Research On Joint Control Of Vehicle Based On Semi-active Suspension

The performance of suspension system is the key to the ride comfort and handling stability of automobile,and it is also the foundation to ensure the good driving performance of automobile.Compared with passive suspension and active suspension,semi-active suspension has the advantages of excellent control quality,low price and simple structure,which can be industrialized in a short time and has great potential in the automotive field.Semi-active suspension is mainly researched from two parts: optimizing hardware and improving control strategy.At present,the hardware optimization technology is basically mature,but there are still some difficult problems in the research of control strategy.Therefore,designing a controller with excellent control effect has become a hot spot in current research.Taking suspension control as the breakthrough point and making the suspension system adapt to different road conditions and speeds,the application of modern control theory in automobile suspension system was deeply studied,and the existing control strategy was improved and verified by experiments combined with actual vehicles.First of all,in order to truly and accurately reflect the pavement conditions with approximately constant pavement spectrum in the low frequency range and simulate the pavement conditions to the greatest extent,the random process theory were introduced,and the single-wheel and fourwheel pavement models was established in Matlab software,and the spectral density curves were compared to verify their effectiveness.Secondly,in order to ensure that the suspension performance was reflected in the controller design process,a 1/4 semi-active suspension system dynamic model was established.According to the actual demand of the suspension system for estimating high-precision parameters,an adaptive inversion slip film controller was designed by planning a reasonable adaptive law through the inversion design concept.At the same time,the stability of the algorithm was proved by theory,and the effectiveness of the algorithm was proved by simulation.Finally,because the performance of local suspension system cannot replace the performance of the whole vehicle,in order to improve the performance of the whole vehicle,the car model was created in Carsim and the double-shift test was carried out Based on the sliding film control of four quarter suspension subsystems,the fuzzy controller was used to coordinate and control the whole vehicle in vertical,roll and pitch directions.A cosimulation platform of Carsim vehicle model and Matlab is established,and the control effect of the controller was verified by C-class road test,speed bump test and double shift test.The results show that the designed controller can optimize the evaluation indexes such as vertical acceleration,pitch acceleration,roll angle and roll angle acceleration at the center of mass of the vehicle,control the suspension of the whole vehicle well,and improve the ride comfort and handling stability of the whole vehicle.