09-94891-01
2) Operation of ESP System
(1) Under steering
What is understeering? ▶
ESP controls during understeer ▶ Understeer is a term for a condition in which the steering wheel is steered to a certain angle
during driving and the front tires slip toward the reverse direction of the desired direction.
Generally, vehicles are designed to have understeer. It is because that the vehicle can return back
to inside of cornering line when the steering wheel is steered toward the inside even when the
front wheels are slipped outward.
As the centrifugal force increases, the tires can easily lose the traction and the vehicle tends to
slip outward when the curve angle gets bigger and the speed increases.
The ESP system recognizes the directional angle with the steering wheel angle sensor and senses
the slipping route that occurs reversely against the vehicle cornering direction during understeer
with the yaw rate sensor and lateral sensor. Then, the ESP system applies the braking force to the
rear inner wheel to compensate the yaw moment value. In this way, the vehicle does not lose its
driving direction and the driver can steer the vehicle as intended.
09-10
(2) Over steering
What is oversteering? ▶
ESP controls during oversteer ▶ Oversteer is a term of a condition in which the steering wheel is steered to a certain angle during
driving and the rear tires slip outward losing traction.
Compared to understeering vehicles, it is hard to control the vehicle during cornering and the
vehicle can spin due to rear wheel moment when the rear tires lose traction and the vehicle speed
increases.
The ESP system recognizes the directional angle with the steering wheel angle sensor and senses
the slipping route that occurs towards the vehicle cornering direction during oversteer with the
yaw rate sensor and lateral sensor. Then the ESP system applies the braking force to the front
outer wheel to compensate the yaw moment value. In this way, the vehicle does not lose its
driving direction and the driver can steer the vehicle as intended.
