This contribution describes the theoretical background of traction analysis in order to derive the boundary conditions which should be taken into account when developing proper structures of empirical relations for modelling traction. The paper addresses the following themes with a brief description of the relevant physical background: (1) specification of modelling objectives; (2) the structure of the traction system, sub-systems and the basic properties; (3) the fixed and variable sub-systems, and stationary and non-stationary behaviour; (4) the regimes of the traction-slip curve; (5) factors influencing the initial slope in the elastic regime (rising part) of the traction curve; (6) the empirical equation for determining the friction of tread-rubber with the road; (7) factors influencing the tribo-elastic regime (traction peak at medium slip; (8) problems of empirical tyre modelling; (9) a case study of the "magic formula"; and (10) on-line and off-line parameter estimation.
Samenvatting