Study On The Anti-rollover Model And Control Method Based On Torsionally Flexible Structure Of Tractor Semi-trailer

Tractor Semi-trailer is playing an increasingly important role in the transportation inrecent years in China because of its large capacity and low cost comparing with othersingle unit heavy vehicles. However, it is easily to rollover because of its owncharacteristics such as the high position of centroid and the narrow track. This paperestablished a torsionally flexible model of a five-axle tractor semi-trailer, and used linearquadratic gauss optimal control method to improve the roll stability.The main contents of this paper are as follows:Firstly, the mechanics of quasi-static roll stability which has a strong relationship withactual occurrence of rollover was analyzed, and the active anti-roll control system helpingpreventing the occurrence of rollover was summarized.Secondly, a state space model for the roll dynamics of tractor semi-trailer was derived.In order to set up a model of this complex system, the derivation started from the generalmodel of rigid body motion. By several assumptions and extensions, the linear model of atorsionally rigid tractor was derived. Finally, the model is further expanded to set upequations of motion of a torsionally flexible tractor semi-trailer considering the influenceof torsionally flexible body.Thirdly, the controllability was analyzed and the controllability referred to use rolltorque generated by active anti-roll bars to regulate lateral load transfer and roll motions.The control objective was to balance the load transfer on all axis using active anti-roll barcontrolled with liner quadratic gauss (LQG) control method.Finally, the model of torsionally flexible tractor semi-trailer was simulated under thecondition of the fishhook input, J-turn input and double-lane change input. It can be drawnfrom the simulation results that the roll stability was distinctly improved by the optimalcontrol strategy.