Collision Avoidance and Parking Assist Systems: Description and Operation

System Description

The Collision Mitigation Brake System (CMBS), anticipates rear-end collisions and assists brake operation to reduce the impact on occupants and vehicle damage. The system works in combination with the e-Pretensioners, which retract the seat belts in anticipation of impact.




CMBS operation

- Warnings are both audible (warning buzzer) and visual (MID)
- Evasive action support and collision-speed reduction by brake control

Main functions of CMBS
- When a collision with a vehicle ahead is about to happen at a vehicle speed greater than 9 mph (15 km/h) and the relative speed (the speed difference from the vehicle ahead) is greater than 9 mph (15 km/h), the system provides warnings (audible and visual) and brake control.
- When approaching a vehicle ahead and the distance to the vehicle ahead is very close, the system provides the collision warning (1st stage) by the MID indication and buzzer sound.
- When the closing distance continues to decrease and there is a high risk of collision, the system applies light braking (2nd stage) with the 1st stage warning.
- When the system judges that a collision is imminent, the system activates emergency brake control.
- The timing of the 1st stage warning can be set to one of two modes by the user. The FAR mode warns sooner than the NEAR mode.

CMBS Control
The CMBS is operated by the adaptive cruise control (ACC) unit. The CMBS has these functions:

Obstacle determination function
The system determines the potential for collision by the distance from the vehicle ahead and the relative speed based on the millimeter wave radar unit and the predictable course calculated by the driving conditions (wheel speed and yaw rate).

Warning function
When there is a high risk of collision, the system sends warning directions to the gauge control module and warns by both audible and visual means.

Brake control function
When there is a high risk of collision, the system sends brake directions to the VSA modulator-control unit and controls braking action.




CMBS Activate Condition

The system can activate (warn the driver, apply the brakes) when it detects or encounters these situation:
- Metallic projections or the road
- Metallic manhole and drain covers
- Signs and guardrails ahead
- Low overpasses and narrow gates
- Approaching vehicle that are turning left or right
- Passing slower vehicles ahead

The system will not activate (no warning or intervention) when it detects or encounters these situations:
- Low-speed, heavy traffic (such as in a traffic jam)
- Being cut-off by a slower vehicle
- Approach a vehicle stopped at an angle
- Driving on curves
- Approaching bicycle or moped
- Dirt or snow stuck on the emblem
- Heavy rain or snow

When the CMBS activates, it sounds and feels just like ABS activation.
The CMBS tends to work better in the FAR mode than the NEAR mode.




Gauge Control Module

When a problem or malfunction is detected, the CMBS indicator comes on. With some problems or malfunctions, the condition is displayed on the MID.

When the CMBS is turned off by the CMBS OFF switch, the CMBS indicator comes on, and the MID indicates that the CMBS is off.




CMBS OFF Switch

The CMBS operation can be switched by the CMBS OFF switch next to the gauge control module. (Press and hold the switch for more than a second.)

Adaptive Cruise Control (ACC) System Inputs And Outputs:

Adaptive Cruise Control (ACC) System Inputs and Outputs