Research And Development Of Vehicle Height Control Base On Hydro-penumatic Suspension

Suspension system is an indispensable part of modern vehicles.Hydro-pneumatic suspension can improve the smoothness and stability of vehicles,and it can solve many problems encountered in practical applications of special vehicles,engineering vehicles and military vehicles.This paper focuses on the research and development of a certain type of vehicle's oil-gas suspension height-adjusting system.It gives a practical solution for a suspension system and the hei ghtadjusting system,including a design matching its K&C characteristics,a mathematical model of the suspension height-adjusting system and its control strategy.The work has important engineering value for the development of heavy-duty vehicles.The suspension system of the hydro-pneumatic suspension was designed.According to the functional requirements and technical specifications,the suspension system was designed,including the design of the elastic damping element scheme,the design of the height-adjustment system,and the design of the guide mechanism.The functional requirements of the vehicle height-adjustment system were analyzed,and then the detailed design of the vehicle height-adjustment system based on the hydro-pneumatic suspension was completed.The performance parameters of the system are determined and the design of the technical parameters of various systems are completed such as the hydro-pneumatic suspension system,elevation control system,and hydraulic power unit.The paper has studied the suspension system's K&C characteristics matching and analysis method,carried out the matching design and calculation of elastic characteristics and damping characteristics,established a 1/4 model of the vehicle,and studied the elasticity characteristics,accumulator matching,calculation of stiffness characteristics,ride comfort simulation and other methods.The matching solution is analyzed via simulation.The control strategy of the suspension system for oil and gas suspension was studied.A 7-degree-of-freedom mathematical simulation model was established for the high-adjustment system of the complete vehicle for the oil-gas suspension,and the road was mathematically modeled.Based on the sliding mode control and the model predictive control algorithm,the vehicle's height adjustment controller is designed.The simulation analysis of the control algorithm under different operating conditions shows that the designed sliding mode controller has good robustness when the vehicle parameters change.The vehicle height can be controlled under different parameters.A joint simulation model of the height adjustment control system for oil and gas vehicles was established to study the influencing factors of the accumulator height parameters,the internal friction of the cylinder,and the characteristics of the proportional solenoid valve.The oil and gas springs were used as test objects to carry out bench tests.The experimental data and the data obtained through the simulation of the mathematical model were analyzed and compared to verify the mathematical model.