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A Spacecraft Attitude Control Method Based on Sigmoid Nonlinear Sliding Mode Function

An attitude control and non-linear technology, applied in attitude control and other directions, can solve problems such as control torque chattering, switching gain conservatism, etc., to achieve the effect of improving dynamic performance, speeding up system response speed, and facilitating engineering realization

Active Publication Date: 2017-02-22
BEIJING MECHANICAL EQUIP INST
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] The purpose of the present invention is to provide a spacecraft attitude control method based on the Sigmoid nonlinear sliding mode function, which solves the sliding mode function gain selection trade-off problem and the control torque of the existing first-order sliding mode attitude control law based on the linear sliding mode function. Chattering, switching gain conservatism, and sensor saturation issues

Method used

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  • A Spacecraft Attitude Control Method Based on Sigmoid Nonlinear Sliding Mode Function
  • A Spacecraft Attitude Control Method Based on Sigmoid Nonlinear Sliding Mode Function
  • A Spacecraft Attitude Control Method Based on Sigmoid Nonlinear Sliding Mode Function

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Embodiment

[0130] The present invention carries out simulation verification under the environment of Matlab2009a. The nominal value of the spacecraft inertia matrix is

[0131]

[0132] The uncertainty range of the inertia array is ±20%, the external disturbance is determined by the orbital parameters of the spacecraft, and the initial inertial attitude variable of the spacecraft is: σ b (t 0 )=0, ω b (t 0 )=0(rad / s). The desired attitude variable is the σ corresponding to the LVLH system of the target orbit d and ω d . Among them, the target orbit is a circular orbit, the orbit radius a=6899807 (m), the eccentricity is 0, the orbit inclination angle i=30°, the right ascension of the ascending node Ω=60°, the argument of perigee ω=0°, the initial true approach point angle f(t 0 )=90°. In the simulation, it is considered that the range of the attitude sensor for measuring the relative attitude angular velocity is 0.02 (rad / s).

[0133] Control law parameter selection: k=0.012...

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Abstract

The invention discloses a spacecraft posture control method based on a Sigmoid nonlinear sliding mode function. The method comprises the steps that a relative posture motion equation when a spacecraft is subjected to large-angle posture maneuvering is expressed to be in a cascading mode, then a typical Sigmoid function is introduced into a sliding mode function, and the Sigmoid nonlinear sliding mode function and a sliding mode posture control law are determined, so that the system state achieves expected equivalent system dynamics in the sliding mode section. The sliding mode posture control law is amended, the buffeting of control torque is restrained, and conservatism for switching gain selections is reduced. By the utilization of the method, the problem of weighing of sliding mode function gain selections of a sliding mode posture control law based on a linear sliding mode function in the prior art is effectively solved, and the control performance of the sliding mode posture control law is improved. In addition, the problem of saturation of a sensor is effectively avoided by utilization of boundedness of the Sigmoid function, and high-performance posture control over the spacecraft is achieved when the relative posture angular speed is restricted.

Description

technical field [0001] The invention relates to a spacecraft attitude control method, in particular to a spacecraft attitude control method based on a Sigmoid nonlinear sliding mode function. Background technique [0002] For rigid-body spacecraft, the coupling between channels is severe during large-angle attitude maneuvering, showing strong nonlinear dynamic characteristics. In addition, various parameter uncertainties and the existence of external disturbances make its attitude control extremely complicated. The key problem to be solved in the design of rigid body spacecraft attitude control system is to design the attitude control law according to the nonlinear attitude motion equation to suppress the influence of parameter uncertainty and external disturbance. [0003] At present, there are many methods for the design of attitude control system of rigid body spacecraft. Among them, sliding mode control is the most widely used robust nonlinear control method. Sliding ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G05D1/08
Inventor 丛炳龙任博马相孚
Owner BEIJING MECHANICAL EQUIP INST