Seatbelt monitoring system for monitoring seatbelts of multiple seats

Abstract

A vehicle seat belt monitoring system for monitoring seat belts of multiple seats (30), comprising: a buckle sensor (22) for each seat (30) configured to determine whether a safety belt is buckled in a buckle mount of each seat (30); and a seatbelt monitor control module (185) coupled to the buckle sensor (22) and configured to receive buckle status data from the buckle sensor (22) for each seat (30), the seatbelt monitor control module (185) further configured to: (i) to determine whether a first safety belt is unbuckled and, if so, to determine whether a second safety belt has subsequently been buckled and is properly worn if the first safety belt has previously been unbuckled; and (ii) determine whether a primary safety belt is unbuckled and, if so, determine whether the primary safety belt has been refastened and is properly worn; characterized in that A vehicle seat belt monitoring system further comprising, for each seat (30), a seat belt webbing output sensor (26) configured to determine an amount of seat belt webbing paid out from a seat belt retractor associated with each seat (30); wherein the seat belt monitor control module (185) is also coupled to the seat belt webbing output sensor (26) and configured to receive seat belt output data from the seat belt webbing output sensor (26) for each seat (30); wherein the seat belt monitor control module (185), in the event that the first or second seat belt is buckled after the first seat belt is unbuckled, determines whether the webbing output of the re-buckled first seat belt or that of the second seat belt is within a threshold range compared to the webbing output of the first seat belt at the time of its unbuckling, and if not, performs one or more of the following actions: (a) generating a warning after a threshold time that a seat belt is buckled but not properly fastened, (b) activating a camera, (c) contacting a monitoring location to report that a seat belt is buckled but not properly fastened.

Description

INTRODUCTION

[0001] The present disclosure relates to a vehicle safety belt monitoring system according to the preamble of claim 1 for monitoring safety belts of multiple seats, as is essentially known from US 6 362 734 B2.

[0002] Seatbelt systems in a vehicle typically employ seatbelt retractors. A seatbelt retractor has a spool around which seatbelt webbing is wound. The seatbelt webbing can be paid out from the spool and secured around vehicle occupants, a child restraint seat, or an object by inserting a locking plate that couples with the seatbelt webbing in a seatbelt buckle. The seatbelt retractor uses a spring to wind seatbelt webbing onto a retractor spool. Seatbelt systems often include a sensor in the seatbelt buckle to determine whether an occupant is buckled. If the occupant is unbelted, an alert device (e.g., audible message, tone, warning light) prompts the occupant to fasten their seatbelt.

[0003] Seatbelt retractors may also include a seatbelt webbing output sensor, which communicates with the seatbelt webbing, usually via the spool, to detect seatbelt webbing output, i.e., the unwinding / retracting of the retractor. This sensor can measure distances or spool rotations.

[0004] Vehicles often include cameras that detect the position of a vehicle occupant and whether or not the occupant is wearing their seatbelt. However, autonomous electric vehicles operate on batteries, which may not have sufficient power to run processor-based detection algorithms that continuously process the occupant's camera images.

[0005] Some vehicles may also include an in-seat occupancy sensor to detect occupant / object presence. These sensors typically detect either pressure or weight on the seat, but can also detect capacitance or biometric signals.

[0006] DE 10 2017 009 573 A1 describes a method for operating a safety system of a motor vehicle. In this method, the safety system detects status signals from multiple sensor devices, each of which indicates a change in the status of a functional unit of the motor vehicle. A chronological sequence of the status changes is then determined and evaluated to detect a consistency or inconsistency with the proper fastening of a seat belt of the motor vehicle. If such an inconsistency is detected and its persistence over a specified period of time is determined, the safety system sends a control signal to a safety device of the motor vehicle.

[0007] Furthermore, US 2008 / 0 073 141 A1 describes a method in which, after a first seat belt has been unfastened, the system checks whether another seat belt may still be fastened. If this is the case, an alarm can be triggered, which can prevent small children from being accidentally left in the car.

[0008] With regard to the further state of the art, reference is made to the documents CN 1 10 949 311 A and DE 11 2017 004 754 T5. SUMMARY

[0009] According to the invention, a vehicle safety belt monitoring system for monitoring safety belts of multiple seats is presented, which is characterized by the features of claim 1.

[0010] In one embodiment, the seat belt monitor control module is configured to determine from the seat belt output data at least one of a stored output and a belt output from a stored static length value.

[0011] In another embodiment, the stored static length value is the smallest seat belt dispensing length after the second seat belt is buckled that is at least within a fixed time window of a threshold T1 after buckling and before the seat belt dispensing that increments a threshold amount L1.

[0012] In yet another embodiment, the threshold amount L1 comprises one of a fixed length or a percentage.

[0013] In yet another embodiment, the seat belt monitor control module is configured to determine from the seat belt output data at least one of a stored output and a strap output from a set static length value.

[0014] In a further embodiment, the set static length value is the smallest seat belt output length occurring in the last threshold time period T2.

[0015] In yet another embodiment, the adjusted static length value is the smallest seat belt output length that is at least one of not a threshold amount L2 that is less than the stored static length and not a threshold amount L3 that is greater than the stored static length.

[0016] In yet another embodiment, when the seat belt webbing output falls outside the window between the threshold amount L2 and the threshold amount L3, the seat belt monitor control module resumes determining the adjusted static length calculation when the output returns to a value between the amounts L2 and L3, either immediately or after a duration T3 between L2 and L3 has been exceeded.

