Modeling and Control of a Telescopic Quadrotor Using Disturbance Observer Based Control

Active Fault Diagnosis and Control of a Morphing Multirotor Subject to a Stuck Arm

“…The solution extends our previous work [25], where a DOBC scheme which copes with external disturbances was designed by joining a Nonlinear Disturbance Observer (NDO) with an inner/outer loop feedback linearization control law. Thus, the main objective is that of extending [25] by considering stuck faults in the morphology-related servomotors. The considered morphing ability is that of telescopic arms (extendable arms), which represent a promising solution to flight into narrow spaces while keeping payload and maneuvering capabilities [12].…”

“…In this paper, we propose an active fault-tolerant control scheme for morphing quadrotors, where the terminology fault-tolerant refers to a control law which is able to cope with faults, and by active it is meant that the fault is directly estimated and feedforwarded in the control loop [23,24]. The solution extends our previous work [25], where a DOBC scheme which copes with external disturbances was designed by joining a Nonlinear Disturbance Observer (NDO) with an inner/outer loop feedback linearization control law. Thus, the main objective is that of extending [25] by considering stuck faults in the morphology-related servomotors.…”

“…Using the R B i,j s and r B i,j s, it is possible to express the inertia matrices J i,j through the parallel axis theorem. The reader can refer to [13,15,25] for details about the calculation of each J i,j .…”

“…The feedback linearization fault-tolerant tracking controller is based on [25], where a DOBC approach is adopted for wind estimation and compensation [21].…”

“…Section 4 handles the overall fault diagnosis, both the residual generator and the active fault diagnosis. Section 5 briefly recalls the DOBC solution provided in [25], which closes the loop. Finally, numerical simulations are discussed in Section 6, where masses and dimensions are taken from commercial components, and practical real-world problems (e.g., input saturation, sensor noise, and different sample rate between the two control loops) are also taken into account.…”