Determination of viscous and Coulomb friction by using velocity responses to torque ramp inputs

Abstract

This paper reports the results of an experimental study conducied on a direct-drive motor t o evaluate the predicted behavior of selected friction models. W e focus the study t o the velocity response when torque ramp inputs are employed. Among the considered friction models, the dynamic friction model so-called LuGre model, captures very well the ezperimental behauior. As a consequence of the study, we derive a simple procedure t o determine the viscous and Coulomb friction from experimental velocity responses.

Inverted Pendulum Nonlinear Controllers Using Two Reaction Wheels: Design and Implementation

“…It is essential to highlight that the pendulum built for the experimental tests has some construction imperfections and presents a nonlinear behavior regarding its friction. The pendulum angular motion has small velocities for which is difficult to model the effect of friction [43]. Therefore, it is imperative to include such a phenomenon in the model of the pendulum with two reaction wheels.…”

“…2 presents the experimental result of releasing the pendulum and waiting for it to stop and compares this result with the 2-RWP equation of motion with the friction model included given by: This model has a very close fit to the experimental result, where C v = 0.0031 Nms/rad and C c = 0.011 Nm. Also, the friction model used here, composed by viscous and Coulomb friction contribution, is trendy in the literature [43]. Moreover, this has not been considered in our previous paper [13], and the friction contribution is significant to be identified and included in the design of the controllers once it has a strong nonlinear behavior and this could influence in the performance of the controllers.…”

Coulomb friction identification for mechatronic servo systems with limited strokes using two reference inputs

“…The control performance depends on the values of Coulomb friction in the mathematical model for which the control is designed, and this model-based approach requires Coulomb friction identification. A procedure to determine Coulomb friction using the steady state response to a speed ramp input is proposed in [28]. A method to estimate Coulomb friction utilizing an adaptive observer on the basis of the Lyapunov technique is investigated in [29].…”

Seismic response of a column like structure with both fractional and dry friction type of dissipation

“…Od modela koji spadaju u grupu statiµ ckih modela trenja, pored navedenih vaµ zno je pomenuti i Amstrongov i Karnopov model. Prvi od njih pogodan je kod modela sa viskoznim trenjem i dobro opisuje Stribekov efekat 2 , v. Keli i Lamas [68,1999], dok je Karnopov model pogodan za numeriµ cke simulacije, v. Aih-Šelner i Firer [42,1998], jer se u podruµ cju malih relativnih brzina uzima da je relativna brzina jednaka nuli, µ cime se izbegava odre †ivanje taµ cnog trenutka u kojem v r postaje jednako nuli., v. Karnop [67,1985], Riµ card i Cutkoski [101,2002]. Zbog prirode statiµ ckog preslikavanja izme †u relativne brzine klizanja i sile trenja, statiµ cki modeli su jednostavni i pogodni za primenu, ali upravo zbog toga oni nisu u stanju da opišu neke procese karakteristiµ cne za trenje, jer ono nema trenutni odziv na promenu brzine, već ima svoju unutrašnju dinamiku.…”

“…Zato je u tim sluµ cajevima pogodno koristiti neki od dinamiµ ckih modela trenja, kao na primer Dalov, Lu-Gre ili Elasto-plastiµ cni model. Kod njih se mikroskopske neravnine površina u kontaktu modeliraju pomoću elastiµ cnih i viskoznih elemenata, a zavisnost sile trenja od relativne brzine izraµ zena je diferencijalnim jednaµ cinama, v. Dal [30,1976], Keli i Lamas [68,1999], Kanudas i dr. [23,1995], Dupont i dr. [40,2000], Dupont i dr. [41,2002], Penestri [94,2007], Garsia [55,2008]. Oni mogu relativno dobro da opišu razne procese ukljuµ cene u fenomen trenja, i samim tim su sloµ zeniji za upotrebu.…”