RETRACTED: Robust variable air speed control of a nonlinear fan system based on backstepping sliding mode control techniques (Retracted article. See vol. 10, 2018)

A backstepping technique combining the sliding mode control method with an integrator and estimator design for variable air speed control is proposed in this article. The self-build fan-plate system is used to derive the mathematical model for air speed control which builds a direct connection between motor rotation and air speed control. Furthermore, the mathematical model also includes effects arising from modelling uncertainties, parameter variations and external disturbances because of modelling errors, load changing and variable loading shifting, respectively. The Lyapunov theory is employed in the controller design procedure that ensures the stability of the system. The experimental results show the great tracking and convergence ability of the proposed controllers even under the time variations and sharply changing commands.