System and method for estimating occupant movement in response to automatic emergency braking

Abstract

A method for controlling an actuatable safety device for protecting an occupant of a vehicle includes utilizing an advanced driver assistance system (ADAS) to determine that a vehicle collision is imminent. In response to determining that an imminent vehicle collision exists, a mass-spring-damper model uses a sensed vehicle longitudinal acceleration (IMU_X) to estimate occupant movement that would result from the imminent vehicle collision. The estimated occupant movement is used to determine how to control deployment of the actuatable safety device in response to the collision.

Description

Technical Field

[0001] This specification relates to vehicle safety systems. More specifically, this specification relates to a vehicle safety system and method for estimating the movement of vehicle occupants when automatic emergency braking of a vehicle is activated. Background Technology

[0002] Vehicle safety systems include actuable restraint devices, such as actuable seatbelt retractors and airbags. The system also includes sensors for sensing the vehicle and / or occupant status, and a controller that monitors the signals provided by the sensors. When a vehicle collision is detected to exceed a threshold magnitude, the controller actuates the actuable restraint device to help protect the occupants.

[0003] Advanced driver assistance systems (ADAS) offer features such as automatic emergency braking. ADAS include sensors, such as radar / liDAR sensors and camera sensors, to provide sensing indications of the area around the vehicle. ADAS also include a controller that monitors the signals provided by the sensors. To implement automatic emergency braking, the controller evaluates the signals from the sensors to detect an impending frontal collision. When an impending frontal collision is detected, the controller causes the vehicle to automatically apply the brakes. Summary of the Invention

[0004] A vehicle safety system implements a method for estimating occupant movement in response to automatic emergency braking. If a vehicle collision occurs after emergency braking, the safety system can tailor the actuation of occupant restraint devices (such as actuable seat belts and / or airbags) based on the estimated occupant movement.

[0005] According to one aspect, a method for controlling an actuable safety device for protecting vehicle occupants includes sensing an impending vehicle collision. The method further includes: in response to sensing the impending vehicle collision, calculating an estimated occupant movement that would result when the impending vehicle collision occurs. The method further includes: in response to the estimated occupant movement, controlling the actuable safety device.

[0006] Sensing an impending vehicle collision may include receiving an Automatic Emergency Braking (AEB) deceleration marker. Receiving an AEB deceleration marker may include polling an Advanced Driver Assistance System (ADAS). The ADAS implements sensors to detect objects near the vehicle, calculates the relative speed between the detected object and the vehicle to sense an impending collision, and outputs an AEB deceleration marker in response. The AEB deceleration marker may be latched for a predetermined period of time, which estimates the duration of the AEB braking curve.

[0007] Sensing an impending vehicle collision may include receiving an Automatic Emergency Braking (AEB) braking marker. Receiving an AEB deceleration marker may include polling the vehicle stability system for that AEB deceleration marker, which is marked ON for the entire duration of the AEB braking curve.

[0008] Calculating the estimated occupant movement may include performing spring-mass damper modeling to estimate occupant movement. Performing spring-mass damper modeling may include evaluating the vehicle's longitudinal acceleration (IMU_X) using a spring-mass damper model to estimate occupant movement.

[0009] Performing spring-mass damper modeling can include implementing a first spring-mass damper model to estimate occupant head movement and a second spring-mass damper model to estimate occupant chest movement.

[0010] Performing spring-mass damper modeling may include implementing: a first spring-mass damper model that estimates occupant movement when the seatbelt is in an unlocked state that allows the seatbelt webbing to be released; and a second spring-mass damper model that estimates occupant movement when the seatbelt is in a locked state that prevents the seatbelt webbing from being released.

[0011] Performing spring-mass damper modeling may include performing a metric to evaluate the change in the magnitude of the vehicle's longitudinal acceleration (IMU_X) over time. A first spring-mass damper model may be implemented in response to the magnitude of the vehicle's longitudinal acceleration remaining below a predetermined threshold associated with mechanical seatbelt locking. A second spring-mass damper model may be implemented in response to the magnitude of the vehicle's longitudinal acceleration exceeding the predetermined threshold associated with mechanical seatbelt locking.

[0012] Performing spring-mass damper modeling may include polling the E-locking state of the actuated controlled constraint seatbelt. A first spring-mass damper model may be implemented in response to the E-locking state being OFF. A second spring-mass damper model may be implemented in response to the E-locking state being ON.

[0013] The method may also include sensing the seatbelt buckle state and suppressing the implementation of the second spring-mass damper model in response to the seatbelt buckle state being unfastened.

[0014] Performing spring-mass damper modeling may include: implementing a first spring-mass damper model that estimates occupant head movement when the seatbelt is in an unlocked state that allows the seatbelt webbing to be released; implementing a second spring-mass damper model that estimates occupant chest movement when the seatbelt is in an unlocked state that allows the seatbelt webbing to be released; implementing a third spring-mass damper model that estimates occupant head movement when the seatbelt is in a locked state that prevents the seatbelt webbing from being released; and implementing a fourth spring-mass damper model that estimates occupant chest movement when the seatbelt is in a locked state that prevents the seatbelt webbing from being released.

[0015] Performing spring-mass damper modeling may include performing a metric to evaluate the magnitude of the change in vehicle longitudinal acceleration (IMU_X) over time. A first and second spring-mass damper model may be implemented in response to the magnitude of the vehicle longitudinal acceleration remaining below a predetermined threshold associated with mechanical seatbelt locking. A third and fourth spring-mass damper model may be implemented in response to the magnitude of the vehicle longitudinal acceleration exceeding the predetermined threshold associated with mechanical seatbelt locking.

[0016] Controlling an actuable safety device in response to estimated occupant movement may include any of the following:

[0017] Determine whether to activate the first and / or second stage of the inflator used to inflate the airbag.

[0018] Determine the timing used to actuate the first and / or second stages of the inflator used to inflate the airbag.

[0019] Determine whether to actuate the actuable discharge device used to expel the inflated fluid from the airbag.

