RPAS (Rear Parking Assist System) is an electronic driving
aid that warns the driver to be cautious while parking or in low speed
environments. The sensor uses ultrasonic waves to detect objects within
proximity of the vehicle.
RPAS consists of four RPS sensors which are detecting the
obstacles and transmit the result separated into three warning levels,
the first, second and third to BCM by Lin communication. BCM decides the
alarm level by the transmitted communication message from the slave
sensors, then operate the buzzer or transmits the data for display.
System Block Diagram
System Operation Specification.
1.
INIT mode
(1)
System initializing time is 500ms after IGN1+ R Gear.
(2)
RPAS recognizes LID and sets the sensor ID up during initialization.
(3)
RPAS activates each sensor and then executes the diagnosis after finishing initialization of BCM
(4)
R-PAS Starting buzzer” is normally worked, when sensor does not send an error message and after finishing error diagnosis.
(5)
If any failure is received from the any sensors, R-PAS
Starting Buzzer” does not work but the failure alarm is operated for a
moment.
If you have display option, warning sign is also shown on it.
(6)
Buzzer for sensor failure is operated once, but display is shown continuously until it is repaired completely.
2.
NORMAL Mode
(1)
Lin communication starts and keeps the routine after IGN1 ON+R gear
(2)
BCM send a message once to each sensor for operating request
to check the initial status of the system and four sensors response at a
time. At this time, if there is no problem, the alarm starts after
500ms of R gear shifting at 300ms intervals.
(3)
After initialization, normal mode starts 100ms later after finishing alarm output.
(4)
Alarm for obstacles is divided into 3 levels.
The first and second are intermittent sound, and the third alarms continuously
(5)
The efficient vehicle speed of RPAS operation is under 10Km/h.
(6)
Refer to ‘Digital PAS Project LIN communication’ for the more detailed communication specification.
Sensing Area
1.
Measurement condition – PVC pole (diameter 75mm, length 3m), normal temperature
2.
Distance range detected objects (Measured directly in front of sensor)
61cm(24.0in) ~ 120cm(47.2in) : ± 15cm(5.9in)
31cm(12.2in) ~ 60cm(23.6in): ± 15cm(5.9in)
Less than 30cm(11.8in) : ± 10cm(3.9in)
Horizontal Sensing Area
Vertical Sensing Area
Distance Measurement
Direct Measurement
Transmission and Reception are executed with one sensor
With two or three sensors, one of them sends the transmission and the others get the reception.
Direct and Indirect Measurement at once
With two or three sensors, the one sensor performs both transmission and reception, and the others perform only reception.
RPAS alarm system
When the RPAS sensor detects the object, warning is operated
by audible alarm device as like buzzer. RPAS sensor sends data to BCM
with LIN communication and BCM implements audible warning for each RPAS
SENSOR by priority. And it performs a role of gateway only when it sends
visible alarm device such as Cluster.
–
Sensor buzzer/display information processing method of BCM In
case of RL/RR sensor information, the BCM handles each sensor
information directly about Display and buzzer output function. Buzzer
output of CL/CR sensor, BCM handles center combination information by
priority both sensor.
System Operation Spec
When the system has the power (after IGN ON and R gear),
MICOM checks every sensor channel. In case it finds any error, it sounds
300ms buzzer 500ms afterward. But it finds any error even a sensor, it
sounds buzzer corresponding fault sensor instead of initial starting
alarm. Function for normal mode entrance is as below
With R Gear, system function is as below
With R gear releasing, system function is as below
※acceptable error range on waveform ±10%
Alarm Output Specification classified by distance between sensors
Condition logic according to priority of alarm level is as below. (the identical sensor)
Second warning area (31cm ~ 80cm / 12.2 ~ 23.6 in.)
3.
Third warning area (less than 30cm / 11.8 in.)
Visible Alarm Indicator Specification
When the gear is applied to R, cluster lights the indicator as below figure.
When the system finds an object, it lights indicator
immediately. During sensing an object, if there is no object, it lights
indicator that is no alarm status for two seconds and then turns out
afterward detecting an object.
(But when it turns third step alarm to No alarm status, it lights third step alarm for two second and turns out.)
–
It shows only the detecting position of obstacles.
–
In third level alarm, indicator flickers at intervals of a second.
–
In normal alarm level display, RCR/RCL indicator is combinated by priority.
Communication Standard
This section defines the communication between RPAS and BCM.
RPAS send a detecting result of object and sensor diagnosis
result to BCM according to this document, and BCM takes a role to alarm.
Indicator shows the transmitted position and alarm data, in
alarm case, it finds the nearest DATA and alarms the nearest DATA first.
(Ex. In case, RL is first step alarm and RR is third step, RR alarm has priority.)
Component Location
1. BCM (Body Control Module)2. Ultrasonic sensor
※ Rear parking assist control unit function is built in IPM (Intelligent integrated Platform Module).
...
Description
To sense the cars exactly in the next lane with the radar,
the direction of the sensor and the direction of the vehicle have to
align.
This is BSD unit alignment. If this alignment is not
performed as below illustration, the degradation of detection
performance and the cause ...