# US 11,999,268 B2 · System, method, and apparatus for classifying an occupant of a vehicle seat > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,999,268 B2 - Document ID: US11999268B2 - Status: Granted - Kind: B2 - Application number: 16/516,310 - Filed: 2019-07-19 - Published: 2021-01-21 - Granted: 2024-06-04 - Earliest claimed: 2019-07-19 - Assignees: Zf Active Safety and Electronics US LLC - Applicants: Zf Active Safety and Electronics US LLC - Inventors: Raymond David; Harshad Dharmatti - Web page: https://patentgrep.com/patent/US11999268B2 ## CPC - G01G 19/4142: {for controlling activation of safety devices, e.g. airbag systems (electrical circuits for triggering safety arrangements in case of vehicle accidents B60R21/015)} - B60N 2/0025: {by using weight measurement} - B60N 2/0031: {mounted on the frame} - B60R 21/01516: {using force or pressure sensing means} - B60W 40/08: related to drivers or passengers - B60N 2/0035: {characterised by the sensor data transmission, e.g. wired connections or wireless transmitters therefor; characterised by the sensor data processing, e.g. seat sensor signal amplification or electric circuits for providing seat sensor information} - B60N 2210/40: Force or pressure sensors - B60N 2230/30: Signal processing of sensor data - B60R 2021/006: {Type of passenger} - B60R 2022/4858: {for sensing pressure on seat} - B60W 2040/0881: {Seat occupation; Driver or passenger presence} - B60W 2050/0029: {Mathematical model of the driver} - B60W 2540/043: Identity of occupants - G01G: WEIGHING (sorting by weighing B07C5/16) - B60N: SEATS SPECIALLY ADAPTED FOR VEHICLES; VEHICLE PASSENGER ACCOMMODATION NOT OTHERWISE PROVIDED FOR - B60R: VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR - B60W: CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT ## Abstract A method for determining an occupant class for a vehicle seat includes obtaining, via first and second seat weight sensors, first and second seat weight indications for the vehicle seat. The first seat weight sensor is located on the lateral side of the vehicle seat at a front location on the vehicle seat. The second seat weight sensor is located on the lateral side of the vehicle seat at a rear location on the vehicle seat. The method also includes obtaining a vehicle acceleration value from a vehicle acceleration sensor. The method also includes determining a raw weight on the vehicle seat as twice the sum of the first and second seat weight indications, and determining a filtered weight based on the raw weight. The method further includes determining the occupant class based on the filtered weight in response to the vehicle acceleration value being less than a predetermined value. ## Claims ### Claim 1 A vehicle safety system comprising at least one vehicle occupant safety device, an airbag ECU, and a controller configured to determine an occupant classification, wherein the airbag ECU is configured to control actuation of the at least one vehicle occupant safety device in response to the occupant classification, and wherein the controller is configured to determine the occupant classification by: communicating with a first seat weight sensor to measure a first seat weight indication for the vehicle seat, wherein the first seat weight sensor is located on a lateral side of the vehicle seat at a front location on the vehicle seat; communicating with a second seat weight sensor to measure a second seat weight indication for the vehicle seat, wherein the second seat weight sensor is located on the lateral side of the vehicle seat at a rear location on the vehicle seat; communicating with a vehicle acceleration sensor to measure a vehicle acceleration value; determining a raw weight on the vehicle seat as twice the sum of the first and second seat weight indications; determining a filtered weight based on the raw weight, wherein the controller is configured to determine the filtered weight by selecting one of an unfiltered weight, a short filtered weight, and a long filtered weight, wherein the short filtered weight is determined using a low pass filter with a comparatively short time constant, and the long filtered weight is determined using a low pass filter with a comparatively long time constant; and determining the occupant class based on the filtered weight in response to the vehicle acceleration value being less than a predetermined value, wherein the controller is configured to select one of an unfiltered weight, a short filtered weight, and a long filtered weight by: selecting the long filtered weight in response to determining that the vehicle is moving and the seat is occupied; and selecting the short filtered weight in response to determining that the vehicle is not moving and the seat is unoccupied. ### Claim 2 (depends on 1) The vehicle safety system recited in claim 1, wherein the controller is further configured to suppress classification changes in response to the vehicle acceleration value being greater than a predetermined threshold value. ### Claim 3 (depends on 2) The vehicle safety system recited in claim 2, wherein the controller is configured to suppress classification changes by suppressing the classifications for a time delay. ### Claim 4 (depends on 2) The vehicle safety system recited in claim 2, wherein the vehicle acceleration value comprises a vehicle lateral acceleration and/or a vehicle longitudinal acceleration. ### Claim 5 (depends on 1) The vehicle safety system recited in claim 1, wherein the occupant class is selected from one of the following classes: no occupant class, child seat class, small adult class, and large adult class. ### Claim 6 (depends on 5) The vehicle safety system recited in claim 5, wherein the no occupant class is associated with measured seat weights up to a first weight, the child seat class is associated with measured seat weights ranging from the first weight up to a second weight, greater than the first weight, the