To determine the manageability and stability of trailer motion passenger bus train
Abstract
The modern development of public transport leads to an increase in the demand for vehicles of large cities and city buses. As a consequence, truck and city bus manufacturers are now designing high-capacity designs in the form of shared and multi-link vehicles. Yes, the German company Göppel Bus. presented a new city bus with a separate passenger trailer. The advantage of such road trains is the ability to easily vary the capacity of the bus depending on the passenger flow, which changes throughout the day, the ability to reduce economic and environmental costs due to the use of a bus with a trailer during peak hours, and the same bus without a trailer during off-peak hours. However, when creating such road trains, it is necessary to solve a number of practical tasks related, first of all, to their configuration, controllability and stability of movement.
The conducted studies confirmed the possibility of creating such a road train under the condition of controllability and stability of movement. It is shown that at a speed of 15.0 m/s we have a steady motion of the road train both for the initial disturbance w=0.05 s-1 and for the initial disturbance w=0.10 s-1. However, when the speed increases to 20 m/s, even with the initial disturbance w=05 s-1, the road train loses stability. In addition, the coefficients of the use of traction forces on the axles of the road train are determined. It is shown that with a coefficient of adhesion j=0.8 (asphalt concrete surface) the speed of steady curvilinear movement is limited by the stability of the controlled axis of the bus. For this axis, the coupling force utilization ratio reaches a critical value equal to unity earlier than the others. At the same time, the loss of stability of the front axle due to the coupling of its wheels with the supporting surface leads to the loss of controllability of the road train. It has been established that the towed road train is characterized by slight excess turning (curvature increases as the speed of the road train increases). The critical speed of the straight-line movement of the road train was determined, which was 29.85 m/s, which indicates the stability of its movement. However, excessive maneuverability of the road train requires more attention to the configuration of the bus train and the loads on both the axle of the bus and the trailer.
Key words: towed vehicle train, equations of motion, lead angles, drift angle, stability, maneuverability, critical speed.
