Active suspension is a new type of suspension developed in the past ten years and controlled by a computer. It brings together the technical knowledge of mechanics and electronics, and is a relatively complex high-tech device. For example, the French Citroen Santilla equipped with an active suspension. The center of the suspension system of the car is a microcomputer. The five sensors on the suspension transmit the vehicle speed, front wheel brake pressure, accelerator pedal speed, and speed to the microcomputer. Data such as the amplitude and frequency in the vertical direction of the vehicle body, steering wheel angle and steering speed. The computer continuously receives these data and compares it with the preset threshold to select the corresponding suspension state. At the same time, the microcomputer independently controls the actuators on each wheel, and generates twitching by controlling the change in the oil pressure in the shock absorber, so that the suspension motion can be produced on any wheel at any time. Therefore, the Santilla car is equipped with a variety of driving mode options. The driver only needs to pull the "normal" or "sports" button on the sub-instrument panel, and the car will automatically be set in the best suspension state for the best Good comfort performance.
Active suspension has the function of controlling body movement. When the inertia of the car braking or cornering causes the spring to deform, the active suspension will produce a force that opposes the inertia, reducing the change of the body position. For example, the German Mercedes-Benz 2000 Cl sports car, when the vehicle is turning, the suspension sensor will immediately detect the body's inclination and lateral acceleration. The computer compares and calculates with the pre-set critical value based on the information of the sensor, and immediately determines at which position how much load is added to the suspension to minimize the inclination of the body.