1、Designation: F811 02 (Reapproved 2010)Standard Practice forAccelerometer Use in Vehicles for Tire Testing1This standard is issued under the fixed designation F811; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of last re
2、vision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon () 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
3、maneuvers such 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
4、 values given 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 o
5、f regulatory limitations prior to use. Specific precau-tions are given in Section 6.2. Referenced Documents2.1 ASTM Standards:2F538 Terminology Relating to the Characteristics and Per-formance of Tires3. Terminology3.1 Definitions:3.1.1 accelerometer, nan instrument that senses inertialreaction to m
6、easure linear or angular acceleration. F5383.1.2 bandwidth, 1/T, nthe range of frequencies withinwhich certain performance characteristics occur; specific limitsnormally apply. F5383.1.3 g, na unit of acceleration where 1 g is equal to theacceleration of gravity, 9.8 m/s2(32.2 ft/s2). F5383.1.4 gyro
7、-stabilized accelerometer, na precision verticalgyroscope fitted with one to three accelerometers to provideorthogonal measurements referenced to the earth-fixed axissystem. F5383.1.5 servo accelerometer, nan accelerometer containingservo mechanisms, electronics, and a seismic element to senseinerti
8、al reaction. F5383.1.6 strain gage accelerometer, nan accelerometer usingstrain gages to sense the motion of the seismic element.F5383.2 Definitions of Terms Specific to This Standard:3.2.1 performance accelerometer, na packaged accelera-tion measuring system with integral data processing capability
9、.4. 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
10、accelerometer 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 m
11、easurements.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
12、at least 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 t
13、he completesystem shall be from DC to a minimum of 20 Hz. The outputshall not vary more than 62 % of the static output over thisfrequency range.1This practice is under the jurisdiction ofASTM Committee F09 on Tires and isthe direct responsibility of Subcommittee F09.10 on Equipment, Facilities andCa
14、libration.Current edition approved Feb. 1, 2010. Published May 2010. Originallyapproved in 1983. Last previous edition approved in 2002 as F811 02. DOI:10.1520/F0811-02R10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For An
15、nual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.1.4 TemperatureThe operating temperature range shallbe, as a minimum, be
16、tween 23 and 66C (10 and 150F)with a temperature sensitivity of less than 0.054 %/C (0.03 %/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 Accel
17、erometerAccelerometers thatare 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 main-tain the accelerometer(s) in a horizontal plane for X and Yaxes, a
18、nd 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. The filter shall be flat 62%(60.2 dB)from DC to 2.5 Hz, 3 dB at 7.5 6 3
19、 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 bandwidth from DC toat least 20 Hz.5.5 Performance Accelerometers:Several co
20、mmercial 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 accelerationmaneuvers derived from the accelerations. Other systems willmeasure the longi
21、tudinal 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 severaldifferent vehicle suspension combinations and will adjust thedata according
22、ly. 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 Orientation: gs measured in plane of roadData Sample Rate: Ten (10) samp
23、les/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 do notproduce g levels outside the operating range or produce voltagel
24、evels 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 thanthat of the accelerometer while performing maneuvers similarto the
25、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 orreplace the accelerometer with another unit with a higherfull-scale range.6.
26、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 The dynamic accuracy (see 5.1.2) should be verifiedannually if used re
27、gularly by returning the accelerometer to themanufacturer or other calibration facility or by means of an3Neill, A. H., et al., “A Note on Filtering Techniques,” Tire Science andTechnology, Vol. 6, No. 4, Nov. 1978, pp. 263275.FIG. 1 Sign ConventionF811 02 (2010)2appropriate shaker-type calibration
28、device. The calibrationshall be traceable to national standards.7. Preparation of Apparatus7.1 Mounting PositionSolidly mount the accelerometer(s)near the vehicle center of gravity (CG). (An alternate mountinglocation may be used if recommended by the manufacturer ofthe accelerometer(s).)7.2 Angular
29、 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 accordance with the specified method outlined inthe manuals for th
30、e 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 accountinteraction effects.8.2 Static CalibrationCalibrate by tilting the acc
31、elerom-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 zero inclination.8.2.2 Mount the accelerometer on the rotary table
32、, 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 the output.8.2.4 Rotate the table to 30 (0.500 g), 45 (0.707 g
33、), 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 sequence of angles specified in 8.2.3 and8.2.4 until the initial
34、 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 versusrecorder reading.8.2.9 Determine the value of calibration con
35、stant 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 inaccordance with Practice F811.9.2 Acceleration shall be report
36、ed 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 letters X, Y, and Z for the stabilized, earth-axis system.9.4 S
37、tate the accelerometer mounting method (body orstable platform) and location within the vehicle with respect tothe center of gravity.FIG. 2 Filter Frequency ResponseF811 02 (2010)310. Precision and Bias10.1 PrecisionThe test method for which this practice isto be used should be consulted for the pre
38、cision 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.11. Keywords11.1 accelerometer; bod
39、y-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 expressly advised that determination of the validity of any
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