Kenichi Ohue

Development of a New Pre-crash Safety System

This paper describes a new pre-crash safety (PCS) system that has been developed which includes an advanced forward collision warning function. The new system is now provided with a driver monitoring sensor that detects the facial direction and degree of eye opening of the driver, and gives warning at an earlier timing only when the vehicle is likely to collide with a forward obstacle and the driver is unaware of its presence. This avoids the problem of providing an unnecessary collision warning to drivers who are driving carefully, thus annoying them. In cases when the driver is not driving with sufficient care and the vehicle is approaching a forward obstacle, an appropriate collision warning is an effective way of avoiding an accident and mitigating the severity of the collision. The authors describe the configuration and functions of the new PCS system that consists of a millimeter wave radar, a PCS electronic control unit (ECU), a seatbelt ECU, a braking control ECU, and a meter ECU. The millimeter wave radar detects vehicles and other potential obstacles based on the position and relative speed of the object. Then the PCS ECU estimates the time to collision based on the detection results. The seatbelt ECU retracts the seatbelts based on this time estimate, the meter ECU indicates warnings in the meter, and the braking control ECU sounds a warning buzzer and controls the brakes. The newly developed PCS system with the driver-monitoring sensor consists of the basic PCS system, augmented by a driver-monitoring sensor with a CCD camera and an image processing ECU. The PCS ECU adjusts the warning buzzer and braking timing based on the information of the facial direction angle, the degree of eye opening, and the estimated time to collision. The PCS system with a driver-monitoring sensor has functions to detect when the driver is not facing ahead or when the driver’s eyes are closed, thus allowing detection of states where the driver is not paying attention to the front. The authors conclude that the newly developed PCS system is expected to prompt the driver to take evasive action, and to mitigate accident damage by increased braking operations whenever a collision is likely to occur.