JT/T 1242-2019Performance requirements and test procedures for advanced emergency braking system of commercial vehicle (English PDF)

3.1 Terms and definitions

The following terms and definitions apply to this document.

3.1.1 Advanced emergency braking system

A system which automatically detect target vehicles or obstacles, detect potential forward collision hazards, issue early warning signals to alert the driver, activate the vehicle's brake system, reduce the speed to avoid or mitigate collision.

3.1.2

Subject vehicle

A vehicle equipped with an advanced emergency braking system as defined in this standard.

3.1.3

Forward vehicle

A vehicle located in front of the subject vehicle.

3.1.4

Target vehicle

On the trajectory line in front of the subject vehicle, the forward vehicle which is closest to the subject vehicle. It is the object of the advanced emergency braking system.

3.1.5

Collision warning

The AEBS alerts the driver of a collision hazard.

3.1.6

Visibility

The length of path as travelled by the non-diffused light emitted by an incandescent lamp which has a color temperature of 2700 K when its illuminance is reduced to 5% of the initial value.

[GB/T 33577-2017, definition 3.14]

4.1 AEBS composition

The AEBS shall include an environment awareness module, a control decision module, a bottom-layer execution module, a human-machine interaction module, a data communication interface. It may include a data storage module and a wireless communication module, the above modules are not limited to independent or integrated forms.

4.2 AEBS classification

According to the functions available, AEBS is divided into two categories, as shown in Table 1.Each row represents a different system type. The collision warning in the Table shall meet the requirements of 5.3.The emergency braking shall comply with the requirements of 5.4.

4.3 AEBS-adapted vehicle

AEBS shall be installed on commercial vehicles which are equipped with an anti-lock brake, an electronic stability control system, disc brakes on all wheels.

4.4 Target obstacle type

Target obstacles that AEBS can detect shall include motor vehicles and pedestrians traveling on public roads.

4.6 Driver control and human-machine interface

The AEBS shall provide the driver with a human-machine interface to interact with the driver. Provides warning information including at least two of audible, visual, or tactile, braking information, operation, cessation, or fault state information of the AEBS. The displayed information shall be clearly displayed in direct sunlight and at night.

4.11 Data backup

4.11.1 For AEBS trigger event data, it shall perform local data backup and remote data backup. The most recent storage time for local data backup shall be not less than 48 h; the remote storage time shall be not less than 60 d.

4.11.2 AEBS trigger event data shall include at least the following information.

4.12 Installation and use requirements

The AEBS system shall be installed and used in accordance with the manufacturer's instructions for use, including AEBS calibration, minimum starting speed, and applicable and non-applicable conditions.

5.1 Running speed

The AEBS shall operate normally at least within the range from a running speed of 15 km/h to the maximum design speed under all load states of the vehicle.

5.2 Target detection area

5.2.1 The minimum detection distance of AEBS shall be not more than 2 m. The maximum detection distance to the target vehicle shall be not less than 150 m.

The maximum detection distance to the pedestrians shall be not less than 60 m.

5.2.3 AEBS shall be capable of detecting the target vehicle on a bend which has a radius of curvature not more than 250 m.

5.3 Collision warning

5.3.1 Warning time

If the TTC or ETTC is more than 4.4 s, the AEBS shall not issue a collision warning.

5.3.2 Warning mode

When the AEBS detects a possible collision with a forward vehicle or pedestrian, it shall be able to output an alarm of not less than two different levels. The level-

1 collision warnings shall be generated 1.4 s before the emergency braking phase. The level-2 collision warnings shall be generated 0.8 s before the emergency braking phase.

5.3.3 Speed reduction in the warning phase

In the warning phase, any speed reduction of the subject vehicle shall not exceed 15 km/h or 30% of total deceleration, whichever is larger.

5.4 Emergency braking

5.4.1 Start of emergency braking

The emergency braking phase shall not begin before the TTC or ETTC is more than or equal to 3 s.

5.4.2 Minimum speed reduction in emergency braking

5.5 In-vehicle communication

The AEBS shall be able to extract the required information from the in-vehicle communication network. The information provided by the in-vehicle communication network includes at least the speed information, the brake, the throttle, the turn signals.

5.6 Vehicle-road communication

5.6.1 Type II AEBS shall have the vehicle-road communication function of wireless mobile communication technology, to realize the interaction with the execution data of roadside unit.

5.6.4 The wireless mobile communication interface of the type II AEBS shall support both cellular access communication mode and direct connection communication mode. The two communication modes shall adopt the same network system.

