This paper presents a novel form of control allocation, designed within
a sliding mode framework, for the fault tolerant control of over-actuated
systems. The control allocation is designed in such a way as to allow a subset of the actuators to remain inactive under nominal fault-free conditions.
In the event that the active set of ...
This paper presents a novel form of control allocation, designed within
a sliding mode framework, for the fault tolerant control of over-actuated
systems. The control allocation is designed in such a way as to allow a subset of the actuators to remain inactive under nominal fault-free conditions.
In the event that the active set of actuators becomes unable to provide
the desired performance, an adaption process takes place which allows
the inactive actuators to compensate. A computationally light gradient
descent algorithm is proposed to govern the adaption which guarantees
that, if possible, actuator saturation is avoided and system performance
is maintained - even in the event of severe actuator faults and failures.
Rigorous conditions are derived, in terms of the faults/failures, uncertainties in fault reconstruction information and the adaptive process, which
ensures sliding occurs in a finite time and that the resulting motion is
stable. To demonstrate the effectiveness of the control scheme, a highfidelity blended wing body aircraft model is also proposed in this paper;
this particular configuration of aircraft is nominally unstable, with poor
control authority and a large amount of redundancy - making it a suitable candidate for testing reconfigurable fault tolerant control laws in the
presence of input constraints.