Under-actuated release control method based on nonlinear space tether system

A space tether and release control technology, applied in non-electric variable control, vehicle position/route/height control, attitude control, etc., can solve the problem of insufficient perturbation factors, time-consuming calculation, and lack of global stability in radial release control gender analysis

Active Publication Date: 2016-10-26
NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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Problems solved by technology

[0003] By paying attention to previous research results, it can be found that the optimal release control strategy of the tether represented by the optimal path or time, the control process usually causes a large oscillation of the tether, and consumes a lot of computing time; the optimal release control strategy r...

Method used

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  • Under-actuated release control method based on nonlinear space tether system
  • Under-actuated release control method based on nonlinear space tether system
  • Under-actuated release control method based on nonlinear space tether system

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Embodiment

[0092] The parameters are selected to numerically verify the stability of the release control process of the tethered satellite system. Let the true anomaly angle v at the initial moment of the system be 0 = 0, dimensionless tether length ξ 0 =0.01, and the eccentricity of the Kepler orbit e=0.05, the stability of the system near the equilibrium point can be determined based on the Floquet theory.

[0093] Study the desired out-of-plane roll angle φ e = 0 where the equilibrium point (θ e ,0,φ e ,0), according to the expression (11) of the value range of the expected in-plane pitch angle, we can get θ e ∈[-π / 4,-0.0334). Numerical simulation can obtain the relationship between the maximum eigenvalue modulus of the single-valued matrix of the system within the definition domain and the pitch angle in the expected plane, as shown in image 3 shown. It can be seen from the figure that for φ e =0, when the desired pitch angle θ e ∈[-π / 4,-0.0334), there is |λ i | max e ∈[-...

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Abstract

The invention provides an under-actuated release control method based on a nonlinear space tether system. The method comprises the following steps: 1, a dumbbell model is adopted, system dynamics differential equations are built according to a second kind Lagrange equation, and a dimensionless form is introduced in the differential equations; 2, based on a normal form expression for the above dynamics differential equations, expected values for a system in-plane pitching angle and an out-plane rolling angle are set, and the balance position of the system in the release process is obtained; 3, starting from the balance position of the system, a tether length change control law for realizing tether release is deduced and obtained; and 4, the range for the expected in-plane pitching angle is determined to ensure the tether release process to be asymptotically stable under effects of the control law. Numerical simulations show that the space tether can be released asymptotically stably under effects of the release control method provided by the invention, and an attractor capable of covering the balance point and an attraction domain with enough thickness can be found out.

Description

technical field [0001] The invention relates to the field of spacecraft control, in particular to an underactuated release control method for a nonlinear space tether system, and can prove that the method is globally stable. Background technique [0002] Space tether release technology has received extensive attention from scholars. For example, Barkow et al. compared the release control effects of various methods such as brake control, Kissel control, and optimal control on tethered satellites. Tanaka et al. designed a set of open-loop control laws for a type of micro-tethered satellite, which can effectively suppress the in-plane pitch angle of the tether during release. Williams constructed the nonlinear dynamic equation of the six-degree-of-freedom tethered satellite, and achieved the optimal release / recovery control of the tether by adjusting the tension, but it caused a large tether swing during the period. Taking into account the rigid-flexible coupling effect, Yu e...

Claims

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Application Information

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IPC IPC(8): G05D1/08
CPCG05D1/0808
Inventor 余本嵩金栋平文浩
Owner NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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