[0020] Determine the timing used to actuate the actuable discharge device for discharging inflated fluid from the airbag.

[0021] Determine whether to activate the seatbelt load limiter.

[0022] Determine whether to activate the seatbelt pretensioner.

[0023] Determine whether to actuate the actuable controlled restraint device (ACR) to tighten the seat belt onto the occupant.

[0024] Calculating the estimated occupant movement that would result in an impending vehicle collision may include any of the following:

[0025] The occupant weight is sensed to calculate the estimated occupant movement.

[0026] The seat position is sensed to calculate the occupant position relative to the vehicle structure.

[0027] The seat tilt is sensed to calculate the occupant position relative to the vehicle structure.

[0028] The position of the steering wheel and / or dashboard is sensed to calculate the occupant position relative to the vehicle structure.

[0029] The seatbelt buckle status is sensed to calculate the estimated occupant movement.

[0030] The method may also include polling the actuable controlled restraint device (ACR) indication for seatbelt release and implementing the indicated seatbelt release as feedback for calculations of the estimated occupant movement.

[0031] A vehicle safety system includes: an actuable safety device; a sensor for sensing an impending vehicle collision; and a controller configured to perform the methods disclosed herein to control the actuable safety device in response to estimated occupant movement. The actuable safety device may include any of the following: an airbag inflator, an actuable airbag deflation device, an actuable seatbelt retractor, or an actuable controlled restraint device (ACR) including a seatbelt retractor. The sensor may include sensors for an advanced driver assistance system (ADAS) configured to assist a driver in driving functions. The controller may include an airbag control unit (ACU).

[0032] A vehicle safety system includes: an airbag module comprising an airbag and an inflator actuated to provide expansion fluid for inflating and deploying the airbag; and an airbag control unit (ACU). The ACU is configured to control the actuation of the inflator and the inflating and deploying of the airbag. The ACU includes an inertial monitoring unit (IMU) operable to measure the longitudinal acceleration of the vehicle and provide a vehicle longitudinal acceleration (IMU_X) value indicating it. The ACU is configured to acquire an automatic emergency braking (AEB) indication from at least one of an advanced driver assistance system (ADAS) and a vehicle stability control system. In response to the AEB indication, the ACU is configured to execute a mass-spring damper model to calculate an estimated occupant movement based on the IMU_X value.

[0033] In response to the AEB instruction, the ACU is configured to execute a mass-spring damper model to calculate the estimated occupant movement based on the IMU_X value.

[0034] According to one aspect, a vehicle safety system is provided. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of a safety system constructed based on an example to help protect the occupants of a vehicle.

[0036] Figure 2 This is a block diagram illustrating a portion of an algorithm implemented in a security system.

[0037] Figure 3 This is a flowchart illustrating a portion of an algorithm implemented in a security system.

[0038] Figure 4 The measurement is shown by the algorithm implemented in the security system. Detailed Implementation

[0039] This invention relates to a vehicle safety system that performs occupant movement estimation to enhance occupant protection in the event of a collision. The system can tailor the actuation of actuable protective devices, such as airbags and seatbelts, in response to the estimated occupant movement.

[0040] Vehicle safety systems

[0041] refer to Figure 1 According to one example configuration, vehicle 12 includes a vehicle safety system 10 for assisting in the protection of vehicle occupants 20. The system 10, including a central control unit, is referred to herein as an airbag control unit (ACU) 50. Safety system 10 includes vehicle sensors 52 operatively connected to the ACU 50. Vehicle sensors 52 include vehicle / occupant status sensors, such as seat weight sensors, seat occupancy sensors, seat position sensors, seat tilt sensors, and seatbelt buckle locking sensors.

[0042] Vehicle sensor 52 may also include sensors (e.g., accelerometers) for measuring vehicle acceleration. These accelerations include longitudinal (X-axis), lateral (Y-axis), and vertical (Z-axis) accelerations. Other accelerations, such as pitch, roll, and yaw, may also be measured. Although the vehicle sensors are shown as being external to and connected to the ACU 50, it is understood that some sensors (such as the aforementioned accelerometers) may be implemented within the ACU 50 itself. These sensors in the ACU 50 may be collectively referred to as inertial measurement unit (IMU) 54. IMU 54 may generate vehicle acceleration signals along the X-axis (IMU_X), Y-axis (IMU_Y), and Z-axis (IMU_Z).

[0043] exist Figure 1In this diagram, vehicle sensor 52 is shown providing the aforementioned status signals directly to ACU 50. However, ACU 50 may acquire some or all of these signals from other controllers or modules via vehicle-based control area network (CAN) bus 88. For example, vehicle 12 may include an occupant classification system (OCS) that uses various seat-based sensors, seatbelt sensors, and even in-vehicle cameras to classify occupants in order to customize the protection provided by system 10. As another example, vehicle 12 may include an in-vehicle monitoring system (IMS) for processing data from multiple in-vehicle sensors, such as in-vehicle cameras, in-vehicle radar sensors, seat weight sensors, buckle sensors, seat position sensors, seat angle sensors, etc. The IMS can use information from the sensors to classify vehicle occupants, such as occupant position sensed by the camera, occupant position sensed by the radar, occupant weight measured by the seat weight sensor, front / rear position measured by the seat position sensor, occupant tilt position measured by the seat angle sensor, occupant buckle status measured by the buckle sensor, etc.

[0044] The ACU 50 can also be operatively connected to actuate one or more actuable protection devices in the vehicle 12, such as Figure 1 The actuable controlled restraint unit (ACR) 60 and front airbag 70 are shown. Other actuable protective devices that the ACU 50 can actuate include curtain airbags, chest airbags, side airbags, and knee airbags. In response to signals obtained from vehicle sensors 52, the ACU 50 can operate to determine the occurrence of an event requiring occupant protection, such as a collision, and in response to control the actuation and / or deployment of the actuable restraint units.

