Second order sliding mode control based on extended state observer for double pendulum overhead cranes

This study proposes a second order sliding mode controller based on an extended state observer for a 3D crane system with a double pendulum effect and constant rope length. A second order sliding mode controller requires an accurate model of the system's parameters. However, in practice, model parameters and external disturbances are difficult to determine in detail. Therefore, the extended state observer is designed to estimate the system state variables and the total disturbance. Finally, a sliding mode controller is developed with the signals taken from the observer. The proposed controller ensures stability according to Lyapunov function. Simulation results show that the proposed method ensures that the trolleys reach the desired trajectory while minimizing vibration even in the presence of disturbances and uncertain components.