An Output Integral Sliding Mode FTC Scheme Using Control Allocation

Abstract

Abstract-In this paper, a new fault tolerant control scheme is proposed for systems where only output information is available. The ideas of integral sliding mode control are used to ensure robustness throughout the entire response of the system, even in certain actuator fault/failure cases. This is accomplished by integrating fixed control allocation within this ISM framework. An unknown input observer is included in the proposed scheme to estimate the states, as it is assumed that there is no information of the true states or knowledge of the faults or failures from a monitoring scheme. A rigorous closed-loop stability analysis is presented, and in fact, a convex representation of the problem is formulated to synthesize a controller. Simulation results on a benchmark civil aircraft model show good tracking of the commanded signals.

An integral sliding mode fault tolerant control scheme for an octorotor using fixed control allocation

“…To address this shortcoming, integral sliding modes (ISM), first proposed in [22], can be used to enforce a sliding mode throughout the entire closed-loop system response. Recently in [13], [14], FTC schemes based on ISMs have been proposed for state feedback and output feedback systems respectively. Both these approaches require an FDI scheme to estimate the effectiveness levels of the actuators, because this information is used explicitly in the control allocation component in the control scheme.…”

Performance Comparison of Controllers with Fault-Dependent Control Allocation for UAVs

“…A further improvement is proposed in [24] using an integral sliding mode (ISM), which combines a controller that handles uncertainties of a system with the sliding mode control. If the system is subjected to external bounded disturbances, the ISM will compensate using sliding mode control while the original controller handles the unperturbed system [25]. In [26], an FTC structure which handles control surface failure is introduced by a combined use of generalized dynamic inversion control and ISM control.…”

“…In [26], an FTC structure which handles control surface failure is introduced by a combined use of generalized dynamic inversion control and ISM control. An over-actuated aircraft can easily maintain the required forces and moments even though a fault has occurred by applying the CA approaches suggested in [1] and [25]. However, many small UAVs are not over-actuated and hence using the CA from [1] is not possible.…”

UAV fault-tolerant control by combined L<inf>1</inf> adaptive backstepping and fault-dependent control allocation

“…Many small UAVs are not over-actuated and hence using CA to obtain redundancy in the actuators, as in [1] and [17], is not possible. Instead, this paper investigates CA of the forces and moments acting on the aircraft.…”