Improvement of vehicle handling by an integrated control system of four wheel steering and ESP with fuzzy logic approach

In this paper, a 4 wheel steering vehicle (4WS) was used as template by bicycle model and using 3 degree of freedom system (experimental). The dynamics governing the Yaw/Roll behavior of a vehicle has been simulated with MATLAB/SIMULINK software. To control this vehicle a controller with two levels was considered. High level: 4WS fuzzy controller that adjusts the rear angle of tires according to the front angle of tires and the electronic stability program (ESP) fuzzy controller which acts on the brake system to generate a corrective yaw moment that guides the vehicle back to the desired track when vehicle is deviating from its track. Two of them worked in parallel actions; consequently, the directional stability property was enhanced. Low level: P- action controllers were used to optimize the results. The results was investigated with vehicle has a very high lateral stiffness which there is infinitesimal slipped on turning or maneuvering (reference), this allows us to correctly identify the amount of slipping in our experimental vehicle, finally, all results was compared with a 2 wheel steering vehicle uncontrolled and a 4 wheel steering vehicle controlled. The results are promising and showed us enhancement significantly.