[0017] In one embodiment, the seat belt monitor control module is activated when the seat belt monitor control module determines that a cabin camera monitoring the occupants of the vehicle system is idle or its view of the seat belt routing is obscured.

[0018] In another embodiment, the seatbelt monitor control module determines when the first seatbelt is unbuckled and no other seatbelt is buckled, and in response performs at least one of: i) alerting an occupant, ii) activating a camera, iii) performing a driving action; and iv) contacting a home office.

[0019] In yet another embodiment, the seatbelt monitor control module terminates certain actions when a seatbelt has been unbuckled and no other seatbelt has been buckled if the stored output was greater than a threshold.

[0020] In yet another embodiment, the seatbelt monitor control module determines when a seatbelt has been unbuckled, with a stored output, and another seatbelt has been buckled, with a belt output that is outside a threshold range compared to the stored output, and responsively produces at least one of: i) alert an occupant, ii) activate a camera, iii) perform a driving action, and iv) contact a home office.

[0021] In another embodiment, the seatbelt monitor control module terminates certain actions when one seatbelt has been unbuckled and another seatbelt has been buckled with a belt output that is outside a threshold range compared to the stored output if the stored output was greater than a threshold.

[0022] In yet another embodiment, the seat belt monitor control module monitors the buckling and routing for a seat when the occupancy sensor detects that the seat is occupied and does not monitor the buckling and routing for a seat when the occupancy sensor does not detect that the seat is occupied.

[0023] In one embodiment, the seat belt monitor control module adjusts at least one of the stored output and the webbing output based on at least one correction factor determined from at least one of a seat position difference and a guide loop position difference.

[0024] It is a further object of the disclosure to provide a vehicle seatbelt monitoring device for monitoring seatbelts of multiple seats, comprising: i) a buckle sensor for each seat configured to determine whether a seatbelt is buckled in a buckle mount of a seat; and ii) a seatbelt monitor control module coupled to the buckle sensor for each seat and configured to receive buckle status data from the buckle sensor. The seatbelt monitor control module is further configured to determine whether a first seatbelt is unbuckled, and if so, to determine whether a second seatbelt is buckled if the first seatbelt is unbuckled.If a seatbelt is unbuckled and no other seatbelt is then buckled, the seatbelt monitor control module will generate at least one of: i) warn, ii) activate a camera, iii) perform a driving action, or iv) contact the home office.

[0025] In one embodiment, the seat belt monitor control module monitors buckling for a seat when the occupancy sensor detects that the seat is occupied and does not monitor buckling for the seat when the occupancy sensor does not detect that the seat is occupied.

[0026] In another embodiment, the seat belt monitor control module generates at least one of: i) stopping a warning action, ii) stopping a driving action, and iii) stopping a home office contact when a seat belt is buckled.

[0027] In yet another embodiment, the seat belt monitor control module generates at least one of: i) warn, ii) turn on a camera, iii) perform a driving action, and iv) contact the home office when a seat is occupied after buckling up.

[0028] Further areas of applicability of the present disclosure will become apparent from the detailed description, claims, and drawings. The detailed description and specific examples are intended for purposes of illustration only. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present disclosure will be more fully understood from the detailed description and the accompanying drawings. Fig. 1A is a functional block diagram of an exemplary vehicle system including a seat belt monitoring system according to the principles of the disclosure. Fig. 1B is a view of a passenger seat in the interior of the vehicle according to an embodiment of the disclosure. Fig. 2A is a flowchart illustrating the operation of the seat belt monitoring system, according to one embodiment of the disclosure. Fig. 2B is a flowchart illustrating the operation of the seat belt monitoring system, according to one embodiment of the disclosure. Fig. 3 is a flowchart showing an optional modification of the operation in Fig. 2B, according to one embodiment of the disclosure. Fig. 4 is a flowchart showing another optional modification of the operation in Fig. 2B, according to one embodiment of the disclosure. Fig. 5 illustrates a graphical representation including a vertical axis for correction factors and a horizontal axis for the difference in position, according to one embodiment of the disclosure. Fig. 6 illustrates a method showing how a correction factor may be applied, according to one embodiment of the disclosure. Fig. 7 illustrates a method showing how a correction factor may be applied, according to one embodiment of the disclosure.

[0030] Reference symbols may be reused in the drawings to identify similar and / or identical elements. DETAILED DESCRIPTION

[0031] The present disclosure describes an apparatus and method for determining whether a person is properly restrained by tracking buckled seating positions and associated seatbelt buckle outputs. This approach can be used for a "buckle to ride" or "buckle to drive" approach on autonomous vehicles and non-autonomous vehicles when a camera is idle or absent during a ride, or when an in-seat occupancy sensor is present or absent. The disclosed method tracks seatbelt-restrained occupants from seating position to seating position via the seatbelt buckle sensor and a webbing output sensor on the seatbelt.The procedure checks the seatbelt buckle attachment and release length to confirm that a person who has been properly buckled in once will remain properly buckled in once they rebuckle after unbuckling a seatbelt. The procedure can be supplemented by an in-seat occupancy sensor that can provide an occupancy signal.

[0032] Fig. 1A is a functional block diagram of an exemplary vehicle system 100 including a seatbelt monitoring system according to the principles of the present disclosure. While a vehicle system for a manually driven hybrid vehicle is shown and described, the present disclosure is also applicable to autonomously driven vehicles and non-hybrid vehicles that include only an internal combustion engine or only electric motors. While the example of a vehicle is provided, the present application is also applicable to non-automotive implementations, such as trains, boats, and aircraft.

