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UI ME 1997-1998 Senior Capstone Design 
Team Zero-G
Electrostatic Levitator
    Literature review
      An Electrostatic Levitator for high-temperature containerless materials processing in 1-g.  Won-Kyu Rhim, et al., Rev. Sci. Intstrum. 64 (10), Oct. 1993 
      Summary:  This paper presents continuing research utilizing the levitator described in the 1985 paper by Dr. Rhim.  This levitator has a six electrode configuration. This configuration provides active damping in three dimensions, but only in 1-g.  This paper also discusses position control system logic.  There is a detailed discussion on capacitive charging and its effect on the launch voltage.  There are very good graphs showing the required launch voltage for different sphere masses.  From this paper (and the 1985 paper) we get a starting point for the range of variables and expected results. 

      Development of an electrostatic positioner for space materials processing. 
      W.  K. Rhim, et al., Rev. Sci. Instrum. 56 (2), February 1985 
      Summary:  This paper featured three electrode configurations: Dish type, Ring and Disk, and Tetrahedral.  Dish type, which will be our first prototype, only has active control in one dimension.  This electrode configuration only works in 1-g, and damping in the radial direction is only due to the viscosity of the gas surrounding the sphere.  Ring and Disk type has similar performance to the Dish type, with the addition of passive damping in the radial direction.  This paper presents basic PID control system algorithms.  A high-voltage amplifier schematic is included which can be used to build your own.   Charging and launching are also discussed in some detail. 

      A Novel Method for Near-Critical Viscosity Measurements in 1-g and in Microgravity.  Ralph S. Budwig, Anthony R. H. Goodwin 
      Summary:  This was a proposal sent to NASA requesting a grant for research.  They were denied, but this paper created the motivation for our experiment, that being, if we could develop the apparatus described in this paper, that there would be a better chance receiving a grant when the paper is resubmitted.  The ultimate goal of this research is to conduct precision viscosity measurement on gasses at the critical point in zero-g.  Our apparatus and experiment requirements are taken from this proposal. 

      Direct Electrostatic Levitation and Propulsion.  Ju Jin, Toshiro Higuchi,  IEEE Transactions on Industrial Electronics. Vol. 44, No. 2, 1997 
      Summary:  This paper presents suggestions for high voltage safety and avoiding electrostatic discharge.  It also presents concepts in electrostatic propulsion.