Design, Validation, and Comparison of UDE-based Pitch-axis Control of Helicopter with existing Conventional and Non-conventional Controllers

Abstract

The demand for high-precision motion control method for complex systems has increased in the recent decade. The significant challenge is to achieve robustness despite insufficient knowledge about the disturbances acting on a real-time system. Uncertainty and Disturbance Estimator (UDE) method is a vital approach that takes up the challenge, ensuring stability and robustness. This paper is dedicated to highlighting the research done in the field of UDE controller applied with other well-known control methods implemented on various linear and nonlinear systems. This work aims to control the position of pitch axis of the nonlinear aerodynamic system. The phase portrait analysis of the system has been done, which reveals the trajectory and existence of limit cycle. The obtained time responses are diverging, indicating the regions of instability. The novelty lies in the formulation of UDE based controller aimed to robustify the helicopter subsystem. Closed-loop stability is analyzed to validate the controller design. Simulation results for the pitch-axis control are demonstrated to display the efficacy of UDE-based control design against uncertainty and disturbances. The methodology’s efficiency is further demonstrated by comparing the results of UDE control with $$\alpha$$ -filter with a well-known fuzzy control technique.