Publication detail

Coulomb Friction Identification Using Harmonic Balance Method of Two Relay System

BLAHA, P.

Original Title

Coulomb Friction Identification Using Harmonic Balance Method of Two Relay System

Type

dissertation

Language

Czech

Original Abstract

This thesis is interested in study of nonlinear system that is composed from linear part and two relay nonlinearities. An inner relay represents Coulomb friction. An outer relay is connected in feedback. It has non-zero hysteresis and ensures the generation of limit cycles. Both relays can be replaced with one nonlinearity. It enables to use harmonic balance method. Because of the dependence of limit cycles on relay amplitudes and on outer relay hysteresis, it is possible to derive algorithm for inner relay amplitude (Coulomb friction) estimation. First, limit cycles are generated in the system using outer relay with fixed amplitude and with fixed hysteresis. The period and amplitude of oscillations are measured when the oscillations are stable. The outer relay amplitude is changed afterwards. The hysteresis is adjusted according to iterative algorithm to obtain the same period of oscillations as they were obtained in first relay experiment. Obtained data can be used in derived formula to compute the Coulomb friction estimate. Outlined algorithm is realized in Simulink environment in Matlab program. Some its blocks are implemented as S-functions using C programming language. The simulation scheme was tested in simulations. The Real Time Workshop toolbox and the Windows application WinCon 3.0 can be used to generate real time application. It was examined during Coulomb friction estimation of DC motor.

Keywords

Coulomb friction, harmonic balance method, describing function, limit cycles, relay feedback

Authors

BLAHA, P.

Released

6. 6. 2001

Publisher

Vědecké spisy Vysokého učení technického v Brně

Location

Brno

ISBN

80-214-1915-6

Book

Coulomb Friction Identification Using Harmonic Balance Method of Two Relay System

Edition

Edice PhD Thesis, sv. 82

Edition number

1

BibTex

@phdthesis{BUT66639,
  author="Petr {Blaha}",
  title="Coulomb Friction Identification Using Harmonic Balance Method of Two Relay System",
  publisher="Vědecké spisy Vysokého učení technického v Brně",
  address="Brno",
  year="2001"
}