[0045] like Figure 1 As shown, the occupant 20 of vehicle 12 is positioned on vehicle seat 30. Seat 30 includes seat base 32 for mounting the seat on floor 14 of vehicle 12. The base supports a base cushion 34 on which the occupant 20 sits, a seat back 36 on which the occupant leans, and a headrest 38 for receiving the occupant's head 22.

[0046] Seatbelt 40 is connected to ACR 60. Figure 1 In the example configuration shown, the seat belt 40 is a conventional three-point seat belt, which includes a lap belt portion 42 that extends across the occupant's waist 26 and a shoulder strap portion 44 that extends across the occupant's shoulders and across the chest / torso 24. A buckle 46 secures the seat belt 40 to the occupant's waist. Figure 1 The seatbelt is fastened as shown. The D-ring 48 guides the seatbelt 40 to the ACR 60.

[0047] The ACR 60 is designed for use with conventional seatbelt retractors. The ACR releases the seatbelt webbing to allow the occupant 20 to extend the shoulder portion 44 and the waist portion 42 across his / her body, and... Figure 1 The buckle 46 engages in the fastened and restrained state. When the occupant 20 unfastens the seatbelt 40, the ACR also retracts the seatbelt webbing, leaving the occupant unrestrained. Furthermore, the ACR 60 can be configured to include components that allow it to function as a pretensioner and / or load limiter. For this purpose, the ACR 60 includes an inertial locking mechanism. For example, the inertial locking mechanism may include a magnetic ball or sphere configured to move to a locked position in response to negative vehicle acceleration or deceleration reaching or exceeding a predetermined level, as used herein.

[0048] The ACR 60 also includes a motor configured to actively control the extension and retraction of the seatbelt webbing. The ACR 60 is operatively connected to an ACU 50, which is operable to control the active extension and retraction of the seatbelt webbing by the ACR. As described herein, the ACU 50 is configured to control the operation of the ACR 60 in response to a vehicle state determined by evaluating data received from vehicle sensors.

[0049] When normal driving conditions are sensed, the ACU 50 is configured to place the seatbelt 40 in a normal restraint state, such as... Figure 1 As shown, the occupant 20 is held in place with a slight force just enough to eliminate any slack in the seatbelt and keep it against the occupant's body. Under normal restraint, the ACR 60 functions as a standard seatbelt retractor, winding up the seatbelt webbing with a slight force, and easily releasing the webbing, for example, if the occupant leans forward.

[0050] When the vehicle decelerates beyond a predetermined level, the inertial locking mechanism locks the retractor and prevents the seatbelt from unwinding. In the event of a collision, and when a collision occurs, the ACU 50 is configured to sense the event and actuate the ACR 60 to provide any desired tension control in response to the collision event. Conventional load-limiting performance can also be achieved here, but it is typically passive in nature, mechanically provided through structures such as torsion bars / torsion springs.

[0051] One advantage provided by the ACR 60 is that, in response to the detection of a hazardous vehicle condition (such as a dangerous driving condition, e.g., off-road driving, rough terrain, lateral slippage, aerial vehicle condition, etc.), the seatbelt 40 is placed in an enhanced restraint state. In the enhanced restraint state, the ACR 60 tightens the seatbelt 40 around the occupant 20 to enhance the degree to which the occupant is restrained in the vehicle seat 30. Once the driving conditions are determined to be normal, the ACU 50 can control the ACR 60 to place the seatbelt 40 in the normal restraint state. Advantageously, the ACR 60 can place the seatbelt 40 in the enhanced restraint state when a hazardous vehicle condition is detected, and can place the seatbelt in the normal restraint state when the hazardous vehicle condition ends.

[0052] Figure 1 The front airbag 70 shown is a passenger front airbag. Other front airbags (such as a driver's front airbag) may also be implemented in safety system 10, and their control and deployment may be controlled in the same or similar manner as described herein with respect to the illustrated airbag 70. The front airbag 70 is mounted in the dashboard 16 of vehicle 12 and can be deployed in response to the actuation of inflator 72 by ACU 50. When deployed, the front airbag 70 is positioned between dashboard 16 and occupant 20, and at least partially fills the space defined by the dashboard, roof 74, and windshield 76 of vehicle 12.

[0053] To provide enhanced occupant protection, the inflator 72 may be a two-stage inflator with a first or primary stage and a second or secondary stage. The first or primary stage is always actuated in response to a vehicle collision, while the second or secondary stage is actuated only when a sensed condition dictates its use. Sensed conditions that may affect whether the second stage is actuated include collision severity, occupant size, seat position, and buckle locking indication. For example, if the occupant is large (e.g., a large male) and the seat 30 is positioned away from the dashboard 16, both stages may be actuated. As another example, if the occupant is small (e.g., a small female or child) and the seat 30 is positioned close to the dashboard 16, only the first stage may be actuated.

[0054] Advanced driver assistance systems

[0055] Vehicle 12 may also include an Advanced Driver Assistance System (ADAS) 80, which, for the purposes of this specification, is considered part of the vehicle safety system 10. ADAS 80 assists the driver through functions such as parking, lane changing, collision avoidance, adaptive cruise control, electronic stability control, anti-lock braking, emergency braking, traction control, blind spot information system, and lane departure warning. Advanced Driver Assistance Systems are still under development and may offer additional features such as active steering and autonomous driving capabilities; driverless cars are also on the horizon.

[0056] ADAS 80 includes one or more controllers that communicate with various ADAS sensors 82 and cameras 84. The sensors 82 and cameras 84 provide ADAS 80 with information relating to the vehicle 12 and its surrounding environment, which ADAS 80 uses to perform necessary calculations to achieve the various functions listed above. Because ADAS 80 can perform so many functions, it may include various separate controllers or modules responsible for performing one or more specific ADAS functions. For example, ADAS 80 may include a stability control module and / or an anti-lock braking system (ABS) module.

[0057] The schematic diagram of ADAS 80 and its associated sensors 82 and cameras 84 is intended to cover any and all system architectures that may be implemented in vehicle 12. Figure 1 As shown, ADAS 80 can transmit data to ACU 50 and receive data from ACU 50 via CAN bus 88.

