scholarly journals Operational Space Dynamics of a Space Robot and Computational Efficient Algorithm

Author(s):  
Satoko Abiko ◽  
Gerd Hirzinger
1996 ◽  
Vol 118 (3) ◽  
pp. 625-629 ◽  
Author(s):  
Subir Kumar Saha

An efficient algorithm for the inverse dynamics of free-flying space robots, consisting of a serial manipulator mounted on a free-base, e.g., a spacecraft, is presented. The kinematic and dynamic models are based on the concepts of the Primary Body (PB) and the Natural Orthogonal Complement, respectively, reported elsewhere. In this paper, besides the efficiency, the usefulness of the PB in deriving different kinematic models and selecting an efficient one is pointed out. Moreover, it is shown that a recursive algorithm for the inverse dynamics of the space robot at hand can be developed even without the consideration of the momenta conservation principle.


Author(s):  
Kishor D. Bhalerao ◽  
James Critchley ◽  
Denny Oetomo ◽  
Roy Featherstone ◽  
Oussama Khatib

This paper presents a new parallel algorithm for the operational space dynamics of unconstrained serial manipulators, which outperforms contemporary sequential and parallel algorithms in the presence of two or more processors. The method employs a hybrid divide and conquer algorithm (DCA) multibody methodology which brings together the best features of the DCA and fast sequential techniques. The method achieves a logarithmic time complexity (O(log(n)) in the number of degrees of freedom (n) for computing the operational space inertia (Λe) of a serial manipulator in presence of O(n) processors. The paper also addresses the efficient sequential and parallel computation of the dynamically consistent generalized inverse (J¯e) of the task Jacobian, the associated null space projection matrix (Ne), and the joint actuator forces (τnull) which only affect the manipulator posture. The sequential algorithms for computing J¯e, Ne, and τnull are of O(n), O(n2), and O(n) computational complexity, respectively, while the corresponding parallel algorithms are of O(log(n)), O(n), and O(log(n)) time complexity in the presence of O(n) processors.


2011 ◽  
Vol 308-310 ◽  
pp. 1975-1980
Author(s):  
Tian Xi Liu ◽  
Lei Liang ◽  
Wei Cheng ◽  
Yang Zhao

With the depth of space exploration and applications, the space robot self-assembling has become more and more important for space on-orbit service. Parameter analysis is an indispensable work of assembling process design. The dynamic model of the space robot with target is established firstly, then the Hertz model is introduced as the collision model between the docking link and the capturing cone, and the operational space control is applied to achieve the assembling operation control under the Cartesian space. Then the paper focuses on the discussion and analysis of the influences of the parameters such as the stiffness coefficient, friction coefficient, leading speed coefficient and vertical speed damping coefficient on the assembling characteristics. The simulation results would provide a basis for assembling control and parameter design and have an important academic value and engineering significance on space service.


2011 ◽  
Vol 189-193 ◽  
pp. 2062-2066 ◽  
Author(s):  
Lei Liang ◽  
Tian Xi Liu ◽  
Wei Cheng ◽  
Yang Zhao

In the space robot self-assembling process, the assembling control becomes quite complicated and important for the nonlinear characteristics, which are caused by the dynamic coupling between the arm and the base, and the collision between the target and the assembling hole on the base. The dynamic model of the space robot with target is established firstly, then the Hertz model is introduced as the collision model between the docking link and the capturing cone, and the operational space control is applied to achieve the assembling operation control under the Cartesian space. Through simulating and analyzing the influence of the stiffness coefficient, the soft and hard behaviors during assembling are discovered, which would provide a basis for assembling control and parameter design. The results would have important academic value and engineering significance on space robot achieving on-orbit self-assembling.


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