Position control of a pendulum using sliding mode controller with finite time disturbance observer

This model combine a finite time disurbance observer with a sliding mode controller.
The disturbance observer is formulated from the work of  Ting Zhang et al.
Zhang, Ting, Xiaohong Jiao, and Zhanmeng Lin. "Finite time trajectory tracking control of autonomous agricultural tractor integrated nonsingular fast terminal sliding mode and disturbance observer." Biosystems Engineering 219 (2022): 153-164