Analysis of a new equation of wheeled vehicle motion

Abstract

Published works of professor G.I. Mamiti impinge on authority of the classical equation of traction balance developed by famed specialists of our domestic automobile science; he offers to substitute these time-proved theoretical developments for a new equation of motion. The purpose of this article is to analyse the validity of hypotheses used when establishing a new equation and to make a conclusion about its applicability for calculations of traction-speed properties of wheeled vehicles. Well-known laws of theoretical mechanics for lever-hinged mechanisms with special experiments and theoretical examples of various situations of wheeled vehicle motion are used as materials and methods of the analysis. G.I. Mamiti considers that moments due to air resistance force, inertia force, force from trailer and climbing resistance force, acting on vehicle body in longitudinal plane, create the opposing torques on driving wheels. It may only be correct for a monolithic structure, but assembled body and wheels constitute the lever-hinged mechanism. Moments, created by above forces, cause only the longitudinal roll of the body and the appearance of forces that lead to changing of normal reactions in suspension and axles, but do not create opposing torques on driving wheels. If the hypothesis of G.I. Mamiti was correct, the reactive moment on body from driving axle (or from cross-mounted power unit in the case of front-wheel drive vehicle), that was transferred, according to his considerations, on driving wheels, would be summarized with the torque transferred to them by transmission. As a result, traction force would be equal to zero, because these moments are identical in value and opposite in direction, so the vehicle could not move. Therefore, the wrong initial hypothesis leads to the establishing of wrong equation; its use, as it is shown in the article, leads to serious errors in calculations and to wrong conclusions on the improvement of wheeled vehicle designs.