Fault detection and isolation (FDI) is a useful tool to investigate proper performance of dynamic systems. With respect to hydraulic actuators, as they are extensively used in industry, and are responsible for producing accurate displacements and high forces, FDI role is crucial. One of the phenomena that can affect the internal leakage detection is the variation in the value of fluid effective...

This paper presents a rigorous analysis and design method for PWM-based control of pneumatic systems. An equivalent analytical model incorporating the effects of a finite PWM switching period is formulated. This equivalent model was motivated by a lack of control design and analysis techniques needed to treat the inherently non-analytical switching models associated with PWM-based systems. The ...

This paper considers the problem of reconstructing, simultaneously occurring actuator and sensor faults in a nonlinear system. The theory which will be developed in this paper is based on a sliding mode observer formulation, designed around an LPV model approximation of the nonlinear system. It extends previous work which has independently considered actuator and sensor faults reconstruction. H...

In this paper, a method of actuator fault accommodation for a class of nonlinear systems is proposed. It concerns the problem of progressive accommodation to actuator failure. This strategy is based on t he optimal nonlinear controller, and its objective to maintain the system closed loop stability. The authors show the interest of the proposed method even for a local analysis when a linear app...

Dual-stage actuator design for hard disk drives via composite nonlinear feedback control is presented, which consists of a primary actuator, the voice coil motor and a secondary actuator, the suspension piezoelectric microactuator. The first is effective in both track seeking and following stages to produce fast rising time and low overshoot and the latter works in track following stage only to...

In this paper, we propose to combine the fuzzy sliding mode control to tolerate actuator faults of unknown nonlinear systems subject to external disturbances. In particular, the idea of using adaptive fuzzy system to tolerate actuator faults of unknown nonlinear systems by approximating the system functions and the effects caused by actuator faults are avoided by the control structure. On the b...

Hydraulic turbine governing system (HTGS) is a complicated nonlinear system that controls the frequency and power output of hydroelectric generating unit (HGU). The modeling of HTGS is an important and difficult task, because some components, like hydraulic turbine and governor actuator, are with strong nonlinearity. In this paper, a novel Takagi–Sugeno (T–S) fuzzy model identification method b...

In this paper, modelling and identification of a hydraulic servoactuator system is presented. The development of the model is important for further understanding the system and for developing a robust force controller. A systems approach is used to model the various subsystems including the servovalve dynamics, fluid dynamics and the vane and load dynamics. Included in the model are line losses...

This paper presents an intelligent fault tolerant flight control system that blends aerodynamic and propulsion actuation for safe flight operation in the presence of actuator failures. Fault tolerance is obtained by a nonlinear adaptive control strategy based on on-line learning neural networks and actuator reallocation scheme. The adaptive control block incorporates a recently developed techni...