FRICTION IDENTIFICATION BASED UPON THE LUGRE AND MAXWELL SLIP MODELS

Three friction identification methods, designated as the LuGre (LG) method, the Non-Linear Regression (NLR) method, and the Dynamic Non-Linear Regression with direct application of the eXcitation (DNLRX) method, are postulated. The first employs the LuGre model structure, the second the basic Maxwell Slip model structure, and the third an extended version of it. The Maxwell Slip model structure accounts for the presliding hysteresis with nonlocal memory, but is confined to providing constant sliding friction. This limitation is circumvented by the extended version postulated, where additional dynamics are introduced. In all methods identification is based upon signals obtained from a single experiment, thus circumventing the need for multiple experiments. The methods are assessed via laboratory signals, and the DNLRX is shown to achieve the best overall performance, followed by the NLR and, finally, the LG method.