small adult class is associated with measured seat weights ranging from the second weight up to a third weight, greater than the second weight, and the large adult class is associated with measured seat weights greater or equal to than the third weight. ### Claim 7 (depends on 1) The vehicle safety system recited in claim 1, wherein the comparatively short time constant is 1-2 seconds and the comparatively long time constant is 5-20 seconds. ### Claim 8 (depends on 1) The vehicle safety system recited in claim 1, wherein the controller is further configured to override the determined occupant class in response to determining an unbuckled status of the seatbelt associated with the vehicle seat. ### Claim 9 (depends on 1) The vehicle safety system recited in claim 1, wherein the controller is configured to determine the occupant class based on a filtered weight by implementing a hysteresis logic function that assigns the occupant class based on the filtered weight and prevents changes in the assigned occupant class due to fluctuations in the filtered weight due to seat loading in response to vehicle operation and/or the occupant changing positions on the seat. ### Claim 10 (depends on 9) The vehicle safety system recited in claim 9, wherein the hysteresis logic function implements overlapping weight ranges for each occupant class, each weight range comprising a high threshold and a low threshold, wherein the hysteresis logic function assigns the next higher occupant class in response to the filtered weight exceeding the high threshold, and wherein the hysteresis logic function assigns the next lower occupant class in response to the filtered weight dropping below the low threshold. ### Claim 11 (depends on 10) The vehicle safety system recited in claim 10, wherein each weight range further comprises a conformance threshold, wherein the conformance threshold is the nominal weight value for the corresponding occupant class, and wherein the conformance threshold is utilized to determine an initial occupant class. ### Claim 12 (depends on 1) The vehicle safety system recited in claim 1, wherein the controller is configured to determine the filtered weight based on the raw weight by implementing a freeze filter function that freezes the filtered weight value in response to a vehicle lateral acceleration being above a predetermined threshold. ### Claim 13 (depends on 1) The vehicle safety system recited in claim 1, wherein: the first seat weight sensor is configured to measure seat weight at a front inboard mounting location of the seat, and the second seat weight sensor is configured to measure seat weight at a rear inboard mounting location of the seat; or the first seat weight sensor is configured to measure seat weight at a front outboard mounting location of the seat, and the second seat weight sensor is configured to measure seat weight at a rear outboard mounting location of the seat. ### Claim 14 A vehicle safety system comprising at least one vehicle occupant safety device, an airbag ECU, and a controller configured to determine an occupant classification, wherein the airbag ECU is configured to control actuation of the at least one vehicle occupant safety device in response to the occupant classification, and wherein the controller is configured to determine the occupant classification by: communicating with a first seat weight sensor to measure a first seat weight indication for the vehicle seat, wherein the first seat weight sensor is located on a lateral side of the vehicle seat at a front location on the vehicle seat; communicating with a second seat weight sensor to measure a second seat weight indication for the vehicle seat, wherein the second seat weight sensor is located on the lateral side of the vehicle seat at a rear location on the vehicle seat; communicating with a vehicle acceleration sensor to measure a vehicle acceleration value; determining a raw weight on the vehicle seat as twice the sum of the first and second seat weight indications; determining a filtered weight based on the raw weight, wherein the controller is configured to determine the filtered weight by selecting one of an unfiltered weight, a short filtered weight, and a long filtered weight, wherein the short filtered weight is determined using a low pass filter with a comparatively short time constant, and the long filtered weight is determined using a low pass filter with a comparatively long time constant; and determining the occupant class based on the filtered weight in response to the vehicle acceleration value being less than a predetermined value, wherein the occupant class is selected from one of the following classes: no occupant class, child seat class, small adult class, and large adult class, wherein the no occupant class is associated with measured seat weights up to a first weight, the child seat class is associated with measured seat weights ranging from the first weight up to a second weight, greater than the first weight, the small adult class is associated with measured seat weights ranging from the second weight up to a third weight, greater than the second weight, and the large adult class is associated with measured seat weights greater or equal to than the third weight, and wherein the first weight is 10.8 kg, the second weight is 29.4 kg, and the third weight is 54.8 kg. ### Claim 15 A vehicle safety system comprising at least one vehicle occupant safety device, an airbag ECU, and a controller configured to determine an occupant classification, wherein the airbag ECU is configured to control actuation of the at least one vehicle occupant safety device in response to the occupant classification, and wherein the controller is configured to determine the occupant classification by: communicating with a first seat weight sensor to measure a first seat weight indication for the vehicle seat, wherein the first seat weight sensor is located on a lateral side of the