Output feedback control for an underactuated benchmark system with bounded torques

In this paper, we consider the stabilization of the translational oscillator with a rotational actuator (TORA) system. Existing control methods for the TORA system are developed on the basis of the assumptions that full state feedback is available, and the actuator can supply control torques with any bounded amplitudes or system parameters are exactly known. In order to relax these assumptions, an amplitude-saturated output feedback controller is proposed for the TORA system. Compared with existing control methods, the proposed method exhibits four remarkable features: free of plant parameters, bounded amplitude, output feedback, and unwinding behavior prevention. Specifically, the passivity of the TORA system is analyzed first. Then, a constructive energy-like function is introduced and a corresponding amplitude-saturated output feedback control law for the TORA system is proposed on the basis of the constructed energy-like function. Lyapunov-based analysis and LaSalle's invariance principle are used to prove the boundedness and convergence of the closed-loop signals. Finally, numerical simulations with comparisons to previous reported methods are implemented to demonstrate the superior performance of the proposed method.

Automated summary

This paper proposes an amplitude-saturated output feedback controller for the TORA system, which exhibits features such as freedom from plant parameters, bounded amplitude, output feedback, and unwinding behavior prevention, and achieves control by introducing an energy-like function.