An actuator fault reconstruction scheme for linear systems

• This study has proposed an actuator fault reconstruction scheme for linear systems with applications to aircraft and crane models.
• The given system is decomposed into two subsystems; a fault-free subsystems and a fault-dependent subsystem.
• A functional observer is introduced to provide the estimate of the linear functions of the state of the fault-free subsystem.
• Robust exact differentiators are adopted to provide the derivative of the measurement output.

This paper presents an actuator fault reconstruction scheme that can be classified into an algebraic decomposition approach in which the original system is decomposed into two subsystems: a fault-free subsystem and a fault-dependent one. From the result of such algebraic decomposition, the fault estimate is obtained as a set of combinational functions of the system input, the measurement output, the estimate of certain linear functionals involving the state of the fault-free subsystem and the first-order derivative of the measurement output. Here a functional observer and robust exact differentiators are adopted to provide the estimate of the linear functionals of the state of the fault-free subsystem and the derivative of the measurement output, respectively. The proposed method is verified through two numerical examples of seventh-order aircraft and fourth-order crane models.