ECS (Electronically Controlled Suspension) System

Road Surface Decision

Damping control determines the road surface condition vertically using acceleration sensors on the front wheel, body, and wheels.

The road surface is classified into 5 types: Normal, Bad Road 1, Rough Road 2, Wave, and Bump, through checking the intensity and frequency of the acceleration signal. The road surface is determined according to a predefined priority, and the calibration parameter is used to calculate the target electric current. The road surface decision parameters can be adjusted through calibration.

Failure Control

The body bounce velocity can be obtained by adding the vertical velocities of the 4 wheels. The vertical velocity of the vehicle body can be estimated by integrating the acceleration signal. The required damping force can be calculated by multiplying the proportional gain and the bounce velocity, and passing the result through a maximum value limit function. The calibration parameters are the gain and the limit value. The front and rear wheels have different values.

Pitch Control

The body pitch velocity can be obtained from the difference between the front and rear wheel body velocities. The required damping force can be calculated by multiplying the proportional gain and the pitch velocity, and passing the result through a maximum value limit function. The calibration parameters are the gain and the limit value. The front and rear wheels have different values.

Roll Control

The body roll velocity can be obtained from the difference between the left and right body velocities. The required damping force can be calculated by multiplying the proportional gain and the roll velocity, and passing the result through a maximum value limit function. The calibration parameters are the gain and the limit value. The front and rear wheels have different values.

Damping Velocity Estimation

The damping velocity can be estimated from the difference between the body and wheel vertical velocities, and the vertical velocities of the body and wheel can be obtained by integrating the acceleration sensor signal. The acceleration at the rear wheel can be estimated from the time delay of the front wheel and the vehicle speed.

Directional Check

The final damping force required by Skyhook is determined by the "passive" state. The passive check determines Y/N of the damping force control. The final required damping force is set by electric solenoid current control when the required damping force and the damping velocity are in the same direction. If they are in opposite directions, it is set as the soft damping force.

Anti-Roll System

The lateral movement of the vehicle can be estimated by the steering wheel angle sensor and the vehicle speed. The maximum electric current control is limited when the lateral jerk signal exceeds the set value. The calibration parameters are the jerk signal level, the damping force control gain, and the damping force control amount, and they can be set according to vehicle speed.

Anti-Dive Control

The vehicle deceleration during braking is calculated from the difference in vehicle speed. The maximum electric current control is limited when the calculated deceleration is greater than the set value. The calibration parameters are the deceleration level and the amount of damping force control.

Anti-Squat Control

The driver's intention to accelerate can be anticipated from the accelerator pedal position information at start. The maximum electric current control is limited during acceleration when the position is outside the set value. The calibration parameters are the deceleration level and the amount of damping force control.

Vehicle Speed Control

This is a function that maintains the minimum damping force depending on the vehicle speed. The maximum electric current is limited. The calibration parameter is the damping force, which controls the amount depending on the vehicle speed.

Damping Control Mode

The driver can select either of two modes (Auto and Sport). Switching the damping mode is linked to the Drive Mode Integrated Control (DMI). ECS control is performed in AUTO mode when NORMAL, ECHO or SNOW mode is selected with the Drive Mode Integrated Control switch. ECS control is performed in SPORT mode when SPORT mode is selected. The calibration parameters stored in the ECU change depending on the selected damping control mode, and vehicle driving characteristics may differ for each mode. Ride comfort and steering stability are optimized overall in AUTO mode. SPORT mode focuses on steering stability.