Forward Collision Warning (FCW) Systems Explained

Forward Collision Warning
➢Forward Collision Warning uses sensors in front of the vehicle to
detect the chances of any collision with front vehicle or other
obejct.
➢This systems consider Ego vehicle‘s current speed, the speed of the
vehicle or other object in front of the ego vehicle (mostly in same
lane) and the distance between them.
➢If it finds the chances of collision, then it alerts the driver by audio /
visual warning on the panel.
➢Some of the FCW systems can also brake lightly to reduce the ego
vehicle speed, but mostly do not stop the vehicle completely.
➢For this purpose another system, known as AEB (Automatic
Emergency Braking) is used in vehicles.
Reference: https://www.youtube.com/watch?v=iRM22oXXn8k (Picture courtesy: Insurance Institute for Highway Assist & Bosch)
FCW from IIHS (using Radar)
FCW from Bosch (using Radar and camera)
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Forward Collision Warning
➢FCW systems are also referred to as “Pre-safe Braking”, “Collision Warning with Auto-Brake”, “Pre-Crash
Warning Systems”, “Collision Mitigation Braking System”, “Predictive Forward Collision Warning”, etc.
➢Some situations on road, where the FCW is specifically useful.
➢A line of cars ahead is stopped at a green light due to an obstacle in the intersection, and you are driving
too fast towards it.
➢Cars are travelling too close to one another and not leaving a safe distance between vehicles.
➢The car ahead unexpectedly slows down to turn without signaling
➢The vehicle ahead decelerates rapidly for a pedestrian crossing the road, but you do not immediately
notice the braking
➢FCW systems are useful whenever a driver is at risk of colliding with a vehicle (or, depending on the type of
system, a pedestrian or animal) directly ahead. It helps to avoid rear end collisions.
Reference: https://brainonboard.ca/safety_features/active_safety_features_fcw.php
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Forward Collision Warning
➢Sensor in FCW
➢Only Radar Based
➢Uses generally LRR (Long Range Radar) which is also use for ACC systems to detect the objects in
front of the vehicle and also to measure speed and direction.
➢Front camera + Radar Based
➢Uses two sensors to compliment each other and increase perception efficiency in front of the vehicle
to detect and classify object correctly
➢Other sensor systems like…(generally used very less)
➢Only camera based
➢Only IR Laser beam based, etc.
Reference
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Forward Collision Warning
➢How FCW alert driver ?
➢Visual
➢Active Symbols on the dashboard
➢Audio
➢Beep sound or other tones
➢Tactile
➢Tightening the seat belts
➢Jerks due to pulsed brake (apply –remove –apply –remove …..)
➢Adjusting the head rest
Image courtesy: IIHS (Insurance Institute for Highway Assist)
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Forward Collision Warning – Radar Sensors FoV and understanding
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