Experimental study on dynamics and control of tethered satellite systems with climber

Mission-function control of tethered satellite/climber system

“…Thus, the complete suppression of the librational motion of a TSS using only the climber motion has not been focused on in [22,24]. Instead, Kojima et al [24] derived optimal climber acceleration profiles to reduce the residual librational motion as much as possible for specific initial conditions, and studied their effectiveness numerically and experimentally.…”

“…Thus, the complete suppression of the librational motion of a TSS using only the climber motion has not been focused on in [22,24]. Instead, Kojima et al [24] derived optimal climber acceleration profiles to reduce the residual librational motion as much as possible for specific initial conditions, and studied their effectiveness numerically and experimentally. The controllers in [20][21][22]24,26] showed good results, however, they are not always applicable to real situations Nomenclature a 1 ; a 2 ; a 3 ; a 4 weighting coefficients for mission-function control k 1 ; k 2 control gains L 0 ; L m initial and desired tether length between mother satellite and subsatellite L total tether length ðL ¼ L 1 þ L 2 Þ L 1 ; L 2 tether lengths between mother satellite and climber and between climber and subsatellite, respectively L m1 ; L m2 desired tether lengths between mother satellite and climber and between climber and subsatellite, respectively L s1 ; L s2 initial tether lengths between mother satellite and climber and between climber and subsatellite, respectively M F ; M F1 ; M F2 mission functions m 1 ; m 2 masses of climber and subsatellite, respectively N conversion factor to non-dimensional scale,…”

“…Even if the simplest tether model is used such as two bars with a bend at the climber position [22][23][24][25], complete regulation of tether librations cannot be achieved with only a single crawling climber, because tether angles cannot be fully controlled with the motion of a crawling climber. Thus, the complete suppression of the librational motion of a TSS using only the climber motion has not been focused on in [22,24].…”

“…The model assumed for SE in [20,21] was a rigid ribbon, which included libration of SE, but did not consider bending at the climber position, although bending occurs for a flexible tether because of the Coriolis force. Instead of the rigid ribbon model, more suitable models for treating bending of tether at the climber position are two bar model [22][23][24][25], three-bar model [26], and multibody model [27,28]. Kojima et al [24] studied the effect of climber moving constant velocity on the dynamic behavior of a two-bar modelled TSS.…”

“…Instead of the rigid ribbon model, more suitable models for treating bending of tether at the climber position are two bar model [22][23][24][25], three-bar model [26], and multibody model [27,28]. Kojima et al [24] studied the effect of climber moving constant velocity on the dynamic behavior of a two-bar modelled TSS. Jung et al [25] studied the effects of the mass ratio, climber velocity and tether length on the dynamic behavior of a two-bar modelled TSS.…”