Adaptive Or Active Suspension System Engineering Essay

Adaptive Or Active Suspension System Engineering Essay What is the use of a suspension system. Its main task is to provide a safe and stable ride for the vehicle. The components are usually passive force elements as they provide a nice trade-off between wear, stability and comfort. Suspension system dampens the shocks and does not allow the jerks to be transmitted to the human body. By selecting the right spring and damper properties, the suspension functions as a barrier to the jerks and only passes those frequencies which come in comfortable range for humans. But at the same time the wheel load variation must be minimum as we need contact of tire with road at all times. A system of links connects the un-sprung mass (wheel, brake, steering hub) to the sprung mass (car body). However there is a trade off at the cornering, as the spring should be stiff enough to avoid over roll of the body. Sometimes an anti-roll bar is used to overcome the exaggerated roll due to damping in corners. However the stiffness of the roll bar is not independe nt as we cannot transmit vibrations of one wheel to the other. The traditional suspension will tilt the tire while cornering. This is because the linkage rotates and the tire connected to it also rotates. This causes the area of contact of the tire to reduce while cornering or turning. This results in the loss of grip and massive body roll of the vehicle. In case of cornering the requirement usually is to get a so-called counter camber. The negative camber angle will cause a favorable deformation of the contact patch, which in combination with the unfavorable deformation due to the cornering forces will lead to a desirable contact patch between the tire and the road. Examples of today’s suspension systems which provide a negative camber are the double wish-bone and the McPherson suspension system. Non-zero static camber can also improve the cornering and bump control of the vehicle. Active Suspension system An active suspension system can prevent suspension travel under a var ying load, theoretically without consuming energy. That is why it is very suitable for leveling car during accelerating, braking and cornering, or for taking care of static load variations. And as these systems are computer-aided, there mathematical models can be fed to a controller to level the car or to improve the comfort level. Design and Working While cornering the average force per suspension strut varies from the static value and its length remains equal as to eliminate body roll. By using the principle of a lever, the varying load can be counter-balanced by a constant force by varying distance from the fulcrum. This system perfectly eliminates body roll and the system would not rotate. Because all relevant forces are perpendicular to the direction of adjustment of the fulcrum and constant force, the adjustment will not cost any energy. A possible application of this principle is shown below: The pre-tensioned secondary spring (inner one) is maximally assisting the primary sp ring (outer one). Initially, the adjustable arms are positioned at an angle of 90Â ° with respect to the position in figure above in order to not produce any torque around the fulcrum. Fulcrum here is the hollow hole on the right side which will get attached to the chassis of the vehicle. This type of system is called a trailing arm suspension system.