Toyota’s pre-crash technologies: Keep Your Eyes on the Road

by John Brennan

The Japanese tend to be more comfortable with technology than Americans, so they tend to be a bit more advanced than we are. Japanese cell phones, GPS systems and even toilets are technological marvels compared to American products. Americans remain uncomfortable with technologies that are commonplace in Japan.

Even when it comes to automotive safety, we are not yet willing to embrace technology as thoroughly as Japanese drivers. Toyota’s newest innovation, due for release in Japan, would make most of us uneasy. For the first time, a car will be able to look into your eyes and decide whether or not you are paying attention to the road.

It’s part of a Pre-Crash Safety system that is already available in some markets. The system continually monitors the road ahead looking for obstacles. The Advanced Obstacle Detection system combines a millimeter-wave radar with a near-infrared camera system, allowing computers to see objects- including pedestrians- in day or night driving conditions from up to 25 meters (82 feet) away.

Data is compared with the vehicle’s speed, direction and yaw rate to decide if there is the threat of collision. The Pre-Crash Safety system also monitors the driver’s level of attentiveness from the moment the vehicle is started. A CCD (charge-coupled device) camera is mounted on top of the steering column cover with six built-in near-infrared LEDs, which enable the system to work accurately both day and night. When the vehicle is started up, the system automatically plots the position of the driver’s facial features – eyes nose and mouth – and measures the width and centre line of the face. This information is used as a reference as it monitors movement of the driver’s head when looking from side to side.

Before being brought to market, the system was tested with more than 100 drivers, covering more than 100,000km (62,000 miles). As long as the driver’s face is in the clear sight-line of the camera, it will function accurately regardless of the driver’s seat position, facial characteristics, or if sunglasses are being worn.

The new development for the Pre-Crash Safety system is the fact that it now will monitor the eyes of the driver. In the first system of its kind in the world, the eye-monitoring system will be able to tell whether or not the driver’s eyes are properly open. It is sensitive enough to detect the upper and lower eyelids, to insure that the driver remains attentive. The system continues to check head position to make sure that the driver is facing the right direction as well.

eyelids - sleep sensor

If the Advanced Obstacle Detection system detects a potential collision, it will warn the driver of the problem. If the Driver Monitoring system detects that the driver has turned his head or does not have his eyes open, it will initiate the warning sequence sooner. When the Advanced Obstacle Detection System identifies obstacles ahead, the Pre-Crash Safety system assesses the likelihood of collision based on the position, speed, and trajectory of the obstacle. If the collision probability is high, a warning buzzer and red BRAKE! Alert on the multi-function display are activated.

After testing the reactions of a number of drivers, Lexus engineers determined the best engagement timing for all PCS functions to improve the chances of the driver reacting in time to prevent the collision happening. Should the driver fail react to the light and buzzer, the vehicle will briefly activate the brakes in an attempt to alert the driver. If the driver continues to ignore the warnings, the vehicle will begin to take over.

The Emergency Steering Assist system is activated, improving the vehicle’s response to driver steering input, selecting the best gear ratio for rapid evasion maneuvers and increasing the chances of avoiding a collision. It works through close interaction between the car’s Variable Gear Ratio Steering (VGRS), Vehicle Dynamics Integrated Management (VDIM) and Adaptive Variable Suspension (AVS) systems.

The VGRS actuator, which is attached to the steering rack, reduces the steering gear ratio to provide more direct steering and improve response to driver input. At the same time, the AVS adopts a stiffer damper setting to minimize body roll and optimize chassis balance, for better vehicle response. The VDIM governs selective brake control, to control the vehicle’s yaw rate, allowing for quick changes of direction without threatening the car’s overall stability.

Should the vehicle determine that collision is probable, it will activate the brakes in an attempt to slow or stop the vehicle prior to impact. It will simultaneously engage the front seatbelt pre-tensioning, allowing the seatbelts to be more effective during the collision. It will also automatically adjust the Pre-Crash Intelligent Headrests. These move up to 60mm (2.3 inches) forwards and 35 mm (1.4 inches) upwards to cushion the head in anticipation of an impact, greatly reducing the risk of whiplash injury. The headrests are fitted with a sensor that measures the distance between the passenger’s head and the headrest itself, so there is no risk of the emergency adjustment itself causing substantial contact. The system does not operate if the seat is unoccupied.

Also available is a Rear Pre-Crash Safety system which constantly scans the area around the back of the car using a millimeter-wave radar, whether the vehicle is moving or parked. If a collision is calculated to be unavoidable, the system activates the front seat Pre-Crash Intelligent Headrests.

Toyota closed-eyes protection pre-crash safety sequence

safety sequence for closed eyes

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