Design of Hydraulically Interconnected Suspension Systems for Tri-axle Straight Trucks with Rear Tandem Axle Bogie Suspensions

This study has proposed a new roll-resistant hydraulically interconnected suspension (HIS) system for a tri-axle straight truck with rear tandem axle bogie suspension to suppress the roll motion of truck body. The equations of motion of the mechanical and hydraulic coupling system are established by incorporating the hydraulic forces as external forces into the mechanical subsystem, in which the hydraulic forces are derived using impedance transfer matrix method and related to the state vectors of mechanical subsystem at the boundaries. Based on the derived equations of the coupling system, modal analysis method is employed to investigate the dynamic characteristics, including natural frequencies, mode shapes and dynamic responses. The results indicate that the proposed HIS system can effectively enhance the natural frequencies of truck body pitch and roll modes, and significantly increase the mode damping. The mode shapes of truck body are also changed. The study of dynamic response indicates that the amplitudes corresponding to the oscillation frequencies of truck body and wheel hop modes are heavily restrained. The proposed HIS system is also able to favorably adjust the dynamic load distribution among wheel stations. Furthermore, parametric analysis shows that natural frequencies of truck with HIS system depend on piston surface areas and installation schematics of actuators. Tire dynamic load coefficients can be favorable changed by adjusting the loss coefficients of damper valves.