Flatness-based fault tolerant control

Fuzzy-Flatness Hybrid Fault-Tolerant Control

“…This property can be exploited for trajectory planning, trajectory tracking, and robust control design. The selection of the flat outputs and the determination of the relationships between those flat outputs and the other system variables is the work of identifying viable flat models [1,4,5].…”

“…Indeed, every system variable must necessarily be described by these flat outputs and their time derivatives: as long as the trajectory is differential to the extent required to describe all the system variables, it is a valid trajectory. Basic polynomials are considered a simple solution for this, but more advanced approaches are required for optimal solutions [1].…”

“…This attribute is useful for trajectory planning and tracking, as the flatness-derived control inputs are guaranteed to converge on the desired outputs. This attribute is furthermore useful for redundant signal estimation for fault tolerant control [1].…”

“…Fault tolerant control (FTC) is another research area of major interest, wielding the promise of significantly reducing maintenance costs and introducing failsafes to a broad class of safety-critical systems, such as aircraft, security, and ground transportation [1,2]. FTC systems are broadly classified in two categories: passive systems, which consider faults in the control design, and; active systems, that react to faults by reconfiguring the control loop [3].…”

“…A similar approach is taken in [5] where the fault is estimated and the faulty sensor signal is conditioned with B-splines. Then [1], working from Mai and Suryawan, introduced an FTC flatness-based approach which sought to eliminate the time delay weakness of earlier approaches by exploiting the redundancies that can be calculated using flat outputs. They also examine the identification of faults using fault signatures based on residuals.…”