Design of Smooth Sliding Mode Controller for Chattering Suppression in Single Axis Positioning System

Tan, Jia Cong (2021) Design of Smooth Sliding Mode Controller for Chattering Suppression in Single Axis Positioning System. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

Text TAN JIA CONG_Full text.pdf Restricted to Registered users only Download (2MB)

Abstract

Sliding mode controller is a robust non-linear controller that is often used in the control system. However, the sliding mode controller will produce a noise that is caused by the signum function inside the controller which is called chattering effect. It will affect the real machine in high frequency switching. The objective of this proposed method is to design a second order sliding mode controller which is super twisting that can reduce the chattering effect existing in the controller. The sliding mode controller contains two components which are switching function and control law. The cause of the chattering effect is the signum function that exists in the control law. To reduce the chattering effect, the signum function was replaced with the smoothing functions such as sigmoid function, saturation function, gauss error function, novel function and new novel saturation function. This can result in lowering down the high frequency switching of the real machine. The maximum tracking error and chattering effect was observed after the replacing of the smoothing function. The gauss error function is the best smoothing function in terms of maximum tracking error and performance. However, the new novel saturation function performs the best in reducing the chattering effect.