State prediction based control schemes for nonlinear systems with input delay and external disturbance

Abstract

Abstract In this paper, a control scheme based on state prediction is proposed for a class of nonlinear systems subject to input delay and external disturbance. Firstly, as for constant input delay, an improved control scheme that combining state prediction with dynamic surface control (DSC) technique is proposed, which can compensate for the input delay completely. Secondly, by considering the constant input delay and external disturbance, an effective controller based on state prediction, DSC technique and disturbance observer is presented to tackle the disturbed input‐delayed nonlinear systems. Thirdly, as for time‐varying input delay and external disturbance, a control scheme that includes state prediction, DSC technique, input saturation and sliding mode disturbance observer is further proposed to tackle the tracking control for the addressed nonlinear systems. Besides, some theorems are given to ensure that all signals in the closed‐loop systems can be semi‐globally ultimately uniformly bounded (UUB) under the proposed control schemes. Finally, by utilising the dynamic model of quadrotor unmanned aerial vehicle (UAV), some simulations are presented to illustrate the effectiveness of our proposed results.

Keywords

• Control system analysis and synthesis methods
• Stability in control theory
• Multivariable control systems
• Self-adjusting control systems
• Time-varying control systems
• Distributed parameter control systems