Description and Operation of Rear Parking Assist Control Module

Description

When driving in reverse, it is difficult for the driver to see objects in blind spots and to determine the distance to an object. To ensure driver safety and convenience, the rear warning system operates when the shift lever is in "R". The ultrasonic sensor emits an ultrasonic wave to the rear and detects the reflected wave. The control module (BCM) calculates the distance to the object using the sensor input signal and outputs the buzzer signal in three stages (first, second, and third alarm).

Block Diagram

System Operation

Initial Mode

1. 1
   The RPAS reset time is 500 ms after the R signal is input.
2. 2
   The RPAS sets the sensor ID and recognizes the LID values (LID1, LID2, LID3) during the initial reset process.
3. 3
   When the BCM completes the initial reset process, the RPAS checks each sensor for fault diagnostics.
4. 4
   When the fault diagnostic test is complete and the sensors do not send a fault code, the RPAS activates the "RPAS start buzzer".
5. 5
   If fault information is received from a sensor, the system activates the "fault buzzer" instead of the "RPAS buzzer". If equipped with a display, fault information is shown on the display.
6. 6
   The fault buzzer sounds only once. However, fault information continues to be displayed until the sensor is repaired.

   

7. 7
   After IGN1 and R signal are input, the RPAS starts LIN communication and continuously maintains the procedure.
8. 8
   To perform the initial system fault check, the BCM calls each sensor once; 4 sensors respond simultaneously. If there is no fault signal, the buzzer sounds 0.5 s after the R signal is input, for 0.3 s.
9. 9
   After the initial process, the general procedure starts 0.2 s after the buzzer output is completed.
10. 10
    The alarm is divided into 1, 2, and 3. Alarms 1 and 2 are intermittent tones, and alarm 3 is a continuous tone.
11. 11
    In case of cluster display, the information from each sensor is transmitted from the BCM to the cluster. Communication for transmission uses CAN and the gateway time is within 50 ms.
12. 12
    The RPAS operating range is 10 km/h or less for vehicle speed.
13. 13
    Horizontal Range

    

14. 14
    Vertical Range

    

15. 15
    System Operation Specification When system power is on (ignition on and reverse signal ON), the MICOM checks each sensor channel. If there is no fault, the buzzer sounds for 0.3 s after 0.5 s. If one of the sensors is in an abnormal state, the initial buzzer does not sound and the corresponding sensor output sounds. Normal mode operation is described below.

    

16. 16
    Alarm Output Specification, Sensor Interval Separation. Status logic as shown below corresponds to the priority phase logic. (Same sensor)

    

    The RPAS operating ranges by distance are shown below.

    1. First Alarm (81 cm ~ 120 cm)

       

    2. Second Alarm (41 cm ~ 80 cm)

       

    3. Third Alarm (40 cm or less)

       

    4. Alarm Cycle. In case of system failure, it indicates the faulty point as follows (3 times for each sensor).

       

       Time tolerance for the above waveform: Time ± 10% Detection may not occur at distances less than 30 cm. The alarm will sound if the reverse vehicle speed does not exceed 10 km/h. For a moving target, the maximum operating speed must be the approach speed to the target of 10 km/h. When the vehicle or target is moving, continuous alarm generation or effective alarm may not function. False alarms or alarm activation failures may occur under the following conditions. Uneven road surface, gravel road, reversing onto grass. Horn sound, motorcycle engine noise, air brakes of a large vehicle, or another object generating ultrasonic waves is nearby. When a wireless transmitter is used near the sensor. Dirt on the sensor. Continuous alarm may not function due to reverse speed or target shape.

Normal Mode Sensor Detection Range Alarm Method When the RPAS sensors detect an object, the audible system activates and sounds an alarm. The RPAS sensor sends alarm data to the BCM via LIN communication. The BCM signals the audible system according to the alarm data received from each RPAS sensor. If the BCM sounds the buzzer, the alarm order depends on the location priority. When alarm data is delivered to the cluster, the BCM acts only as a gateway.