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This standard is prepared in accordance with the rules given in GB/T 1.1-2009.
This standard is not equivalent to ISO 15623:2013(E) Transport information and control systems—Forward vehicle collision warning systems—Performance requirements and test procedures.
This standard is under the jurisdiction of the Intelligent Transportation Systems of Standardization Administration of China(SAC/TC 268) and the National Technical Committee of Auto Standardization (SAC/TC 114).
Introduction
Automobile manufacturers and component suppliers throughout the world have been vigorously pursuing the development and commercialization of forward vehicle collision warning systems (FVCWS). Systems of this type have already been introduced to the market in some countries. Therefore, the International Organization of Standardization issued ISO 15623:2013 Transport information and control systems—Forward vehicle collision warning systems—Performance requirements and test procedures, while the Intelligent Transportation Systems of Standardization Administration of China also issued GB/T 20608-2006 Intelligent transportation systems—Adaptive cruise control systems—Performance requirements and test procedures. This standard adopts the contents of the standards mentioned above by modifying some of the technical parameters. It describes the basic performance requirements and test procedures for FVCWS. The specified performance requirements and test procedures are applicable to FVCWS in the Chinese market, and can be used as the basis of standards on other more advanced vehicle products and services.
Intelligent transportation systems- Forward vehicle collision warning systems—
Performance requirements and test procedures
1 Scope
This standard specifies performance requirements and test procedures for forward vehicle collision warning systems (FVCWS).
It covers operations on roads with curve radii over 125 m, and motor vehicle including cars, trucks, buses, and motorcycles.
Note: Responsibility for the safe operation of the vehicle remains with the driver.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated reference, only the edition cited applies. For undated references, the latest edition (including any amendment) applies.
GB 7247.1-2012 Safety of laser products — Part 1: Equipment classification and requirements
GB/T 20608-2006 Intelligent transportation systems—Adaptive cruise control systems—Performance requirements and test procedures.
JTG B01-2014 Technical standard of highway engineering
3 Terms and definitions
For the purpose of this document, the following terms and definitions apply.
3.1
collision warning
information that the system gives to the driver indicating the need for urgent action to avoid or reduce the severity of a potential rear end collision with another forward vehicle
Note: This warning is issued in the advanced stages of a dangerous situation to warn the driver of the need to perform emergency braking, lane changing or other emergency maneuvers in order to avoid a collision.
3.2
preliminary collision warning
information that the system gives to the driver in the early stages of a potentially dangerous situation that may result in a rear end collision
Note: The system may provide this warning prior to the collision warning, and is usually issued when the driver is inattentive, or when the vehicle ahead suddenly changes driving status which may lead to a collision.
3.3
subject vehicle
SV
vehicle equipped with FVCWS as defined herein
3.4
forward vehicle
vehicle in front of and moving in the same direction and travelling on the same roadway as the subject vehicle
3.5
forward vehicle collision warning system
system capable of warning the driver of a potential collision with another forward vehicle in the forward path of the subject vehicle
3.6
obstacle vehicle
vehicles, both moving and stationary, considered potential hazards that can be detected by this system
Note: Vehicles in this standard refers to motor vehicles only, that is, cars, trucks, buses, and motorcycles.
3.7
target vehicle
TV
forward vehicle that is closest in the forward path of the subject vehicle; forward vehicle that the FVCWS operates on
3.8
clearance
distance from the target vehicle trailing surface to the subject vehicle leading surface
3.9
time headway
THW
the elapsed time between the front of the forward vehicle passing a point and the front of the following vehicle passing the same point, which is calculated by dividing the clearance by the velocity of subject vehicle
3.10
relative velocity
difference between the longitudinal velocities of the subject vehicle (SV) and the target vehicle (TV), given by the Equation (1).
vr(t)=vTV(t)-vSV(t) (1)
where,
vr(t)——relative velocity;
vTV(t)——target vehicle speed;
vSV(t)——subject vehicle speed;
Relative velocity is equivalently the rate of change with respect to time of the distance between the two vehicles. A positive value of relative velocity indicates that the target vehicle is moving faster than the subject vehicle, and that the distance between them is increasing with time.
3.11
time to collision
TTC
When the relative velocity is not zero, the time to collision (TTC) of two vehicles that travel on the same path with constant relative velocity can be calculated through equation (2). TTC value can be estimated by dividing the clearance between subject vehicle and the target vehicle by the relative velocity. When the calculation conditions are not satisfied, or the calculation result of TTC is negative, it suggests that collision is unlikely under the above assumptions.
(2)
where,
xc(t)——clearance.
