“…For example, state observers based on the LuGre dynamic model [41][42][43], the Burckhardt model [44][45][46][47], the Magic Formula model [48,49], the quarter wheel model [50], and the tire torsion model [51] were designed to identify the TRFC. RLS methods, which are mainly based on the brush model [37], the Burckhardt model [52,53], longitudinal vehicle model [54][55][56][57][58], single-wheel model [59] and six-degree-of-freedom (DOF) vehicle model [60], have been extensively studied in recent years. It is well known that the RLS usually has only one degree of freedom to adjust the adaptivity of the filter, which may limit its application.…”