Various automobile suspensions and their advantages and disadvantages.

There are two kinds of suspension of modern cars, one is passive suspension and the other is active suspension.

Passive suspension, that is, traditional suspension, consists of spring, shock absorber (shock absorber cylinder) and guiding mechanism, in which the spring mainly plays the role of slowing down the impact force and the shock absorber mainly plays the role of damping vibration. Because this kind of suspension is driven by external force, it is called driven suspension. Because the starting point of passive suspension design is to compromise between vehicle ride comfort and handling stability, for different use requirements, secondary performance can only be sacrificed on the basis of meeting the main performance requirements. The advantages of passive suspension are low cost and high reliability. The disadvantage is that the contradictory requirements between ride comfort and handling stability cannot be solved at the same time. Rigid helical springs keep the wheels in contact with the road surface, improving the tire's grip on the ground. But the disadvantage of doing so is that there is a strong sense of bumps when riding. The soft coil spring is used to adapt to the rugged road surface and improve the stability and comfort when riding. But this kind of car has poor handling.

In the control link of active suspension, a device that can produce twitch is installed, and the force suppression method is used to suppress the impact of road surface on the car body and the tilting force of the car body. This kind of suspension is called active suspension because it can generate force by itself. Active suspension is a new type of suspension controlled by computer. It has a power source that can generate a force, and the actuator can transmit this force and work continuously. It has all kinds of sensors, and concentrates the relevant data on a microcomputer to operate and determine the control mode. Therefore, active suspension is a complex high-tech device, which combines mechanical and electronic technical knowledge. The advantage of using active suspension is that it can control roll, pitch, yaw and body more quickly and accurately, improve the stability of high-speed driving and cornering, and reduce body roll. When braking, the body leans forward slightly, and starting and rapid acceleration can reduce the backward tilt. Even on bad roads, the car body bounces less and the adhesion of tires to the ground is improved. Disadvantages are complex equipment, high technical requirements and high price.

There is also a semi-active suspension, which can be regarded as a suspension system with variable characteristics composed of springs and shock absorbers. Although it can't be optimally controlled and adjusted by external input, it can adjust the stiffness of the spring and the damping state of the shock absorber under various conditions according to the optimal parameter instructions of the optimal spring and shock absorber stored in the computer. Advantages and disadvantages are between passive suspension and active suspension.