Motion planning for the large space manipulators with complicated dynamics

SUMMARYBecause space manipulators must satisfy the law of conservation of momentum, any motion of a manipulator within a space-manipulator system disturbs the position and attitude of its free-floating base. In this study, the authors have designed a multi-swarm particle swarm optimization (PSO) algorithm to address the motion planning problem and so minimize base disturbances for 6-DOF space manipulators. First, the equation of kinematics for space manipulators in the form of a generalized Jacobian matrix (GJM) is introduced. Second, sinusoidal and polynomial functions are used to parameterize joint motion, and a quaternion representation is used to represent the attitude of the base. Moreover, by transforming the planning problem into an optimization problem, the objective function is analyzed and the proposed algorithm explained in detail. Finally, numerical simulation results are used to verify the validity of the proposed algorithm.

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Motion planning of strongly controllable stratified systems

Robotica ◽

10.1017/s0263574714002859 ◽

2015 ◽

Vol 34 (10) ◽

pp. 2223-2240

Author(s):

Ignacy Duleba ◽

Michal Opalka

Keyword(s):

Motion Planning ◽

Special Class ◽

Reliable Systems ◽

Space Manipulators ◽

Strong Controllability ◽

Simulation Results

SUMMARYIn this paper a motion planner for nonholonomic stratified systems was proposed. Those systems may arise easily when reliable systems are designed to be robust against failures in difficult servicing environments. For a special class of the systems, a strong controllability condition was introduced, and a criterion to satisfy the condition was formulated and used to plan the motion of free-floating space manipulators. Modules of the planner were enumerated and their roles were emphasized. Some features of the planner were examined and discussed based on simulation results performed on two models of space manipulators.

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Dynamic Modeling and Analysis of Space Manipulator Considering the Flexible of Joint and Link

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.823.270 ◽

2013 ◽

Vol 823 ◽

pp. 270-275 ◽

Cited By ~ 1

Author(s):

Pan Dong ◽

Zhao Yang ◽

Zhang Yue ◽

Wei Cheng ◽

E Wei

Keyword(s):

Joint Stiffness ◽

Low Frequency ◽

Flexible Link ◽

Large Space ◽

Flexible Joint ◽

Modeling And Analysis ◽

Position Accuracy ◽

Low Frequency Vibration ◽

Space Manipulators ◽

The Impact

The long length, light weight, low frequency, flexible joint and link of large space manipulators impact dynamic stability and position accuracy seriously. In this paper, dynamical model of space flexible manipulators system is build base on Lagrange method. With three DOF manipulators as the research object, the impact of flexible link, joint stiffness and clearance on the system frequency and end position accuracy of manipulator is simulated and analyzed. The results indicate that the flexible joint lead to low frequency vibration and flexible link lead to high frequency vibration. Low frequency vibration is the dominant impact of end position accuracy, Flexible joint have greater impact on the dynamic characteristics of system than that of flexible link.

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Seti Space Missions

International Astronomical Union Colloquium ◽

10.1017/s0252921100015372 ◽

1997 ◽

Vol 161 ◽

pp. 761-776 ◽

Cited By ~ 1

Author(s):

Claudio Maccone

Keyword(s):

Electromagnetic Waves ◽

Space Missions ◽

Gravitational Lens ◽

The Sun ◽

Space Antenna ◽

Focal Distance ◽

Large Space ◽

The Earth ◽

Space Antennas ◽

New Space

AbstractSETI from space is currently envisaged in three ways: i) by large space antennas orbiting the Earth that could be used for both VLBI and SETI (VSOP and RadioAstron missions), ii) by a radiotelescope inside the Saha far side Moon crater and an Earth-link antenna on the Mare Smythii near side plain. Such SETIMOON mission would require no astronaut work since a Tether, deployed in Moon orbit until the two antennas landed softly, would also be the cable connecting them. Alternatively, a data relay satellite orbiting the Earth-Moon Lagrangian pointL2would avoid the Earthlink antenna, iii) by a large space antenna put at the foci of the Sun gravitational lens: 1) for electromagnetic waves, the minimal focal distance is 550 Astronomical Units (AU) or 14 times beyond Pluto. One could use the huge radio magnifications of sources aligned to the Sun and spacecraft; 2) for gravitational waves and neutrinos, the focus lies between 22.45 and 29.59 AU (Uranus and Neptune orbits), with a flight time of less than 30 years. Two new space missions, of SETI interest if ET’s use neutrinos for communications, are proposed.

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