Research On Three-axle Heavy-duty Truck Handling And Stability Under Typical Gust

In recent years, with the development of engineering construction and transportation,there has been a large demand for heavy-duty truck and the advantages such ashigh load ability, low transportation cost and good economic benefit have expandedits market.Varieties of natural and artificial gust exist prevalently, the problems of automotivehandling and stability under gust get more and more serious, and its importance ofresearch on this field is more and more concerned.As the main sales of heavy-duty truck, three-axle heavy-duty truck occupies a highmarket share. Three-axle heavy truck has lager bulk, longer body, and it is easier tobe affected by the gust and to threaten the safety.Based on the transient process of automobile driving across the entire gust andeffect of gust distributed force on automobile, handling and stability of three-axleheavy-duty truck under typical gust were studied and the rules revealed. Two andthree degree of freedom linear vehicle model and TruckSim nonlinear dynamicmodel were built to study handling and stability of three-axle heavy-duty truck undertypical gust. The aim that simple model reveals the rules and complicated modelclose the actual results was achieved.First, description of effect the typical two-dimensional gust on vehicle wasestablished. The process of the vehicle driving across the gust was described, andtypical unilateral, bilateral and trilateral gusts were defined. Unilateral gust has fiveconfigurations. According to the relationship of gust length and truck body length,bilateral gust had four different work conditions, and trilateral gust had thirteen workconditions. The formula of lateral force and yaw moment forced on vehicle werederived under every gust configuration during the process of vehicle driving.Second, handling and stability of three-axle heavy-duty truck under typical two-dimensional gust was analyzed. Based on the gust force and moment, twodegree of freedom linear model of three-axle automobile was established, andhandling and stability of the truck under two-dimensional gust was analyzed inopen-loop. Typical conditions that affected the truck and its handling and stabilitywere determined. Based on the typical conditions and two degree of freedom linearmodel close-loop model combined road-vehicle–driver, handling and stability of thetruck was analyzed in closed-loop.Finally, handling and stability of three-axle heavy-duty truck under typicalthree-dimensional gust was analyzed. Constant gust and linear gust force andmoment on the vehicle were described, combined the three degree of freedom linearvehicle model, handling and stability of the truck under the typical two gustconfiguration was analyzed in open-loop. The aerodynamic coefficients were gotaccording to the formula of aerodynamic force and moment. The aerodynamic modeland vehicle model were established and handling and stability of the truck undertypical three-dimensional gust was analyzed in TruckSim. The constant gust hadmore effect on the truck and handling and stability of the truck with open-loop andclosed-loop, different drivers and road type was analyzed. The effects of somefactors on handling and stability of the truck under gust were studied.In the process of automobile driving across the gust, differing from previous researchbased on wind speed, handling and stability of three-axle heavy-duty truck wasstudied based on gust distributed force. Handling and stability of the truck undertypical three-dimensional gust was analyzed based on two and three degree offreedom linear vehicle model and TruckSim nonlinear dynamic model. The basicrules were found by the simple model and the actual results were closed bycomplicated model. The research laid the foundation for future study on handling andstability of heavy-duty truck under gust and the exploration research fromsteady-state to transient transformation was done in TruckSim.