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This study addresses the event‐triggered fault detection for a class of discrete‐time systems with unknown but bounded external disturbance and measurement noise. In order to save limited network bandwidth, an adaptively adjusted event‐triggered scheme is designed by considering the probability of system failure and the fault detection progress. Based on the event‐triggered system output, an H_/L∞ fault detection observer is well designed in finite frequency ranges, such that the generated residual is sensitive to injected faults and robust against disturbance and noise. Moreover, a novel zonotope‐based residual evaluation strategy is constructed to reduce conservatism by considering the impacts of external disturbance, measurement noise and measured error caused by event‐triggered scheme. Finally, simulation results are provided to demonstrate the effective performance of the proposed event‐triggered fault detection strategy. [ABSTRACT FROM AUTHOR]

This study concentrates on the fault‐tolerant control and fault estimation problems for a class of descriptor stochastic systems with state‐dependent faults. A new extended observer method is presented to solve these design problems. First, the descriptor stochastic system is transformed into a non‐singular system, and an augmented system is constructed by assembling the fault states into the augmented vector. Then, a novel sliding mode observer with two discontinuous input terms is designed to estimate the states and faults of system. A state‐feedback control scheme based on the state estimates is synthesised to guarantee the closed‐loop systems stable. Finally, a numerical example is presented to show the effectiveness of the proposed design approach. [ABSTRACT FROM AUTHOR]

A robust output‐feedback attitude controller for three‐degree‐of‐freedom laboratory helicopter is proposed in this study. The laboratory helicopter has three rotational degree‐of‐freedom and preserves essential control challenges in the attitude control of actual helicopter. An output injection sliding‐mode observer is developed to estimate the angular velocities and the external disturbances in finite time. The estimations are used to construct a robust LQR controller that requires angular position measurements only and compensates the external disturbances. The finite time asymptotic convergence of the observed states and disturbances to the actual values is proved and the results are verified numerically through simulation. [ABSTRACT FROM AUTHOR]

Global output feedback stabilisation problem for a class of stochastic feedforward non‐linear systems with state time delay is investigated in this study for the first time. By introducing the homogeneous domination approach in the stochastic system, constructing an implementable homogeneous reduced‐order observer and choosing an appropriate Lyapunov–Krasoviskii functional, an output feedback controller is designed to render the closed‐loop system globally asymptotically stable in probability and the output can be regulated to the origin almost surely. A simulation example is provided to show the effectiveness of the designed controller. [ABSTRACT FROM AUTHOR]

Active suspension systems have received increased importance for improving automotive safety and comfort. In active suspensions, actuators are placed between the car body and wheel‐axle, and are able to both add and dissipate energy from the system, which enables the suspension to control the attitude of the vehicle, to reduce the effects of the vibrations, and then to increase ride comfort and vehicle road handling. However, the attained benefits are paralleled with the increasing possibility of component failures. In this study, a fault‐tolerant control approach is proposed to deal with the problem of fault accommodation for unknown actuator failures of active suspension systems, where an adaptive robust controller is designed to adapt and compensate the parameter uncertainties, external disturbances and uncertain non‐linearities generated by the system itself and actuator failures. Comparative simulation studies are then given to illustrate the effectiveness of the proposed controllers. [ABSTRACT FROM AUTHOR]