[0033] An engine 102 combusts an air / fuel mixture to produce drive torque. A machine control module (ECM) 106 controls the engine 102 based on one or more driver inputs or vehicle inputs. For example, the ECM 106 may control the actuation of engine actuators, such as a throttle valve, one or more spark plugs, one or more fuel injectors, valve actuators, camshaft phasers, an exhaust gas recirculation (EGR) valve, one or more boost devices, and other suitable engine actuators.

[0034] The engine 102 may output torque to a transmission 110. A transmission control module (TCM) 114 controls the operation of the transmission 110. For example, the TCM 114 may control gear selection within the transmission 110 and one or more torque-transmitting devices (e.g., a torque converter, one or more clutches, etc.).

[0035] The vehicle system 100 may include one or more electric motors. For example, an electric motor 118 may be implemented within the transmission 110, as in the example of Fig. 1A. An electric motor can act as either a generator or a motor at a given time. When operating as a generator, the electric motor converts mechanical energy into electrical energy. The electrical energy can charge a battery 126 via a power control device (PCD) 130. When operating as a motor, the electric motor generates torque that can be used to supplement or replace torque output by the engine 102. While the example of an electric motor is provided, the vehicle may include no electric motor or more than one electric motor.

[0036] A power inverter control module (PIM) 134 may control the electric motor 118 and the PCD 130. The PCD 130 applies (e.g., direct current) power from the battery 126 to the (e.g., alternating current) electric motor 118 based on signals from the PIM 134, and the PCD 130 provides, for example, power output from the electric motor 118 to the battery 126. The PIM 134 may be referred to as a power inverter control module (PIM) in various implementations.

[0037] For example, a steering control module 140 controls the steering / turning of the vehicle's wheels based on the driver turning a steering wheel within the vehicle and / or steering commands from one or more vehicle control modules. A steering wheel angle sensor (SWA) 141 monitors the rotational position of the steering wheel and generates an SWA signal 142 based on the position of the steering wheel. As an example, the steering control module 140 may control the vehicle's steering via an EPS motor 144 based on the SWA signal 142. However, the vehicle may include a different type of steering system. An electronic brake control module (EBCM) 150 may selectively control the vehicle's brakes 154.

[0038] Vehicle modules may share parameters via a controller area network (CAN) 162. CAN 162 may also be referred to as an automotive area network. For example, CAN 162 may include one or more data buses. Various parameters may be made available by a given control module to other control modules via network 162.

[0039] For example, driver inputs may include an accelerator pedal position (APP) 166, which may be provided to the ECM 106. A brake pedal position (BPP) 170 may be provided to the EBCM 150. A park, reverse, neutral, drive lever (PRNDL) position 174 may be provided to the TCM 114. An ignition state 178 may be provided to a body control module (BCM) 180. For example, the ignition state 178 may be input by a driver via an ignition key, button, or switch. For example, the ignition state 178 may be one of off, accessory, on, or crank.

[0040] According to an exemplary embodiment of the present disclosure, the vehicle system 100 further includes a seatbelt monitor control module 185, one or more seatbelt webbing dispensing sensors 26, one or more buckle sensors 22, optionally one or more in-seat occupancy sensors 24, one or more in-cabin sensors 25, one or more seat position sensors 28 (possibly more than one per seat position), one or more guide loop position sensors 29, an annunciator display module 190, and a wireless transceiver (XCVR) module 195. If the vehicle system 100 is operated by a ride-sharing company or a rental company, the seatbelt monitor control module 185 may use the wireless transceiver module 194 to communicate with the operating company to send a seatbelt status to the operating company so that corrective action can be taken.The seat belt monitor control module 185 uses an annunciation indicator module 190 to communicate the status of a seat belt to the occupant. For example, the annunciation indicator module 190 may generate: i) a warning tone or ping, ii) a spoken audio message, iii) a warning light, iv) an instrument panel icon, v) an instrument panel text message, vi) a haptic signal, and the like.

[0041] During normal driving conditions, an occupant (or passenger) of the vehicle system 100 may unbuckle their seat belt for comfort, to reach an object, to move to a non-seating location, or to another seat. The occupant may then fail to refasten the seat belt. Additionally, an occupant may avoid a seat belt crossing the torso (or chest) by lifting the chest seat belt over their head and placing the seat belt behind their back while the seat belt is still held across their abdomen and inserted into the seat's seat belt buckle attachment. The seat belt monitor control module 185 continuously monitors the seat belt webbing output sensor 26 and the buckle sensor 22 to determine whether the seat belt has been unbuckled or misused in either situation.The seatbelt monitor control module 185 can also detect other misuse situations, such as wearing only the chest belt, routing the chest belt under the arm, routing the chest belt on the wrong side of the head, routing the chest belt from the shoulder with additional slack, holding the seatbelt out, or clipping it into an extended state to introduce more slack. The seatbelt monitor control module 185 uses the seatbelt buckle sensor and the output length to confirm that a person, once properly buckled, remains properly buckled after re-buckles the seatbelt.

[0042] According to the principles of the present disclosure, the seatbelt monitor control module 185 may determine a stored output, which is either a stored static length value or a set static length value, as hard-coded into the algorithm, or a calibratable selection. The stored output is recorded in memory after the seatbelt is buckled and is retained in memory after the seatbelt is unbuckled so that it can be compared to the output after a seatbelt is buckled. The "stored static length value" is the smallest seatbelt output length after the seatbelt is buckled that: A) is within a fixed time window of a threshold T1 (in seconds) after buckling; and B) is before the seatbelt output increments a threshold amount L1 (e.g., a fixed length or percentage).For example, the fixed time window T1 can be 5 seconds and the amount L1 can be 20 millimeters.

