Kinematics & compliance analysis of double wishbone air suspension with frictions and joint clearances

Currently available suspension kinematics and compliance (K&C) model is mainly used for qualitative analysis rather than quantitative analysis. In order to reproduce actual suspension K&C characteristic, all the suspension components need to take into account as much details as possible. Suspension stiffness non-linearity, suspension components friction and kinematic joint clearances are examples of how the component models can be made more specific. This paper proposes a modeling technique that can not only reliably represent the hysteretic characteristic but also analyze the effect of joint clearances. The suspension air spring model and bushing model are composed of nonlinear elastic force and Berg's friction force. The suspension supporting components are modeled as flexible bodies. The suspension parameter identification and model validation are also proposed. The test procedure of a new K&C test rig based on non-contact binocular vision system is introduced and the simulation results are compared with the experimental results. Results from tests show good agreement between the proposed suspension model and experimental data. Effects of the suspension components friction and clearance joints are investigated. This type of study can provide useful information on the vehicle design, analysis and optimization.