vehicle seat at a front location on the vehicle seat; communicating with a second seat weight sensor to measure a second seat weight indication for the vehicle seat, wherein the second seat weight sensor is located on the lateral side of the vehicle seat at a rear location on the vehicle seat; communicating with a vehicle acceleration sensor to measure a vehicle acceleration value; determining a raw weight on the vehicle seat as twice the sum of the first and second seat weight indications; determining a filtered weight based on the raw weight, wherein the controller is configured to determine the filtered weight by selecting one of an unfiltered weight, a short filtered weight, and a long filtered weight, wherein the short filtered weight is determined using a low pass filter with a comparatively short time constant, and the long filtered weight is determined using a low pass filter with a comparatively long time constant; and determining the occupant class based on the filtered weight in response to the vehicle acceleration value being less than a predetermined value, wherein the controller is configured to select one of an unfiltered weight, a short filtered weight, and a long filtered weight by: selecting the unfiltered weight for a predetermined startup time; selecting the short filtered weight after the startup time expires; selecting the long filtered weight in response to determining that the vehicle is moving and the seat is occupied; and selecting the short filtered weight in response to determining that the vehicle is not moving and the seat is unoccupied. ### Claim 16 (depends on 15) The vehicle safety system recited in claim 15, wherein the controller is further configured to suppress classification changes in response to the vehicle acceleration value being greater than a predetermined threshold value. ### Claim 17 (depends on 16) The vehicle safety system recited in claim 16, wherein the controller is configured to suppress classification changes by suppressing the classifications for a time delay. ### Claim 18 (depends on 16) The vehicle safety system recited in claim 16, wherein the vehicle acceleration value comprises a vehicle lateral acceleration and/or a vehicle longitudinal acceleration. ### Claim 19 (depends on 15) The vehicle safety system recited in claim 15, wherein the occupant class is selected from one of the following classes: no occupant class, child seat class, small adult class, and large adult class. ### Claim 20 (depends on 19) The vehicle safety system recited in claim 19, wherein the no occupant class is associated with measured seat weights up to a first weight, the child seat class is associated with measured seat weights ranging from the first weight up to a second weight, greater than the first weight, the small adult class is associated with measured seat weights ranging from the second weight up to a third weight, greater than the second weight, and the large adult class is associated with measured seat weights greater or equal to than the third weight. ### Claim 21 (depends on 15) The vehicle safety system recited in claim 15, wherein the comparatively short time constant is 1-2 seconds and the comparatively long time constant is 5-20 seconds. ### Claim 22 (depends on 15) The vehicle safety system recited in claim 15, wherein the controller is further configured to override the determined occupant class in response to determining an unbuckled status of the seatbelt associated with the vehicle seat. ### Claim 23 (depends on 15) The vehicle safety system recited in claim 15, wherein the controller is configured to determine the occupant class based on a filtered weight by implementing a hysteresis logic function that assigns the occupant class based on the filtered weight and prevents changes in the assigned occupant class due to fluctuations in the filtered weight due to seat loading in response to vehicle operation and/or the occupant changing positions on the seat. ### Claim 24 (depends on 23) The vehicle safety system recited in claim 23, wherein the hysteresis logic function implements overlapping weight ranges for each occupant class, each weight range comprising a high threshold and a low threshold, wherein the hysteresis logic function assigns the next higher occupant class in response to the filtered weight exceeding the high threshold, and wherein the hysteresis logic function assigns the next lower occupant class in response to the filtered weight dropping below the low threshold. ### Claim 25 (depends on 24) The vehicle safety system recited in claim 24, wherein each weight range further comprises a conformance threshold, wherein the conformance threshold is the nominal weight value for the corresponding occupant class, and wherein the conformance threshold is utilized to determine an initial occupant class. ### Claim 26 (depends on 15) The vehicle safety system recited in claim 15, wherein the controller is configured to determine the filtered weight based on the raw weight by implementing a freeze filter function that freezes the filtered weight value in response to a vehicle lateral acceleration being above a predetermined threshold. ### Claim 27 (depends on 15) The vehicle safety system recited in claim 15, wherein: the first seat weight sensor is configured to measure seat weight at a front inboard mounting location of the seat, and the second seat weight sensor is configured to measure seat weight at a rear inboard mounting location of the seat; or the first seat weight sensor is configured to measure seat weight at a front outboard mounting location of the seat, and the second seat weight sensor is configured to measure seat weight at a rear outboard mounting location of the seat. ### Claim 28 A vehicle safety system comprising at least one vehicle occupant safety device, an airbag ECU, and a controller configured to determine an occupant classification, wherein the airbag ECU is configured to control