Elastokinematics and compliance of a rectilinear rear independent suspension

A rectilinear rear independent suspension has a distinct difference from the traditional ones in that its wheel alignment parameters remain invariable in theoretical kinematics. However, they change within a narrow interval during jounce and rebound when the elasticity of parts, especially the rubber bushings, is taken into account. With the aim of investigating the compliance of the rectilinear rear independent suspension, an elastokinematic model is established in accordance with static equilibrium equations and compatibility conditions. The elastokinematic model has 28 unknowns corresponding to the 5 static equilibrium equations and 23 compatibility equations. Different configurations of rubber bushing and the sensitivity of the suspension stiffness to that of the rubber bushing are analysed. The analytical results indicate that the rubber bushings are best mounted close to the knuckle, and the suspension stiffness is sensitive to the compressive stiffness and the torsional stiffness about the z-axis of the rubber bushing. In addition, the results from kinematic and compliance tests not only verified the elastokinematic model but also revealed the excellent wheel alignment capacity of the rectilinear rear independent suspension compared with that of the MacPherson suspension. This work provided the foundations for the engineering design of a rectilinear rear independent suspension.