Abstract
The nonlinear dynamic model of a class of underactuated mechanical systems (UMSs) in a potential field is built with the Lagrangian method and some system properties are analyzed such as the system passivity. A genetic algorithm (GA) based stable intelligent control algorithm is proposed for the class of UMSs combining fuzzy control and sliding mode control. The real-valued GA is used to adjust the parameters of stable intelligent controller to improve the system performance. The underactuated double-pendulum-type overhead crane(DPTOC) is used to validate the proposed control algorithm. The system is proved to be stabilized asymptotically to its equilibrium with sliding mode theory. Simulation results illustrate the system's complexity and the validity of proposed control algorithm under different conditions.