Disturbance Rejection and Robust Least-Squares Control Allocation in Flight Control System

The problem of disturbance rejection and control allocation with an uncertain control effectiveness matrix is investigated in this paper for a flight control system. AnH2=H1 feedback controller is designed to produce the three axismoments and simultaneously suppress disturbance noise. A feedforward controller is used to track the reference signals.Under the condition of uncertainty included in the control effectivenessmatrix, a robust least-squares scheme is employed to deal with the problem of distributing the three axis moments to the corresponding control surfaces. The proposed robust least-squares control allocation is studied for both unstructured and structured uncertainties. To illustrate the effectiveness of the proposed scheme, a simulation for an experimental satellite launch vehiclemodel is conducted. Comparisons of robust least-squares control allocation and pseudoinverse control allocation are presented. Results show that a disturbance is rejected and robust least-squares control allocation is effectively robust to uncertain control effectiveness matrix.

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