[0058] Crew movement estimation

[0059] Vehicle safety system 10 is configured to implement a control algorithm that uses sensed vehicle and / or occupant data to estimate occupant movement in the event of an impending collision and uses the estimated occupant movement to tailor the actuation and deployment of actuable protective devices (i.e., ACR 60 and / or front airbags 70). For example, the control algorithm may be implemented in ACU 50. The determination of an impending collision may be made via ADAS 80.

[0060] ADAS 80 continuously assesses the distance and relative speed of the vehicle and other vehicles / objects ahead to determine when a collision is imminent. Initially, ADAS 80 may issue an Automatic Emergency Braking (AEB) deceleration warning, providing the driver with a visual / auditory / tactile warning that braking is necessary. If the situation is not resolved or worsens, ADAS 80 and / or the stability control module may issue an AEB braking warning, which causes the vehicle to automatically apply the brakes. In some vehicles, automatic braking can be performed in stages, from partial braking to full braking.

[0061] Advantageously, the control algorithm implemented by system 10 utilizes AEB markers to trigger an estimation of occupant movement relative to the vehicle based on sensed vehicle longitudinal acceleration (i.e., negative acceleration or deceleration as used herein). The estimated occupant movement is calculated for the movement of the occupant's head and chest relative to the vehicle. The estimated occupant movement also takes into account the fact that initial occupant movement is substantially unrestricted because seatbelt 30 is configured to extend, and that once a predetermined level of vehicle deceleration is exceeded, the seatbelt inertial mechanism of ACR 60 will prevent seatbelt extension. Therefore, the estimated occupant movement includes both seatbelt unlocking and seatbelt locking components.

[0062] Mass-Spring Damper Model

[0063] The control algorithm implemented by vehicle safety system 10 utilizes a mass-spring damper model to estimate occupant movement relative to the vehicle. U.S. Patent No. 5,935,182 to Foo et al. discloses the use of a mass-spring damper model to estimate occupant movement in response to a collision, the entire contents of which are incorporated herein by reference. The mass-spring damper modeling implemented in system 10 is performed by ACU 50 in a manner similar to or identical to that disclosed by Foo et al. The principles of this modeling are described in the following paragraphs.

[0064] The occupant mass-spring model considers an occupant with a known or assumed mass. In the event of a vehicle collision, the vehicle acceleration caused by the collision results in the occupant moving forward relative to the vehicle. Therefore, vehicle acceleration is the input to the model, used to estimate occupant movement. The seatbelt is used to counteract the occupant's forward movement. To account for this, the model employs a spring constant k representing the seatbelt constraint. The model also employs a damping constant c representing the frictional effects (such as release, extension, load limiting, etc.) exerted by the seatbelt system on the occupant.

[0065] Considering the different masses of the occupant's head and torso, the tighter restraint of the torso to the seat 30 by the seatbelt 40, and the possibility of head movement relative to the torso, system 10 can estimate head movement and torso movement separately using a mass-spring-damped model. Since the occupant's chest impacts the airbag 70, the calculations related to the estimated torso movement are referred to herein as chest movement. The calculations performed by system 10 to estimate these movements are identical for both the head and chest, differing only in the head / chest mass and its associated spring and damping constants.

[0066] Furthermore, in a collision scenario, the seatbelt will initially release the seatbelt webbing, and eventually, the ACR 60 will lock the seatbelt 40, and the load-limiting feature will come into play. Therefore, the spring and damping constants implemented in the mass-spring damper model will change as the vehicle collision progresses from the seatbelt-unlocked, released state to the seatbelt-locked, load-limiting state. Before the seatbelt locks, the constants implemented in the model rarely consider the seatbelt's spring and damping constants. Once the seatbelt locks, the spring and damping constants change to account for the significant impact of the seatbelt on occupant movement. Therefore, System 10 implements four different equations for estimating occupant movement using mass-spring damper modeling:

[0067] Estimate head movement without seatbelt force.

[0068] Estimate chest movement without seatbelt force.

[0069] Estimate head movement while the seatbelt is in place.

[0070] Estimate chest movement while seatbelt force is applied.

[0071] Because these equations are very similar, the derivation of one equation for occupant movement is sufficient to express the derivation of the others. Therefore, the derivation of the equation used to determine the estimated occupant movement will be described below, without addressing the body part to which the estimation is made, but it should be understood that this equation represents the head and chest equations listed above. The following variables are implemented by the mass-spring damper modeling implemented in System 10:

[0072] x1 = Vehicle displacement.

[0073] x2 = Crew displacement.

[0074]

[0075]

[0076]

[0077]

[0078] m O = Passenger mass.

[0079] k O = Crew spring constant.

[0080] c O = Passenger damping constant.

[0081] The equation for the motion of the occupants is:

[0082]

[0083] Add to both sides of the equation

[0084]

[0085] Define a relative coordinate x, which represents the distance the occupant has moved relative to the vehicle:

[0086] x = (x2 - x1) (Equation 3)

[0087] Substituting equation 3 into equation 2 yields the general equation for passenger movement:

[0088]

[0089] Using Equation 4, we can base it on vehicle acceleration. The input is used to calculate the estimated occupant movement x relative to the vehicle. Thus, it will be understood that system 10 can infer and implement four different mass-spring damper models to determine the estimated movement of the occupant's head and chest in both seatbelt-equipped and seatbelt-free scenarios:

[0090] Estimated head movement without seatbelt support:

[0091]

[0092] Estimated chest movement without seatbelt force:

[0093]

[0094] Estimated head movement under seatbelt force:

[0095]

[0096] Estimated chest movement under seatbelt force:

[0097]

[0098] in:

[0099] m h = Mass of the occupant's head.

[0100] m c = Cockpit mass.

[0101] k h = Occupant head spring constant (without seat belt force).

[0102] c h = Occupant head damping constant (without seat belt force).

[0103] k C = Occupant chest spring constant (without seat belt force).

[0104] c c = Occupant chest damping constant (without seat belt force).

[0105] k hsb = Passenger head spring constant (with seat belt force).