3.12
enhanced time to collision
ETTC
When subject vehicle (SV) has an acceleration different from that of the target vehicle , and SV speed, acceleration and clearance meets the condition of (vTV-vSV)2-2 x (aTV-aSV) x xc> 0, the enhanced time to collision (ETTC) can be calculated by Equation (3). The ETTC is the time that it will take a subject vehicle to collide with the target vehicle assuming the relative acceleration between the subject vehicle (SV) and target vehicle (TV) remains constant. When the calculation conditions are not satisfied, or the calculation result of ETTC is negative, it suggests that collision is unlikely under the above assumptions.
(3)
where,
aTV——target vehicle acceleration;
aSV——subject vehicle acceleration.
3.13
warning distance
distance between two vehicles when the system detects potential collision danger with the forward vehicle
3.14
visibility
distance which the illuminance of a non-diffusive beam of white light with the color temperature of 2700 K is decreased to 5% of its original light source illuminance
3.15
conventional cruise control
a system that controls the driving speed of a vehicle according to the driver's setting
[GB/T 20608-2006, definition 3.1.5]
3.16
adaptive cruise control
ACC
enhancement to conventional cruise control systems (see 3.15 "conventional cruise control") which allows the subject vehicle to follow a forward vehicle at an appropriate distance by controlling the engine and/or power train and optionally the brake
[GB/T 20608-2006, definition 3.1.2]
3.17
adjacent lane
lane of travel sharing one lane boundary with the lane in which the subject vehicle is traveling and having the same direction of travel as the subject vehicle lane
3.18
cut-in vehicle
forward adjacent vehicle that has a lateral component of motion towards the path of the subject vehicle
3.19
jerk
first derivative with respect to time of the position of an object; equivalently the rate of change of the acceleration of an object; considered a measure of harshness of vehicle motion
3.20
minimum velocity
minimum subject vehicle (SV) speed for which the FVCWS must be capable of initiating a warning
3.21
rear-end collision
forward vehicle collision in which the front of the subject vehicle strikes the rear of the forward vehicle
3.22
required deceleration
minimum deceleration that, if constant, would enable the subject vehicle to match the velocity of the target vehicle without contacting the target vehicle and thus prevent a collision. See Equation (4):
(4)
where,
areq——required deceleration;
xr(t)——the amount of reduction in the clearance distance due to reaction time.
3.23
braking warning
action in which FVCWS respond to detection of a possible rear-end collision by automatically applying the brake for a short period of time to provide a warning to the driver
3.24
FVCWS warning modalities
means used to convey the different type of FVCWS warnings to the driver, including visual, auditory, and/or haptic cues
3.25
lateral offset
lateral distance between the longitudinal centerlines of a subject vehicle (SV) and a target vehicle (TV), measured as a percentage of the width of the SV, such that if the centers of the two vehicles are aligned, the value is zero
4 Specifications and requirements
4.1 System functionality
The purpose of the FVCWS is to provide warnings that will assist drivers in avoiding or reducing the severity of rear end crashes. This is realized by assessing the following information:
a) The relative distance between the subject vehicle and the forward vehicle;
b) The relative velocity of the subject vehicle and the forward vehicle;
c) Whether a forward vehicle is in the subject vehicle trajectory.
Based upon the information acquired, the controller identified as "FVCWS target selection and warning strategy" in Figure 1 produces the warning to the driver.
The purpose of the FVCWS is to provide warnings that will assist drivers in avoiding or reducing the severity of rear end crashes. These warnings should be provided in time to help drivers avoid most common rear end crashes by applying the brakes only. The timing of the alerts should be selected such that they strive to provide alerts early enough to help the driver avoid the crash or mitigate the harm caused by the crash without introducing other alerts perceived as nuisance or false.
Figure 1 Functional forward vehicle collision warning system's elements
4.2 Necessary functions
Vehicles equipped with FVCWS shall fulfil the following functions.
a) Detect the presence of forward vehicles;
b) Determine measure or measures for relative position and position dynamic of the detected forward vehicles with respect to the subject vehicle;
c) Determine the subject vehicle velocity;
d) Estimate the path of the subject vehicle (Class II and III, see 4.6 for classification);
e) Provide driver warnings in accordance with the FVCWS function and requirements.
4.3 Operating model
4.3.1 State transition
Figure 2 shows the state transition diagram for the FVCWS.
Foreword II
Introduction
1 Scope
2 Normative references
3 Terms and definitions
4 Specifications and requirements
5 Test method for performance
Annex A (Normative) Considerations of collision warning
Annex B (Normative) Requirements for obstacle detection along curves
Annex C (Normative) Performance requirements and test targets of sensors
Bibliography
