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The study in the paper is aimed to develop a yaw stability controller (YSC) by way of actively dynamic distribution of the longitudinal tire forces, which is considered to be one of the promising means of chassis control, so as to substantially improve the vehicle active safety even under some critical conditions. The control law, which ensures the vehicle follow the desired dynamic model via the feedforward control of side slip angle and the fuzzy control of the errors between the desired states and the corresponding practical ones, has been designed and implemented by using the hardware-in-the-loop (HiL) simulation technology under the Matlab/Simulink environment.

An EV prototype, with all the wheels respectively driven by 4 inwheel motors, is developed, and undergoes a series of practical measurements and road tests. Based on the obtained vehicle parameters, a multi-body dynamics model is built by using SolidWorks and Adams/Car, and then validated by track test data. The virtual prototype is served as the control plant in simulation. An adaptive fractional order PID (A-FO-PID) controller is designed to enhance the handling and stability performance of the EV. Considering the model uncertainties, e.g. the variation in body mass distribution and the consequent change in yaw moment of inertial, a Parameter Self-Adjusting Differential Evolution (PSA-DE) algorithm is adopted for tuning the controller parameters, i.e. KP, KI, KD, λ and μ. As a modification of traditional DE algorithm, the so-called Variance of Population’s Fitness is utilized to evaluate the diversity of the population.