title: A method for evaluating the thrust of a space propulsion device with wide range time variations using a disturbance observer.
abstract: A new method for evaluating thrust with high-frequency variations beyond the resonant frequency using a disturbance observer is presented. Setpoint control is applied to a conventional pendulum-type thrust stand to keep the pendulum at the target position using a solenoid actuator. During control, pendulum acceleration and solenoid-actuator current are measured, and the disturbance observer determines thrust with a wide range of frequency variations. The method allows thrust to be evaluated not only with constant and low-frequency variations, but also with high-frequency variations outside the resonant frequency. A thrust measurement device is prototyped to investigate accuracy over a wide frequency range from 0 to 100 Hz and the effects of the proportional-derivative-integral (PID) controller design. Calibration yields thrust measurement errors of 20% below 90 Hz. PID controller design has a smaller influence on the accuracy of the proposed method than the conventional null-balance method, so the proposed method requires the same stability under PID control as that for the null-balance method.
authors.affiliation: Department of Mechanical Design Systems Engineering, University of Miyazaki, 1-1 Gakuenkibanadai-nishi, Miyazaki 889-2192, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Kakami
authors.affiliation: Department of Mechanical Systems Engineering, University of Miyazaki, 1-1 Gakuenkibanadai-nishi, Miyazaki 889-2192, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Muto
authors.affiliation: Faculty of Engineering, University of Miyazaki, 1-1 Gakuenkibanadai-nishi, Miyazaki 889-2192, Japan.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Yano
authors.affiliation: Department of Mechanical Engineering, Kyushu Institute of Technology, 1-1 Sensui-cho, Tobata, Kitakyushu, Fukuoka 884-8550, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Tachibana