ROBUST SUPER-TWISTING SLIDING MODE CONTROL FOR BALANCING REACTION WHEEL PENDULUM

Underactuated systems are one of the emerging research topics due to their challenging problems and applications in real-world engineering systems. In this paper, we consider the control problem of balancing the reaction wheel pendulum. Many control methods have been adopted to control the system and one of the common controls is based on sliding mode control (SMC). In SMC, the chattering phenomenon and its solution are widely discussed. Several approaches have been proposed, for example replacing the switching function, second-order SMC, and higher-order SMC. Here, the balancing of the reaction wheel pendulum with disturbances is considered. First, the system model derivation based on the Euler-Lagrange method is discussed. Second, a different approach to designing a controller is given where feedback linearization and robust super-twisting sliding mode control are used. The control performances are compared with those of standard and modified switching functions of first-order sliding mode control. For second-order sliding mode control, the super-twisting and PID super-twisting controllers are employed. In each controller, similar disturbances, namely, impulse signal and sinusoidal signal are used to verify the effectiveness of the controller. We conduct the comparison studies in Matlab/Simulink with fixed controller's gains and the controllers effectively stabilize the pendulum upright and reject the given external disturbances.