A Fuzzy Logic Based Approach to Measure Complex Load Dynamics for Accurate Motion Control of Hydraulic Actuators.

This paper investigates the estimate issue of complex unknowns, e.g., the unmeasured load and parameter uncertainties, to improve motion control accuracy for hydraulic actuators in aero-engines. Fuzzy-logic-based estimators are designed to be adaptively updated and employed to handle all unmeasured nonlinearities, arising from aero-engine unknown aerodynamic load force with a novel recursive procedure of adaptive backstepping for motion control. To reduce the unnecessary bandwidth occupation in aero-engine networked control systems, a concurrent event-triggered mechanism is proposed on the basis of both actual and virtual control inputs. It indicates that the dynamic behavior inside the controller can be monitored by the event trigger, thus effectively reducing the amplitude fluctuation of triggering inputs and further improving motion and estimation performance. Since virtual control signal used for hydraulic system is not always continuous at triggering instants, the resulting event-triggered system is modeled into impulsive dynamical systems. By the stability analysis of impulsive dynamical systems, the closed-loop system is to be stable and a sufficiently small set of convergence is ensured for the track error with the proposed control scheme. Moreover, Zeno behavior is excluded for the proposed event trigger. Simulation and experiment studies on hydraulic actuators are conducted to demonstrate the superiority and effectiveness of the proposed scheme in the aero-engine Hardware-in-the-loop (HIL) platform.