ABSTRACT
This chapter seeks to provide an in-depth analysis of the chattering problem. The term chattering describes the phenomenon of finite-frequency, finite-amplitude oscillations appearing in many sliding mode implementations. The fact of local instability explains why chattering may appear in the systems with discontinuous controls at the presence of unmodeled dynamics. An asymptotic observer in the control loop can eliminate chattering despite discontinuous control laws. In light of recent advances of high-speed circuitry and insufficient linear control methodologies for internally nonlinear high-order plants such as AC motors, sliding mode control has become increasingly popular. The observer-based solution requires slightly more effort in the control design. However, in many control applications, observers for immeasurable states are vital parts of the overall system and can be readily included into the control design. The regular form approach to prevent chattering is especially intriguing for systems with electrical actuators in which control input discontinuities are often imposed by the system specifications.
