A 3-R(SRS)RP Multi-Loop Mechanism for Space Manipulation: Design, Kinematics, Singularity, and Workspace

Abstract

Space manipulation has great prospects in aerospace applications. In this work, a multiloop robot, namely 3-R(SRS)RP multiloop mechanism, is presented. Its design, kinematics, singularity, and workspace are studied. The novel design is mainly reflected in the robot’s structure, variable section, and novel compound hinge. Given these features, the forward-displacement undertaken with a closed-loop method leads to a complex mapping diagram. Only numerical solutions are obtained in this model due to the variable section parameter λ. This variable affects kinematic performances such as bending and folding properties. Moreover, the node differential kinematics and the Jacobian matrix are solved to analyze singular configurations of the mechanism. The workspace is then evaluated via a numerical method with varying λ. The bending and folding properties and the continuous workspace of the given robot vary while changing λ. Hence, the robot has great potentials of good performances in various applications. With this robot, a multimodule manipulator with a wide range of operations, increased mobility and rigidity, variable geometry, and adaptable shape based on mission requirements can be constructed.

Mobility and singularity analyses of a symmetric multi-loop mechanism for space applications

“…The singularities derived via CDMSA are identical to those obtained by using the geometric method reported earlier, 12 thereby verifying the correctness of the analysis and the effectiveness the CDMSA. Moreover, the CDMSA, an algebraic method, can be generalized to other multi-loop mechanisms, whereas, the geometric method can be only employed in mechanisms with special geometic patterns, such as that of an hexagonal prism.…”

“…The DTMLM, shown in Figure 1, 12 carries six revolute, three prismatic, and three SRS joints, of axis passing through the centers of the spherical joints. Therefore, each SRS joint is composed of two concentric shperical joints, coupled by a revolute joint.…”

“…The geometric singularity of the DTMLM is revealed via a combination of a node-differential-kinematics model and the geometric patterns. 12 In this section, the configuration singularity of the DTMLM is analyzed by resorting to an algebraic method.…”

“…4,5 On the other hand, two-layer, two-loop mechanisms 6,7 have low stiffness and limited load-carrying capacity; hybrid mechanisms [8][9][10][11] have limited workspace. In this regard, Li et al 12 proposed a novel multi-loop mechanism for space applications, which, in this paper, is referred to as the double-tripod multiloop mechanism (DTMLM). The base platform (BP) of the mechanism is attached to the spacecraft, while the moving platform (MP) is the free terminal platform.…”

“…However, there are no studies, to the authors' knowledge, addressing the singularity analysis of spatial multi-loop mechanisms with coupled closed chains, such as the Hoberman switch-pitch ball, 1 magic balls, 2 magic cubes, 3 and the DTMLM. 12 These chains include complex, coupled, closed subchains, thus resulting in complicated kinematics relations that are untractable with established techniques. Therefore, new methods should be explored.…”