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GB/T 40499-2021 English PDF (GBT40499-2021)

GB/T 40499-2021 English PDF (GBT40499-2021)

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GB/T 40499-2021: General condition of vehicle dynamics test for heavy vehicles and buses

This document specifies methods of vehicle dynamics test for heavy vehicles and buses. This document applies to M1, M2, M3, N2, N3 vehicles whose total mass is more than 3 500 kg.
GB/T 40499-2021
GB
NATIONAL STANDARD OF THE
PEOPLE REPUBLIC OF CHINA
ICS 43.020
CCS T 00
General condition of vehicle dynamics test for heavy
vehicles and buses
(ISO 15037-2:2002, Road vehicles - Vehicle dynamics test methods -
Part 2: General conditions for heavy vehicles and buses, MOD)
ISSUED ON: AUGUST 20, 2021
IMPLEMENTED ON: MARCH 01, 2022
Issued by: State Administration for Market Regulation;
Standardization Administration of the PEOPLE Republic of
China.
Table of Contents
Foreword ... 3
1 Scope ... 6
2 Normative references ... 6
3 Terms and definitions ... 6
4 Variables ... 6
5 Measurement equipment ... 7
6 Test conditions ... 11
7 Test preparation ... 13
Appendix A (Informative) Structural changes between this document and ISO 15037-2:2002 ... 17
Appendix B (Normative) Test report - General data ... 19
Appendix C (Informative) Sensor and its installation ... 23
Appendix D (Informative) Analog signal filtering: Butterworth filter ... 29 Appendix E (Normative) Test conditions ... 31
General condition of vehicle dynamics test for heavy
vehicles and buses
1 Scope
This document specifies methods of vehicle dynamics test for heavy vehicles and buses.
This document applies to M1, M2, M3, N2, N3 vehicles whose total mass is more than 3 500 kg.
2 Normative references
The contents of the following documents constitute the indispensable clauses of this document through normative references in the text. For dated references, only the version corresponding to that date is applicable to this document; for undated references, the latest version (including all amendments) is applicable to this document.
GB/T 12549-2013, Terms and Definitions for Vehicle Controllability and
Stability (ISO 8855:2011, NEQ)
3 Terms and definitions
The following terms and definitions are applicable to this document.
3.1
Vehicle unit
A unit of vehicles that are connected by a yaw articulation.
Note: The number of vehicle units is one more than the number of yaw
articulations.
4 Variables
4.1 Reference frame
The motion variables recorded in the test shall meet the definition of coordinate system in GB/T 12549-2013. The origin of the coordinate is usually taken at the Hz. In the frequency range of 0 Hz ~ 2 Hz, the amplitude error shall be less than ??0.5%. All analog signals shall be processed with filters of the same phase characteristics, so as to ensure that the time delay caused by filtering is the same.
Note: In order to save the low frequency signal, DC coupling shall be adopted as the signal. Since the analog signal filtering process of different
frequency components will be phase shifted, it is recommended to use
the digital signal processing method that is described in 5.3.3.
5.3.3 Aliasing error and anti-aliasing filter
5.3.3.1 Preparations for analog signal processing include: selecting the sampling frequency and filter amplitude attenuation characteristics to avoid aliasing errors, and the phase lag and time delay characteristics of the filter. 5.3.3.2 Contents to be considered for sampling and digitization:
a) The pre-sampling amplification ratio that ensures the smallest digitization error;
b) The number of bits per sampling;
c) The number of samples per cycle;
d) Sampling and holding amplifier;
e) Sample space;
f) For other digital filters without phase shift, the selection of passband, stopband, attenuation, allowable ripple, and the correction of filter phase lag shall be considered.
5.3.3.3 In order to achieve an acquisition accuracy of ??0.5% for the overall data, the above influencing factors shall be considered comprehensively.
5.3.3.4 For the attenuation and phase shift information of the Butterworth filter, see Appendix D. In order to avoid uncorrectable aliasing errors, the analog signal shall be properly filtered before sampling and digitization. The filter order and its passband shall be selected according to the frequency range of interest and the signal flatness requirements at the corresponding sampling frequency. The minimum filtering characteristics and minimum sampling frequency shall meet:
a) In the frequency range of 0 Hz ~ 2 Hz, the maximum attenuation of the analog signal shall be less than the resolution of signal digitization; b) At half the sampling frequency (i.e., Nyquist frequency or folding
frequency), the size of all frequency components of the signal and noise shall be reduced to less than the digital resolution.
