Rodolfo Suárez

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Stick-slip friction-induced oscillations appearing in oilwell drillstrings are a source of failures which reduce penetration rates and increase drilling operation costs. For this reason, a major problem to solve is modelling the drillstring torsional behaviour and proposing control solutions to help reduce stick-slip phenomenon. This paper is focused on(More)
We consider one-dimensional, time-invariant sampled-data linear systems with constant feedback gain, an arbitrary fixed time delay, which is amultiple of the sampling period and a zero-order hold for reconstructing the sampled signal of the system in the feedback control. We obtain sufficient conditions on the coefficients of the characteristic polynomial(More)