SAE J 1698 3-2015 Event Data Recorder - Compliance Assessment.pdf

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4、side USA)Fax: 724-776-0790Email: CustomerServicesae.orgSAE WEB ADDRESS: http:/www.sae.orgSAE values your input. To provide feedbackon this Technical Report, please visithttp:/www.sae.org/technical/standards/J1698/3_201512SURFACE VEHICLERECOMMENDED PRACTICEJ1698/3 DEC2015Issued 2015-06Revised 2015-12

5、Superseding J1698/3 JUN2013Event Data Recorder - Compliance AssessmentRATIONALEThis Recommended Practice defines a methodology for measuring validity of Event Data Recorder (EDR) output record, relative to input data.TABLE OF CONTENTS1. SCOPE. 21.1 Purpose 22. REFERENCES. 22.1 Applicable Documents .

6、 22.1.1 SAE Publications 22.1.2 Government Publications. 33. DEFINITIONS 34. GENERAL ACQUISITION PARAMETERS 34.1 General Conditions 34.1.1 Attachment method and location . 44.1.2 Signal acquisition . 44.1.3 Reference sensor validation 44.1.4 General certification of other parameters. 54.2 Vehicle Sy

7、stem Considerations . 54.2.1 Sensor signal clipping 54.2.2 Spurious input signals during test 64.2.3 Other 65. LONGITUDINAL DELTA-V PARAMETERS 65.1 Delta V Longitudinal. 65.2 Maximum Delta V Longitudinal 125.3 Time, Maximum Delta V. 13SAE INTERNATIONAL J1698/3 DEC2015 Page 2 of 176. OTHER TABLE 1 PA

8、RAMETERS . 156.1 Ignition Cycle, Crash 156.2 Ignition Cycle, Download 166.3 Frontal Air Bag Deployment, Time to Deploy; Driver (1st Stage) . 166.4 Frontal Air Bag Deployment, Time to Deploy; Passenger (1st Stage) . 166.5 Engine Throttle, % Full. 166.6 Service Brake, On/Off 176.7 Safety Belt Status,

9、Driver. 176.8 Other Table 1 Elements . 177. NOTES. 177.1 Revision Indicator. 17Figure 1 Example of event with clipped acceleration signal. . 5Figure 2 Example of event with velocity difference based on clipped acceleration signal. 6Figure 3 Example (x) crash acceleration signal . 7Figure 4 Example (

10、x) delta velocity signal 8Figure 5 Example (x) delta velocity signal with UCL and LCL . 9Figure 6 Example (x,y) delta velocity signal with UCL and LCL and EDR data. 10Figure 7 Example (x) delta velocity signal with t_squib alignment. 11Figure 8 Example (x) delta velocity signal with UCL and LCL and

11、EDR data; with maximum delta V longitudinal. 13Figure 9 Example (x) delta velocity signal with UCL and LCL and EDR data; with time, maximum delta V longitudinal 14Figure 10 Example composite conformance graph 151. SCOPEThis SAE Recommended Practice defines procedures intended to be used to validate

12、that relevant EDR output records conform within specified limits to measured sensor input to the device.1.1 PurposeVehicle EDRs exist to enable the analysis of vehicle crash and crash-like events that meet specified trigger criteria. Government and vehicle manufacturer laboratory crash testing provi

13、des a basis for assessment of conformance. This recommended practice outlines methods which may be employed to assess conformance for select EDR output parameters. The limitations of these methods are also described.2. REFERENCES2.1 Applicable DocumentsThe following publications form a part of this

14、specification to the extent specified herein. Unless otherwise indicated, the latest issue of SAE publications shall apply.2.1.1 SAE PublicationsAvailable from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or +1 724-776-4970 (outside

15、USA), www.sae.org.SAE J211-1 Instrumentation for Impact Test - Part 1 - Electronic InstrumentationSAE J1698-1 Event Data Recorder - Output Data DefinitionSAE J2570 Performance Specifications for Anthropomorphic Test Device TransducersSAE INTERNATIONAL J1698/3 DEC2015 Page 3 of 172.1.2 Government Pub

16、licationsCopies of these documents are available online at http:/quicksearch.dla.mil.49 CFR Part 563Docket No. NHTSA20110106; response 201149 CFR Part 563Docket No. NHTSA20080004; EDR Final Rule ResponseFMVSS Standard 208 Occupant Crash ProtectionFMVSS Standard 214 Side Impact Protection3. DEFINITIO

