Two-state dynamic friction model with elasto-plasticity

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• Friction modeling for simulation and control purposes.
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• We propose a novel two-state dynamic friction model.
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• The ease of implementation and identification is required for applications.
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• Friction dynamics is not directly decomposable from the overall system dynamics.
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• Presliding hysteresis and transient sliding state are considered.

A novel two-state dynamic friction model with elasto-plasticity that we call 2SEP friction model is described. Being primarily intended for control, the modeled friction dynamics constitutes a linear combination of two nonlinear state variables. One independent and one dependent friction states capture the presliding hysteresis and transient sliding response. The overall dynamic friction with lag converges towards the velocity-dependent steady-state which is described by the Stribeck characteristic curve plus a linear viscous friction term. The proposed model requires seven parameters only of which already five are attributed to the steady-state friction characteristics. The 2SEP friction model is experimentally evaluated and compared with state-of-the-art friction models namely LuGre and GMS. The model identification is performed under real circumstances of the actuated motion close to the applications with electro-mechanical drives. The 2SEP friction model, being easy to implement and robust against real noisy signals, proves to be quite accurate in prediction and well favorably comparable with the LuGre and GMS one.