Adaptive Compensation for Unknown External Disturbances for an Inverted Pendulum Based on the Internal Model Principle

In this paper, an adaptive compensator for unknown external disturbances for an inverted pendulum based on the internal model principle is designed. The inverted pendulum is a typical system that has many applications in social life, such as missile launchers, pendubots, human walking and segways, and so on. Furthermore, the inverted pendulum is a high-order nonlinear system, and its parameters are difficult to determine accurately. The physical constraints lead to the complexity of its control design. Besides, there are some unknown external disturbances that affect the inverted pendulum when it operates. The designed adaptive compensation ensures the outputs of the system’s convergence to the desired values while also ensuring a stable system with variable parameters and unknown disturbances. The simulation results are illustrated and compared with the linear quadratic regulator (LQR) controller to show the effectiveness of the proposed compensator.