Research On Vehicle Suspension System Control Based On Pneumatic Artificial Muscle Theory

With the rapid development of transportation network,travel convenience and comfort have become a very concerned issue.As an important means of transportation,large and medium-sized passenger cars occupy an increasing proportion in China year by year,and their importance is self-evident.Vehicle suspension system directly affects the ride comfort and safety of driver and passenger.Passive suspension system has poor adaptability to different road surfaces due to its fixed parameters.Active suspension system consumes huge energy and has poor economy.Semi-active suspension system takes into account both energy consumption and performance and has a large development space,which has huge potential and broad development prospects.This paper takes medium-sized passenger car as research object,combines relevant research in bionics field,applies the theory of Pneumatic Artificial Muscle(hereinafter referred to as PAM)to semi-active suspension system of vehicle,and carries out dynamic characteristics analysis and control strategy research of vehicle suspension and seat suspension system.By analyzing the static and dynamic models of PAM,the influence of internal air pressure on its dynamic characteristics is studied.The results show that the higher the effective air pressure of internal airbag,the greater the output force and the stronger the nonlinearity.According to the relevant theories of system dynamics,the mathematical models of vehicle semi-active suspension system and seat suspension system are established.A fuzzy PID control strategy based on PAM theory is proposed for vehicle semiactive air suspension system.The experimental results show that compared with passive suspension,the vertical acceleration of vehicle body decreases by 72%,the dynamic load of wheel decreases by 41.2%,and the peak power spectral density decreases significantly,which indicates that it is effective for improving ride comfort.To further improve the ride comfort of the vehicle,a friction feed-forward compensation adaptive seat suspension system controller is designed for the seat suspension system,taking into account the multiple non-linear factors of man-seat and PAM.The experimental results show that compared with passive suspension,the vertical acceleration and displacement of the human body are reduced by 78% and 26%,respectively,and the ride comfort of the driver is improved from extremely uncomfortable to uncomfortable.Frequency domain simulation results show that,in the frequency range of 3～25Hz,the damage to human organs caused by continuous vibration is effectively reduced.Friction feedforward adaptive control of seat suspension system further optimizes various indexes.It can be seen that the suspension control method proposed in this paper is effective in improving ride comfort and safety of vehicle suspension system.