[0106] c hsb = Occupant head damping constant (with seat belt force).

[0107] k csb = Occupant chest spring constant (with seat belt force).

[0108] c csb = Occupant chest damping constant (with seat belt force).

[0109] Signal conditioning and model implementation

[0110] Figure 2 This is a block diagram illustrating an occupant movement estimation algorithm 100 implemented in a vehicle safety system 10. Equations 5 to 8 for estimating occupant head and chest movement are implemented in a mass-spring damper modeling function 110 implemented in algorithm 100. Figure 2 The occupant movement estimation algorithm 100 also illustrates some signal conditioning that the sensor data undergoes before being implemented in the modeling function 110. In the example construction of the vehicle safety system shown herein, at least a portion of algorithm 100 can be implemented in the ACU 50.

[0111] like Figure 2As shown, the vehicle longitudinal acceleration signal IMU_X, measured by IMU 54 integrated in ACU 50, is provided to a low-pass filter function (LPF 102) to remove high-frequency noise, such as engine or road vibrations, from the signal. For this purpose, LPF 102 may, for example, have a cutoff frequency of 8 Hz. The low-pass filtered acceleration signal from LPF 102 is provided to an acceleration moving average calculation function (AMA 104) to smooth the filtered acceleration signal. For this purpose, AMA 104 has an adjustable window, which in the example embodiment may be 0.05 seconds.

[0112] The filtered moving average signal from AMA 104 is provided to dead-zone filter 106, which filters out small accelerations that can be used as noise in the system. In one example implementation, dead-zone filter 106 can filter out accelerations in the ±0.05G range. The adjustment signal from block 106 is provided to mass-spring damper model function 110, which is configured as described in equations 5 to 8 above. The adjusted vehicle longitudinal acceleration IMU_X was evaluated to estimate the occupant's head and chest movement under seatbelt force and without seatbelt force.

[0113] Also Figure 2 As shown, an Automatic Emergency Braking Deceleration (AEB_DECEL) flag is provided to latch block 108. In the example configuration of system 10 shown herein, the AEB_DECEL flag can be obtained from ADAS 60 via ACU 50 through CAN bus 88. The AEB_DECEL flag indicates that ADAS 60 has detected an object (such as another vehicle) in the path of vehicle 12, a collision may occur, and vehicle deceleration is necessary. Therefore, the AEB_DECEL flag is a command to initiate automatic emergency braking. Because the AEB_DECEL signal does not need to be maintained throughout the entire AEB braking curve, it is latched at block 108 for a predetermined time period, which can be adjusted to the braking actuation curve implemented by ADAS 60. For example, the latching time period can be approximately 3 seconds.

[0114] Latch block 108 serves as a Boolean switch for mass-spring damper model function 110, which, when activated, performs occupant movement estimation calculations according to equations 5 to 8 in response to the activation or ON of latch block 108. Figure 2As shown, the mass-spring damper model function 110 can generate estimated displacements and velocities of the occupant's head and chest, which will occur in response to an automatic braking scenario detected by ADAS 60. Mass-spring damper calculations performed by model 110 are known and can be performed, for example, in the manner disclosed in U.S. Patent No. 5,935,182 to Foo et al., the contents of which are incorporated herein by reference.

[0115] Seatbelt force switching

[0116] Figure 3 This is a flowchart illustrating the seatbelt force switching process or function 120 implemented by the mass-spring damper model function 110. (See flowchart for example.) Figure 3 As shown, the switching function 120 is a cyclic function. When the model function 110 is enabled, that is, when the latch block 108 is ON and the function is activated, the cyclic function is continuously updated.

[0117] In step or block 122, it is determined whether the seatbelt activation force is ON. This determination refers to whether the inertial locking mechanism of the ACR 60 is actuated. Since the inertial locking mechanism is mechanical, for example, a magnetic ball or sphere configured to move to a locked position in response to vehicle deceleration reaching or exceeding a predetermined level, there is no active signal that can be polled for this determination. Therefore, this determination is made via software modeling, which will be discussed below. Figure 4 Describe it.

[0118] If a determination is made in block 122 that the seatbelt activation force is not ON, as indicated by the line marked "OFF", then function 120 will proceed to step or block 126 and implement equations 5 and 6 in the model using the head and chest spring constants and damping constants for the no-seatbelt-force scenario. Function 120 then proceeds to step or block 128, where equations 5 and 6 are used to calculate the occupant's displacement and velocity.

[0119] If a determination is made in block 122 that the seatbelt activation force is ON, as indicated by the line marked "ON", then function 120 will proceed to step or block 124 and implement equations 7 and 8 in the model using the head and chest spring constants and damping constants for the seatbelt force scenario. Function 120 then proceeds to step or block 128, where equations 7 and 8 are used to calculate the occupant's displacement and velocity.

[0120] Seatbelt force determination

[0121] Figure 4 This is a graph representing a software metric used to determine whether the seatbelt activation force is ON or OFF. This metric is determined at... Figure 3 The switching process / function 120 is implemented at step 122 or block 122.

[0122] like Figure 4 As shown, the model is implemented as a seatbelt force activation metric, generally represented as 150, which is implemented in system 10, for example, as a component or module of occupant movement estimation algorithm 100 implemented in the system. For example, seatbelt force activation metric 150 may be a component or module of mass-spring damper model 110 implemented in ACU 50.

[0123] The seatbelt force activation metric 150 evaluates the vehicle's longitudinal acceleration IMU_X over time. Because braking involves negative acceleration (deceleration), metric 150 shows the negative direction (i.e., Figure 4 The acceleration value visible downwards. The IMU_X evaluated by metric 150 can be from... Figure 2 The adjustment filter value for dead zone block 106. Metric 150 determines whether the IMU_X negative acceleration exceeds a predetermined amplitude corresponding to the point where the ACR 60's inertial locking mechanism should lock. This amplitude can be adjusted for any specific requirements of the ACR60's specific configuration, specific vehicle platform, or vehicle manufacturer. Figure 4 In an example implementation of the seatbelt force activation metric 150, the predetermined IMU_X deceleration value representing the locking of the ACR inertial seatbelt locking mechanism is 0.4G, such as... Figure 4 The threshold value of 152 is indicated by the dashed line in the figure. However, as mentioned above, this value is adjustable.

