Nonlinear Adaptive Sliding Mode Control for a Rotary Inverted Pendulum

Due to the nature of Proportional-Integrative-Derivative (PID) controller, the inverted pendulum will seldom be in the steady state in a noisy uncertainty environment, which degrades the usefulness of PID controller in a system that requires high precision. Lyapunov-based sliding mode and adaptive controllers are proposed for a rotary inverted pendulum in this research. They are applied to stabilize the pendulum around the balancing state in the Lyapunov sense. Both the simulation and the experimental results show that not only can strong robustness with respect to system uncertainties and nonlinearities be obtained but also the pendulum position can dynamically converge to the desired balancing state by using nonlinear Lyapunov-based controllers.