Research On Structure Optimization And Mechanical Properties Of Double-front Axle Steering Mechanism For A8×8Vehicle

In this paper, an88vehicle with double-front axle steering mechanism wasresearched. But its steering tires were often abnormally wore. In the modification process,the equipment of hub motors led to increased unsprung mass, which made the steeringsystem less reliable and led to abnormal rod damage phenomenon. Some statistics showthat incorrect steering mechanism design is an important factor leading to abnormal tirewear, and the tremendous impact caused by unsprung mass during steering will lead tosteering linkage’s premature damage. Therefore, it was necessary to optimize the structureof the steering mechanism and analyze its stress situation. This research providedoptimization methods and reference materials for structural improvements of the steeringmechanism.Based on the88vehicle, the double-front axle mechanical steering System wastaken as the research object. The kinematic and dynamic property of the steering systemwere analyzed. The research was focused on the modeling of steering suspension system,the simulation of steering performance, the design optimization of steering mechanism andthe mechanical properties’ analysis of some key bars of steering system.Depending on the structure of the double-front axle steering mechanism, themathematical model was derived by using spatial analysis method and the simulation modelwas built in the MATLAB software. At the same time, the virtual prototype modelcomposed by steering system and suspension system was built by using dynamic simulationsoftware ADAMS/VIEW. The above two models can verify each other. Using the twomodels, steering performance was analyzed. The simulation results showed that thereliability of model was high and the model had a certain range to be optimized.Considering the influences on steering errors caused by wheel jump, Using parametricanalysis method, and based on the theory of double-front axle steering, the erroraccumulation between the theoretical value and actual value of the steering wheel’s steeringangle was taken as the objective function. Simulation analysis and structural optimizationwere done by using MATLAB and ADAMS software respectively. The simulation resultsshowed that the steering characteristics of the optimized model were closer to the idealsteering characteristics and the accuracy was further improved.The dynamic simulation analysis was done based on the optimized virtual prototype model by using ADAMS/VIEW software. Research on mechanical properties of steeringmechanism was done at one condition with full load and zero speed and another conditionwith full load and a certain constant speed. The simulation results showed that: when thevehicle was spot steering, the stress of tie rod and drag link was bigger than otherconditions at the common maximum steering angle; when the vehicle was in a constantspeed and had the same steering speed, the stress of each rod increased with the increases ofvehicle’s speed; at the highest speed with a steering angular velocity of400degrees/second,the force value had a sharp increase and instability phenomenon existed; at the samesteering angle with a low constant vehicle speed and a steering angular velocity of250degrees/second, the stress value of each rod was bigger after the equipment of hub motorsthan before; at the same steering angle with a low constant vehicle speed and the equipmentof hub motors, the stress value of each rod was increasing with the increase of steeringspeed; the stress value of each rod was within the design range.