How ESP works
Under certain road conditions and vehicle load conditions, the maximum adhesion that the wheel can provide is constant, that is, in the extreme case, the longitudinal force (in the direction of wheel rolling) and the lateral force (vertical wheel rolling direction) of the wheel are This relationship is different. The electronic stability program controls the longitudinal braking force of each wheel separately, thereby exerting an influence on the lateral force, thereby improving the handling performance of the vehicle.
When the longitudinal force reaches the extreme value (such as the wheel lock), the lateral force is 0. At this time, the lateral movement of the vehicle will be uncontrolled, that is, side slip occurs. At this time, it may not be possible to change lanes or turn according to the driver's wishes. . The electronic stability program detects and prevents vehicle skidding. When the electronic stability program detects that the vehicle is about to get out of control, it applies a braking force to a particular wheel to help the vehicle move in the direction the driver wants.
When turning, a feasible control strategy is: when the vehicle has a tendency to understeer, the system can apply braking force to the rear wheel on the inside of the turn, and the lateral force that can be provided is reduced due to the increase of the longitudinal force of the wheel. , with the help of the body to help the steering torque; when there is a tendency to oversteer, the system can apply braking force to the front wheel outside the turn, due to the increase of the longitudinal force of the wheel, the lateral force can be reduced, with It produces a torque against the body that resists steering. This ensures stable driving. Some electronic stability program systems also reduce engine power when the vehicle is out of control.