Example: For a resolution of 0.05%, the filter attenuation is less than 0.05% in the 2 Hz range. For all frequencies above one-half the sampling
frequency, the attenuation is greater than 99.95%.
5.3.3.5 The anti-aliasing filter is recommended to be fourth-order or higher; see Appendix D. Anti-aliasing filter shall be used; excessive analog signal filtering shall also be avoided. In addition, all filters shall have the same phase characteristics, so as to ensure that the time delay difference between the signals meets the requirements of time domain measurement accuracy.
Note: Because when the measured variable amplitude is multiplied, the phase shift and the corresponding time delay will increase, so, when the
measured variable is multiplied to form a new variable, the phase shift shall be paid special attention. By increasing the cutoff frequency f0 of the filter, the phase shift and time delay can be reduced.
5.3.4 Sampling and digitization
5.3.4.1 At 2 Hz, the amplitude change of the signal per millisecond can reach 3%. In order to limit the dynamic error that is caused by the analog input change exceeding 0.1%, the sampling or digitization time shall be less than 32 ??s. The data of each pair or group of to-be-compared samples shall be collected at the same time or in a short enough time.
5.3.4.2 Digitization shall adopt a system, of which the resolution is 12-bit or higher (??0.05%) and the accuracy is 2 LSB (??0.1%). The amplification of the analog signal before digitization shall be guaranteed: in the digitization process, the comprehensive error caused by the limited resolution and the inaccuracy of digitization shall be less than 0.2%.
5.3.5 Digital filter without phase shift
For the filtering that is used to evaluate the data, the digital filter without phase shift (zero phase shift) shall have the following characteristics (see Figure 1): -- The range of the passband shall be 0 Hz ~ 2 Hz;
-- The stop band shall start between 6 Hz ~ 10 Hz;
-- The passband filter gain shall be 1 ?? 0.005;
-- The stop band filter gain shall be ??0.01.
The wind speed of the surrounding environment during the test shall not exceed 5 m/s. For each test, the test report shall record the climatic conditions during the test; see Appendix E.
6.4 Test vehicle
The basic data information of the test vehicle shall be recorded in the test report in Appendix B. For any changes in vehicle parameters (such as load), the basic data information shall be recorded again.
6.5 Tires
6.5.1 The tires shall be selected and installed on the test vehicle according to the manufacturer's instructions. If the tire manufacturer does not clearly indicate, the tire shall be run-in at least 150 km on the tested car or similar car, but it must be ensured that there is no excessive use, such as emergency braking, rapid acceleration, sharp turns, road shoulder pressure. After running-in, the tire shall be kept in the same position for testing.
6.5.2 The tire tread depth (including the entire width of the tire contacting the ground and the entire tire surface) shall be more than 90% of the initial tire tread depth.
6.5.3 The production date of the tire shall be recorded in the test conditions; see Appendix E; the test tire shall not exceed one year from the production date. 6.5.4 The tires shall be inflated according to the pressure corresponding to the test environment temperature that is specified by the automobile manufacturer. The tire cold inflation pressure shall meet the technical requirements of the vehicle; the error shall not exceed 10 kPa.
6.5.5 The tire pressure and the depth of the tire tread pattern before preheating shall be recorded in the test report; see Appendix E.
6.5.6 In addition to the basic tire conditions, tests can also be carried out under other conditions. The specific details shall be recorded in the test report; see Appendix E.
6.6 Key components
6.6.1 The model and type of key components that affect the performance test of the entire vehicle and the design parameters that affect the test (such as shock absorber parameters and suspension geometric parameters) shall meet the manufacturer's instructions. Any data that deviates from the manufacturer's instructions shall be recorded in the basic information; see Appendix B. 6.6.2 The leveling system that is suspended on the chassis and the cab has an impact on the response, and shall be disabled in the steady state and step-input tests.