[0043] The "set static length" is the smallest seat belt output length that: A) occurs in the last threshold time window T2 (in seconds) (i.e., a continuous movement of the time window of a duration T2); B) no threshold amount L2 (fixed length or percentage) is less than the stored static length; and C) no threshold amount L3 (fixed length or percentage) is greater than the stored static length. If the seat belt webbing output falls outside the window between amounts L2 and L3, the set static length calculation resumes when: i) the output returns within the window length between amounts L2 and L3; and ii) the output has been within that window length for a threshold duration T3 (in seconds).The set static length compensates for certain actions by the occupant that affect the static length value, such as: i) tightening the seatbelt over a bulky winter jacket (resulting in a small set static length), ii) moving in the seat (causing a tightened seatbelt to loosen around a bulky winter jacket, resulting in a larger set static length), or ii) leaning in the seat, which, depending on the direction of leaning or sliding, can result in either a larger or smaller set static length. The stored output for the set static length is the last set static length value before unbuckling.

[0044] Fig. 1B is a view of a passenger seat in the interior of the vehicle according to an embodiment of the present disclosure. Referring to Fig. 1B illustrates a safety restraint system 10 for a motor vehicle according to one embodiment of the invention. The safety restraint system 10 includes a seatbelt retractor 12, a seatbelt webbing 14, a guide loop 16, a latch plate 18, a buckle 20, a seatbelt buckle sensor 22, a remote occupancy sensor 24, an in-seat occupancy sensor 25, a seatbelt webbing dispensing sensor 26, an automatic locking retractor (ALR) sensor 27, one or more seat position sensors 28 (if a movable seat is present), and one or more guide loop position sensors 29 (if a movable guide loop is present). The seatbelt retractor 12 may include an automatic locking mechanism and would thus be referred to as an automatic locking retractor.If the seatbelt retractor 12 includes an ALR, the seatbelt retractor 12 also includes an ALR sensor 27 that detects engagement or disengagement of the automatic locking mechanism. The seatbelt retractor 12 is fixed to a structural member of the motor vehicle adjacent a vehicle seat 30. For example, the seatbelt retractor 12 is bolted to the base of the B-pillar 32 or another structural member of the vehicle, such as a structure behind or above the seat or in the roof. Alternatively, the seatbelt retractor 12 may be integrated with and fixedly attached to the base of the seat 30 of the motor vehicle. A frame 34 of the seatbelt retractor 12 is configured to rotatably support a spool 36 for controlled rotation within the retractor 12.

[0045] A spring (not shown) is operatively connected to the retractor frame 34 at one end of the spring and to the spool 36 at another end of the spring to retract the seat belt webbing 14 onto the spool 36 and into the retractor 12. The seat belt webbing 14 is at least partially wound around the spool 36 to store the seat belt webbing 14 in the retractor 12 when the safety restraint system 10 is not in use. When the safety restraint system 10 is in use, the seat belt webbing 14 is unwound from the spool 36 and pulled out of the retractor 12 by a vehicle occupant. The seat belt webbing 14 is typically made of a woven fabric material, such as woven nylon or polyester.

[0046] The seat belt webbing payout sensor 26 is in communication with the retractor spool 36. The webbing payout sensor 26 is configured to detect the rotation of the retractor spool 36. The seat belt monitor control module 185 receives a spool rotation signal from the webbing payout sensor 26 and is configured to determine the length of webbing payout from the rotation of the spool 36 of the retractor 12 or the amount of rotation of the spool 36. The seat belt webbing payout sensor 26 can also be used to detect engagement or disengagement from the ALR's automatic locking mechanism. Additionally, there may be other ways to measure payout by detecting markings on the seat belt via a sensor, such as an optical sensor, so the webbing payout sensor 26 can also track webbing payout based on this approach.

[0047] The guide loop 16 is fixedly secured to the motor vehicle generally toward the top of the B-pillar 32 of the motor vehicle. An optional slot 40 is provided in the guide loop 16 which receives and slidably engages the seat belt webbing 14. The seat belt webbing 14 typically extends from the retractor 12 upward and along the B-pillar 32 and is threaded or guided through the guide loop 16, where the seat belt webbing 14 is directed downward toward the base of the seat 30 and secured at a terminal end 41 to a structural member of the motor vehicle or to the seat 30. In some embodiments of the guide loop 16, the height position thereof may be adjusted via a mechanical or motorized mechanism. For embodiments with height adjustment, a guide loop position sensor 29 may track the position of the guide loop 16.The guide loop position sensor 29 transmits a control signal to the seat belt monitor control module 185.

[0048] The locking plate 18 includes a slot 44 through which seat belt webbing is threaded to slidably engage the locking plate 18 with the seat belt webbing 14. The locking plate 18 is located on the seat belt webbing 14 generally between the guide loop 16 and the terminal end 41 of the seat belt webbing 14. The terminal end 41 can be located either on the seat 30 or the vehicle structure. The buckle 20 is configured to releasably capture the locking plate 18. Typically, the locking plate 18 is pushed into a slot 42 in the buckle 20. After the locking plate 18 is fully inserted into the buckle 20, the locking plate 18 is locked in the buckle 20. A button on the buckle 20 is pushed to release the locking plate 18 from the buckle 20.

