Spacecraft Vibration Using Pulse-Width Pulse-Frequency Modulated Input Shaper

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Authors
Song, G.
N. Buck
Agrawal, B.N.
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Advisors
Date of Issue
1997
Date
August 11-13, 1997
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Language
Abstract
Minimizing vibrations of a exible spacecraft actuated by on-off thrusters is a challenging task. This paper presents the rst study of pulse-width pulse-frequency modulated thruster control using command input shaping. Input shaping is a technique that uses a shaped command to ensure zero residual vibration of a exible structure. Pulse-width pulse-frequency modulation is a control method that provides pseudolinear operation for an on-off thruster. The proposed method takesfull advantage of the pseudolinear property of a pulse-width pulse-frequency modulator and integrates it with a command shaper to minimize the vibration of a exible spacecraft induced by on-offthruster ring. Compared to other methods, this new approachhas numerous advantages:1) effectiveness in vibration suppression, 2) dependence only on modal frequency and damping, 3) robustness to variationsin modal frequency and damping, and 4) easy computation. Numerical simulations performed on an eight-mode model of the Flexible Spacecraft Simulator in the Spacecraft Research and Design Center at the U.S. Naval Postgraduate School demonstrate the ef cacy and robustness of the method. Minimizing vibrations of a exible spacecraft actuated by on-off thrusters is a challenging task. This paper presents the rst study of pulse-width pulse-frequency modulated thruster control using command input shaping. Input shaping is a technique that uses a shaped command to ensure zero residual vibration of a exible structure. Pulse-width pulse-frequency modulation is a control method that provides pseudolinear operation for an on-off thruster. The proposed method takesfull advantage of the pseudolinear property of a pulse-width pulse-frequency modulator and integrates it with a command shaper to minimize the vibration of a exible spacecraft induced by on-offthruster ring. Compared to other methods, this new approachhas numerous advantages:1) effectiveness in vibration suppression, 2) dependence only on modal frequency and damping, 3) robustness to variationsin modal frequency and damping, and 4) easy computation. Numerical simulations performed on an eight-mode model of the Flexible Spacecraft Simulator in the Spacecraft Research and Design Center at the U.S. Naval Postgraduate School demonstrate the ef cacy and robustness of the method. Minimizing vibrations of a exible spacecraft actuated by on-off thrusters is a challenging task. This paper presents the rst study of pulse-width pulse-frequency modulated thruster control using command input shaping. Input shaping is a technique that uses a shaped command to ensure zero residual vibration of a exible structure. Pulse-width pulse-frequency modulation is a control method that provides pseudolinear operation for an on-off thruster. The proposed method takesfull advantage of the pseudolinear property of a pulse-width pulse-frequency modulator and integrates it with a command shaper to minimize the vibration of a exible spacecraft induced by on-offthruster ring. Compared to other methods, this new approachhas numerous advantages:1) effectiveness in vibration suppression, 2) dependence only on modal frequency and damping, 3) robustness to variationsin modal frequency and damping, and 4) easy computation. Numerical simulations performed on an eight-mode model of the Flexible Spacecraft Simulator in the Spacecraft Research and Design Center at the U.S. Naval Postgraduate School demonstrate the ef cacy and robustness of the method. Minimizing vibrations of a exible spacecraft actuated by on-off thrusters is a challenging task. This paper presents the rst study of pulse-width pulse-frequency modulated thruster control using command input shaping. Input shaping is a technique that uses a shaped command to ensure zero residual vibration of a exible structure. Pulse-width pulse-frequency modulation is a control method that provides pseudolinear operation for an on-off thruster. The proposed method takesfull advantage of the pseudolinear property of a pulse-width pulse-frequency modulator and integrates it with a command shaper to minimize the vibration of a exible spacecraft induced by on-offthruster ring. Compared to other methods, this new approachhas numerous advantages:1) effectiveness in vibration suppression, 2) dependence only on modal frequency and damping, 3) robustness to variationsin modal frequency and damping, and 4) easy computation. Numerical simulations performed on an eight-mode model of the Flexible Spacecraft Simulator in the Spacecraft Research and Design Center at the U.S. Naval Postgraduate School demonstrate the ef cacy and robustness of the method.
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The article of record as published may be found at http://dx.doi.org/10.2514/6.1997-3748
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Department of Mechanical and Aerospace Engineering
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AIAA Guidance, Navigation, and Control Conference, New Orleans, LA, August 11-13, 1997.
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This publication is a work of the U.S. Government as defined
in Title 17, United States Code, Section 101. As such, it is in the
public domain, and under the provisions of Title 17, United States
Code, Section 105, is not copyrighted in the U.S.
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