| VELOSTER(FS) >2013 > G 1.6 GDI > 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 during parking or low speed when after detecting an object on side and behind of vehicle by using the feature of ultrasonic waves. RPAS consists of four RPS sensors which detect the obstacles and transmit the result in three separate 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 ID and sets the sensor ID up during initialization.
(3) | RPAS activates each sensor and then executes the diagnosis after finishing initialization of BCM
(4) | RPAS 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, RPAS 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) 81cm(31.9in) ~ 120cm(47.2in) : ± 15cm(5.9in) 41cm(16.1in) ~ 80cm(31.5in): ± 15cm(5.9in) Less than 40cm(15.7in) : ± 10cm(3.9in)
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. 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 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 (81cm ~ 120cm)
2. | Second warning area (41cm ~ 80cm)
3. | Third warning area (less than 40cm)
4. | Period of fault alarm
(1) | With visible display
(2) | Without visible display When the system has error channel in initial time, sensor channel notify 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 of 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.)