1、Designation: E950/E950M 09 (Reapproved 2018)Standard Test Method forMeasuring the Longitudinal Profile of Traveled Surfaceswith an Accelerometer-Established Inertial ProfilingReference1This standard is issued under the fixed designation E950/E950M; the number immediately following the designation in
2、dicates the yearof original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the measurement
3、and recordingof the profile of vehicular-traveled surfaces with anaccelerometer-established inertial reference on a profile mea-suring vehicle.1.2 The test method uses measurement of the distancebetween an inertial plane of reference and the traveled surfacealong with the acceleration of the inertia
4、l platform to detectchanges in elevation of the surface along the length beingtraversed by the instrumented vehicle. In order to meet aparticular class, the transducers shall meet accuracy require-ments and the calculated profile shall meet the specifications ofthat class.1.3 The values measured rep
5、resent a filtered profile mea-sured from a moving plane of reference using the equipmentand procedures stated herein. The profile measurements ob-tained should agree with actual elevation measurements thatare subjected to the same filtering. Selection of proper filteringallows the user to obtain sui
6、table wavelength information forthe intended data processing.1.4 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningv
7、alues from the two systems may result in nonconformancewith the standard.1.5 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, health, and environmental practice
8、s and deter-mine the applicability of regulatory limitations prior to use.Specific precautionary information is given in Section 7.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for
9、 theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2E178 Practice for Dealing With Outlying ObservationsE867 Terminology Relating to Vehicle-Pavement Syste
10、msE1364 Test Method for Measuring Road Roughness byStatic Level MethodF457 Test Method for Speed and Distance Calibration ofFifth Wheel Equipped With Either Analog or DigitalInstrumentation3. Terminology3.1 Definitions:3.1.1 aliasing, vin the context of this practice, spectrum ofa digitized data rec
11、ord exists over the range of frequenciesfrom zero to one-half the sampling frequency. If the spectrumof the original signal extends beyond one-half the samplingfrequency, then those components of the signal at frequencieshigher than one-half the sampling frequency will, whendigitized, be folded back
12、 into the spectrum of the digitizedsignal. The excessively high-frequency components will thusbe “aliased” into low-frequency components.3.1.2 anti-aliasing filter, nlow-pass analog filter applied tothe original analog profile signal to suppress those componentsof the signal at frequencies higher th
13、an one-half the intendeddigital sampling frequency.3.1.3 frequency domain filtering, vfiltering operation per-formed by first calculating the the spectrum of the profilerecord and then multiplying the spectral components by thefrequency response transfer function of the filter.1This test method is u
14、nder the jurisdiction of ASTM Committee E17 on Vehicle- Pavement Systems and is the direct responsibility of Subcommittee E17.31 onMethods for Measuring Profile and Roughness.Current edition approved Jan. 1, 2018. Published January 2018. Originallyapproved in 1983. Last previous edition approved in
15、2009 as E950/E950M 09.DOI: 10.1520/E0950_E0950M-09R18.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyrig
16、ht ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of Internationa
17、l Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.13.1.4 profile record, ndata record of the surface elevation,slope, or acceleration, of arbitrary length.3.1.5 profile segment, nthat part of a profile record forwhich the profi
18、le index will be calculated.3.1.6 spatial domain filtering, va filtering operation per-formed directly on the profile record.4. Summary of Test Method4.1 The test apparatus consists of a vehicle equipped withthe necessary transducers, computing, and recording equip-ment to measure and record elevati
19、on profile of the traveledsurface (1).34.2 The sampling rate is selected and depends on theanticipated roadway conditions and data requirements for theintended data processing.4.3 The test apparatus is driven in the wheel tracks or in thecorrect lateral location over the section of traveled surface
