Speed control for the lateral swing of aerial cameras based on an improved extended state observer

Abstract

This study proposes an improved extended state observer (ESO) to eliminate the effects of disturbances on the speed control system of an aerial camera lateral swing. First, a mechatronics model of lateral swing, which includes a rotating mechanism, principal axis, and motor, is constructed. Meanwhile, a mathematical model of the motor speed loop is built to design the improved ESO. Second, a new nonlinear function that exhibits better continuity and smoothness than previously available functions is proposed to reduce high-frequency flutter. The improved ESO is designed based on the new nonlinear function. The nonlinear dynamics, model uncertainty, and external disturbances of the speed control system are extended to a new state, and the improved ESO is implemented to observe this state. The overtime variation of the speed control system is predicted and compensated for in real time using the improved ESO. The improved ESO sufficiently eliminates the disturbances on the speed control system of the aerial camera lateral swing. Third, the parameters of the improved ESO are determined, and its convergence is analyzed. Finally, simulation experiments and discussions were conducted and results show that the speed control system with the improved ESO exhibits better performance.