Design And Realization Of Electronic Control Unit For Air Suspension Based On Height Adjustment Of Automotive Body

Suspension is closely related to vehicle's driving smoothness and handing stability.Passive suspension can not change its parameters with load,speed or road conditions and other unpredictable factors,makes it difficult to satisfy the requirements of driving smoothness and handing stability.Electronically controlled semi-active suspension was composed by the electronic control unit,adjustable height air spring and the adjustable damping absorber.Electronic control unit calculated the regulating amount rapidly with the external environment,and then filled and deflated the air spring to realize the adjustment of body height and the absorber damping,so that the parameters of suspension system with the external environment can change automatically regulation,and thus meet the requirements of the stability and smoothness.Electronically controlled air suspension will become an inevitable trend in vehicle suspension technology in China and have a broad prospects.At present,electronically controlled air suspension for the study is mainly based on the stiffness of the air spring,but because of the stiffness control structure is more complex and more energy consumption,so there is not yet a mature product used in the market.In this paper,by the filled and deflated the air springs test,identified the relationship of the stiffness-the time-the height,and based on the test data processed simulation,compare and analysis between stiffness adjustment and height adjustment these two air springs,drew that the latter is better,and there are easy to achieve,energy-saving,simple structure these advantages.This article design and develop the electronic control unit based on the height adjustment air suspension-the core content of the full text.The control unit chooses the MC9S08GB60 MCU by Freescale company as the core,the peripheral circuits,included height signal detect circuit,speed signal detect circuit,output drive circuit,power circuit,communication circuit etc.In the external circuit design the expandability and generality of the controller have been considered,so that it can be suitable for many other applications.In the course of developing the software system,according to the principle of reliability and practicability,configuration and modularization design method were adopted,Takes into account the controller will be used for more serious conditions,it is the system software and hardware to carry out the anti-jamming design.In the upshot,by detecting the electronic circuit board and study the results of the vehicle road test and compared electronically controlled air suspension with passive suspension, experiments show that the electronic control unit can effectively and timely change the height and absorber damping according to detecting signals,improved the driving smoothness and handing stability,so the result of test is ideal.