On-line fault diagnosis of spacecraft attitude control thruster based on improved Maksimov estimation algorithm

By considering that the present spacecraft attitude control thruster fault diagnosis systems have limited functions and have not involved low leakage fault diagnosis, a scheme for spacecraft attitude control thruster fault diagnosis is proposed based on nonlinear attitude dynamics and improved Maksimov nonlinear input estimate algorithm. According to the estimated spacecraft attitude control input from Maksimov algorithm, thrust effectiveness factor is calculated and the detection of thrust loss is carried out, and based on absolute optical encoder, reaction torque estimate of flywheel is presented and the detection of propellant leak, especially low propellant leak is implemented. Thrust loss and propellant leak faults are simulated and diagnosed by the proposed scheme, and the effectiveness and practicality of the scheme are demonstrated.