Modelling and Simulation of the Rolling Dynamics of a Tractor-Trailer Truck Vehicle

In this work, a 6 degree-of-freedom analytical model that describes the rolling dynamics of an articulated heavy-duty vehicle composed by a tractor and a trailer was developed and numerically simulated. The behaviour of a typical medium-duty truck-trailer set was evaluated in two common traffic manoeuvres, namely, performing a constant steering wheel angle curve and a change of direction, both at constant velocity (36 km/h). In the latter case, in order to simulate a sudden change, steering amplitude ranging from zero to 30° was imposed to the front wheels through a step function during 2 s. Results of the first trial revealed that the tractor roll angle presents a peak of 2.6° and achieves a steady value of 0.8° respectively at 4 and 20 s after the beginning of the manoeuvre. Roll angle amplitudes of the trailer, spanning from −0.015 to 0.023° (a negative value means the vehicle is leaning inwards at the curve), revealed an oscillatory characteristic, before reaching a stable value of 0.0025° in about 15 s. In the second trial, roll angles of both tractor and trailer reach maximum values higher than those of the previous test (respectively 11.5 and −0.5°); in addition, the oscillatory movement of the trailer was enhanced, since positive and negative roll angles alternated five times until both units return to a steady (zero roll angle) condition after about 20 s from the beginning of the manoeuvre. Those results are compatible with the expected behaviour of actual vehicles, thus suggesting that the proposed model can be tailored to include other truck-trailer configurations and manoeuvres.