Spacecraft Vibration Reduction 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 takes full 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-off thruster ring. Compared to other methods, this new approach has numerous advantages: 1) effectiveness in vibration suppression, 2) dependence only on modal frequency and damping, 3) robustness to variations in 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.

Vibration suppression of flexible spacecraft during attitude control

“…Due to nonlinear nature of the modulator, analytic methods such as describing function cannot produce accurately prediction over a large operation range. Instead, extensive numerical simulations have been carried out to study the e ects of these parameters on the performances of the modulator and the FSS [7,13] prior to this research. This paper only presents results from the numerical studies and details on PWPF parameter selection can be found in [13].…”

Design of an Adaptive Controller of a Satellite using Thruster Actuator

“…In general, pulse modulators produce a pulse command sequence to thruster valves by adjusting pulse width and/or pulse frequency [5]. So far different Pulse modulators such as pseudo-rate modulator [6], integral-pulse frequency modulator [7,8] and Pulse-Width Pulse-Frequency (PWPF) modulator [9,10,11,12] have been proposed and examined. In comparison with others, the PWPF modulator has several superior advantages such as close to linear operation, high accuracy and adjustable pulse width and pulse frequency [5].…”

Maneuvers and Vibration Suppression of Flexible Spacecraft Integrating Variable Structure Control and Input Shaping Technique

“…Banerjee and Singhose 4,5) proposed application of input shaping for minimum-time control of a twolink flexible manipulator. Song et al 6) treated application of input shaping for reduction of vibration of a flexible spacecraft, using pulse-width pulse-frequency modulated thrusters. References 7 to 9 repeated experimental testing of command shaping techniques on flexible link manipulators.…”