Rigid spacecraft preset time fault-tolerant attitude control strategy

Abstract

The invention discloses a rigid spacecraft preset time fault-tolerant attitude control strategy, which is characterized in that a control target is achieved through the construction of a preset time fault-tolerant controller and a preset time attitude controller, wherein system upper bounds with incomplete fault of an actuator, saturation of an actuator, external interference and uncertainty of system inertial parameters are estimated in real time within a preset time through an obstacle self-adaptive law based on an integral sliding mode while uncertain items of the system within the preset time are compensated so as to realize fault-tolerant control within the preset time, and then a preset time attitude controller based on a second-order sliding mode variable is designed to realize that an attitude tracking error converges to zero within preset time. According to the control strategy, the attitude tracking control problem of the rigid spacecraft under the conditions of incomplete actuator fault, actuator saturation, external interference and uncertainty of system inertial parameters is solved, the algorithm robustness is high, fault-tolerant control is realized within preset time, and the tracking performance is good.

Description

technical field [0001] The invention relates to the technical field of attitude control of small spacecraft, in particular to a predetermined time fault-tolerant attitude control strategy for a small rigid body spacecraft system with actuator failure and actuator saturation, which can be applied to small rigid body spacecraft and contributes to small spacecraft deep Developments in the field of space exploration. Background technique [0002] Small spacecraft refers to a spacecraft with a mass of less than 1000kg. Since the 1950s, with the development of technologies such as computers, new materials, and new processes, small spacecraft with high functional density and strong technology have become the focus of research in various countries. Compared with larger spacecraft, it not only has a series of advantages such as small size, light weight, and high technical content, but also has a short development cycle and a flexible launch platform. At the same time, small spacecra...

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Problems solved by technology

[0003] It should be noted that the spacecraft has been in a high-radiation, low-temperature, and vacuum environment for a long time. It is affected by environmental disturbances and uncertain inertial parameters due to fuel consumption. The design of a high-performance spacecraft attitude controller still faces challenges. many challenges

First of all, due to working in a harsh environment for a long time, various failures will inevitably occur during the operation cycle of the orbiting spacecraft. Among them, the more common actuator mechanism failures, such as incomplete failure of the actuator, saturation of the actuator and random drift failures, if the spacecraft fails, it is basically impossible to repair

Subsequently, the time for spacecraft fault tolerance and spacecraft attitude convergence can only be roughly estimated as a bound and cannot be given directly when designing a spacecraft. Therefore, there is an urgent need for a predetermined time fault-tolerant attitude control strategy for small rigid-body spacecraft , to ensure the robustness and reliability of the system under external disturbances, parameter perturbations, actuator failures, and saturation conditions

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