17、NSReference SAE J1698 for definitions.Unique definitions / terms for this procedure:3.1 ARRAYAn arrangement of data elements in a defined method. In an EDR, an array will consist of an arrangement of data elements sampled at a defined time instance for a defined duration.3.2 COMPLIANCEThe act adheri

18、ng to, and demonstrating adherence to, a standard or regulation. 3.3 LCLLower Control Limits: Used to define the bottom limit for compliance testing of a variable.3.4 UCLUpper Control Limits: Used to define the upper limit for compliance testing of a variable.3.5 WINDOWA region of acceptance defined

19、 as the values between the UCL and LCL for a given variable. This may include parameters for a single or multiple variables.Unless otherwise noted, x axis refers to longitudinal components (of acceleration or velocity), y axis refers to lateral components, and z axis refers vertical components.4. GE

20、NERAL ACQUISITION PARAMETERS4.1 General ConditionsAcceleration signals used to derive Longitudinal Delta-V and its related parameters (Maximum Value and Time to Maximum Value) are acquired during FMVSS2xx Testing (xx=08,14), including those called out in Part 563 compliance tests. To assess the comp

21、liance and accuracy of these reported parameters, these tests must be conducted with instrumentation that allows a post-test comparison of the EDR output and corresponding laboratory signals. The instrumentation should consist of reference accelerometer(s) installed and monitored under the following

22、 conditions:SAE INTERNATIONAL J1698/3 DEC2015 Page 4 of 174.1.1 Attachment method and locationThe placement and orientation of the reference sensor(s) shall comply with SAE J211 guidelines to maximize desired signal transmission, and insure off-axis signals, transmissibility, and other factors are m

23、et. The accelerometer shall be installed in a manner such that the attachment method of the reference signal provides the full signal content that can be realized by the sensor. The x reference signal used to compute the upper and lower control limits should be located close to the EDRs acceleromete

24、r location, on a similar mounting surface to provide equivalent signal coupling. If this is not possible, additional tolerances may be required to satisfy compliance due to other factors that affect the signals and attenuations, i.e., non-rigid body parameters, especially for events containing multi

25、ple vector inputs. For this scenario, consultation with the vehicle manufacturer is recommended. If squib current measurements are used for correlating events and times, an acceptable method, as agreed with the OEM, shall be utilized. The vehicle manufacturer shall provide recommended accelerometer

26、placement based upon internal test practices, and support interface recommendations for the squib monitoring method(s).4.1.2 Signal acquisitionAn example of a typical reference signal and acquisition requirements would be:Variable Ref RequirementFrequency class SAE J211-1 Class 1,000 (1000 Hz cut-of

27、f).Range (amplitude) class SAE J211-1,SAE J2570Class 1,000 gs; appropriate for the location noted.Resolution SAE J211-1 .5g or greater. Digital word lengths of at least 12 bits (including sign) shall be used to be assured of reasonable accuracy in processing.The least significant bit shall correspon

28、d to no greater than 0.2% of the CAC (channel amplitude class).The vehicle manufacturer may provide recommended accelerometer parameters based upon internal test practices.4.1.3 Reference sensor validationIn the course of applicable laboratory crash testing, it may be necessary to confirm that the r

29、eference signal is valid if the EDR and reference signal do not demonstrate compliance to the limits defined within this practice, or determine a valid alternate source for compliance testing. The following assessments are recommended for this purpose.4.1.3.1 ClippingEvaluate the reference signal fo

30、r signs of clipping. If evident, this signal may not be a valid source to establish complianceto the limits defined within this practice.4.1.3.2 Comparison with related parametersCompare the reference signal with related parameters (e.g., target vehicle speed, measured speed at time of impact, etc.)

31、. If the reference signal demonstrates reasonable correlation with these related parameters, then the reference signal may be deemed valid. If the primary reference signal does not demonstrate correlation with related parameters, consider alternate vehicle-mounted sensors that may be expected to yie

32、ld an output similar to that of the primary (target) reference signal (e.g., accelerometers mounted in close proximity to the primary reference sensor). If this alternate reference signal demonstrates reasonable correlation with the related parameters described herein, then this reference signal may

33、 be used as a substitute for the primary reference. However, it is noted that appropriate adjustment of the compliance limits may be required to allow for the differences in location. Specifically, the alternate location may introduce additional errors in the delta-V slope and or timing of this sign

