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GB/T 40501-2021 English PDF (GBT40501-2021)

GB/T 40501-2021 English PDF (GBT40501-2021)

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GB/T 40501-2021: General condition of vehicle dynamics test for passenger cars

This Standard specifies general condition of vehicle dynamics test for passenger cars. This Standard is applicable to M1, M2 and N1 vehicles whose maximum design total mass does not exceed 3.5t.
GB/T 40501-2021
GB
NATIONAL STANDARD OF THE
PEOPLE REPUBLIC OF CHINA
ICS 43.020
CCS T 00
General condition of vehicle dynamics test for
passenger cars
(ISO 15037-1:2019, Road vehicles - Vehicle dynamics test methods -
Part 1: General conditions for passenger cars, MOD)
ISSUED ON: AUGUST 20, 2021
IMPLEMENTED ON: MARCH 01, 2022
Issued by: State Administration for Market Regulation;
Standardization Administration of the People's Republic of
China.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions ... 5
4 Reference coordinate system ... 5
5 Measurement ... 6
6 Test conditions ... 10
7 Test preparation ... 12
Annex A (informative) Structural changes of this Standard compared with ISO 15037-1:2019 ... 15
Annex B (normative) Test report -- General data ... 17
Annex C (informative) Sensor and its installation ... 20
Annex D (informative) Analog signal filtering: Butterworth filter ... 26 Annex E (normative) Test conditions ... 28
General condition of vehicle dynamics test for
passenger cars
1 Scope
This Standard specifies general condition of vehicle dynamics test for
passenger cars.
This Standard is applicable to M1, M2 and N1 vehicles whose maximum design total mass does not exceed 3.5t.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 12549-2013, Terms and definitions for vehicle controllability and
stability (ISO 8855:2011, NEQ)
3 Terms and definitions
There are no terms and definitions that need to be defined in this document. 4 Reference coordinate system
4.1 Reference coordinate system
The motion variables recorded in the test shall meet the coordinate system definition in GB/T 12549-2013. The origin of the coordinates is usually taken at the center of mass of the vehicle. It can also be taken at other locations, but it shall be recorded in the test report, see Annex B.
4.2 Variables that shall be determined
The main variables of driver input and vehicle response description related to vehicle handling and stability are as follows:
- Steering wheel angle, ??H;
recommended to use the digital signal processing method described in 5.3.3. 5.3.3 Aliasing error and anti-aliasing filter
5.3.3.1 The preparations for analog signal processing include: selecting the sampling frequency to avoid aliasing errors, the filter amplitude attenuation characteristics, and the filter's phase lag and time delay characteristics. 5.3.3.2 What shall be considered for sampling and digitization:
a) The pre-sampling magnification rate that guarantees the smallest
digitization error;
b) The number of bits per sampling;
c) The number of samples per cycle;
d) Sampling and hold amplifier;
e) Sample space;
f) For other digital filters without phase shift, the choice of passband, stopband, attenuation, allowable ripple, and correction of the filter phase lag shall be considered.
5.3.3.3 To achieve a collection accuracy of ??0.5% for the overall data, the above-mentioned influencing factors shall be considered comprehensively. 5.3.3.4 See Annex D for the attenuation and phase shift information of the Butterworth filter. Avoid uncorrectable aliasing errors. The analog signal shall be properly filtered before sampling and digitizing. 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 0Hz~fmax (fmax=5Hz), the maximum attenuation of the analog signal shall be less than the resolution of signal digitization; b) At half the sampling frequency (i.e., the 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 amplitude attenuation of the filter in the range of 5 Hz is less than 0.05%. For all frequencies above half of the sampling frequency, the amplitude attenuation is greater than 99.95%.
5.3.3.5 The recommended anti-aliasing filter is fourth-order or higher, see Annex D.
braking, rapid acceleration, sharp turns, road shoulders. 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 Annex E. The test tire shall not exceed one year from the date of production. 6.5.4 The tires shall be inflated according to the pressure of the test environment temperature specified by the car manufacturer. For tire pressure less than or equal to 250kPa, the error of cold inflation pressure is ??5kPa. When the tire pressure exceeds 250kPa, the error does not exceed 2%.
6.5.5 The tire pressure and the depth of the tire tread pattern before warm-up shall be recorded in the test report, see Annex 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 Annex E).
