Passenger vehicle air suspension Multibody Dynamics Modeling and Simulation

With the development of urban transport in China, people transit bus ride comfort and handling stability put forward higher requirements. Air suspension can better satisfy this requirement, and the air suspension can also improve the grounding of the tire to reduce road damage, etc., this paper YBL6891H-type air suspension bus as the research object, the use of multi-body dynamics software SIMPACK established multi-body vehicle dynamics model, the road vehicle ride through the experimental verification of the correctness of the model based on the vehicle model in the front and rear damper and air spring and vehicle damping force matches the joint simulation of fuzzy control, and to rubber the impact on vehicle performance bushings and air springs model has been further studied. First, based on the multi-body dynamics theory, according to the kinematic relationship building topology, by measuring, testing, calculation and establishment of three-dimensional model using CATIA and other methods, the quality of the various components obtained parameters, positional parameters and other basic parameters, establishment of multi-body vehicle dynamics model, the vehicle model simulation of random road input, at the same time a smooth road test vehicle to verify the accuracy of the model for further research foundation. Second, multi-body vehicle dynamics model, based on four typical working conditions for damping and air spring before and after the match. Change within a certain range before and after the damping, the results show that the body vertical acceleration, suspension stroke and tire load moving are different. Third, considering the vehicle's vertical, pitch and roll movement, with eight plates vehicle control strategy, in the MATLAB / Simulink to design a vehicle system, fuzzy controller, including the vertical control, pitch control and roll control , and then set up a joint SIMPACK and MATLAB simulation model, simulation results show that fuzzy control based on damping improve the vehicle ride comfort. Finally, detailed analysis of the oriented institutions around the rubber bushing stiffness of the body vertical acceleration, pitch, roll angular acceleration and angular acceleration effects, the results show that the radial stiffness of rubber bush of small, significant stiffness of torsion angle, the anterior longitudinal thrust rod, the first V-thrust rod, bar and after the V-thrust thrust rod and the posterior longitudinal torsion stiffness of rubber bushing in turn increases their impact. On this basis, considering the non-ideal gas on the air spring stiffness, which is based on Van der Waals equation of the re-establishment of the three types of air-spring stiffness model, the introduction of non-ideal gas correction factor improved the model H, to establish model of the air spring stiffness adaptation expanded. 

Key words: SIMPACK, air suspension, combined simulation, rubber bushings, non-ideal gas correction factor