The Optimized Design Of The Front And Rear Steering Trapezoid Of The Commercial Vehicle

The rapid development of electronic technology promotes the innovation of theautomotive technology. Consumers need the cars which are safer and morecomfortable. The vehicles of4ws can catch the trend. The control technology hasbecome more and more mature, which maintains the reliability of the four-wheelsteering technology. All the wheels of the vehicles of4ws are steering wheels, andrear steering wheel can be controlled according to the requirements of the controlstrategy. When the vehicles pass through the narrow roads, the rear wheels rotate inthe opposite direction with the front wheels to reduce the turning radius andimprove the vehicle passing ability. When the vehicles are at high speed, the rearwheels rotate in the same direction with the front wheels to improve the handlingstability.As for the commercial vehicle of four-wheel steering, the plane model, spatialmodel and ADAMS model of the steering trapezoid are established. There are twomethods to determine the parameters of plane model that are the traditional methodsand improved methods. As for the plane model, the three-dimensional model andthe ADAMS model, the relationship of the steering angles of inner wheel and outerwheel are compared. The relationship of angles of inner and outer steering wheelsof the optimized plane model and the relationship of angles of inner and outersteering wheels of the spatial model match with each other.Based on the parameters of the trapezoid arm length and trapezoid corner, theevaluation function is established to ensure that the vehicle in the front steering statehas the actual and ideal steering degrees as close as possible. Simulation analysisshows that the value of the evaluation function is sensitive to the front trapezoidcorner. The original and the optimized trapezoids are compared and the optimizedtrapezoid is better in the graphical method.The reasons of the steering deviation of the instantaneous center are analyzed,and the evaluation function based on the rear trapezoid parameters is established.The optimal parameters of the steering trapezoid are gained, using Matlab functionfmincon. A three-dimensional surface plot and a contour map are gained. The results show that the evaluation function is mainly determined by the value of the trapezoidcorner.The degrees of steering wheels and the steering trapezoid of the commercialvehicle parameters can determine the deviation of the instantaneous center, andchoose the proper relationship of the turning degree of the front and rear steeringwheels is the key to reduce the amount of wear. The effects of lateral force andwheel alignment parameters on the instantaneous center bias remains are to bestudied.