6.5.7 When the tire tread depth or uneven wear has a significant impact on the test results, it is recommended to consider this factor when comparing
performance between cars or tires.
6.6 Key components
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 Annex B.
6.7 Load condition
6.7.1 The total test mass shall be between the vehicle's curb weight and the maximum allowable total mass. The maximum axle load shall not exceed the allowable value.
6.7.2 It shall be ensured that the position of the center of gravity and the inertia have the smallest deviation from the normal load conditions. The wheel load shall be measured and recorded in the test report, see Annex B.
6.8 Power transmission state
For vehicles with regenerative braking capability, the specific settings of the vehicle can change the dynamic behavior of the vehicle when the accelerator pedal is released and/or the brake pedal is depressed. For this type of vehicle, the dynamic behavior of the vehicle shall be tested with or without active regenerative braking during the test. The selected regenerative braking capability level and shift lever position shall be recorded in the test report. 6.9 Active system
For vehicles with active systems that affect test results such as active steering, electronic stability control or active suspension, the impact of different system modes on the dynamic behavior of the vehicle shall be considered during the test. If the driver can choose a different mode, such as "sports/comfort" mode, the selected mode shall be recorded in the test report.
7 Test preparation
7.1 Warm up
Before the start of the test, all relevant parts of the car shall be preheated so that its temperature can reach a temperature representative of normal driving conditions. The tires shall also be preheated to reach a balanced temperature and pressure that can represent normal driving conditions. The car is driven at a test speed of 10km or 500m with a lateral acceleration of 3m/s2 (including turning to the left and turning to the right) to warm up the tires.
7.2 Initial conditions
7.2.1 Overview
7.2.1.1 The initial driving state of the vehicle handling and stability test is steady- state straight-line driving or steady-state circular driving.
7.2.1.2 If there is no special requirement in the test standard, during the test, for manual transmissions, the highest applicable gear shall be selected for multiple gears; for automatic transmissions, gear D shall be used. The shift lever position and the selected driving mode shall be recorded in the test report, see Annex E.
7.2.1.3 Under initial driving conditions, the position of the steering wheel and the position of the accelerator pedal shall be kept as unchanged as possible. The observation time tss used to estimate the steady-state condition is defined as the time point between 0.5s and 0.8s before the reference time point t0. When the observation time tss reaches the requirements of 7.2.2 or 7.2.3 (as shown in Figure 2, the defined t1 and t2), the initial conditions are considered stable.
Annex C
(informative)
Sensor and its installation
C.1 General
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. Record the installation location of the equipment on the car on the test data table (see Annex B).
The sensor error requirements for various directly measured variables are shown in the following clauses. For a variable calculated by several sensor output signals, the percentage error 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. They are connected to the rear of the steering wheel through gears or to the "additional steering wheel".
C.3 Longitudinal speed
The longitudinal speed sensor shall be installed as close as possible to the reference point. During data processing, the installation position of the speed sensor shall be recorded. Make the necessary signal corrections to obtain the reference point longitudinal velocity. The typical sensor is a five-wheel instrument. Its accuracy is 0.2km/h. For "non-contact" speed sensor based on optical or Doppler principle, the optical-based speed sensor has an accuracy of 0.1km/h. The speed sensor based on Doppler has an accuracy of 0.5km/h. The steady-state signal of the five-wheel instrument is very close to the horizontal speed. 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 Lateral speed and slip angle
The two-way speed sensor based on the optical principle installed according to the product manual can directly measure the lateral speed of a given point. The installation location of the sensor shall be recorded. The lateral velocity of any other point can be obtained by interpolation or extrapolation of the two lateral velocity sensors. It can also be obtained by multiplying the lateral velocity of the measuring point plus the yaw rate and the distance between the desired point and the measuring point. The slip angle is obtained by dividing the lateral velocity by the tangent of the longitudinal velocity.
The lateral velocity can also be obtained by integrating the lateral acceleration (corrected by position, roll angle and surface inclination errors) minus the product of the longitudinal velocity and the yaw rate. The slip angle can then 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 rate, roll rate and pitch rate can be directly measured by the angular rate sensor installed in accordance with the product manual. The traditional angular velocity sensor refers to a gyroscope. In general, good gyroscope performance includes: Within 1/2 full scale range, linearity is ??0.2%~??0.5% of full scale; In the range of 1/2 to full scale, linearity is ??1%~??2% of full scale; 0.04% cross sensitivity; threshold of ??0.05% of full scale; hysteresis of 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: full scale ??0.1%~1% linearity; 0.01% threshold sensitivity; zero hysteresis.
