Fault-tolerant sliding-mode control method for near-space vehicle

Abstract

The invention discloses a fault-tolerant sliding-mode control method for a near-space vehicle. According to the fault-tolerant sliding-mode control method for the near-space vehicle, for the situation that the order of the magnitude of external disturbance in a quick loop and slow loop system is greatly larger than the order of the magnitude of uncertain times of the system, the nonlinear disturbance observer technology is used for processing hybrid disturbance, and unknown hybrid disturbance is estimated by a disturbance observer through known system information; in order to solve the problem that saturation of the control surface of the near-space vehicle is limited, the upper bound of the deflection angle output of a steering engine is applied to design of a control law, it is guaranteed that the input is within a certain range, auxiliary variables are designed, the deflection angle output of the steering engine is automatically adjusted through the self-adaption law, and therefore the situation that when the upper bound of the deflection angle is too large, the output is too large is avoided; a compensator is established through a radial basis function neural network and is used for fault-tolerant compensation when the steering engine breaks down, and therefore the problem that the steering engine of the near-space vehicle breaks down is solved. By the adoption of the fault-tolerant sliding-mode control method for the near-space vehicle, under the conditions of system uncertainties, unknown external disturbance, limited input saturation and a fault of the steering engine, the near-space vehicle has good control performance.

Description

technical field [0001] The invention relates to the technical field of flight control, in particular to a fault-tolerant sliding mode control method for a near-space aircraft. Background technique [0002] A near-space vehicle (NSV) refers to an aircraft that operates in a near space (usually refers to the airspace 20-100 kilometers above the ground). The airspace below the near space is the operating space of traditional aircraft. The airspace above is the spacecraft operating space. Near-space vehicles have the advantages of strong maneuverability, large flight envelope, and strong survivability. It is difficult to study the flight control of such vehicles. [0003] First of all, in order to design a control system with high precision and strong robust stabilization capability, it is necessary to fully consider the system structure uncertainty and the influence of external disturbances on the system when designing the controller of the near-space vehicle; secondly, the de...

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Problems solved by technology

[0007] The existing fault-tolerant sliding mode control methods for near-space vehicles generally use the T-S fuzzy model to approach the dynamic attitude model of the space vehicle, and rarely consider external disturbances and actuator saturation phenomena, and mostly treat external disturbances and actuator saturation phenomena as Fault-tolerant information is processed, which cannot fully reflect its dynamic characteristics. Fault diagnosis is required before fault tolerance, and fault tolerance is performed based on diagnostic information. This type of method has high requirements for fault diagnosis. If the fault information cannot be accurately diagnosed, it will be impossible To a very good fault-tolerant effect, it can not even guarantee the stable flight of the aircraft and cause the crash of the aircraft entering the space

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