Optimal placement of semi-active joints in large-space truss structures

2002 ◽  
Author(s):  
Jan Wirnitzer ◽  
A. Kistner ◽  
Lothar Gaul
Keyword(s):  
Optimal Placement ◽  
Truss Structures ◽  
Large Space ◽  
Space Truss ◽  
Active Joints

scholarly journals Semi-Active Friction Damping of Large Space Truss Structures

2004 ◽  
Vol 11 (3-4) ◽  
pp. 173-186 ◽  
Author(s):  
L. Gaul ◽  
H. Albrecht ◽  
J. Wirnitzer
Keyword(s):  
Vibration Suppression ◽  
Flexible Structures ◽  
Truss Structure ◽  
Truss Structures ◽  
Friction Damping ◽  
Large Space ◽  
Normal Forces ◽  
Space Truss ◽  
Active Friction ◽  
Local Feedback

The present approach for vibration suppression of flexible structures is based on friction damping in semi-active joints. At optimal locations conventional rigid connections of a large truss structure are replaced by semi-active friction joints. Two different concepts for the control of the normal forces in the friction interfaces are implemented. In the first approach each semi-active joint has its own local feedback controller, whereas the second concept uses a global, clipped-optimal controller. Simulation results of a 10-bay truss structure show the potential of the proposed semi-active concept.

Sequence planning for human and robot cooperative assembly of large space truss structures

2017 ◽  
Vol 89 (6) ◽  
pp. 804-808 ◽  
Author(s):  
Jifeng Guo ◽  
Chengchao Bai ◽  
Cheng Chen
Keyword(s):  
Ant Colony Algorithm ◽  
Truss Structures ◽  
Large Space ◽  
Content Type ◽  
Space Truss ◽  
Assembly Sequences ◽  
Planning Algorithm ◽  
Assembly Tasks ◽  
Cooperative Assembly

Purpose In the future, large space truss structures will be likely to require on-orbit assembly. One of the several proposed methods includes cooperative assembly performed by pressure-suited astronauts during extravehicular activity (EVA) and space robots. An intelligent planning method was presented to generate optimal assembly tasks. Design/methodology/approach Firstly, the inherent hierarchical nature of truss structures allows assembly sequences to be considered from strut level and structural volume element (SVE) level. Then, a serial assembly strategy in human-robot environment was applied. Furthermore, a two-level planning algorithm was presented. At the first-level planning, one ant colony algorithm for assembly sequence planning was improved to adopt assembly direction and time as heuristic information and did not consider assembly tasks. And, at the second-level planning, another novel colony algorithm for assembly task planning mainly considered results of the first-level planning, human-robot interactive information, serial assembly strategy and assembly task distributions. Findings The proposed two-level planning algorithm is very effective for solving the human and robot cooperative assembly of large space truss structures. Research limitations/implications In this paper, the case study is based on the following assumptions: each tetrahedron is assembled by two astronauts; each pentahedron is assembled by three astronauts. Practical implications A case illustrates the results of the two-level planning. From this case study, because of geometrical symmetry nature of large space truss structures, the optimal assembly sequences are not only one. Originality/value The improved ant colony algorithm can deal with the assembly sequence and task planning in human-robot environment more effectively.

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