Design and optimisation of a tribometer system to characterise friction in near zero velocity

Abstract

This project presents the experimental observations of friction behaviour at reversal point in the vicinity of zero velocity, as a further investigation of Coulomb’s model of dry friction. It attempts to characterise the relationship between friction force and velocity and friction and displacement under different normal loads imposed.

The experiment is carried out using a tribometer developed by the author and collaborators. The tribometer is connected to a DC motor, which is given a sinusoidal signal input (periodic sine wave) with certain values of amplitude and frequency. MATLAB/Simulink software is used to create a closed loop control system, which includes PI controller, displacement sensor and force sensor. Experimental data is monitored and recorded using dSPACE ControlDesk software. Further discussion on the experimental setup is presented in this report. Data interpretation through graph plotting will also be presented in this report.

Investigation is carried out using certain set of parameters: amplitude, frequency, and normal load, in which the behaviour of friction force is observed. The main focus of the experiment is thus to investigate the friction behaviour in each case, which may be useful for further studies that involves compensating friction and monitoring wear.