[0124] Figure 4 The relationship between the metric value and the ON / OFF state of the seatbelt force activation signal is shown. The magnitude of the longitudinal vehicle acceleration IMU_X is evaluated over time (time is represented on the horizontal axis of metric 150) to determine whether it reaches or exceeds a predetermined magnitude. Figure 4 In the example implementation, the predetermined amplitude is 0.4G, which is in Figure 4 The figure is shown as a dashed line. As shown in the graph of metric 150, curve 152, representing IMU_X, hovers around zero G until the point where vehicle deceleration occurs. At this point, the metric deviates from zero, and the magnitude of the negative acceleration of IMU_X increases. During this time, the output of seatbelt force activation metric 150 is OFF.

[0125] When the negative acceleration of IMU_X exceeds the threshold 152, a time delay (ΔT) can be triggered to account for the delay of the ACR inertial seatbelt locking mechanism. During this time delay, the output of the seatbelt force activation metric 150 remains OFF. Once the time delay ends, the output of the seatbelt force activation metric 150 will switch to ON and be latched as ON for a predetermined period of time or until the magnitude of the metric falls below the threshold (0.4G).

[0126] The seatbelt force activation ON / OFF is determined at block 122 of seatbelt force switching function 120 by implementing metric 150. When the ACR inertial seatbelt locking mechanism is locked, function 120 allows stiffer spring and damping constants for Equations 7 and 8 implemented in mass-spring damper model function 100, and allows less stiff constants for Equations 5 and 6 when the mechanism is not locked. An example of the constants, parameters, and tolerances in occupant movement estimation algorithm 100 is shown below:

[0127]

[0128] This allows the occupant movement estimation algorithm 100 to more accurately estimate occupant movement and speed by calculating seatbelt locking and unlocking estimates in response to automatic braking conditions detected by ADAS 80.

[0129] Improved occupant movement estimation can be implemented through vehicle safety system 10 to improve controlled deployment of ACR 60 and / or airbag 70. For example, safety system 10 can be configured to pretension seat belt 40 at different times and / or to different degrees based on the improved estimated occupant displacement and / or velocity. As another example, safety system 10 can be configured to control the actuation of the first and second stages of inflator 72, such as the timing of the activation of the first stage or whether the second stage is fully activated, based on the improved estimated occupant displacement and / or velocity.

[0130] Improvements to the occupant movement estimation algorithm

[0131] Advantageously, the occupant movement estimation algorithm 100 implemented in the vehicle safety system 10 can achieve good performance while relying on only two inputs (IMU_X and AEB_DECEL) to perform the calculations and determinations described above. However, the performance of algorithm 100 can be improved. For example, algorithm 100 can be improved by providing additional inputs to the algorithm, supplying additional parameters to the algorithm, or making some static values ​​or parameters in the algorithm dynamic.

[0132] Initial state input

[0133] The performance of the occupant movement estimation algorithm 100 implemented in the vehicle safety system 10 can be improved by providing additional inputs that can be used to better calculate the estimated position of the occupant relative to the vehicle structure (such as the steering wheel and / or dashboard). For example, knowing the occupant's position relative to the vehicle structure when issuing an AEB_DECEL allows the occupant movement estimation algorithm 100 to determine the occupant position derived from the estimated movement, which can help provide information for decisions on how to deploy safety devices (e.g., seatbelt pretensioning and / or inflator stage 1 / 2 actuation).

[0134] To improve the performance of Algorithm 100 by providing initial state data, optional inputs (in) can be implemented in the occupant movement estimation algorithm 100. Figure 2 The overall value is represented by 112 (indicated by this) to help refine and / or improve the performance of the algorithm. For example... Figure 2 As shown, additional input 112 may include an AEB_BRAKE flag and one or more initial state inputs. For the additional initial state input, the following values ​​can be provided:

[0135]

[0136] Occupant weight input can be implemented as a dynamic variable rather than a constant in occupant movement estimation equations 5 through 8. Using actual occupant weight instead of assumed weight can improve the accuracy and responsiveness of estimated occupant head and chest movements. Although the actual occupant weight may not affect the head mass (m) implemented in the equations... h It will have a significant impact, but may affect the trunk / chest mass (m) implemented in the equation. c This has a significant impact. For example, when the actual occupant weight is available in the occupant movement estimation algorithm 100, chest mass (m) c This can be calculated as a predetermined percentage of the occupant's weight.

[0137] Seat position input and / or seat tilt input and / or steering wheel / dashboard position input can be used to improve the calculation of the distance between the occupant and the vehicle structure. This distance can be combined with estimated occupant movement and / or speed to determine how to adjust the actuation of protective devices (i.e., airbag 70 and / or ACR 60). For example, based on any combination of these inputs, ACU 50 can:

[0138] Delay / accelerate seatbelt tensioning.

[0139] Delay / accelerate seatbelt load limit.

[0140] Delay / accelerate the second stage of inflator activation.

[0141] Delayed / accelerated deflatable airbag.

[0142] For example, if these inputs indicate that an occupant is near the dashboard / steering wheel or out-of-position (OOP) occupant, ACU 50 can be configured to control ACR 60 to increase the magnitude and / or timing of seatbelt pretensioning and / or load limiting. Furthermore, ACU 50 can also adjust the timing of the first / second stage of the inflator 72. ACU 50 can determine whether the second stage is fully activated due to the proximity / OOP occupant. ACU 50 can further determine whether active exhaust is actuated in response to the proximity / OOP occupant. As another example, if these inputs indicate that an occupant is sufficiently spaced from the vehicle structure, ACU 50 can control ACR 60 to reduce the seatbelt pretension tension and / or timing. ACU 50 can also adjust the timing of the first / second stage of the inflator 72. ACU 50 can also determine whether actuating the second stage of the inflator is necessary. ACU 50 can further determine whether active exhaust is actuated or the timing of active exhaust is adjusted in response to the distance between the occupant and the vehicle structure.

