Active safety technology will become increasingly important in preventing collisions in the future.

The possibility of accidents occurring due to instability in vehicle dynamics leading to deviation from the lane is particularly high when a vehicle enters a corner too fast or is on an icy or snow-covered road, or makes a sudden maneuver to avoid collision with an obstacle during a turn.

To contribute to the solution of this situation, the research described in this paper studies a method of minimizing deviation through optimal control of moment and velocity and then utilizing four-wheel slip control based on estimates of vehicle dynamics.

First, this project studied a system to control deviation from the intended course by providing accurate, real time estimates and control of four-wheel tire gripping forces based on estimates of vehicle dynamics parameters and the road friction coefficient. The method of the vehicle dynamics control utilized in this system was VSA (Vehicle Stability Assist).

Next, the project studied a method of providing comprehensive control. This method utilizes information from the vehicle’s navigation system to quantitatively predict the form of a corner before the vehicle enters it. This data is then utilized in combination with VSA to further minimize deviation from the lane.

These two systems were fitted in a test vehicle and tested on snow-covered road surfaces. The results of these tests clearly demonstrate that this system reduces the incidence of deviation from the lane and will therefore be effective in reducing the number of accidents.