Search Results

The paper builds the non-linear vehicle dynamic model firstly, and the lateral stability region of the vehicle considering steering is estimated based on lyapunov function. Stable equilibrium points of non-straight driving are obtained and the lyapunov function matrix is reconstructed which prove that the closed-loop system composed of yaw rate and lateral velocity is satisfied with negative definite property. The simulation results show that the estimated system stability region is satisfied with handling stability on different roads, steering angle and longitudinal velocity.

The paper proposes an energy-oriented torque allocation strategy to reduce the energy consumption of four-wheel independent driving (4WID) electric vehicles (EVs). To compute its energy efficiency accurately, the measured efficiency map is fitted by the cubic spline interpolation method. The energy-oriented torque allocation strategy is designed by minimizing the energy consumption during vehicle driving and braking. According to the varying requirement of torque and speed, the torque of front and rear axle cab be allocated dynamically by adjusting the torque allocation coefficients. To ensure the high efficiency of motors and reduce the energy consumption caused by current shock, the torque allocation coefficients are obtained from two kinds of sub strategies. A fuzzy logic controller is designed to combine the derived torque allocation coefficient above, by adopting Mamdani structure with 2 inputs and 1 output.

This paper proposes a semi-active hybrid battery system (HBS), composed by lithium iron phosphate battery (LFP) and lithium titanate battery (LTO) for electric vehicle (EV) to reduce the life cycle cost of energy storage system. Firstly, the topology of this HBS is introduced. The high energy-density battery, LFP is adopted as the primary energy source, while the high power-density one, LTO is connected in parallel with a bidirectional DC-DC converter and used as secondary energy source to extend the lifetime of HBS by reducing the current stress of LFP. The dynamic model of this HBS is built, in which, the LFP and LTO are both modeled as second-order RC model. In addition, dynamic semi-empirical degradation model of the LFP battery is chosen to estimate the lifetime of HBS. Secondly, a fuzzy logic controller with 3 inputs and 1 output is proposed to decide the power split between the primary and secondary power sources.

Knowledge of vehicle dynamics variables is very important for vehicle control systems that aim to improve handling characteristics and passenger safety. However for both technical and economical reasons some fundamental data (e.g., Lateral tire-road forces and vehicle sideslip angle) are difficult to measure in a standard car. This paper proposes a novel Interacting Multiple Model Filter-Based method to estimate lateral tire-road forces by utilizing real-time measurements. The estimation method of lateral tire-road forces is based on an interacting multiple model (IMM) filter that integrates in-vehicle sensors of in-wheel-motor-driven electric vehicles to adaptively adjusted multiple vehicle-road system models to match variable driving conditions. A four-wheel nonlinear vehicle dynamics model (NVDM) is built considering extended roll dynamics and load transfer.