5.6.5 The wireless communication technology as used in type II AEBS shall comply with the provisions of JT/T 794.

5.6.6 The maximum air interface time delay of the direct connection

communication mode of the type II AEBS not exceed 20 ms.

5.6.7 The communication distance between the subject vehicle and the

roadside unit shall be not less than 200 m.

6.1 Electrical environment adaptability

6.1.1 Working voltage range

The working power supply of AEBS shall be the vehicle DC power supply. The working voltage range shall meet the requirements of Table 3.

6.1.2 Overvoltage performance

The overvoltage performance of AEBS shall comply with the requirements of

4.3 of GB/T 28046.2-2011.

6.1.3 Reverse voltage performance

The reverse voltage performance of AEBS shall comply with the requirements of 4.7.2.3 of GB/T 28046.2- 2011.

6.1.4 Climate environment adaptability

The AEBS shall be able to adapt to a storage temperature of at least -40 ��C ~

85 ��C and a working temperature of at least - 30 ��C ~ 70 ��C.

6.2 Mechanical environment adaptability

6.2.1 Vibration

The mechanical vibration resistance of AEBS shall comply with the requirements of 4.1 of GB/T 28046.3-2011.

6.2.2 Impact

The mechanical impact resistance of AEBS shall comply with the requirements of 4.2 of GB/T 28046.3-2011 according to the installation position of AEBS.

6.3 Electromagnetic environment adaptability

7.1 Test target

The target for the test shall be the category M1 passenger car and pedestrian model. Alternatively, it may also use a flexible target vehicle with characterization parameters representative of the above vehicle and adapted to the AEBS sensor.

7.2 Environmental conditions

The test shall be carried out on a level and dry concrete, asphalt pavement which has good adhesion. The horizontal visibility shall be more than 1 km.

The range of test ambient temperature shall be - 20 ��C ~ 45 ��C. The ambient wind speed shall be less than 5 m/s.

7.3 Vehicle conditions

During the entire course of test, the subject vehicle shall be fully loaded.

7.4 Test of advanced emergency braking system

7.4.1 Test of target detection distance

7.4.2 Test of target detection width

7.4.2.1 Test procedure

The target vehicle is stationary, in the direction same as the subject vehicle.

Before the arrival test is started, the subject vehicle is located at the center line of the lane. Respectively locate the target vehicle at the leftmost and rightmost sides of the lane. The direction of the head of the vehicle shall be consistent with that of the subject vehicle.

of the lane, to perform 1 test each.

7.4.3 Target vehicle stationary test

7.4.3.1 Test procedure

The target vehicle is stationary, in the same direction with the subject vehicle.

When the subject vehicle drives at a speed of 80 km/h and 40 km/h, at a distance of 150 m from the target vehicle, the test starts. The driver maintains the position of accelerator pedal and maintains the vehicle speed. When the subject vehicle collides with the target vehicle or avoids collision, the test is over.

The test procedure is as shown in Figure 4.

7.4.3.2 Test validity requirements

The test validity is subject to the following rules.

7.4.4 Target vehicle movement test

7.4.4.1 Test procedure

The target vehicle and the subject vehicle are in the same direction. During the test, the subject vehicle is kept at a speed of 80 km/h and traveled straight along the centerline of the lane. The target vehicle runs straightly at a speed of 12 km/h along the centerline of the lane. When the distance between the subject vehicle and the target vehicle is equal to 150 m, the test starts. The driver maintains the accelerator pedal's position to maintain the vehicle speed. The test procedure is as shown in Figure 5.

7.4.5 Test bend and target identification performance test

7.4.5.1 Test procedures

The test is carried out along a bend which has a radius of 250 m or 150 m.

When the bend's radius is 250 m, the subject vehicle, the forward vehicle in the adjacent lane, the target vehicle run in the same direction at a speed of not less than 50 km/h. When the bend's radius is 150 m, the subject vehicle, the forward vehicle in the adjacent lane, the target vehicle run in the same direction at a speed of not less than 40 km/h. The test procedure is as shown in Figure 6.

Legend.

7.5 Remote data backup

7.5.1 Ensure that there is wireless network coverage on the test road around the test site. The remote server required for the test establishes a connection with the AEBS of the vehicle. When performing the test items involved in 7.4.3

~ 7.4.8, the subject vehicle shall send the backup data to the remote server in real time.

7.5.2 The test validity shall comply with the corresponding requirements of 7.4.3

~ 7.4.8.

7.5.3 In all validity tests, the information in the remote server backup data shall be identical to the AEBS related information as monitored in the field.

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