1、Designation: F 811 02Standard Practice forAccelerometer Use in Vehicles for Tire Testing1This standard is issued under the fixed designation F 811; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number
2、 in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers guidelines for using accelerometersin test vehicles to evaluate dynamic accelerations resultingfrom various maneuvers s
3、uch as braking, accelerating, orcornering.1.2 This practice is applicable to accelerometers that arerigidly attached to the body of the test vehicle or stabilized tothe earth-fixed axis system by means of a gyroscope.1.3 The values stated in SI units are to be regarded as thestandard. The values giv
4、en in parentheses are for informationonly.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulator
5、y limitations prior to use. Specific precau-tions are given in Section 6.2. Referenced Documents2.1 ASTM Standards:F 538 Terminology Relating to the Characteristics and Per-formance of Tires23. Terminology3.1 Definitions:3.1.1 accelerometer, nan instrument that senses inertialreaction to measure lin
6、ear or angular acceleration. F 5383.1.2 bandwidth, 1/T, nthe range of frequencies withinwhich certain performance characteristics occur; specific limitsnormally apply. F 5383.1.3 g, na unit of acceleration where 1 g is equal to theacceleration of gravity, 9.8 m/s2(32.2 ft/s2). F 5383.1.4 gyro-stabil
7、ized accelerometer, na precision verticalgyroscope fitted with one to three accelerometers to provideorthogonal measurements referenced to the earth-fixed axissystem. F 5383.1.5 servo accelerometer, nan accelerometer containingservo mechanisms, electronics, and a seismic element to senseinertial rea
8、ction. F 5383.1.6 strain gage accelerometer, nan accelerometer usingstrain gages to sense the motion of the seismic element.F 5383.2 Definitions of Terms Specific to This Standard:3.2.1 performance accelerometer, na packaged accelera-tion measuring system with integral data processing capability.4.
9、Significance and Use4.1 The measured accelerometer output can be used tocalculate traction properties of combined tire-vehicle systemsfor passenger cars, light trucks, and heavy trucks through useof applicable methods of testing.4.2 This practice is intended to achieve uniformity in testvehicle acce
10、lerometer use and in accelerometer signal process-ing. Through such usage, a basis for meaningful comparisonsof test results from different sources will be obtained.4.3 This practice is not applicable to accelerometers used indestructive testing, such as vehicle crash tests or vehiclevibration measu
11、rements.5. Apparatus5.1 Body-Mounted AccelerometerAn accelerometer shallbe used to measure vehicle accelerations in any of the threeprimary vehicle axes (use x, y, z as illustrated in Fig. 1) andshall have the following specifications:5.1.1 RangeThe full-scale range of the accelerometershall be at l
12、east 61.0 g and not more than 65.0 g for units usedin the x and y axes, and at least 62.0 g and not more than 65.0g for units used in the z axis.5.1.2 AccuracyAmplitude accuracy shall be equal orbetter than 61 % of full scale including all error sources.5.1.3 BandwidthThe frequency response of the c
13、ompletesystem shall be from DC to a minimum of 20 Hz. The outputshall not vary more than 62 % of the static output over thisfrequency range.5.1.4 TemperatureThe operating temperature range shallbe, as a minimum, between 23 and 66C (10 and 150F)with a temperature sensitivity of less than 0.054 %/C (0
14、.03 %/F) of full scale of the sensor.5.1.5 Cross-Axis SensitivityThe measured output shall notbe affected by more than 63 % of the accelerations actingperpendicular to the measurement axis.5.2 Gyro-Stabilized AccelerometerAccelerometers that1This practice is under the jurisdiction of ASTM Committee
15、F09 on Tires and isthe direct responsibility of Subcommittee F09.10 on Equipment, Facilities, andCalibration.Current edition approved October 10, 2002. Published October 2002. Originallypublished as F 811 83. Last previous edition F 811 01.2Annual Book of ASTM Standards, Vol 09.02.1Copyright ASTM In
16、ternational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.are attached to a gyro-stabilized platform for the purpose ofeliminating the effects of vehicle pitch or roll attitudes mustmeet the requirements of 5.1.5.2.1 Gyro-Stabilized PlatformThe platform shall m
17、ain-tain the accelerometer(s) in a horizontal plane for X and Yaxes, and in a vertical plane for Z axis, referenced to the earthwithin 60.25 during data collection.5.3 Low-Pass FilterA low-pass filter shall be used tominimize the effect of vehicle-, tire-, and roadway-relatedvibration on the data. T
18、he filter shall be flat 62%(60.2 dB)from DC to 2.5 Hz, 3 dB at 7.5 6 3 Hz with a roll-offbetween 24 and 48 dB per octave. The frequency response shallfall entirely within the shaded area in Fig. 2.35.4 RecorderThe recorder shall have an accuracy equal toor greater than 1 % of full scale over a bandw
19、idth from DC toat least 20 Hz.5.5 Performance Accelerometers:Several commercial manufacturers have developed solid-state packaged systems to measure the longitudinal and lateralaccelerations of a test platform. One system will calculatespeed and distance traveled during braking or accelerationmaneuv
20、ers derived from the accelerations. Other systems willmeasure the longitudinal and lateral accelerations during cor-nering or acceleration maneuvers. These systems have in-vehicle calibration procedures suitable for test stability. Thesoftware for these units considers the roll rates for severaldiff
