Output-feedback sliding mode control of uncertain systems with unknown control direction: A periodic switching function approach

This work addresses the design of a sliding mode tracking controller for single-input-single-output (SISO) uncertain linear plants with relative degree one and unknown sign of the high frequency gain, i.e., the control direction is considered unknown. The goal is to achieve global exact tracking using only output-feedback. A periodic switching function is designed to cope with the lack of the knowledge of the control direction.