roll value of a vehicle and providing a signal indicative of the sensed roll value of the vehicle, a pitch sensor for sensing a pitch value of the vehicle and providing a signal indicative of the sensed pitch of the vehicle, further comprising, the controller uses the signals provided by the accelerometer, the roll sensor, and the pitch sensor, a roll discrimination metric for discriminating the occurrence of a rollover event or an embankment rollover event in response to the vehicle roll rate (R_RATE) having a magnitude exceeding a predetermined threshold roll rate (R_RATE), and A vehicle safety system configured to execute a switching metric that reduces the predetermined threshold roll rate (R_RATE) in response to the vehicle pitch rate (P_RATE) having a magnitude exceeding a predetermined threshold pitch rate (P_RATE). **Claim 18**: The vehicle safety system according to claim 17, wherein the operable restraint device comprises at least one of a seat belt anchor pretensioner, a seat belt retractor pretensioner, a curtain airbag, a chest airbag, and a side airbag. A vehicle safety system.

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