Control Design and Analysis of Servo-System with Stick-Slip Friction and Backlash Using Novel Quasi-linear Approaches

Abstract

The control system design problem for a stabilized tracking platform was addressed focusing on nonlinear effects of friction and backlash. The control design methodology is based on the Quantitative Feedback Theory (QFT) synthesis method combined with novel quasi-linear analytical approaches for stick-slip friction and backlash phenomena, providing realistic insight throughout the design stages. An experiment is performed to assess the validity of the proposed methodology. Thus, low frequency limit cycling is successfully predicted when analyzing the quasi-linearized system in the Nichols plane. The results imply applicability of the suggested method to other servo-systems representing typical two-mass dynamics including both friction and backlash effects.