34、al when compared to the EDR (reference) location that may require additional tolerances added to the noted values to provide compliance to the limits defined in this practice due to different signals occurring in that area, or due to the type of event tested.SAE INTERNATIONAL J1698/3 DEC2015 Page 5

35、of 174.1.4 General certification of other parametersMany tests elements noted in Part 563 Table I include variables that are not reasonably tested at the point of crash certification (i.e., Table III parameters, accuracies for Speed vehicle indicated, throttle position, etc.). For these instances, r

36、efer to the vehicle manufacturer / supplier for a compliance report on the requirements of the appropriate variables.4.2 Vehicle System ConsiderationsIt is noted that vehicle systems are designed to optimize restraint performance. In some cases, these designs may impose constraints on the ability to

37、 comply with specific Part 563 requirements. Examples of these constraints are provided in the following sections.4.2.1 Sensor signal clippingThe EDR may incorporate sensor designs that are optimized for discrimination performance and thus, may not satisfy the requirements denoted in Part 563 for so

38、me elements during an impact event. An example of this may be element g range, which could result in clipping and correlation differences when compared to a (laboratory) reference sensor captured during a test event. This error may translate into deviations for those elements denoted in Part 563. Th

39、e saturation of the (EDR) internal sensor may be demonstrated with processing of the reference sensor to the (modeled) internal sensor signal and/or EDR acceleration data. Incorporation of an internal flag within the EDR denoting the time of saturation from the trigger mayalso be used to indicate th

40、is occurrence.An example illustration of this is provided below:Figure 1 - Example of event with clipped acceleration signal.SAE INTERNATIONAL J1698/3 DEC2015 Page 6 of 17Figure 2 - Example of event with velocity difference based on clipped acceleration signal.4.2.2 Spurious input signals during tes

41、tThe method of conducting vehicle certification tests may create additional signals during the test that may be interpreted by the system as a trigger (may be either at (0) and/or initiate a wake-up signal to the algorithm that may increase the stored time records for a given test condition). Such s

42、ignals may be created by vehicle tow systems, or other methods used to conduct the specific test. 4.2.3 OtherThe following is a list of additional test conditions that may introduce error when comparing the reference and EDR signals.a. Reference Sensor location / signal coupling concerns (with respe

43、ct to module internal sensors).b. Signal acquisition concerns; Sampling, ranges, filtering.c. Reference sensor faults. Non-consistent reference sensor signal responses (erratic, rail), clipping, etc.d. Translational errors due to the positioning of reference sensors with respect to the module intern

44、al sensors (cross-axis, dynamic signals due to non rigid-body dynamics).e. Test event variations; including vehicle rotation during test, or signals from off-axis coupling into the primary axis during test, or variations during test.If any of these concerns are suspected, consult with the vehicle ma

45、nufacturer for review and/or recommendations.5. LONGITUDINAL DELTA-V PARAMETERS5.1 Delta V LongitudinalData Element NameRecording interval/time (relative to time zero)Data Sample Rate (samples per second)Minimum Range Accuracy ResolutionDeltaV, longitudinal0 to 250 ms, or 0 to End of Event Time plus

46、 30 ms, whichever is shorter.100 -100 km/h to + 100 km/h10% (of full scale value)1 km/hSAE INTERNATIONAL J1698/3 DEC2015 Page 7 of 17To verify that the EDR output conforms with the requirements stated, the EDR output is compared with the reference accelerometer sensor data according to the following

47、 process:(Unless otherwise noted, the t_deploy is the first deployed restraint)EXAMPLE:Consider an example crash longitudinal acceleration signal:Figure 3 - Example (x) crash acceleration signalEquation 1: delta_v_x calc; ref 1(Eq. 1)Where: V_ref = Delta velocity of the reference signal (in kilomete

48、rs per hour)t_final = t(0) + 0.3sect(0) = vehicle contact with barrier (typically derived from related contact switch)a_ref_raw = the acceleration reference sensor signal captured during the event under the prescribed conditions. (gs)t = time (seconds) finalttdttrawrefahkmrefV_)0()(_*304.35)/(_SAE I

49、NTERNATIONAL J1698/3 DEC2015 Page 8 of 17This yields the following example longitudinal velocity curve for the given acceleration signal:Figure 4 - Example (x) delta velocity signalThe reference signal is processed as shown in Equation 2 x tolerance limit = (10% of lat_v_max OR long_v_max OR 10% of max range (10km/h)1x | Maximum Delta_v_max_ref Delta_v_max_edr | max | delta-v longitudinal (t) |; In this appro