H_∞ output tracking control of Electric-motor-driven aerodynamic Load Simulator with external active motion disturbance and nonlinearity

The work presented in this paper seeks to address the tracking problem for an Electric-motor-driven aerodynamic Load Simulator (ELS). The tracking performance of ELS is mainly affected by the actuator'sactive motion disturbance, friction nonlinear, and parametric uncertainties. Most of the previous studies on ELS focus on the actuator's active motion disturbance, while deemphasizing the other two factors. This paper concerns ELS as a motion loading system. A new high performancecontrol scheme is developed to deal with the three factors based on the established nonlinear mode of ELS. The control scheme is based on neural networks and the Linear Difference Inclusions (LDI) model. Aparallel distributed compensation (PDC) structure and H_∞ performance criterion are used to attenuate external disturbances. The stability of the whole closed-loop model is investigated using the well-known quadratic Lyapunovfunction. Both asimulation and an experiment are performed to validate the effectiveness of the developed algorithm.