The angular velocity sensor is usually fixed on the car. Therefore, they measure the yaw rate of the ground plane multiplied by the cosine of the body roll angle during steady-state steering. In order to obtain the yaw rate of the ground plane, the roll angle and pitch angle of the vehicle shall be corrected.
If the slip angle sensor is installed on the front axle and the rear axle at the same time, the yaw rate of the vehicle in the ground plane can be calculated by dividing the difference between the lateral speed of the front axle and the rear axle by the longitudinal distance between the two sensors.
C.6 Lateral acceleration
In most working conditions, especially under steady-state conditions, the focus is on centripetal acceleration. Typically, the actual measured quantity is lateral acceleration. If the state quantities of other cars are known, the centripetal acceleration can be obtained through lateral acceleration.
Lateral acceleration (aY) can be measured by an accelerometer with sufficient be measured by a two-axis gyroscope. It can choose no reference gyroscope or gravity reference vertical gyroscope. Free gyroscope is frame structure. When not measuring, it shall be locked on its shell. When the frame structure is unlocked, it remains unchanged in the inertial space and can measure the angle of car movement. 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 with the vertical system failure shall "drift" at a maximum speed of 0.5??~1?? per minute. A vertical gyroscope that is effectively installed with a vertical system will search for the "vertical line of sight" at a rate of 2??~5?? per minute. It is the vector sum of gravity and lateral acceleration. When there is no lateral acceleration, the vertical accuracy of the vertical gyroscope can reach ??0.15??~??0.1??.
The roll and pitch angle of the car 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 trolley.
b) Through ultrasonic or optical sensors, the vertical distance from the reference point at the front, back or side of the car to the ground is
measured. Ultrasonic or optical sensors with a measurement accuracy of
0.5mm are sufficient. The road surface is far from flat, and its roughness cannot be ignored and it is obvious. Three car sensors will define a plane. This is used to calculate the pitch and roll angles relative to the road surface. It is recommended to install the ultrasonic sensor or optical
sensor as far as possible to improve the measurement accuracy.
c) The measurement of wheel run-out relative to the sprung mass mainly
considers the influence of the suspension link (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. To obtain the roll angle and pitch angle of the car 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. This is because the entire signal including the zero-point drift will be accumulated.
NOTE 1: A car with a suspended cab or a separate cab will have two body angles. One is the angle of the cab relative to the road surface. The other is the car body angle of the chassis relative to the road surface.
NOTE 2: The roll angle obtained by measuring the vertical distance change of the reference points on both sides of the car with respect to the road surface by ultrasonic sensors or optical sensors may be different from the measurement results of other methods. This method is related to the roll stiffness of the car chassis. For cars with independent chassis or very long cars, this effect shall be paid special attention to. Depending on the end use, the road inclination angle shall be used to correct the measured roll angle data relative to the road surface or the direction of gravity.
C.8 Steering wheel torque
The steering wheel torque can be measured by a torque sensor installed in accordance with the product manual. It mainly measures the torque acting on the steering wheel relative to the axis of rotation. In some tests, if the inertia of the steering wheel is inconsistent with the original car, its measurement results are inaccurate.
C.9 Wheel steering angle
The steering angle of the wheel relative to the sprung mass can be measured by an angle sensor. The sensor is located between the sprung mass and the steering knuckle assembly. It is mounted on the bearing of the wheel hub. It is connected to the sprung mass by allowing the constraints of forward/backward, vertical and camber movements. Or use the linear displacement or angular displacement sensor installed on the steering rod to measure.
The front wheel steering angle formed by suspension kinematics and elastic kinematics can be calculated by subtracting the steering wheel angle of the preceding vehicle and dividing by the total steering gear ratio.
Except for cars with four-wheel steering, the steering angle formed by
suspension movement and elastic deformation of the rear wheels is equal to the measured value of the steering angle of the rear wheels of the vehicle. C.10 Tire slip angle
Tire slip angle can be directly measured by optical sensors. Another method is to calculate it by subtracting the corresponding wheel angle from the front and rear wheel slip angle.
C.11 Car track

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