| In recent years, there has been an increasing interest in developing safer and more reliable control systems. However, the application of fault tolerant control (FTC) strategies towards improving the performance of faulty fluid power systems remains sparse. This thesis investigates, for the first time, the robust fault tolerant control of an electrohydraulic positioning system with a faulty actuator piston seal. A faulty piston seal causes the internal leakage of hydraulic fluid between the chambers of the actuator and alters the dynamics of the system by increasing the damping and decreasing the loop gain. The goal of this thesis is to develop a control system, tolerant to various levels of the internal leakage fault with application to the positioning of aircraft flight control surfaces. Towards this objective, and to support continued research in this area, a novel experimental test station is designed and constructed to allow the experimental simulation of many faults common to fluid power systems. Then, the quantitative feedback theory (QFT) is employed for the controller design. (Abstract shortened by UMI.)... |
