Modeling of McPherson System

The McPherson strut suspension is a very popular mechanism for independent

front suspension of street cars and was invented by Earl McPherson in the 1940 . It was first introduced on the 1949 Ford Vedette, and also adopted in the 1951 Ford Consul, and then

become one of the dominating suspension systems because it’s compactness

and has a low cost.

Let's learn to model this system as an inverted slider mechanism.

This image represents the kinematics model of McPherson suspension system.

Let's assume

length of link 1 = a

length of link 2 = b

length of link 3 = c

length of link NB = d

Considering M = (0,0) we can find out the other co-ordinates

A= (b cosθ2, b sinθ2)

N= (a,0)

B= (a + d cosθ4, d sinθ4)

Coordinates of A in terms of link 3 (c) = (a + d cosθ4 -c sinθ4 ,d sinθ4-c cosθ4)

b cosθ2 = a + d cosθ4 -c sinθ4

b sinθ2 = d sinθ4-c cosθ4

These two equations can be solved easily.