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Ride performance characteristics of a road vehicle involving different suspension system layouts are investigated. The suspension layouts consist of conventional rectangular 4-wheel, novel diamond-shaped 4-wheel, triangular 3-wheel and inverse-triangular 3-wheel. A generalized full-vehicle model integrating different suspension system layouts is formulated. The fundamental suspension properties are compared in terms of bounce-, roll- and pitch-mode. The ride dynamic responses and power consumption characteristics are explored under two measured road roughness excitations and a range of vehicle speeds. The results demonstrate that the novel diamond-shaped suspension system layout could yield significantly enhanced vehicle ride performance in an energy-saving manner.

This study proposes a novel semi-active hydro-pneumatic suspension design and investigates its performance potentials. The proposed new semi-active suspension design involves pneumatic interconnection between the front and rear suspension struts of the vehicle. The analytical formulations of suspension forces due to two suspension configurations, a passive unconnected and the proposed semi-active interconnected, are derived to analyze suspension properties. Based on a validated pitch-plane vehicle braking model, vehicle dynamic responses are conducted under a range of measured road roughness excitations and driving speeds, as well as braking inputs.

In a conventional vehicle, the longitudinal shocks caused by the road obstacles cannot be effectively absorbed due to the fact that the longitudinal connections between the chassis and wheels are typically very stiff compared with the vertical strut where the regular spring is mounted. To overcome this limitation, a concept design of a planar suspension system (PSS) is proposed. The rather stiff longitudinal linkages are replaced by a spring-damping strut in a PSS so that the vibration along any direction in the wheel plane can be effectively isolated. For a vehicle with such suspension systems, the wheels can move forth and back with respect to the chassis. The wheelbase and load distribution at the front and rear wheels can change as a consequence of the implementation of the PSS on a vehicle. The planar system can induce changes in the vehicle dynamic behavior. This paper presents the overview introduction of a dynamic study of a vehicle with such suspension systems.

This paper proposes a vehicle performance/safety method using combined active steering and differential braking to achieve yaw stability and rollover avoidance. The advantages and disadvantages of active steering and differential braking control methods are identified under a variety of input signals, such as J-turn, sinusoidal, and fishhook inputs by using the implemented linear 4 DOF model. Also, the nonlinear model of the vehicle is evaluated and verified through individual and integrated controller. Each controller gives the correction steering angle and correction moment to the simplified steering and braking actuators. The integrated active steering and differential braking control are shown to be most efficient in achieving yaw stability and rollover avoidance, while active steering and differential braking control has been shown to improve the vehicle performance and safety only in yaw stability and rollover avoidance, respectively.

The on-road lateral stability of an articulated steer vehicle is investigated for both small and high deviations. First, for small deviations, a linear model of the vehicle is devised and analyzed. This planar model is generated based on some simplifying assumptions. For instance, the equations describing the tire forces and moments are linearized, and the tire rolling resistance is neglected. A linear stability analysis of the straight line motion of the vehicle with constant forward speed is conducted by using this simplified model for different values of the torsional stiffness and damping at the articulation joint. To investigate the lateral stability of the vehicle at higher deviations, the motion of a virtual prototype of the vehicle in ADAMS/View is simulated for different conditions. Finally, the results from the simulations and the linear stability analyses are compared.