[0049] The seatbelt buckle sensor 22 is provided in the seatbelt buckle 20. The buckle sensor 22 is configured to detect the presence of the locking plate 18. The buckle sensor 22 transmits a control signal to the seatbelt monitor control module 185. The seatbelt monitor control module 185 includes a control algorithm that receives the control signal from the buckle sensor 22 and determines whether the locking plate 18 is present in the seatbelt buckle 20.

[0050] One or more occupancy sensors 24, 25 are provided to detect the presence of an occupant in the vehicle seat 30. The occupancy sensor 24 is located adjacent the vehicle seat 30. The occupancy sensor 25 is disposed within the vehicle seat 30. The occupancy seat sensor 25 assesses occupant presence via various means, such as one or more pressure pads, weight pads, load cells, resistive pads, capacitive pads, and biometric sensors. Some types of occupancy sensor 25 cannot distinguish between live animals / people and inanimate objects / car restraint seats, and some can distinguish between them. The occupancy sensor 24 would assess occupant presence via various means, such as one or more cameras, radars, ultrasonic sensors, infrared sensors, and the like.The occupancy sensors 24, 25 are configured to detect the presence of a vehicle occupant in the vehicle seat 30. Furthermore, the remotely located occupancy sensor 24 may also have additional functionality and be capable of detecting the routing of the seat belt webbing 14, such as if this sensor were a camera that could view the webbing, the seat 30, and the occupant. The remotely located occupancy sensor 24 may also be capable of detecting occupants located in non-seating position locations, and the distinction between tasks, child restraint seats, animals, and people. Each occupancy sensor 24, 25 transmits a control signal to the seat belt monitor control module 185.

[0051] The seat belt monitor control module 185 includes a control algorithm that receives the control signal from the occupancy sensors 24, 25 and determines whether the occupant is present in the vehicle seat 30. The occupancy sensors 24, 25 can detect elements in the seat such as occupants, animals, objects, child restraint seats, and combinations thereof. The occupancy sensors 24, 25 can have one or more detection thresholds to distinguish between occupants, animals, child restraint seats, and objects, to detect the size of the occupant, to detect the orientation of the child restraint seat, to detect the size of the object, and to detect the location of the occupant relative to the seating surface of the vehicle seat 30. The occupancy sensor 24, located adjacent to the seat, can also detect the seat position and the guide loop position.

[0052] The seat 30 may include one or more seat position sensors 28. These sensors may detect a seat forward-backward position, a seat vertical position, a seat bottom tilt, a seat back tilt, and other adjustable seat parameters. Each seat position sensor 28 transmits a control signal to the seat belt monitor control module 185.

[0053] Fig. 2A is a flowchart illustrating the operation of the seat belt monitoring system according to an embodiment of the present disclosure. Fig. 2B is a flowchart illustrating the operation of the seat belt monitoring system according to an embodiment of the present disclosure. At 205, the seat belt monitor control module 185 continuously stores seat belt buckle status data and seat belt output data, whether stored static length or set static length, as stored output for each seat 30. At optional box 207, the ride is initiated. At 210, the cabin camera enters sleep mode to conserve power or if its view of the seat belt may be partially or completely obscured. Alternatively, the cabin camera may not be present. At 215, the seat belt monitor control module 185 determines if a first seat belt is unbuckled. If "NO" at 215, the seat belt monitor control module 185 determines at 220 whether the ride has ended at 221.If "YES" at 220, the seat belt monitor control module 185 stops execution. If "NO" at 220, the seat belt monitor control module 185 returns to 215 and continues to determine whether the first seat belt is unbuckled.

[0054] If "YES" in 215, the seatbelt monitor control module 185 may optionally determine in 222 whether the seat was previously occupied when the first seatbelt was unbuckled. If "NO" in 222, the seatbelt monitor control module 185 returns to 220 to determine whether the trip has ended, and if then "NO," continues in 215 to determine whether a seatbelt is unbuckled. If "YES" in 222, the seatbelt monitor control module 185 determines in 225 whether the first seatbelt or a second seatbelt has been buckled. Alternatively, if the optional process in 222 is not performed when "YES" in 215, the seatbelt monitor control module 185 goes directly from 215 to 225 and determines whether the first seatbelt or a second seatbelt has been buckled. The company determines in 225 whether the occupant buckled up in the first seat or moved to a second seat.

