A satellite active fault-tolerant control method based on observer and online control assignment

Abstract

The invention relates to a satellite active fault-tolerant control method based on an observer and online control allocation. The active fault-tolerant control method based on the iterative learning observer is provided for the problems of actuator faults, limited input saturation and external disturbance in the satellite attitude control process. The method comprises the following steps that a satellite attitude control system model is established by considering the actuator faults and the external disturbance subjected by a satellite; the iterative learning observer is designed, and invalidation factors of an actuator are estimated; a virtual feedback controller is constructed based on fault estimation information, online control allocation is conducted simultaneously, and therefore precise estimation of the actuator faults and controller reconstruction can be conducted through the satellite. According to the method, the stability of the attitude control system is guaranteed when an on-orbit working satellite is subjected to actuator faults, and the method has the advantages that the control accuracy is high, and the fault-tolerant capability and robustness to the external disturbance are high.

Description

technical field [0001] The invention relates to an active fault-tolerant control method for satellites based on observers and online control distribution, which is mainly used in attitude control where actuator failures occur when satellites are in orbit and are subject to external disturbance moments from space and amplitude saturation constraints of actuators The system belongs to the technical field of spacecraft control. Background technique [0002] April 23, 2016 is my country's first "China Aerospace Day". At the same time, as the first year of the "13th Five-Year Plan", China's Mars exploration mission was officially approved, and the construction of the national civil space infrastructure project was fully launched. "Chang'e-4 "The mission was fully launched, "Chang'e-5" entered the decisive stage, the "Beidou" navigation system accelerated the global networking, "Tiangong-2" and "Shenzhou-11" launched and docked, and the "Mozi" quantum science experiment satellite h...

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Problems solved by technology

Relevant data show that in the entire spacecraft system, the failures of the two major subsystems of attitude control and energy account for 59% of the total failures; during the satellite's orbital operation, the flywheel is in a running state for a long time, which is affected by factors such as the space environment and frictional torque , is prone to failure, and some degree of failure is fatal, which will lead to the complete loss of control of the spacecraft, resulting in the complete failure of the space mission. One type of actuator failure is a failure failure. For example, the increase of the friction torque between the stator and rotor of the reaction flywheel will affect the change rate of the flywheel wheel body speed, so that the actual output control torque of the flywheel is reduced in proportion to the nominal torque, resulting in the loss of part of the flywheel output torque. ; During orbital operation, the spacecraft exhibits strong nonlinearity and will be affected by various disturbance moments from space, and in the actual system, because the control torque provided by the actuator is limited, it may not be able to provide the required torque. It affects the control performance to a certain extent; therefore, considering these problems, improving the fault tolerance and robustness of the system while ensuring satisfactory control accuracy and control requirements is the focus and difficulty of the satellite attitude control system

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