The Design Of Electronical Controlled Air Suspension System On Multi-Axis Vehicle

Electrically controlled air suspension use gradually increased nonlinear air springs as the elastic element.Then,it can get better ride comfort.Through deflated and inflated the air suspension,we can adjust the height of the vehicle.The ideal suspension type is that when we improve the vehicle's high-speed steering we can ensure the traffic ability and the stability of the off-road vehicle at the same time.Multi-axle vehicle suspension is a complex statically indeterminate system.And the multi-axle vehicle requires compact structure and each wheel has the high load.As for those reasons,to design of air suspension will meet more and bigger challenge.For the parameter and requirement of the multi-axle vehicle,the writer have done those following studies redesign the electrically controlled air suspension,model the air suspension,and optimize the parameter of the air suspension and the algorithm of adjusting the height of vehicle.1.Based on aerodynamics,hydrodynamics and thermodynamics,the writer builds the mathematical models of the air suspension.In the LMS Imagine.Lab AMESim,the writer establishes the simulation model of the air spring suspension.Then the writer tests the static and dynamic stiffness of the sample of the air suspension.Next the writer also simulates the sample of the air suspension in AMESim.Through those researches,we can verify the correctness of the simulation model.Finally,we can base on simulation model of the air spring suspension and then build the simulation model of the entire vehicle.2.In MATLAB,the writer builds a semi-vehicle model and use the ARMA to construct the time-domain model with different road roughness conditions.Considering the performance of the varied vehicles and the different road surfaces,we study the comprehensive evaluation method of the vehicle performance.Then we can optimize the parameter of the air suspension.3.In AMESim,we conduct the simulation of the stiffness when the air suspension is in the different heights.Then I fit the simulation curve and input those data to the entire vehicle modeling to simulate the stability of the vehicle.Combining the results of simulation and the evaluation index,we can get the optimal parameter when the air suspension under different conditions.4.In order to solve the problem of adjusting the height of multi-axle vehicle which have the complex statically indeterminate system,I design the fuzzy PID control strategy that conforms the features of the multi-axle vehicle.In Simulink-stateflow,use AMESim vehicle modeling.Then we can achieve the joint simulation of control system and mechanism,finally,the joint simulation can demonstrate the effectiveness of the control strategy.