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Rendezvous guidance trajectories via multiple-subarc sequential gradient-restoration algorithm
被引:0
|作者:
Miele, A.
[1
]
Ciarcì, M.
[1
]
Weeks, M.W.
[2
]
机构:
[1] Rice Univ., Houston, TX 77005, United States
[2] NASA-Johnson Space Center, Houston, TX 77005, United States
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We consider the three-dimensional rendezvous between a target spacecraft in a circular orbit and a chaser spacecraft with an initial separation distance and an initial separation velocity. We assume that the chaser spacecraft has variable mass and that its trajectory is governed by three controls;
one determining the thrust magnitude and two determining the thrust direction. We employ the Clohessy-Wiltshire equations;
describing the relative motion of the chaser vis--vis the target;
and the multiple-subarc sequential gradient-restoration algorithm to produce first optimal trajectories and then guidance trajectories for the following problems: P1-minimum time;
fuel free;
P2-minimum fuel;
time free;
P3-minimum time;
fuel given;
P4-minimum fuel;
time given;
and P5-minimum timefuel;
time and fuel free. Clearly;
P1 and P2 are basic problems;
while P3;
P4;
and P5 are compromise problems. Problem P1 leads to a two-subarc solution including a max-thrust subarc followed by another max-thrust subarc. Problem P2 leads to a four-subarc solution including two coasting subarcs alternating with two max-thrust subarcs. Problems P5 leads to a three-subarc solution including two max-thrust subarcs alternating with one coasting subarc. Problems P3 and P4 include P1;
P2;
and P5 as particular cases and lead to two-;
three-;
or four-subarcs solutions depending on the prescribed value of fuel or time. For all problems;
the thrust magnitude control is saturated at one of its extreme values: in optimization studies;
we determine the best thrust direction controls;
in guidance studies;
we force the thrust direction controls to be constant in each subarc and determine the best thrust direction parameters. Of course;
the time lengths of all the subarcs must also be determined. The computational results show that;
for Problems P1-P5;
the performance index of the multiple-subarc guidance trajectory approximates well the performance index of the multiple-subarc optimal trajectory: the pairwise relative differences in performance index are less than 1100 in all cases. To sum up;
the produced guidance trajectories are highly efficient and yet quite simple in implementation. © 2009 ASCE;
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页码:160 / 172
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