Analysis of vertical dynamic characteristics of hub direct drive air suspension system

To solve the problems of unsprung with increasing mass and unbalanced electromagnetic force of motor, the vertical dynamic characteristics of hub direct drive air suspension（HDD-AS） system was analyzed. The coupling model of in-wheel-motor and air suspension with auxiliary chamber was established. With the coupling effect of road excitation and unbalanced electromagnetic force, variation trends of eccentricity, unbalanced electromagnetic force, sprung mass acceleration, suspension dynamic travel, tire dynamic load and RMS value of unsprung mass acceleration in HDD-AS system were analyzed. The effects of auxiliary chamber volume and damping coefficient on eccentricity, sprung mass acceleration, suspension dynamic travel, tire dynamic load and unsprung mass acceleration in frequency domain were also investigated. The results show that the auxiliary chamber volume and the damping coefficient have great influence on suspension performance and in-wheel-motor vibration of HDD-AS system.