[0143] The buckle status input can be used to improve the response of system 10 when the occupant is unfastened. If the buckle status input indicates that the occupant is fastened, system 10 can implement the occupant movement estimation algorithm 100 as described above. ACU 50 can control the actuation of ACR 60 to pretension the seat belt in a normal manner, and ACR and airbag 70 can be deployed based on both occupant movement estimation, seat belt force calculations, and unfastened seat belt force calculations (Equations 5 to 8). The buckle status input can help determine whether first / second stage actuation and its timing are included, as well as the actuation and timing of active deflation.

[0144] However, if the buckle status indicates that the occupant is not fastened, system 10 can implement a modified version of occupant movement estimation algorithm 100. In this scenario, seatbelt pretensioning is irrelevant, and therefore actuating ACR 60 is unnecessary and would not contribute to occupant protection. With this in mind, the modified version of occupant movement estimation algorithm 100 is triggered, and occupant movement is estimated using only calculations without seatbelt force (i.e., only Equations 5 and 6). Therefore, the estimated displacement and velocity will be significantly increased.

[0145] Taking into account the estimated increase in occupant displacement and velocity, and recognizing that seatbelts cannot help protect occupants, the ACU 50 can customize the actuation of the airbag 70. As described above, this customization can be performed with or without any additional inputs to further tailor the airbag actuation. For example, the ACU 50 can actuate the first and / or second stages of the inflator 72 more quickly in response to a sensed collision event, based on the determination that an unfastened occupant will impact the airbag faster than a fastened occupant. The ACU 50 can also appropriately control active deflation.

[0146] AEB braking marking (AEB_BRAKE)

[0147] The AEB braking flag AEB_BRAKE is issued by the vehicle stability control module and can be received by the ACU 50 via the CAN bus 88 for implementation in the occupant movement estimation algorithm 100. The AEB_BRAKE flag operates throughout the AEB braking curve and can therefore supplement or completely replace the implementation of the AEB_DECEL flag. For example, the AEB_DECEL flag can be used in the manner described, i.e., locked ON, to initialize the occupant movement estimation (see...). Figure 2 The AEB_BRAKE flag can be used to unlock the AEB_DECEL flag and take over, continuing occupant movement estimation for the duration of the AEB_BRAKE flag (instead of the predetermined latching time in block 108). Alternatively, the AEB_BRAKE flag can replace the AEB_DECEL flag, so occupant movement estimation is performed only during actual AEB braking.

[0148] E-Lock and other ACR features

[0149] Some configurations of the ACR 60 may include so-called E-locking. The E-locking feature replaces the traditional mechanical seatbelt retractor locking mechanism with an electronic locking mechanism, such as a solenoid. Actuation of the E-locking is controlled via an inertial sensor, which can be a local sensor of the ACR 60 or an IMU_X inertial sensor in the ACU 50. In either case, when the inertial sensor reaches or exceeds a predetermined negative acceleration value (such as the aforementioned 0.4G), an E-locking command can be generated either within the ACR 60 or at the ACU 50 (regardless of where the inertial sensing is performed). If performed at the ACU 50, the E-locking command can be sent to the ACR 60 via CAN bus 88.

[0150] E-locking features can replace Figure 4 The seatbelt force activation measurement 150 is shown in the diagram. Therefore, the E-lock command can replace the seatbelt force switching process or function 120 (see [reference]). Figure 3 The determination is made at block 122. In this case, it is necessary to determine whether the E-lock command exists. If the E-lock command exists, process 120 proceeds to block 124, and the head and chest spring constants and damping constants (with seatbelt force, Equations 7 and 8) are used for mass-spring damper modeling. If the E-lock command does not exist, process 120 proceeds to block 126, and the head and chest spring constants and damping constants (without seatbelt force, Equations 5 and 6) are used for mass-spring damper modeling.

[0151] Another feature that can be enabled by ACR 60 involves improving occupant movement estimation through the ACR interface. For example, ACR 60 may include an extension / retraction sensor that monitors or counts the amount of seatbelt webbing extended and retracted. These sensors may provide extension / retraction values ​​to ACU 50, for example, via CAN bus 88. These values ​​(especially extension values) can be used to provide a direct indication of occupant movement, rather than an estimated movement. Therefore, the extension value can be used not only as feedback to indicate the distance occupant has moved, but also as a definitive indication that occupant movement has begun.

[0152] Based on the foregoing description of the invention, those skilled in the art will recognize improvements, variations, and modifications. For example, the seatbelt described herein is associated with an ACR 60. System 10, and particularly the control algorithm disclosed herein, can be implemented without an ACR 60 using a seatbelt with a conventional seatbelt retractor. Of course, some features described herein do indeed require an ACR 60 to function, but the ACR is only necessary for those features where its presence is required. These and other such improvements, variations, and / or modifications within the scope of the art are intended to be covered by the appended claims.

Claims

1. A method for controlling an actuable safety device for protecting vehicle occupants, the method comprising: Sensing an impending vehicle collision, including receiving automatic emergency braking (AEB) deceleration markers; In response to sensing the impending vehicle collision, the estimated occupant movement that would occur upon the occurrence of the impending vehicle collision is calculated; as well as The actuable safety device is controlled in response to the estimated occupant movement.

2. The method of claim 1, wherein receiving the Automatic Emergency Braking (AEB) deceleration marker includes polling an Advanced Driver Assistance System (ADAS) that implements sensors to detect objects near the vehicle, calculates the relative speed between the detected objects and the vehicle to sense the impending vehicle collision, and outputs the Automatic Emergency Braking (AEB) deceleration marker in response to sensing the impending vehicle collision.

3. The method of claim 2 further includes latching the Automatic Emergency Braking (AEB) deceleration marker for a predetermined time period, the predetermined time period being used to estimate the duration of the Automatic Emergency Braking (AEB) braking curve.

