Research On Semi-active Suspension Control Algorithms

With the development of technology,vehicles become more and more intelligent.Both manufacturers and consumers put forward higher requirements for performance of vehicles.Because the traditional passive suspension cannot take into account the requirements of vehicle handling stability and ride comfort,the concept of active suspension is proposed.It can adjust the damping and stiffness coefficient of the system according to the running state,vibration characteristics and external excitation of the vehicle,and improve the suspension performance significantly,but it has some problems such as high cost,high energy consumption,etc.The performance of semi-active suspension is close to that of active suspension,and it has less energy consumption,lower cost,simple structure and easy to realize than active suspension.Among them,the structure design and control algorithm design of semi-active suspension are the main contents of the study,and the control algorithm design is the key problem of the study of semi-active suspension.Based on the 1/4 suspension subsystem model and the whole vehicle suspension model,the semi-active suspension control strategies of the whole vehicle were studied in this paper.Firstly,the 1/4 semi-active suspension subsystem model and the C-level random road model were established.The composite control of model reference adaptive control and sliding mode control was adopted.The hybrid model was selected as the reference model,the theory of sliding mode variable structure control was introduced,the sliding mode controller based on the reference model was designed,and the chattering phenomenon was reduced by using the law of constant velocity approach.Matlab/Simulink software was used to simulate the system model under random road excitation.The result shows that the performance of controlled suspension is optimized,and the ride comfort of the vehicle is significantly improved.Secondly,considering that the four suspension subsystems are not independent,but interdependent.And the improvement of suspension subsystem performance cannot represent the improvement of vehicle ride comfort and handling stability.Therefore,based on the optimization of the suspension subsystems,in order to suppress the vibration caused by the four suspension subsystems,the vehicle coordinated control was further realized.The theory of fuzzy mathematics was adopted,fuzzy controller was designed and simulated under the excitation of C-level random road.The result shows that the designed controller can suppress the vertical,pitch and roll vibration of the vehicle,the performance of suspension is improved effectively.Finally,in order to further verify the control effect of the designed controller,the designed controller was simulated under the excitation of discrete impact road.The result shows that the designed controller can optimize the performance evaluation index of the suspension system,and the effectiveness of the controller is verified.