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In this paper, a nonlinear force model of an electromagnetic damper (EMD) is established and the model’s parameters are obtained by experiments. The effect of nonlinear force on vibration control of vehicle suspension system is analyzed by comparing the simulation data. Firstly, according to the mechanical and circuit structure of the EMD, a nonlinear model including electromagnetic force, friction force, and inertial force is established. Based on the EMD bench test, the mechanical parameters of the DC motor and the ball screw are obtained by the least square method. Then a quarter-car model including the electromagnetic suspension is established. By analyzing the transmission rate of the suspension response to the road excitation, the nonlinear force of the EMD shows an obvious influence on the high-frequency vibration performance of the suspension.

In this paper, a new roll-plane hydraulically interconnected suspension (HIS) system is proposed to enhance the roll and lateral dynamics of a two-axle bus. It is well-known that the suspension tuning is of great importance in the design process and has also been explored in a number of studies, while only minimal efforts have been made for suspension tuning for the newly proposed HIS system especially considering lateral stability. This study aims to explore lateral dynamics and suspension tuning of a two-axle bus with HIS system, which could also provide valuable information for roll dynamics analysis. Based on a ten-DOFs lumped-mass full-car model of a bus either integrating transient mechanical-hydraulic model for HIS or the traditional suspension components, three newly promoted parameters of HIS system are defined and analyzed-namely the total roll stiffness (TRS), roll stiffness distribution ratio (RSDR) and roll-plane damping (RPD).

The vibration and instability experienced in an ambulance can lead to secondary injury to a patient and discourage a paramedic from emergency care. This paper presents a hydraulically interconnected suspension (HIS) system which can achieve enhanced cooperative control of roll, pitch and bounce motion modes to improve the ambulance's ride comfort and handling performance. A lumped-mass model integrated with a mechanical and hydraulic coupled system is developed by using free-body diagram and transfer matrix methods. The mechanical-fluid boundary condition in the double-acting cylinders is modelled as an external force on the mechanical system and a moving boundary on the fluid system. A special modal analysis method is employed to reveal the vibration characteristics of the ambulance with the HIS.