4. The method of claim 1, wherein sensing the impending vehicle collision includes receiving an automatic emergency braking (AEB) signal.

5. The method of claim 4, wherein receiving an Automatic Emergency Braking (AEB) deceleration marker includes polling a vehicle stability system for the AEB deceleration marker, the AEB deceleration marker being marked ON for the entire duration of the AEB braking curve.

6. The method of claim 1, wherein calculating the estimated occupant movement includes performing spring-mass damper modeling to estimate the occupant movement.

7. The method of claim 6, wherein performing spring-mass damper modeling includes using the spring-mass damper model to evaluate the vehicle longitudinal acceleration (IMU_X) to estimate the occupant movement.

8. The method of claim 6, wherein performing the spring-mass damper modeling includes implementing a first spring-mass damper model for estimating occupant head movement and a second spring-mass damper model for estimating occupant chest movement.

9. The method of claim 6, wherein performing the spring-mass damper modeling includes implementing a first spring-mass damper model for estimating occupant movement when the seatbelt is in an unlocked state that allows the seatbelt webbing to be released, and a second spring-mass damper model for estimating occupant movement when the seatbelt is in a locked state that prevents the seatbelt webbing from being released.

10. The method of claim 9, further comprising: Perform an evaluation of the magnitude of the vehicle's longitudinal acceleration (IMU_X) over time; In response to the magnitude of the vehicle's longitudinal acceleration remaining below a predetermined threshold associated with mechanical seatbelt locking, the first spring-mass damper model is implemented; and In response to the magnitude of the vehicle's longitudinal acceleration exceeding the predetermined threshold associated with the mechanical seatbelt locking, the second spring-mass damper model is implemented.

11. The method of claim 9, further comprising: Poll the E-lock status of the actuable controlled restraint seat belt; In response to the E-lock state being OFF, the first spring-mass damper model is implemented; as well as In response to the E-locking state being ON, the second spring-mass damper model is implemented.

12. The method according to claim 9, further comprising: Sensing the seatbelt buckle status; as well as In response to the seatbelt buckle being unfastened, the implementation of the second spring-mass damper model is suppressed.

13. The method of claim 6, wherein performing the spring-mass damper modeling includes implementing: The first spring-mass damper model estimates occupant head movement when the seatbelt is in an unlocked state that allows the seatbelt webbing to be released. A second spring-mass damper model is used to estimate occupant chest movement when the seatbelt is in an unlocked state that allows the seatbelt webbing to be released. A third spring-mass damper model is used to estimate occupant head movement when the seatbelt is in a locked state that prevents the seatbelt webbing from being released. as well as A fourth spring-mass damper model is used to estimate occupant chest movement when the seatbelt is in a locked state that prevents the seatbelt webbing from being released.

14. The method of claim 13, further comprising: Perform an evaluation of the magnitude of the vehicle's longitudinal acceleration (IMU_X) over time; In response to the vehicle's longitudinal acceleration remaining below a predetermined threshold associated with mechanical seatbelt locking, the first spring-mass damper model and the second spring-mass damper model are implemented; and In response to the magnitude of the vehicle's longitudinal acceleration exceeding the predetermined threshold associated with the mechanical seatbelt locking, the third spring-mass damper model and the fourth spring-mass damper model are implemented.

15. The method of claim 1, wherein controlling the actuable safety device in response to the estimated occupant movement comprises at least one of the following: Determine whether to activate the first and / or second stage of the inflator used to inflate the airbag; Determine the timing used to actuate the first and / or second stages of the inflator used to inflate the airbag; Determine whether to actuate the actuable discharge device for discharging inflated fluid from the airbag; Determine the timing for actuating the actuable discharge device used to expel inflated fluid from the airbag; Determine whether to activate the seatbelt load limiter; Determine whether to activate the seatbelt pretensioner; as well as Determine whether to actuate the actuable controlled restraint device (ACR) to tighten the seat belt onto the occupant.

16. The method of claim 1, wherein calculating the estimated occupant movement that would result when the impending vehicle collision occurs further comprises at least one of the following: The occupant weight is sensed to calculate the estimated occupant movement; The seat position is sensed to calculate the occupant position relative to the vehicle structure; The seat tilt is sensed to calculate the occupant position relative to the vehicle structure; Implement sensing of the steering wheel and / or dashboard position to calculate occupant position relative to the vehicle structure; The seatbelt buckle status is sensed to calculate the estimated occupant movement.

17. The method of claim 1, further comprising polling an actuable controlled restraint device (ACR) indication for seatbelt release, and implementing the indicated seatbelt release as feedback for calculations of the estimated occupant movement.

18. A vehicle safety system, comprising: Actuable safety device; Sensors, used to detect impending vehicle collisions; as well as A controller configured to perform the method of claim 1 to control the actuable safety device in response to an estimated occupant movement.

19. The vehicle safety system according to claim 18, wherein: The actuable safety device includes at least one of an airbag inflator, an actuable airbag deflation device, an actuable seatbelt retractor, and an actuable controlled restraint device (ACR) including a seatbelt retractor. The sensors include those of an advanced driver assistance system (ADAS) configured to assist the driver in driving functions; and The controller includes an airbag control unit (ACU).

20. A vehicle safety system, comprising: An airbag module, comprising an airbag and an inflator, the inflator being actuated to provide expansion fluid for inflating and deploying the airbag; An airbag control unit (ACU) is configured to control the actuation of the inflator and the inflation and deployment of the airbag. The airbag control unit includes an inertial monitoring unit (IMU) operable to measure the longitudinal acceleration of the vehicle and provide a vehicle longitudinal acceleration (IMU_X) value indicating the longitudinal acceleration of the vehicle. The airbag control unit (ACU) is configured to receive automatic emergency braking (AEB) indications from at least one of an advanced driver assistance system (ADAS) and a vehicle stability control system; and In response to an automatic emergency braking (AEB) instruction, the airbag control unit (ACU) is configured to execute a mass spring damper model to calculate the estimated occupant movement based on the IMU_X value.

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