A wheeled inverted pendulum (WIP) system is a
typical unstable complex nonlinear system widely utilized for educational purposes and control research. The dynamic of a WIP system can be represented as two second-order subsystems
which represent the angle of body and the position of wheel. This paper proposes a decoupled fuzzy sliding-mode balance control (DFSBC) system based on a time-varying sliding surface for a WIP system. A decoupled sliding surface which includes
the information of two-subsystem is designed to make the state trajectories of both subsystems move toward their sliding surface and then simultaneously approach zeros. The control effort of a WIP system is generated based on the idea that the state can quickly reach the decoupled sliding surface without large overshoot. Moreover, the slope of the decoupled sliding surface is adjusted by a fuzzy system, whose fuzzy rules are
constructed based on the idea that the convergence time of the state trajectories can be reduced. Finally, an 8-bit microcontroller-based WIP system is setup. Experimental results show that the proposed DFSBC system can achieve favorable balance control response for the simultaneous control of the angle of body and the position of wheel.
Proceedings of the International MultiConference of Engineers and Computer Scientists 2012 II, pp.823-827