Rear Parking Assist System

Specifications

Specification

Components and Component Location

Component Location

Description and Operation

System Overview

RPAS (Rear Parking Assist System) is an electronic driving assist system that warns the driver to be careful when parking or driving at low speed. The sensors use ultrasonic waves to detect objects in the immediate vicinity of the vehicle.

RPAS consists of four RPAS sensors that detect obstacles and transmit the result, divided into three warning levels (first, second and third), to the BCM via the communication line. The BCM determines the warning level from the message transmitted by the slave sensors, and then activates the buzzer or transmits data for display.

System Operation Specification

1. 1

   INITIAL Mode

   1. The system initialization time is 500 ms after IGN1 + R gear.

   2. RPAS recognizes the LID and sets the sensor identifier during initialization.

   3. The RPAS activates each sensor and then performs diagnostics after the BCM initialization is completed.

   4. If diagnosis is complete and no sensor malfunction is detected, the RPAS starting buzzer operates normally.

   5. If a malfunction is received from any sensor, the RPAS starting buzzer does not operate, but the alarm sounds momentarily.

      If equipped with a display, a warning indicator is also displayed.

   6. When a sensor malfunction occurs, the buzzer sounds once, but the sensor malfunction status is displayed until the malfunction is repaired.

2. 2

   Normal Mode

   1. LIN communication starts and maintains the procedure after IGN1 ON + R gear input.

   2. The BCM sends a operation request message once to each sensor to check the initial state of the system, and the four sensors are activated all together. At this time, if there is no problem, the alarm starts after 500 ms of shifting to R, at 300 ms intervals.

   3. After initialization, normal mode starts 100 ms after completion. Warning output.

   4. The obstacle warning is divided into 3 levels.

      The first and second levels sound intermittently, and the third warning sounds continuously.

   5. The effective vehicle speed for RPAS operation is less than 10 km/h.

   6. For details, refer to the section "Digital PAS Project LIN Communication" for the detailed communication specification.

Detection Area

1. 1

   Measurement conditions: PVC pole (diameter 75 mm, length 1 m), normal temperature.

2. 2

   Distance to detected objects (measured directly in front of the sensor)

   61 cm (24.0 in) - 120 cm (47.2 in): ± 15 cm (5.9 in)

   31 cm (12.2 in) - 60 cm (23.6 in): ± 15 cm (5.9 in)

   Less than 30 cm (11.8 in): ± 10 cm (3.9 in)

Horizontal Sensing Area

Vertical detection area

Distance measurement

Direct measurement

Transmission and reception are performed by one sensor

(RL, RCL, RCR, RR for each sensor version)

Indirect measurement

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

With two or three sensors, one of them sends the transmission and the others receive the reception.

Direct and indirect measurement at one time

With two or three sensors, one sensor performs both transmission and reception, and the others perform reception only.

RPAS Warning System

When an RPAS sensor detects an object, the warning is given by the buzzer device. The RPAS sensor sends data to the BCM via LIN communication, and the BCM implements the audible warning for each RPAS SENSOR by priority. It acts as a gateway only when it sends the visual warning device, such as the cluster.

• Sensor Buzzer / Information Processing Method in BCM Display In the case of RL / RR sensor information, the BCM processes each sensor's information directly for the display and buzzer function. For the CL/CR sensor buzzer output, the BCM processes the central combination information according to the priority of both sensors.

System Operation Specification

When the system is powered (after IGN ON and shifting to R), the MICOM checks each sensor channel. If any error is detected, it sounds a buzzer for 300 ms after 500 ms. If an error is detected even in a sensor, it sounds a buzzer corresponding to the faulty sensor instead of the initial starting signal. The operation to enter normal mode is as follows.

With R gear engaged, the system operates as follows.

With R gear disengaged, the system operates as follows.

※ The allowable error range in the waveform is ±10%.

Warning Output Specification is classified by the distance between sensors

The state logic according to warning level priority is as follows. (identical sensors)

* Determination of α value

1. 1

   Low priority sensor off: α = 0 ms

2. 2

   Low priority sensor - 1st level warning: α < 340 ms

3. 3

   Low priority sensor - 2nd level warning: α < 170 ms

*Determination of β value

1. 1

   Low priority sensor - 1st level warning: β = 1700 ms

2. 2

   Low priority sensor - 2nd level warning: β = 1700 ms

3. 3

   Low priority sensor - 3rd level warning: β = 700 ms

Alarm control by detection distance is as follows.

1. 1

   First Warning Zone (31.9 in. (81 cm) - 47.2 in. (120 cm))

   

2. 2

   Second Warning Zone (16.1 in. (41 cm) - 31.5 in. (80 cm))

   

3. 3

   Third Warning Zone (less than 15.7 in. (40 cm))

   

Visual Warning Indicator Specification

When the transmission is shifted to R, the cluster controls the indicator as follows.

When the system detects an object, the indicator illuminates immediately. If the object disappears during RPAS detection operation, the indicator remains on for 2 seconds before turning off.

(However, when the third-step alarm changes to the "No Alarm" state, the third-step indicator stays on for two seconds.)

• It only indicates the obstacle detection position.

• At the third warning level, the indicator flashes at one-second intervals.

• In normal warning mode, the built-in display RCR/RCL

Communication Standard

This section defines the communication between the RPAS and the BCM.

The RPAS transmits the object detection result and the sensor diagnosis result to the BCM according to this document, and the BCM takes over the alarm signal function.

The indicator shows the transmitted position and alarm data. In alarm mode, it finds the nearest data and first alarms for the nearest data.

(Example: If RL is a first-step alarm and RR is a third-step alarm, the RR alarm has priority.)