actuation of the at least one vehicle occupant safety device in response to the occupant classification, and wherein the controller is configured to determine the occupant classification by: communicating with a first seat weight sensor to measure a first seat weight indication for the vehicle seat, wherein the first seat weight sensor is located on a lateral side of the vehicle seat at a front location on the vehicle seat; communicating with a second seat weight sensor to measure a second seat weight indication for the vehicle seat, wherein the second seat weight sensor is located on the lateral side of the vehicle seat at a rear location on the vehicle seat; communicating with a vehicle acceleration sensor to measure a vehicle acceleration value; determining a raw weight on the vehicle seat as twice the sum of the first and second seat weight indications; determining a filtered weight based on the raw weight, wherein the controller is configured to determine the filtered weight by selecting one of an unfiltered weight, a short filtered weight, and a long filtered weight, wherein the short filtered weight is determined using a low pass filter with a comparatively short time constant, and the long filtered weight is determined using a low pass filter with a comparatively long time constant; and determining the occupant class based on the filtered weight in response to the vehicle acceleration value being less than a predetermined value, wherein the controller is configured to select one of an unfiltered weight, a short filtered weight, and a long filtered weight by: selecting the unfiltered weight for an initial startup time; selecting the short filtered weight until the vehicle is moving and the seat is occupied; and thereafter selecting the long filtered weight until the vehicle stops moving. ### Claim 29 (depends on 28) The vehicle safety system recited in claim 28, wherein the controller is further configured to suppress classification changes in response to the vehicle acceleration value being greater than a predetermined threshold value. ### Claim 30 (depends on 29) The vehicle safety system recited in claim 29, wherein the controller is configured to suppress classification changes by suppressing the classifications for a time delay. ### Claim 31 (depends on 29) The vehicle safety system recited in claim 29, wherein the vehicle acceleration value comprises a vehicle lateral acceleration and/or a vehicle longitudinal acceleration. ### Claim 32 (depends on 28) The vehicle safety system recited in claim 28, wherein the occupant class is selected from one of the following classes: no occupant class, child seat class, small adult class, and large adult class. ### Claim 33 (depends on 32) The vehicle safety system recited in claim 32, wherein the no occupant class is associated with measured seat weights up to a first weight, the child seat class is associated with measured seat weights ranging from the first weight up to a second weight, greater than the first weight, the small adult class is associated with measured seat weights ranging from the second weight up to a third weight, greater than the second weight, and the large adult class is associated with measured seat weights greater or equal to than the third weight. ### Claim 34 (depends on 28) The vehicle safety system recited in claim 28, wherein the comparatively short time constant is 1-2 seconds and the comparatively long time constant is 5-20 seconds. ### Claim 35 (depends on 28) The vehicle safety system recited in claim 28, wherein the controller is further configured to override the determined occupant class in response to determining an unbuckled status of the seatbelt associated with the vehicle seat. ### Claim 36 (depends on 28) The vehicle safety system recited in claim 28, wherein the controller is configured to determine the occupant class based on a filtered weight by implementing a hysteresis logic function that assigns the occupant class based on the filtered weight and prevents changes in the assigned occupant class due to fluctuations in the filtered weight due to seat loading in response to vehicle operation and/or the occupant changing positions on the seat. ### Claim 37 (depends on 36) The vehicle safety system recited in claim 36, wherein the hysteresis logic function implements overlapping weight ranges for each occupant class, each weight range comprising a high threshold and a low threshold, wherein the hysteresis logic function assigns the next higher occupant class in response to the filtered weight exceeding the high threshold, and wherein the hysteresis logic function assigns the next lower occupant class in response to the filtered weight dropping below the low threshold. ### Claim 38 (depends on 37) The vehicle safety system recited in claim 37, wherein each weight range further comprises a conformance threshold, wherein the conformance threshold is the nominal weight value for the corresponding occupant class, and wherein the conformance threshold is utilized to determine an initial occupant class. ### Claim 39 (depends on 28) The vehicle safety system recited in claim 28, wherein the controller is configured to determine the filtered weight based on the raw weight by implementing a freeze filter function that freezes the filtered weight value in response to a vehicle lateral acceleration being above a predetermined threshold. ### Claim 40 (depends on 28) The vehicle safety system recited in claim 28, wherein: the first seat weight sensor is configured to measure seat weight at a front inboard mounting location of the seat, and the second seat weight sensor is configured to measure seat weight at a rear inboard mounting location of the seat; or the first seat weight sensor is configured to measure seat weight at a front outboard mounting location of the seat, and the second seat weight sensor is configured to measure seat weight at a rear outboard mounting location of the seat.