20、to beprofiled. Transducers measure vertical acceleration of thevehicle and the vertical distance between the accelerometer andthe traveled surface and the longitudinal distance. Thesetransducer signals are combined by a computer to produce thelongitudinal profile of the traveled surface.5. Significa
21、nce and Use5.1 The measurement of vehicular-traveled surfaces usingan instrumented vehicle with an inertial plane of referenceprovides a satisfactory method for acquiring traveled surfaceprofile data (1).5.2 The profile data can be processed to produce, bysimulation, the outputs of other devices. Th
22、is can be doneonline in real time or can be computed as a post process. Someof the devices that can be simulated include road meters (2),various straightedge devices (3), profilographs, (4), as well aspavers and grinders. Comparisons of various equipment andtheir profile computer programs are given
23、in References (5, 6).5.3 The raw data or the profile data can also be recorded fordata processing at a later time and for analysis by morecomplex data processing procedures.6. Apparatus6.1 The test apparatus consists of a vehicle equipped withtransducers and profile computing and recording equipment
24、.The transducers are used to measure vertical acceleration,displacement, and the distance traveled. The computer is usedto process the transducer outputs to produce the computedprofile of the traveled surface. The test apparatus shall havetransducer capability for one or more tracks and a mass stora
25、gedevice for long-term storage of the data. If two wheel tracks aremeasured, the displacement transducers shall be mounted 1.5to 1.8 m 58 to 71 in. apart so that they measure in the twowheel tracks of the traveled surface.Aset of gauge blocks shallbe included to calibrate and validate static transdu
26、cer opera-tion. Other supporting apparatus can include a driver speeddisplay and a graphical display of the profile or data. Someform of data display is recommended to ensure correct data isbeing collected.6.2 Vehicle RequirementsThe vehicle is the platform forthe mounting of the profile measuring e
27、quipment. The vehicleshall be large enough to accommodate all the required equip-ment without major structural modifications. The engine,steering mechanisms, and suspension components shall beadequate to allow smooth maintenance of speed and directionof travel. The environment of the interior of the
28、 vehicle shall bemaintained within tolerable limits of the instrumentation andoperators.6.3 Transducers:6.3.1 AccelerometerThe accelerometer measures the ac-celeration used to establish the inertial reference. A high-quality accelerometer shall be used that meets the classrequirements of the profili
29、ng device. The accelerometer shallbe mounted on the measuring vehicle with the accelerometerssensitive axis perpendicular to the traveled surface. The accel-erometer range shall be large enough to accommodate thelevels of acceleration expected from the bounce motions of themeasuring vehicle (typical
30、ly 61 g). The accelerometer shall bebiased to account for the 1-g acceleration of gravity. Theaccelerometer or external circuitry shall contain a self-calibration external voltage source that, on command, causesthe output of the acceleration signal level to change a prede-termined value. The acceler
31、ometer shall have a minimumresolution to allow profile calculation and accuracy and bias tomeet the class requirements as given in this test method.6.3.2 Displacement MeasurementA displacement trans-ducer measures the distance between the accelerometer and thetraveled surface. The transducer shall b
32、e mounted on thevehicle with its measuring axis perpendicular to the traveledsurface and in line with the sensitive axis of the accelerometer.The displacement transducer shall measure the vertical dis-tance to the traveled surface continuously or sample at intervalsnot greater than that needed to al
33、low calculated profile as givenin Table 1. The vertical resolution is that necessary to meet theclass given in Table 2.6.3.3 Distance MeasurementThe distance transducer maybe of the type that produces a series of pulses, the intervals ofwhich represent a distance along the traveled surface to aresol
34、ution needed to satisfy Table 1. The pulses are used tomeasure speed and can be used to convert from a function oftime to a function of distance traveled.Any distance transducerthat produces analog or digital signals with sufficient accuracymay be used. The accuracy of the distance measurement isest
35、ablished by calibration (see 9.2.3).6.3.4 Location MarkersUse of a section start, intermedi-ate feature location(s), and section end shall be identified bylocation marks that can be accurately detected by an automatic3The boldface numbers in parentheses refer to the list of references at the end oft
