APPARATUS AND METHOD FOR ESTIMATING A GRIP FACTOR OF A WHEEL OF A ROAD VEHICLE AND RELATIVE ROAD VEHICLE

Apparatus (16) for estimating a grip factor (G) of at least one wheel (2, 3) comprising: a control unit (10) configured to process a current slip angle (a) of said wheel (2, 3); a storage unit (19), within which, in a consultation table (CT), a plurality of grip curves (GC) correlating a plurality of values of a steering parameter comprising the rack force (RF) with a plurality of values of the slip angle (a) are recorded; along a same curve, the value of the grip factor (G) remains unchanged; wherein the control unit (10) is configured to cyclically estimate at least one raw value (RG) of the grip factor (G) of said at least one wheel (2, 3) based on the position of a current condition (AC) within the consultation table (CT), as a function of the current slip angle (a) and of the current rack force (RF).