Fault-tolerant Reconfigurable Control for Reusable Launch Vehicle Using NESO

Reusable launch vehicle (RLV) has multiple different kinds of control effectors. These redundant effectors provide RLV the potential to maintain acceptable stability and performance even when some of them get failures. Proper control allocation and re-allocation after control effectors failure are necessary for RLV. A new fault-tolerant reconfigurable controller integrating control allocation is proposed in this paper. The new controller contains two parts: the basic controller and the compensated controller. The basic controller is designed to guarantee high performance without thinking the disturbances of the RLV. Nonlinear extended state observer (NESO) is used to estimate the disturbances. The compensated control uses the estimation to build the compensation command and eliminate the influence of disturbances. Control allocation is used to distribute the virtual control command to aerodynamic control effectors and reaction control system. After the fault is located, the re-allocation will be conducted to use the healthy control effectors to compensate the failed ones. Simulation results show that the proposed controller could achieve satisfactory performance dealing with the disturbances and control effector failures.