Research On Characteristics Of Anti-roll Bar And Its Parameter Optimization For Interconnected Air Suspension

Interconnected air suspension(IAS) has a broad prospect for application due to its excellent performance of vibration isolation and car body torsion elimination, but it tends to intensify the body roll under the cornering condition, which to some extent hinders its development and application. As an important anti-roll component of vehicles, anti-roll bar shows a great potential for solving the rolling problem of IAS vehicle. In this paper, research was conducted on the influence of anti-roll bar on IAS vehicle’s roll characteristics and handling stability as well as the optimization of the anti-roll bars’ roll stiffness and structural parameters.First of all, the structure and working principle of IAS and anti-roll bar was briefly introduced, followed by theoretical analysis of the relation between anti-roll bar and IAS vehicle’s roll characteristics and handling stability. Besides, an IAS full car model with 9 DOFs was built based on the theories of thermodynamics and kinetics and was verified through the simulation of double lane change test.Then, the influence of total roll stiffness of the front and rear anti-roll bars, i.e.,Kφb as well as the ratio of the front anti-roll bar’s roll stiffness to the rear anti-roll bar’s roll stiffness, i.e., λ on the roll characteristics and handling stability of IAS vehicle and non-IAS vehicle was comparatively analyzed by means of simulation.The results show that among the roll chacteristics and handling stability indexes, roll angle and roll angluar acceration are mainly affected by Kφb while the tire load tranfer rate of front and rear axles as well as vehicle yaw rate are mainly influenced by λ.More specifically, roll angle is positively related with Kφb while roll angular acceration is negetively related with it; that means an increase of Kφb will generally cause roll angle to decrease and cause roll angular acceration to go up. In addition, it should be noted that, both the influence of Kφb and that of λ on IAS vehicle’s roll characteristics and handling stability appears to be more significant than that on non-IAS vehicle’s roll characteristics and handling stability. After the simulatinganalysis, a testing system comprised of an IAS vehicle platform and some data collection devices was established, via which static and dynamic roll characteristics experiments were carried out respectively on IAS vehicle with no stabilizer bar dismantled, only rear stabilizer bar dismantled and all stabilizer bars dismantled.Finally, a multi-objective roll stiffness optimization model of the front and rear anti-roll bars in an IAS vehicle was established, and then it was converted into a single-objective model by means of an improved linear weighted sum method of which the weights are changeable under different conditions. After that, the single-objective model was solved using genetic algorithm. The result indicates that the optimal Kφb and λ are respectively 1563 N·m/deg and 3, which means the optimal roll stiffness of front and rear anti-roll bars are respectively 1172 N·m/deg and 391N·m/deg. To analyze the optimization results, double lane change condition simulating tests were comparatively conducted on the IAS vehicle equipped with the optimal anti-roll bar and the original one.