Robust H∞H∞ attitude control of a laboratory helicopter

•Tracking control performances of the 3-DOF laboratory helicopter is improved.•The model is considered as a linear system with equivalent disturbances.•Equivalent disturbances contain various uncertainties.•A robust compensator is introduced to restrain effects of equivalent disturbances.•Experiments demonstrate the improved performances of the proposed control strategy.

This paper deals with the attitude tracking control problem for a three degree-of-freedom laboratory helicopter, which aims to improve tracking control performances of elevation and pitch channels. The model of each channel is considered as a linear system with equivalent disturbances which contain nonlinear uncertainties, coupling effects, parameter perturbations, and external disturbances. A state-feedback H∞H∞ controller is applied to the linear model and a robust compensator is introduced to restrain the effects of equivalent disturbances. The robust properties of the closed-loop control system with the proposed controller are shown better than the standard H∞H∞ controller. Experimental results demonstrate the improved performances of the proposed control strategy.