Determination of normal reactions of the supporting surface during the movement of a modular three-link trailed road train as part of a “car-tractor - two-axle trolley-three-axle semi-trailer” in the braking mode

Abstract

An efficient means of reducing the number of vehicles while maintaining the volume of cargo transportation is the use of trains. Nowadays, trains are used in many countries around the world. Due to their relative structural simplicity and shorter length with the same load capacity, and taking into account a number of other advantages, truck trains have received considerable recognition and are the most widespread in providing freight transportation.
Given the increasing intensity of traffic on modern highways, it is necessary to increase the safety of vehicles in order to avoid accidents that result in deterioration of human health and significant material losses in the damage of vehicles and goods. This issue is particularly acute in the case of car trains, the process of which is much more complicated than the single car. It is necessary for the braking system to regulate the speed of the road train over a wide range, to counter skidding, as well as to prevent the assembly of links of the vehicle and its collision with other cars, that is, providing adequate stability. The driver must as far as possible control the behavior of the vehicle while driving and, if necessary, stop it quickly and safely.
Therefore, improving the performance of road trains in modern driving conditions is one of the priority tasks to ensure a high level of safety of their operation with maximum efficiency of use. Achieving these requirements is possible only subject to possible changes in the technical condition of road trains during operation. In particular, considerable attention should be paid to changes that can occur in the braking system of the link of the train, which can lead to the violation of optimal indicators of regulation and distribution of the braking forces on the axles and sides of the vehicle, which inevitably leads to loss of stability of its movement, even at low speeds, especially at maximum load.

The solution to these problems is impossible without the development of a mathematical model of motion of a modular three-link trailer road train, which would take into account the basic kinematic and geometric ratios, angles of installation of axles, normal reactions of the supporting surface and lateral forces on the wheels of the axles of the links, taking into account their redistribution at axles self-propelled trains in curvilinear and straight-line traffic, as well as the angles of removal of the wheels of the tractor-car, the rolling cart and the semi-trailer.
That is why this work is devoted to the determination of the normal reactions of the reference surface when driving a modular three-link trailer train in the composition "tractor-truck - two-axle rolling cart - three-axle semi-trailer" in braking mode.
Keywords: road train; modular three-link trailer trains; layout diagram; trailed link; trailer; semi-trailer; rolling cart; mathematical model; operational properties; stability; support surface; normal reactions; brake mode.