[0055] If "NO" in 225, the seatbelt monitor control module 185 may perform one or more of several actions in 230, including: i) if a threshold time value T4 has expired, warning the occupant that the seatbelt is unbuckled; ii) turning on the camera; iii) performing a driving action (e.g., decelerating or stopping the vehicle if an autonomous vehicle); iv) contacting a home office or other supervisory agent to report that the seatbelt is unbuckled; and v) storing that no seatbelt has been buckled and, optionally, that the seat has been occupied, in a buffer. Thereafter, the seatbelt monitor control module 185 determines whether the trip has ended in 235. If "YES" in 235, the seatbelt monitor control module 185 stops execution.If "NO" in 235, the seatbelt monitor control module 185 returns to 215 to process other seating positions and also process the seating position where the seatbelt was unbuckled and the seat was occupied. For this latter seating position, the condition where the unbuckled seatbelt is in an occupied seat must be released by buckling or by the seat becoming unoccupied to clear the buffer for that seating position. Otherwise, the buffer condition is executed through steps 215 (seatbelt is unbuckled), 222 (seat is occupied), and 225 (no seatbelt was buckled). If "YES" in 225, the seatbelt monitor control module 185 may optionally determine in 237 whether the seating position is occupied only after the seatbelt for that seating position was buckled in 225. This captures whether the seatbelt was buckled before or after an occupant or object is in the seat.If "YES" at 237, then the seatbelt monitor control module 185 may perform one or more of several actions at 238, including: i) warning that an occupant or possibly an object is not restrained by the seatbelt; ii) turning on the camera; iii) performing a driving action (e.g., decelerating or stopping the vehicle if an autonomous vehicle); iv) contacting a home office or other supervisory agent to report that the occupant or possibly the object is not buckled; and v) storing that the seatbelt was buckled, but after the seat was occupied, in a buffer. After that, the seatbelt monitor control module 185 determines at 235 whether the trip has ended.If "NO" in 235, the seat belt monitor control module 185 returns to 215 to process other seating positions and also to process the seating position where the seat belt was buckled after the seat was occupied. For this latter seating position, the condition where the seat belt that was buckled before the seat was occupied must be released by unbuckling / rebuckling, or the seat must become unoccupied to clear the buffer for this seating position. Otherwise, the buffer condition is passed through steps 215 (seat belt was initially unbuckled), 222 (seat is occupied), 225 (this seat belt was later buckled), and 237 (seat position was occupied after the seat belt was buckled).

[0056] If "YES" in 225 or "NO" in optional step 237, the seat belt monitor control module 185 may determine in 240 whether the webbing output (i.e., the new stored static length or the set static length of the currently buckled seat belt) is within the threshold length +L5 or the threshold length -L6 of the stored output value at the time of unbuckling. This would indicate whether or not the re-buckled seat belt is of a similar length to the previously unbuckled length, indicating that similar routing conditions either exist or do not exist. If "YES" in 240, the seat belt monitor control module 185 may optionally perform one or more of the following actions: a) in 250, display a "Properly Buckled" message or notification (e.g., tone, audible message, flashing light, etc.) to notify the occupant that the seatbelt has been successfully buckled and guided around, b) provide no message, c) not alter the trip in any way, and c) not contact the home office. The seatbelt monitor control module 185 may then return to 215 and continue to determine whether a seatbelt is unbuckled.

[0057] If "NO" in 240, the seat belt monitor control module 185 may perform one or more of several actions in 245, including: i) if a threshold time value T7 has expired, alert the occupant that the seat belt is buckled but not properly routed; ii) turn on the camera; iii) perform a driving action (e.g., decelerate or stop the vehicle); iv) contact a home office or other supervisory agent to report that the seat belt is buckled but not properly routed; and v) store that the seat belt output is outside the range +L5 to -L6 in a buffer. After that, the seat belt monitor control module 185 determines in 235 whether the trip has ended. If "YES" in 235, the seat belt monitor control module 185 stops execution.If "NO" in 235, the seat belt monitor control module 185 will return to 215 to process other seat positions, and also process the seat position where the seat belt output was outside the range +L5 to -L6. For this latter seat position, the condition where the seat belt that was buckled before the seat was occupied must be released by setting the output within the range +L5 to -L6, the seat belt must be unbuckled and rebuckled, or the seat must likely be unoccupied after unbuckling to clear the buffer for this seat position. Otherwise, the buffer condition is passed through steps 215 (seat belt was initially unbuckled), 222 (seat is occupied), 225 (this seat belt was later buckled), 237 (seat position was occupied before the seat belt was buckled), and 240 (seat belt was outside the range +L5 to -L6).

[0058] It should be noted that for some seating positions, the seat belt length is the same, so the range +L5 to -L6 is directly transferable in size between seating positions. For other seating positions, the seat belt length may be different, such as for the center seating position when compared to an adjacent outboard seating position. The center seating position typically has a seat belt connection end 41, the buckle 20, and the guide loop 16 positioned laterally closer together. Thus, an adjustment factor may be required to adjust the range +L5 to -L6 between these seating positions. The adjustment factor may be an addition or subtraction of a length, a multiplication or division of an adjustment value to this threshold length, or a combination of both.

[0059] Fig. 3 is a flowchart showing an optional modification of the operation in Fig. 2B, according to one embodiment of the present disclosure. Fig. 3 provides an optional logic path that includes a decision point 227 between the decision point 225 and the notification 230 of Fig. 2B is used. Fig. 3 differs from Fig. 2A by adding new elements 227 and 228, which are not in Fig. 2A are elements 240, 245, and 250 in Fig. 2A are still in Fig. 3, although they are not shown for the sake of simplicity.

[0060] At 225, the seatbelt monitor control module 185 determines whether the first seatbelt or a second seatbelt has been buckled. This would indicate that the occupant rebuckled themselves into the first seat or moved to the second seat. If "NO" at 225, the seatbelt monitor control module 185 determines at 227 whether the stored output is greater than L8. This operation determines whether the stored output was large enough to indicate that the seatbelt is looping around an object or occupant. Otherwise, if the stored output is equal to or less than L8, the seatbelt may have been buckled over an empty seat, or a different latch plate may have been buckled in the seatbelt buckle.

