Impact of plasma noise on a direct thrust measurement system.
Pottinger, SJ, Lamprou, D, Knoll, AK and Lappas, VJ (2012) Impact of plasma noise on a direct thrust measurement system. Rev Sci Instrum, 83 (3).
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In order to evaluate the accuracy and sensitivity of a pendulum-type thrust measurement system, a linear variable differential transformer (LVDT) and a laser optical displacement sensor have been used simultaneously to determine the displacement resulting from an applied thrust. The LVDT sensor uses an analog interface, whereas the laser sensor uses a digital interface to communicate the displacement readings to the data acquisition equipment. The data collected by both sensors show good agreement for static mass calibrations and validation with a cold gas thruster. However, the data obtained using the LVDT deviate significantly from that of the laser sensor when operating two varieties of plasma thrusters: a radio frequency (RF) driven plasma thruster, and a DC powered plasma thruster. Results establish that even with appropriate shielding and signal filtering the LVDT sensor is subject to plasma noise and radio frequency interactions which result in anomalous thrust readings. Experimental data show that the thrust determined using the LVDT system in a direct current plasma environment and a RF discharge is approximately a factor of three higher than the thrust values obtained using a laser sensor system for the operating conditions investigated. These findings are of significance to the electric propulsion community as LVDT sensors are often utilized in thrust measurement systems and accurate thrust measurement and the reproducibility of thrust data is key to analyzing thruster performance. Methods are proposed to evaluate system susceptibility to plasma noise and an effective filtering scheme presented for DC discharges.
|Divisions :||Faculty of Engineering and Physical Sciences > Electronic Engineering > Surrey Space Centre|
|Date :||March 2012|
|Identification Number :||https://doi.org/10.1063/1.3692740|
|Additional Information :||
Copyright 2012 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.
The following article appeared in Review of Scientific Instruments, 83 (3) and may be found at S. J. Pottinger et al., Rev. Sci. Instrum. 83, (2012)
|Depositing User :||Symplectic Elements|
|Date Deposited :||21 Oct 2013 08:54|
|Last Modified :||21 Oct 2013 08:54|
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