Friction identification and compensation of its effects in stabilized platforms

Sincar, Eyyüp
A frequent problem encountered in the stabilization of a dynamic system supported by a moving base is the disturbance rejection associated with moving components. Due to relative motion of adjacent components, the friction induces a destabilizing force from base motion to the stabilized object, which degrades the motion accuracy. Therefore, the compensation of frictional effects is necessary in order to obtain a highly precise stabilization performance, especially, when the stabilized system undergoes low-velocity or reversal motions at which the friction is the dominant destabilizing factor. Since the friction has quite complex and nonlinear behaviors, classical industrial control techniques such as PI and PID are insufficient to compensate frictional effects. In this thesis, the frictional behaviors observed by different researchers and notable friction compensation techniques proposed in literature are presented. The compensation methods are compared in terms of their capability to capture frictional effects and their simplicity to be applicable. Various types of friction identification experiments are performed on a test setup in order to observe frictional behaviors and to estimate friction model parameters. System performance is analyzed on an experimental level by applying two different compensations methods which are model-based and model-free. The improvement in stabilization performance is determined and compared for these compensations techniques.
Citation Formats
E. Sincar, “Friction identification and compensation of its effects in stabilized platforms,” M.S. - Master of Science, Middle East Technical University, 2013.