Research On Handling Stability And Optimization Of The Centre Axle Trailer Train

The centre axle trailer train consists of towing vehicles and centre axle trailers.Compared with semi-trailer trains,it has a larger volume and lower transportation costs with a good application prospect.However,there are still complex destabilization phenomena for centre axle trailer trains such as folding,tail flicking,and lateral shimmy.Therefore,it is of great significance to study the stability of the centre axle trailer train and improve it for safe driving.In this dissertation,the prototype model of a centre axle trailer train was first established,whose performance under different operating conditions was simulated and analyzed.Based on the analysis of the structural characteristics of the centre axle trailer train,model of vehicle body,steering system,powertrain and other subsystems of the prototype vehicle was built by TruckSim.A single lane change real-vehicle test was set up by using the handling stability test system.The accuracy of the model was verified by comparing the results of the simulation with the actual vehicle.Then the handling stability of the prototype was studied by using steady-state rotation,serpentine,steering wheel angle step input and steering wheel angle pulse input test conditions.Since the optimization of the handling stability affects the passing ability,the curve passability simulation conditions have also been constructed to study the passing ability of the prototype vehicle.Based on the above,the structural parameters of centre axle trailer train were optimized.The sensitivity of the load transfer rate LTR,the peak lateral acceleration a₁of the tractor,the lateral acceleration amplification factor ARA in the single lane change test and the peak yaw rate?₁ of the tractor,the peak yaw rate?₂ of the trailer in the serpentine test was analyzed.Six parameters with higher average contribution to the target response were obtained.Taking the above six parameters as design variables and five responses as objective functions.The design variable variation interval,passability index and understeering degree were used as constraints.The Pareto optimal solution set was obtained by multi-objective optimization with NSGA-II,and the optimal compromise solution was calculated using the combination weighting method.The results show that the peak values of lateral acceleration,yaw rate,lateral slip angle,load transfer rate,etc.of the optimized vehicle under single lane change limit condition are reduced.The research method has guiding significance for the design of centre axle trailer trains.