[0061] If "YES" in 227, the seatbelt monitor control module 185 may perform one or more of several actions in 230, including: i) if a threshold time value T4 has expired, warning the occupant that the seatbelt is unbuckled; ii) turning on the camera; iii) performing a driving action (e.g., decelerating or stopping the vehicle if an autonomous vehicle); iv) contacting a home office or other supervisory agent to report that the seatbelt is unbuckled; and v) storing that no seatbelt has been buckled and, optionally, that the seat has been occupied, in a buffer. If "NO" in 227, the seatbelt monitor control module 185 may optionally generate an "unbuckled or unworn seatbelt" message or notification (e.g., sound, audible message, flashing light, etc.) in 228 to notify the occupant.The seat belt monitor control module 185 determines at 235 whether the trip has ended. In this manner, warnings and actions may only occur at 230 if the stored output was a large amount, indicating that the seat belt was likely routed around an object or occupant.

[0062] Fig. Figure 4 is a flowchart illustrating another optional modification to the operation in Fig. 2B, according to one embodiment of the present disclosure. Fig. 4 provides an optional logic path that connects the decision point 242 between the decision point 240 and the notification 245 of Fig. 2B is used. Fig. 4 differs from Fig. 2A by adding new elements 242 and 243, which are not in Fig. 2A are elements 225, 230, and 250 in Fig. 2A are still in Fig. 4, although they are not shown for the sake of simplicity.

[0063] The seat belt monitor control module 185 may determine at 240 whether the webbing output (i.e., the new stored static length or set static length of the currently buckled seat belt) is within the threshold length +L5 to the threshold length -L6 of the stored output value at the time of unbuckling. This would indicate whether or not the re-buckled seat belt is of a similar length to the previously unbuckled length, indicating that similar routing conditions either exist or do not exist. If "NO" at 240, the seat belt monitor control module 185 determines at 242 whether the stored output is greater than L9. This operation determines whether the stored output is large enough to indicate that the seat belt is being routed around an object or occupant.Otherwise, if equal to or less than L9, the seat belt may have been buckled over an empty vehicle seat or a different locking plate may have been buckled in the seat belt buckle.

[0064] If "YES" in 242, the seat belt monitor control module 185 may perform one or more of several actions in 245, including: i) if a threshold time value T7 has expired, warning the occupant that the seat belt is buckled but not properly routed; ii) turning on the camera; iii) performing a driving action (e.g., decelerating or stopping the vehicle if an autonomous vehicle); iv) contacting a home office or other supervisory agent to report that the seat belt is buckled but not properly routed; and v) storing that the seat belt output is outside the range +L5 to -L6 in a buffer. If "NO" in 242, the seat belt monitor control module 185 may optionally generate a "buckled around an unknown entity" message or notification (e.g., tone, audible message, flashing light, etc.) in 243 to notify the occupant.The seat belt monitor control module 185 determines at 235 whether the trip has ended. In this manner, certain warnings and actions may only occur at 245 if the stored output was a large amount, indicating that the seat belt was likely routed around an object or occupant.

[0065] For vehicle configurations with movable seats, a seat location correction factor 501 may be applied to either the stored output or the post-buckle tape output based on the seat position difference for the seat where the first seat belt was unbuckled and the seat where either the first or second seat belt was later buckled. The seat position difference may be determined by one or more seat position sensors 28 in the seats, the occupancy sensor 24, or a combination of these. Note that the seat position for the first seat belt could be moved while the seat belt was unbuckled, so this evaluation also applies to the seat position for the first seat belt.

[0066] Fig. 5 illustrates a graph 500 including a vertical axis 506 for the seat location correction factor 501 and the guide loop location correction factor 502, and a horizontal axis 508 for the difference in seat position 504 and the guide loop position 505. Curves 510, 512, and 514 represent some examples of the many possible correction approaches. From graph 500, it is easy to determine a correction factor 501, 502 from a difference in position 504, 505. Note that a different curve 510, 512, 514 may be used for each correction factor 501, 502 determined using correction factors 501A, 501B, 501C, etc.

[0067] In the descriptions of Fig. 6 and Fig. 7 that follow, the thresholds L1, T1, L2, T2, L3, T3, T4, L5, L6, T7, L8 and L9 can all be hard-coded into the logic here or can be separate calibratable inputs that can be set outside of the hard code.

[0068] Fig. 6 illustrates a method 600 showing how a correction factor may be applied. At 602, the seat position, buckle state, and stored output are stored for all seat positions. At 604, the difference in seat position for the recently unbelted seat position and the recently buckled seat position is determined. A seat location correction factor 501 is then applied at 606 based on the difference between the seat positions. The correction factor 501 may be determined from a graphical representation 500, a lookup table, or a formula. One or more correction factors 501A, 501B, 501C, etc., may be determined for each possible seat movement, such as seat fore-and-aft movement, vertical seat movement, lower seat tilt movement, etc., or a total correction factor may be determined, which could be the multiplication of the correction factors for each movement.

[0069] In this manner, the stored output or the webbing output for the recently buckled seat belt (such as a first or second seat belt) can be adjusted by the correction factor by either dividing or multiplying it by one of these output values, allowing a direct comparison of output lengths corrected for seat position. For vehicle configurations with movable guide loops, a guide loop location correction factor 502 can be applied to either the stored output or the webbing output after buckling based on the guide loop position difference for the seat where the first seat belt was unbuckled and the seat where the first or second seat belt was later buckled.The difference in guide loop position can be determined by one or more guide loop position sensors 29, the occupancy sensor 24, or a combination thereof. Note that the guide loop position for the primary seat belt could be moved while the seat belt was unbuckled, so this evaluation also applies to the seating position for the primary seat belt.

