Optimization of rollover stability for a three-wheeler vehicle

An auto rickshaw is a three-wheeled motor vehicle commonly found in Asia, with one front steering wheel and two driven wheels at the back. In automobiles, suspension is used to keep the wheels planted during motion. The trailing arm suspension generally found in Indian automobiles has its roll center on the ground. The vehicle＇s center of gravity is above the ground, which creates a moment during vehicle turning known as the roll moment. When this roll moment exceeds a certain limit, the vehicle becomes unstable. Roll rate can be expressed as degrees per lateral acceleration of the vehicle＇s sprung mass, and is influenced by factors such as wheel rate, motion ratio, and suspension rate. In order to determine an optimized three-wheeler suspension setup, a matrix selection method was used, in which every available suspension type in the market is rated based on selected suspension parameters such as handling, dynamics, and simplicity. From the overall weightage, each suspension type is analyzed and the most appropriate is selected. In order to achieve the objective of improving the overall rollover stability, certain modifications have been applied in the selected suspension design. Generally, if the roll rate of a specific vehicle axle is high, the percentage of weight transfer on the axle will also be high. By improving roll stiffness, the amount of roll can be decreased, and by optimizing the motion ratio, the roll moment can be controlled, thereby increasing the overall rollover stability.

Integrated yaw and rollover control based on differential braking for off-road vehicles with mechanical elastic wheel

Aiming at the issue of yaw and rollover stability control for off-road vehicles with non-pneumatic mechanical elastic wheel(MEW),an integrated control system based on fuzzy differential braking is developed.By simplifying the structure of the MEW,a corresponding fitting brush tire model is constructed and its longitudinal and lateral tire force expressions are set up,respectively.Then,a nonlinear vehicle simulation model with MEW is established to validate the proposed control scheme based on Carsim.The designed yaw and rollover control system is a two-level structure with the upper additional moment controller,which utilizes a predictive load transfer ratio(PLTR)as the rollover index.In order to design the upper integrated control algorithm,fuzzy proportional-integral-derivative(PID)is adopted to coordinate the yaw and rollover control,simultaneously.And the lower control allocator realizes the additional moment to the vehicle by differential braking.Finally,a Carsim-simulink co-simulation model is constructed,and simulation results show that the integrated control system could improve the vehicle yaw and roll stability,and prevent rollover happening.