Analysis Of Steering Tires Adhesion Improvement Of Formula Student Car Under Extreme Working Conditions

For formula student vehicle, which is always going on cornering and S-shaped autodrome, maneuverability is significant. So the adhesion ability of steering tires is very important. The non-linear characteristics of vehicle tire make the adhesion summit located at a special side slip angle. Usually the drivers judge the summit by the steering wheel torque. To improve the adhesion ability of the tire, increase of the adhesion summit and improvement of the steering wheel torque character are needed. Main contents of this paper are listed as follows.To bring the adhesion summit of tire into full play:the relationship between adhesion and tire/rim/camber angle, the relationship between the camber angle and tire temperature has been analyzed based on the FSAE TTC tire data. And the best camber angle has been achieved by vehicle test. Characters of a simple suspension structure have been analyzed, which could change the camber angle and decrease the eccentric wear. The mathematical model of the suspension has been built, witch could calculate the camber angle and kingpin caster angle.To improve the steering wheel torque character:the caster arm length of two kinds of suspension have been compared and analyzed. The steering wheel torque character could be improved by a variable kingpin and the kingpin parameters could be changed by modifying the suspension hard points.Two kinds of suspensions have been modeled in ADAMS. Characters of them have been compared by suspension simulation and full-vehicle simulations. The new suspension has been proved to be able to improve the adhesion effect and the steering wheel torque character.