Probabilistic model identification of the bit–rock-interaction-model uncertainties in nonlinear dynamics of a drill-string

This paper deals with a procedure to perform the identification of the probabilistic model of uncertainties in a bit–rock interaction model for the nonlinear dynamics of a drill-string. The bit–rock interaction model is represented by a nonlinear constitutive equation, whose uncertainties are modeled using the nonparametric probabilistic approach. The identification of the parameter of this probabilistic model is carried out using the maximum likelihood method together with a statistical reduction in the frequency domain using the Principal Component Analysis.