Real-Time Optimization for use in a Control Allocation System to Recover from Pilot Induced Oscillations

Abstract

Integration of the Control Allocation technique to recover from Pilot Induced Oscillations (CAPIO) System into the control system of a Short Takeoff and Landing Mobility Concept Vehicle simulation presents a challenge because the CAPIO formulation requires that constrained optimization problems be solved at the controller operating frequency. We present a solution that utilizes a modified version of the well-known L-BFGS-B solver. Despite the iterative nature of the solver, the method is seen to converge in real time with sufficient reliability to support three weeks of piloted runs at the NASA Ames Vertical Motion Simulator (VMS) facility. The results of the optimization are seen to be excellent in the vast majority of real-time frames. Deficiencies in the quality of the results in some frames are shown to be improvable with simple termination criteria adjustments, though more real-time optimization iterations would be required.

Adaptive Closed-Loop Control Allocation-Based Fault Tolerant Flight Control for an Overactuated Aircraft

“…the direct control allocation method, the interior point method, the active set method, the adaptive estimation method etc., which can be found in [18]- [21]. In [22]- [24], a sequential quadratic programming technique is used to cope with the control allocation problem. Reference [25] proposes an adaptive sliding-modebased control allocation scheme to accommodate actuator faults, which is used to redistribute virtual control signals among the available actuators under faulty conditions.…”

Piloted Evaluation of a Control Allocation Technique to Recover from Pilot-Induced Oscillations

“…At each frame, the optimizer used the solution of the last problem as its initial point. For more details on the implementation, see [24].…”