Fault-Tolerant Flight Control Based on Two-Stage Approach and Interior Point Method

Abstract : The main objective of this paper is how to make the best use of remaining available actuators when an aircraft with an aerodynamic actuator failure tries to perform a guidance maneuver. Considering the flight dynamics of a transportation aircraft can be expressed as an input affine nonlinear system, a two-stage control approach is adopted here. At the first stage, nonlinear inverse control technique is used to generate virtual inputs related to the intended maneuver. At the second stage, an actuator reassignment problem how to achieve necessary virtual inputs by remaining available actuators is considered. Taking into account the physical limits of the remaining actuators and of the aircraft structure, the problem is formulated as a quadratic programming problem to get the corresponding control signals sent to the remaining actuators. The proposed solution method for this quadratic mathematical programming problem is based on a primal-dual path following interior point method. Numerical simulation studies based on the nonlinear aircraft models show that the proposed solution approach appears to provide acceptable response times to perform accurately the guidance maneuver.