6.7 Loading conditions
6.7.1 General conditions
6.7.1.1 The total mass of the test shall not exceed the maximum total mass and the maximum axial load that are specified by the manufacturer; the total mass and the centre-of-gravity position (longitudinal, lateral, vertical) shall be stated. 6.7.1.2 In order to test the vehicle mass, center of gravity position and moment of inertia, it shall be close to the design; its increased load shall be evenly distributed; the wheel load shall be measured and recorded in the test report. See Appendix B.
6.7.2 Maximum loading condition
The maximum loading condition refers to the condition that the total mass of the tractor or trailer is equal to the complete vehicle kerb mass plus the designed maximum loading mass, or the state where the test vehicle is in the designed maximum total mass, and at the same time, it shall be ensured that the load on any axle does not exceed the maximum axial load of standard requirements. The height of center of gravity of the test vehicle and the mass distribution of the additional load shall reflect the application of the test vehicle. The maximum loading condition is the standard test condition.
6.7.3 Minimum loading condition
The minimum loading condition of heavy vehicles and buses refers to the curb weight of each unit plus the mass of the test equipment. For those that the traction unit should be added with the driver's mass, the mass of an equipment operator or observer can be added as needed. The minimum loading condition is optional.
6.7.4 Other loading conditions
Other loading conditions can be used to represent special transportation conditions.
7 Test preparation
7.1 Preheating
Before the start of the test, all relevant parts of the motor vehicle shall be preheated, so that its temperature can reach a temperature representative of Appendix C
(Informative)
Sensor and its installation
C.1 Overview
Sensors (including commercial and customized) are mainly used to measure required and optional variables. If the sensor cannot directly measure the required variable, the sensor signal shall be appropriately adjusted to obtain this variable on the basis of ensuring accuracy.
Since there are many types of test instruments, each type of equipment used shall be recorded; the installation location of the equipment on the motor vehicle shall be recorded on the test data table (see Appendix B).
The sensor error requirements for various directly measured variables are shown in the following clauses. The percentage error of the variable that is calculated from the output signals of several sensors can be obtained by dividing the differential value of the calculated variable by the variable. C.2 Steering wheel angle
Typical sensors are multi-turn potentiometers or digital photoelectric encoders, which are connected to the rear of the steering wheel through gears or
connected to the "additional steering wheel".
C.3 Longitudinal velocity
The longitudinal velocity sensor shall be installed as close as possible to the reference point. In the process of data processing, the installation position of the speed sensor shall be recorded, and necessary signal corrections shall be made to obtain the reference point longitudinal velocity. The typical sensor is a five-wheel instrument whose accuracy is 0.2 km/h; a "non-contact" speed sensor that is based on optics or Doppler principle. The speed sensor based on optics has an accuracy of 0.1 km/h; the speed sensor based on Doppler has an accuracy of 0.5 km/h. The steady-state signal of the five-wheel instrument is very close to the horizontal velocity, while the optical sensor measures the longitudinal velocity (the component of the horizontal velocity in the X direction is equal to the product of the horizontal velocity and the cosine of the slip angle). Another alternative method of measuring longitudinal velocity is to use the Global Navigation Satellite System (GNSS) (see C.11).
C.4 Side velocity and sideslip angle
The two-way speed sensor based on the optical principle that is installed according to the product manual can directly measure the side velocity of a given point. The installation location of the sensor shall be recorded. The side velocity of any other point can be obtained by interpolation or extrapolation by two side velocity sensors, or by the product of the side velocity of the measuring point plus the yaw velocity AND the distance between the desired point and the measuring point. The slip angle is obtained by dividing the side velocity by the tangent of the longitudinal velocity. The commercial two-way speed sensor full scale is ??10 m/s, the steady-state full scale accuracy is ??1%.
The side velocity can also be obtained by the integral of the difference by subtracting the side acceleration (corrected by position, roll angle and surface inclination errors) by the product of the longitudinal velocity and the yaw velocity; then, the side slip angle can be calculated. Because the net acceleration error (including zero offset) will accumulate, this method is only suitable for short- term testing.
