Dynamics analysis and design methodology of roll-resistant hydraulically interconnected suspensions for tri-axle straight trucks

A new hydraulically interconnected suspension (HIS) system is proposed to enhance the roll dynamics of the tri-axle straight trucks. The impedance of the hydraulic system is derived with impedance transfer matrix method, and integrated to establish the equations of motion of the mechanical and hydraulic coupling system. Based on the obtained equations, the additional mode stiffness/damping of the vehicle body and wheel state forces are explicitly described with the physical parameters of the hydraulic system. The obtained results indicate that the proposed HIS system can be able to independently enhance the mode stiffness/damping, in which the additional bounce/pitch and roll/warp mode stiffness are determined by the difference and summation of the top and the corresponding bottom piston surface area, respectively. The mode damping is caused by the direction and roll damper valves, simultaneously. The later valves alter the mode damping like the accumulators change the mode stiffness. The comparison of dynamic responses between the trucks with the conventional suspension and the HIS system shows that the HIS system can effectively suppress the roll motion of the truck body and favorably reduce the warp mode force for the wheel stations. Finally, the loss coefficients of the damper valves are tuned in terms of dimensionless factors to handle the compromising indices based on the dynamic responses.