Collision Mitigation Braking System Description
Collision Mitigation Braking System Description
The collision mitigation braking system (CMBS) anticipates 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 is about to happen and the relative speed (the speed difference from the object ahead) is greater than 9 mph (15 km/h), the system provides warnings (audible and visual) and brake control.
- When approaching a object ahead and the distance to the vehicle is very close, the system provides the collision warning (1st stage) by MID indication and buzzer sounding.
- 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 and applies strong seat belt tension.
CMBS Control
The CMBS is operated by the ACC unit. The CMBS has the following 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 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 Activation Conditions
The system might activate (warn the driver, apply the brakes) when it detects or encounters these situations:
- Metallic projections on the road
- Metallic manhole and drain covers
- Signs and guardrails ahead
- Low overpasses and narrow gates
- Approaching vehicles that are turning left or right
- Passing slower vehicles ahead
The system might 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
- Approaching a vehicle stopped at an angle
- Driving on curves
- Approaching a bicycle or moped
- Dirt or snow stuck on the front radar cover
- Heavy rain or snow
When the CMBS activates, it sounds and feels just like ABS activation.
Adaptive Cruise Control (ACC) Unit Inputs and Outputs