[0070] Fig.7 illustrates a method 700 showing how a correction factor may be applied. At 702, the guide loop position, buckle state, and stored output are stored for all seating positions. At 704, the difference in the guide loop position for the recently unbelted seating position and the recently buckled seating position is determined. A guide loop location correction factor 502 is then applied at 706 based on the difference between the guide loop positions. The guide loop location correction factor 502 may be determined from a graphical representation 500, a lookup table, or a formula.In this manner, the stored output or the strap output for the recently buckled seat belt (such as for a first or second seat belt) can be adjusted by the guide loop location correction factor 502 by either dividing it or multiplying it by one of these output values, so that a direct comparison of the output length corrected for the guide loop position can be made.

[0071] It is possible to have both a seat location correction factor 501 for seat movement and a guide loop location correction factor 502 for guide loop movement. A total correction factor 503 can then be obtained by multiplying the seat location correction factor 501 and the guide loop location correction factor 502 together, and this can then be used to adjust either the stored output or the webbing output for the recently buckled seat belt by either dividing it or multiplying it by one of these output values.

[0072] It should be noted that the method disclosed in this application implies that the seatbelt control module 185 tracks which seat positions have a buckled seatbelt and which seat positions have an unbuckled seatbelt, so that the number of buckled and unbuckled seatbelts is known from the start of the trip, during the trip, and until the end of the trip. The number of seatbelts buckled at the start of the trip should match the number during the trip; otherwise, the method takes action. Variants of this method simply look for the set of buckled and unbuckled seatbelts for occupied seat positions, and variants of this method also track the output length for the buckled seat positions being tracked.In this manner, the seat belt control module 185 can keep track of seat belt usage, seat occupancy, and seat belt issue accounting and the associated past history of these measurements for each seating position.

[0073] Throughout this document, the primary seat belt may refer to a seat belt that was recently unbuckled, regardless of which of several seating positions that seat belt is located, and the secondary seat belt may refer to a different seat belt than the primary seat belt, regardless of which of several seating positions that seat belt is located. Thus, the terms "primary seat belt" and "secondary seat belt" do not refer to specific seat belt locations within a vehicle.

Claims

[1] A vehicle seat belt monitoring system for monitoring seat belts of multiple seats (30), comprising: a buckle sensor (22) for each seat (30) configured to determine whether a safety belt is buckled in a buckle mount of each seat (30); and a seatbelt monitor control module (185) coupled to the buckle sensor (22) and configured to receive buckle status data from the buckle sensor (22) for each seat (30), the seatbelt monitor control module (185) further configured to: (i) to determine whether a first safety belt is unbuckled and, if so, to determine whether a second safety belt has subsequently been buckled and is properly worn if the first safety belt has previously been unbuckled; and (ii) determine whether a primary safety belt is unbuckled and, if so, determine whether the primary safety belt has been refastened and is properly worn; characterized by , that A vehicle seat belt monitoring system further comprising, for each seat (30), a seat belt webbing output sensor (26) configured to determine an amount of seat belt webbing paid out from a seat belt retractor associated with each seat (30); wherein the seat belt monitor control module (185) is also coupled to the seat belt webbing output sensor (26) and configured to receive seat belt output data from the seat belt webbing output sensor (26) for each seat (30); wherein the seat belt monitor control module (185), in the event that the first or second seat belt is buckled after the first seat belt is unbuckled, determines whether the webbing output of the re-buckled first seat belt or that of the second seat belt is within a threshold range compared to the webbing output of the first seat belt at the time of its unbuckling, and if not, performs one or more of the following actions: (a) generating a warning after a threshold time that a seat belt is buckled but not properly fastened, (b) activating a camera, (c) contacting a monitoring location to report that a seat belt is buckled but not properly fastened. [2] The seat belt monitoring system of claim 1, wherein the seat belt monitor control module (185) is configured to determine from the seat belt output data at least one of a stored output and a strap output from a stored static length value. [3] The seat belt monitoring system of claim 2, wherein the stored static length value is the smallest seat belt output length after either the first or second seat belt is buckled, at least one of which is within a fixed time window of a threshold T1 after buckling and before the seat belt output incrementing a threshold amount L1. [4] A seat belt monitoring system according to claim 3, wherein the threshold amount L1 comprises one of a fixed length or a percentage. [5] The seat belt monitoring system of claim 3, wherein the seat belt monitor control module (185) is configured to determine from the seat belt output data at least one of a stored output and a strap output from a set static length value. [6] A seatbelt monitoring system according to claim 5, wherein the set static length value is the smallest seatbelt output length that occurs in the last threshold time period T2 after either the first or second seatbelt is buckled. [7] The seat belt monitoring system according to claim 6, wherein the set static length value is the smallest seat belt output length which is at least one of not a threshold amount L2 smaller than the stored static length and not a threshold amount L3 larger than the stored static length. [8] The seat belt monitoring system of claim 7, wherein when the seat belt webbing output falls outside the window between the threshold amount L2 and the threshold amount L3, the seat belt monitor control module (185) resumes determining the adjusted static length calculation when the output returns to a value between the amounts L2 and L3 either immediately or after a duration T3 between L2 and L3 has been exceeded. [9] The seat belt monitoring system of claim 1, wherein the seat belt monitor control module (185) is activated when the seat belt monitor control module (185) determines that a cabin camera monitoring the occupants of the vehicle system is idle or its view of the seat belt routing is obscured. [10] The seat belt monitoring system of claim 1, wherein the seat belt monitor control module (185) determines that the first seat belt and no other seat belt has been buckled when the first seat belt has been unbuckled, and in response performs at least one of: i) alerting an occupant, ii) activating a camera, iii) taking a driving action; and iv) contacting a home office.

Images