Stability Properties and Cross-Coupling Performance of the Control Allocation Scheme CAPIO.

This paper is concerned with further development of a recently proposed algorithm for control allocation to recover from pilot-induced oscillations (CAPIO). When actuators are ate-saturated due to either an aggressive pilot command, high gain of the flight control system, or some anomaly in the system, the effective time delay in the control loop may increase. This effective time-delay increase manifests itself as a phase shift between the commanded and actual signals and can instigate pilot-induced oscillations. CAPIO reduces the effective time delay by minimizing the phase shift between the commanded and the actual attitude accelerations. Theoretical stability analysis results are presented for a scalar input-signal case. Simulation results for an unstable aircraft with cross-coupling and multiple control channels demonstrate the potential of CAPIO serving as an effective pilot-induced oscillation handler in adverse conditions. [ABSTRACT FROM AUTHOR]