Research On Characteristics Of Hybrid-interconnected Hydro-Pneumatic Suspension And Analysis Of Ride Comfort

As for engineering vehicle, it is easier to roll over because of its high center of gravity. In order to enhance the handling performance and safety of those vehicles, it is necessary to increase the roll stiffness of suspension. At the same time, in order to maintain the ride comfort, the pitch stiffness and wrap stiffness should be decreased. At present, most of interconnected hydro-pneumatic suspensions will increase the pitch stiffness and warp stiffness while improve the roll stiffness.The research object of this paper is hybrid-interconnected hydro-pneumatic suspension which can provide high roll stiffness as well as small scale of pitch stiffness and warp stiffness. This paper includes following aspects:(1) Build mathematic model of hydraulic components of suspension by considering the change of oil velocity and gas volume in accumulator caused by the motion of vehicle body when vehicle is in running status. Base on the hydraulic model set up the output force characteristic model and nonlinear mathematic stiffness model as well as its damping model of suspension. At the same time, analyze the different of motion mode of vehicle, build the mathematic model of the output force or torque. On the other hand, utilizing AMESim software to verify the accuracy of the mathematic model as well as analyze the output forces of different form of hydro-pneumatic suspensions.(2) Verify design rules for suspension, and set up the mathematic relationship among parameters of hydraulic components and the design rules according to mutual relationship of design rules with stiffness and damping coefficient as well as analyze component parameter's effect for the frequency and damping ratio.(3) Building the dynamics model of vehicle and the road model for the vehicle. According to the theory related to ride comfort, compare the ride comfort of two different form of interconnected hydro-pneumatic suspensions through build co-simulation model by AMESim/Simulink both in random road and pulse input. In addition, this paper applies skyhook control theory for semi-active hybrid-interconnected hydro-pneumatic suspension based on co-simulation to improve the ride comfort of vehicles in pulse input.(4) Analyze the ride comfort of five-axle vehicle which utilize hybrid-interconnected hydro-pneumatic suspension both in random road and pulse input. Analyze influences of accumulator and orifice size for ride comfort.This paper has built the mathematic model of hybrid-interconnected hydro-pneumatic suspension, and compares three different form of suspensions, it is proved that hybrid-interconnected hydro-pneumatic suspension can provide high roll stiffness as well as small scale of pitch stiffness and warp stiffness. Verify the connection between design rules and components parameters, provide a reliable theory for the design of the hybrid-interconnected suspension. This paper also compares two-axle vehicle's ride comfort based on two different forms of suspensions, it's proved that hybrid-interconnected hydro-pneumatic suspension can offer better ride comfort while offer a large scale of roll stiffness, in addition, this paper applied skyhook control theory for semi-active hybrid-interconnected hydro-pneumatic suspension based on co-simulation, which provide a method to come true the semi-active control. Thus, this paper not only shows a theoretical significance but also a practical significance.