This paper studies the design of a robust discrete-time sliding mode control (DT-SMC) for a high precision electro-hydraulic actuator (EHA) system with nonlinear actuator friction. Nonlinear friction in the hydraulic actuator can greatly influence the performance and accuracy of the hydraulic actuators; however, it is difficult to accurately model nonlinear friction characteristics. In this paper, it is proposed to characterize frictions as an uncertainty in the system matrices. Indeed, the effects of variations of the nonlinear friction coefficients are considered as norm bounded uncertainties that span a bounded region to cover a wide range of real actuator friction. For such a discrete-time dynamic model for the EHA system with system matrices uncertainties and a nonlinear term, a sufficient condition for the existence of stable sliding surfaces is proposed by using the linear matrix inequality (LMI) approach. Based on this existence condition, a discrete-time sliding mode controller is developed such that the reaching motion satisfies the discrete-time sliding mode reaching condition for uncertain systems. Simulation and comparison studies on the EHA system model illustrate the effectiveness of the proposed method. The study is simulation based only as it is important to establish the feasibility and stability of the controller before attempting to apply the controller to a physical system.Copyright © 2009 by ASME

Modeling and Robust Discrete-Time Sliding Mode Control Design for a Fluid Power Electrohydraulic Actuator (EHA) System

A multi-source information fusion fault diagnosis for aviation hydraulic pump based on the new evidence similarity distance

https://digitalcommons.odu.edu/cgi/viewcontent.cgi?article=1027&context=engtech_fac_pubs

Active Fault Tolerant Control for Vertical Tail Damaged Aircraft with Dissimilar Redundant Actuation System

Moving towards the more electric aircraft (MEA), a hybrid actuator configuration provides an opportunity to introduce electromechanical actuator (EMA) into primary flight control. In the hybrid actuation system (HAS), an electro-hydraulic servo actuator (EHSA) and an EMA operate on the same control surface. In order to solve force fighting problem in HAS, this paper proposes a novel linear extended state observer (LESO)-based motion synchronization control method. To cope with the problem of unavailability of the state signals required by the motion synchronization controller, LESO is designed for EHSA and EMA to observe the state variables. Based on the observed states of LESO, motion synchronization controllers could enable EHSA and EMA to simultaneously track the desired motion trajectories. Additionally, nonlinearities, uncertainties and unknown disturbances as well as the coupling term between EHSA and EMA can be estimated and compensated by using the extended state of the proposed LESO. Finally, comparative simulation results indicate that the proposed LESO-based motion synchronization controller could reduce significant force fighting between EHSA and EMA.

https://www.mdpi.com/1424-8220/17/11/2444/pdf

Linear Extended State Observer-Based Motion Synchronization Control for Hybrid Actuation System of More Electric Aircraft.

An efficient single-loop strategy for reliability-based multidisciplinary design optimization under non-probabilistic set theory

Adaptive decoupling synchronous control of dissimilar redundant actuation system for large civil aircraft

For the gradual faults of the new hybrid collaboration actuation system composed by hydraulic actuator(HA) and electro-hydraulic actuator(EHA), this paper develops a control law with the function of passive fault-tolerant. In this study, HA is active and EHA is passive, and the gradual faults such as leakage and flow changes are characterized as uncertainties of the system, then an equivalent model is derived from the original system based on the assumption that the uncertain matrices are norm bounded. The fixed controller is designed based on the concept of model reference tracking control. Meanwhile, relevant parameters are solved by Lyapunov stability theory and linear matrix inequality(LMI) approach. simulation results verify the effectiveness of the control law design.

Passive fault -tolerant control for dissimilar redundant actuation system-based on LMI approach

Dissimilar redundant actuation system has high reliability because of getting rid of central hydraulic power and avoiding common cause failures, which conform to the development trend of future actuation systems in large civil aircraft. Despite these advantages, force fighting widely exists in dissimilar redundant actuation systems due to the different driving principle and system parameters of different actuators. All these factors can affect output precision, shorten operation life, or even lead to system failure. To cope with this problem, this paper proposes a new adaptive decoupling controller based on motion state synchronization. The parameter adaption law is designed for the parametric uncertainties in the dissimilar redundant actuation system and motion state synchronization is proposed to deal with the differences between two different actuators. The comparative simulation results between the proposed algorithm and traditional method indicate that the proposed synchronous controller is capable of achieving better tracking control performance and effectively solving the force fighting problem between different actuators.

Jun Wang

Papers

Adaptive decoupling synchronous control of dissimilar redundant actuation system for large civil aircraft

Passive fault -tolerant control for dissimilar redundant actuation system-based on LMI approach

Synchronous controller design for dissimilar redundant actuation system of large civil aircraft