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

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.