Improvement of Vehicle Handling by an Integrated Control System of 6WS and ESP With Fuzzy Logic Approach

In this paper, a 6-wheel steering vehicle (6WS) was studied as a template by using a 2 degree of freedom model (experimental). To control this vehicle, a two-level controller was employed. High level consists of an open and a close loop controllers. The open loop is a 6WS fuzzy controller that adjusts the angle of rear tires according to the angle of front tires. Also the close loop is the electronic stability program (ESP) fuzzy controller which acts on the brake system to generate a corrective yaw moment. The resultant yaw moment guides the vehicle back to the desired track when it is deviating from its track. Performances of these two controllers in parallel situations result in enhancement of the directional stability property. A P-Action controller was used as a low level controller to regulate the proportional parameters. The results were compared with a vehicle which has a very high lateral stiffness and infinitesimal slipping on turning or maneuvering (reference). This allows us to measure the amount of slipping in our experimental vehicle correctly. The results demonstrated a significant enhancement.