21、erent vehicle suspension combinations and will adjust thedata accordingly. The minimum specifications of these units isas follows:Transducer System: One, two or three accelerometers in orthogonalalignment either referenced to earth gravityor component axisMeasurement Resolution: 60.01 gMeasurement O
22、rientation: gs measured in plane of roadData Sample Rate: Ten (10) samples/second (minimum)Anti-Alias Filter: Third order Bessel function or Nyquist filterto 2.56:1 (25 samples/s)6. Hazards6.1 Upon completion of the installation, verify that vehicledynamics and vibrations acting on the accelerometer
23、 do notproduce g levels outside the operating range or produce voltagelevels that would exceed the input rating of the filter.6.1.1 When using a body mounted accelerometer or gyro-stabilized platform, observe the unfiltered accelerometer outputon an oscilloscope or recorder with a bandwidth greater
24、thanthat of the accelerometer while performing maneuvers similarto the type that will be encountered in actual testing.6.1.2 Should the signal exceed the full-scale range (forexample, due to vibration caused by local effects and structuralringing), either provide a more rigid mounting method orrepla
25、ce the accelerometer with another unit with a higherfull-scale range.6.2 The accuracy of body-mounted accelerometers willdepend on the change in horizontal attitude during dynamicvehicle testing where an error is introduced into the data that isequal (in g) to the sine of the roll or pitch angle.6.3
26、 The dynamic accuracy (see 5.1.2) should be verifiedannually if used regularly by returning the accelerometer to themanufacturer or other calibration facility or by means of anappropriate shaker-type calibration device. The calibrationshall be traceable to national standards.7. Preparation of Appara
27、tus7.1 Mounting PositionSolidly mount the accelerometer(s)3Neill, A. H., et al., “A Note on Filtering Techniques,” Tire Science andTechnology, Vol. 6, No. 4, Nov. 1978, pp. 263275.FIG. 1 Sign ConventionF811022near the vehicle center of gravity (CG). (An alternate mountinglocation may be used if reco
28、mmended by the manufacturer ofthe accelerometer(s).)7.2 Angular AlignmentInstall each accelerometer, or thegyro-stabilized platform, with its measurement axis alignedwith the vehicle axis of interest within 62.8. Calibration8.1 Calibrate the solid-state accelerometer/recording system(see 5.5) in acc
29、ordance with the specified method outlined inthe manuals for the system. For a component system, calibratewith all elements of the system (that is, accelerometer, filter,and recorder) connected. Evaluate each subsystem individuallyand compare results to the total accuracy, taking into accountinterac
30、tion effects.8.2 Static CalibrationCalibrate by tilting the accelerom-eter on a rotary table or other test fixture to incrementallyincrease or decrease angles with respect to the horizontal plane.Record the output values for each angle on the recorder used intesting.8.2.1 Set the rotary table at zer
31、o inclination.8.2.2 Mount the accelerometer on the rotary table, with thesensitive axis horizontal and in the plane of rotation within61, and adjust the amplifier or recorder setting, or both, untilthe recorder indicates zero.8.2.3 Rotate the table about the horizontal axis to 10 (0.174g) and record
32、 the output.8.2.4 Rotate the table to 30 (0.500 g), 45 (0.707 g), 60(0.866 g), and 90 (1.000 g) and record the output.8.2.5 Rotate the table from the 90 (1.000 g) position to the60 (0.866 g) position and record the output.8.2.6 Continue to rotate the rotary table incrementallythrough the remaining s
33、equence of angles specified in 8.2.3 and8.2.4 until the initial zero value is reached. Record the outputat each increment.8.2.7 Repeat 8.2.2 through 8.2.6 such that negative g valuescan be recorded, for example, 10 (0.174 g), 30 (0.500g), etc.8.2.8 Tabulate the values of known acceleration in g vers
34、usrecorder reading.8.2.9 Determine the value of calibration constant C, theslope of the curve of known acceleration versus recorderreading. Record calibration values, date of calibration, andmodel and serial number of the accelerometer.9. Report9.1 State that the accelerometer measurement was made i
35、naccordance with Practice F 811.9.2 Acceleration shall be reported in g. If stopping distance,acceleration time and distance is the requirement, note theseparameters.9.3 The sign convention shown in Fig. 1 shall be used, usingthe lower case letters x, y, and z for the vehicle axis system, andcapital
36、 letters X, Y, and Z for the stabilized, earth-axis system.9.4 State the accelerometer mounting method (body orstable platform) and location within the vehicle with respect tothe center of gravity.10. Precision and Bias10.1 PrecisionThe test method for which this practice isto be used should be cons
37、ulted for the precision of thatparticular method.10.2 BiasManufacturers specifications should be con-sulted for information concerning the bias of each particularaccelerometer, filter, or recorder, assuming that the individualunit meets or exceeds the requirements in this practice.FIG. 2 Filter Freq
38、uency ResponseF81102311. Keywords11.1 accelerometer; body-mounted accelerometer; gyro-stabilized accelerometer; tire testingASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are exp
39、ressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revis
40、ed, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may
41、 attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).F811024
