Finite-Time Prescribed Performance Fault-Tolerant Attitude Control for Rocket Substage Recovery by Parafoil

Parafoil is one of the important approaches for achieving low-cost and precise recovery of the rocket substage. To address the challenges posed by uncertain disturbances and faults such as partial failures and biases in parafoil actuators arising from the extreme multiphysics field coupling environment which involves force, thermal, electrical, and magnetic effects, as well as the strong coupling and nonlinearity inherent in the rocket substage and parafoil, a fault-tolerant attitude controller is proposed in this article, which integrates finite-time prescribed performance backstepping sliding mode control (FPBSMC) with sliding mode disturbance observer (SMDO) to effectively compensate for actuator faults and suppress uncertain lumped disturbances, ensuring stable attitude control of the parafoil-substage combination (PSC). First, the nonlinear model of the PSC and the actuator fault model are established. Second, the SMDO is proposed to estimate the lumped disturbance torque caused by uncertain disturbances and actuator faults. Third, the FPBSMC fault-tolerant attitude controller is developed to compensate for the lumped disturbance torque and achieve high-precision, rapid fault-tolerant attitude control of the PSC. Finally, numerical simulations and hardware-in-loop experiments are conducted to validate the controller’s performance under various fault scenarios. The experimental results demonstrate that the proposed FPBSMC and SMDO-based controller achieves excellent fault-tolerant performance and attitude tracking accuracy, even under actuator faults and uncertain disturbances.