C.5 Angular velocity
The yaw velocity, roll velocity and pitch velocity can be directly measured by the angular velocity sensor that is installed in accordance with the product manual. The traditional angular velocity sensor refers to a gyroscope. In general, good gyroscope performance includes: in the range of 1/2 full scale, the linearity is ??0.2% ~ ??0.5% of full scale; in the range of 1/2 to full scale, the linearity is ??1% ~ ??2% of full scale; the cross sensitivity is 0.04%; the threshold is ??0.05% of full scale; the hysteresis is 0.15% of full scale. Angular velocity sensors based on Coriolis acceleration, optical fiber, laser or other physical principles have been commercialized. They usually have the following characteristics: the linearity is ??0.1% ~ 1% of full scale, the threshold sensitivity is 0.01%; the hysteresis is zero.
The angular velocity sensor is usually fixed on the motor vehicle. Therefore, they measure the yaw velocity of the ground plane multiplied by the cosine of the vehicle roll angle during steady-state steering. In order to obtain the yaw velocity of the ground plane, the vehicle roll angle and pitch angle shall be corrected.
If the sideslip angle sensors are installed on the front axle and the rear axle at the same time, the yaw velocity of the vehicle in the ground plane can be calculated by dividing the difference between the side velocity of the front axle and the rear axle by the longitudinal distance between the two sensors. C.6 Side acceleration
In most working conditions, especially in steady-state conditions, the focus is on centripetal acceleration. Typically, the actual measured quantity is side Note: The side acceleration is the component of the acceleration vector at this point in the Y direction.
C.7 Vehicle angle
The vehicle roll angle and pitch angle relative to the direction of gravity can be measured by a two-axis gyroscope; a non-reference gyroscope or a gravity reference vertical gyroscope can be selected. The free gyroscope has a frame structure and shall be locked on its shell when not measuring. When the frame structure is unlocked, it remains unchanged in the inertial space and can measure the angle of car movement. The free gyroscopes can be used to
measure roll and yaw angles, or roll and pitch motions. By actively controlling the action of the slow-rotating torque motor, the vertical gyroscope is "upright" with respect to the vertical direction of gravity. Neither of the above two types of gyroscopes can obtain the required measured acceleration under long-term stable steering. According to the product manual, the free gyroscope and the vertical gyroscope of failure vertical system "drift" at a maximum speed of 0.5?? ~ 1?? per minute; the vertical gyroscope that is effectively installed a vertical system will search for "vertical line of sight" at a rate of 2?? ~ 5?? per minute, which is the vector sum of gravity and side acceleration. When there is no side acceleration, the vertical accuracy of the vertical gyroscope can reach ??0.15?? ~ ??0.1??.
The roll and pitch angles of the vehicle relative to the road can be measured by the following methods:
a) The angle measurement sensor shall be installed on the roll and pitch balance frame of the side-sliding vehicle.
b) Through ultrasonic or optical sensors, measure the change in the vertical distance from a reference point located in front of, behind or on the side of the vehicle to the ground. It?€?s sufficient for ultrasonic or optical sensors to achieve a measurement accuracy of 0.5 mm. The road surface is far
from flat, and its roughness cannot be ignored and it is also obvious. Three automobile sensors will define a plane, which is used for calculating the pitch and roll angles relative to the road. It is recommended to install the ultrasonic sensor or optical sensor as far as possible, so as to improve the measurement accuracy.
c) The measurement of the wheel runout relative to the sprung mass mainly considers the influence of the suspension connecting rod (the method
does not consider the tire deformation).
In each of the above methods, when there are no other constraints in the test experiment, the accuracy of its description can be achieved. In order to obtain the vehicle roll angle and pitch angle relative to the ground plane, the measurement signal shall be corrected by the angle of the road plane relative to the horizontal plane.
The amount of change of the vehicle's roll angle and pitch angle relative to the initial test conditions can be measured by the integral measurement of the angular velocity gyroscope signal. This method is only suitable for short-term testing, because the entire signal including zero drift will be accumulated. Note 1: For cars with a suspended cab or a separate cab, there will be two body angles. One is the car body angle of the cab relative to the road surface, and the other is the car body angle of the chassis relative to the road surface.
Note 2: The roll angle which is obtained by measuring the vertical distance change between the reference points on both sides of the vehicle with
respect to the road surface by ultrasonic sensors or optical sensors may be different from the measurement results of other methods, which is
related to the roll stiffness of the car chassis. For motor vehicles with independent chassis or those which are very long, this effect shall ...

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