36、his standard.TABLE 1 Longitudinal SamplingClass 1 less than or equal to 25 mm 1 in.Class 2 greater than 25 mm 1 in. to 150 mm 6 in.Class 3 greater than 150 mm 6 in. to 300 mm 12 in.Class 4 greater than 300 mm 12 in.E950/E950M 09 (2018)2means, such as magnetic detection, photocells detection ofreflec
37、tive tape, or similar means.6.4 Profile ComputationA computer shall be used toprocess acceleration and distance transducer outputs to producemeasured traveled surface profile. There are two basic methodsof computing measured traveled surface profile:6.4.1 Spatial BasedIn the spatial-based method, th
38、e trans-ducer outputs are acquired and profile data points are computedas a function of the distance traveled. In the spatial-basedmethod, the computation of measured road profile is indepen-dent of the vehicle measuring speed.6.4.2 Time BasedIn the time-based system, the transduceroutputs are acqui
39、red and profile data points are computed as afunction of a fixed time interval. In the time-based method, thecomputation of measured road profile is not independent of thevehicle measuring speed.6.4.3 Filtering that permits the computation of measuredelevation profile with no attenuation or amplific
40、ation of roadprofile wavelengths at least 60 m 200 ft long at test speeds of25 to 95 km/h 15 to 60 mph shall be provided. The computerand system shall not add noise in excess of 10 % of thedisplacement measuring transducer resolutions given in Table2.6.4.4 As part of the profile computation equipmen
41、t, acomputer terminal shall be provided that will allow theoperator to perform system calibration, select systemparameters, and monitor system outputs.6.5 Driver Speed Display:6.5.1 The vehicle speed shall be displayed conveniently forthe driver to assist in maintaining the desired measuring speedon
42、 systems requiring constant speed during measurement.Some systems, especially in the case of spatial-based systems,are independent of speed and the speedometer is sufficient.6.5.2 The displayed vehicle speed, when required, may becomputed by the profile computer from the distance pulses.Other means
43、of measuring vehicle speed are acceptable.6.6 DisplayA display should be used that allows visualmonitoring of the systems outputs. The display should allowprofile amplitudes to be displayed as a function of time ordistance traveled. Amplitude and distance scaling shall becontrolled by the operator t
44、hrough the profile computer termi-nal.6.7 Storage DeviceA device shall be provided for therecording and long-term storage of data or computed profile, orboth. The device shall have playback ability for additionalon-board processing or for later processing. Profile data forrecording shall be scaled b
45、y the computer to maintain storageresolution of the computed profile and to accommodate the fullrange of amplitudes encountered during normal profile mea-suring operation. Signal-to-noise (S/N) ratio shall be 10 orbetter.6.8 Event MarkerThe operator shall be provided themeans to event mark location
46、data as part of the data records.The system may use a transducer (optionally) to automaticallysense and record location markers that have been placed on thetraveled surface.7. Safety Precautions7.1 The test vehicle, as well as all attachments to it, shallcomply with all applicable state and federal
47、laws. Necessaryprecautions imposed by laws and regulations, as well asvehicle manufacturers, shall be taken to ensure safety ofoperating personnel and other traffic.8. Digital Profile Recording8.1 The computed profile shall be recorded at adequateintervals for accurate representation of the traveled
48、 surface forthe intended use of the data. Also, anti-aliasing filters arerequired when the folding frequency (one-half of samplingfrequency) is close to the upper frequency of interest (seeTerminology E867). Identical anti-aliasing filtering shall beapplied to both the accelerometer signal and to th
49、e displace-ment measurement signal before computing profiles. The upperfilter frequency depends upon the intended use of the profile.8.2 Where two or more paths of traveled surface aremeasured, the recorded profile data for the paths shall be at thesame longitudinal location. This requirement is not necessary ifthe analysis to be used is independent of the wheel tracks (forexample, only quarter-car analysis used).9. Calibration Procedures9.1 Because of the level of performance required of theclass of traveled surface profile measuring apparatus, i
