Kia Cee'd: Rear Parking Assist System / Description and operation

Kia Cee'd JD Service Manual / Body Electrical System / Rear Parking Assist System / Description and operation

System Overview

RPAS(Rear Parking Assist System) is an electronic driving aid device warning driver to be cautious when they park or speed low after detecting an object on side and behind of vehicle by using the feature of ultrasonic waves.

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.

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.

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 (Front sensor have second and third alarms.)

(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

Distance range detected objects (Measured directly in front of sensor)

Position	Level	Distance range
Position	Level	cm	inch
Rear	1st	61 ~120 (±15)	24.0 ~ 47.2 (±5.9)
	2nd	31 ~ 60 (±15)	12.2 ~ 23.6 (±5.9)
	3rd	Less than 30 (±10)	Less than 11.8 (±3.9)

Horizontal Sensing Area

Vertical Sensing Area

Distance Measurement

Direct Measurement

Transmission and Reception are executed with one sensor

(RL, RCL, RCR, RR each sensor execution)

Indirect Measurement

(RCL → RL, RCL → RCR, RCR → RCL, RCR → RR Execution in order)

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.

PAS 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 is not find 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)

*α value definition

1.	low priority sensor off : α = 0ms

2.	low priority sensor is 1st warning level : α < 340ms

3.	low priority sensor is 2nd warning level : α < 170ms

*β value definition

1.	low priority sensor is 1st warning level : β = 1700ms

2.	low priority sensor is 2nd warning level : β = 1700ms

3.	low priority sensor is 3rd warning level : β = 700ms

Alarm control by sensing distance is as below

1.	First warning area (61cm ~ 120cm)

2.	Second warning area (31cm ~ 60cm)

3.	Third warning area (less than 30cm)

Period of fault alarm

(1)	With visible display

(2)

Without visible display

When the system has error channel in initial time, sensor channel let us know the location of error via hearing device. (Three times for each sensor)

1)	Time tolerance of the above waveform : Time ± 10%

2)	At nearer distance than 30cm, detection may not occur.

3)	Alarm will be generated with vehicle reversing speed 10km/h or less.

4)	For moving target, maximum operation speed shall be target approach speed of 10km/h.

5)	When the vehicle or the target is moving, sequential alarm generation or effective alarm may be failed.

6)	False alarm, or failure of the alarm to trigger may occur in the following conditions.

–	Irregular road surface, gravel road, reversing toward grass.

–	Horn, motor cycle engine noise, large vehicle air brake, or other object generating ultrasonic wave is near.

–	When a wireless transmitter is used near to the sensor.

–	Dirt on the sensor.

–	Sequential alarm may not occur due to the reversing speed or the target shape.

Error Handling

LIN BUS Off Error Case

Section	Error recognition condition	Error releasing condition
Initial Routine	LIN BUS OFF sensing once	Error is not released in initial mode.
Normal Routine	LIN BUS OFF is sensed times in a row	The fault is released when BCM or LIN Master senses LIN BUS ON four times in a row in normal mode

※ Remark :

1.	In fault counting, output message or signal should be transmitted as a Last Valid value.

2.	Error in initial mode, fault buzzer (BCM) is operated.

Sensor Fault (LIN Msg : 0x08)

Section	Error recognition condition	Error releasing condition
Initial Routine	Sensor fault Message sensing once	Error is not released in initial mode.
Normal Routine	Sensor fault Message sensing four times in a row	The fault is released when BCM or LIN Master senses LIN BUS ON four times in a row in normal mode

※ Remark :

1.	In fault counting, output message or signal should be transmitted as a Last Valid value.

2.	Error in initial mode, fault buzzer (BCM) is operated.

3.	When the error occurs in direct condition, the sensors sent the same status of error for indirect condition

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.)

Components and components location

Component Location ※ Parking assist control unit function and buzzer are built in BCM (Body Control Module) ...

Parking Assist Sensor Components and components location

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