Two Actuation Methods for a Complete Morphing System Composed of a VGTM and a Compliant Parallel Mechanism

2021 ◽  
pp. 1-39
Author(s):  
Fengfeng. F. F. Xi ◽  
Yinjun Zhao ◽  
Jieyu Wang ◽  
Wenbin Wang ◽  
Yingzhong Tian
Keyword(s):  
Control Strategies ◽  
Driving Mechanism ◽  
Variable Geometry ◽  
Comparison Study ◽  
Passive System ◽  
Flexible Panel ◽  
Pros And Cons ◽  
Flexible Panels ◽  
Variable Geometry Truss Manipulator ◽  
Variable Geometry Truss

Abstract Presented in this paper is a complete morphing system consisting of a variable geometry truss manipulator (VGTM) that is fully covered by a flexible panel skin. Two approaches are studied for morphing control. The first one is to have the VGTM act as a driving mechanism and the flexible panels as a passive system. In this case, the VGTM is composed of active members and passive lockable members. It is shown that the morphing system can reach the desired shapes through intermediate steps. The second method is to have the flexible panels act as drivers and the VGTM as a passive supporting structure. In this case, the VGTM is only composed of passive lockable members. The morphing system can also achieve the desired poses through intermediate steps. The control strategies of the two methods are discussed along with kinematic analysis, a comparison study is conducted to show their pros and cons, and two prototypes are fabricated to verify the feasibility of two actuation methods.

Analytical Model Method for Dynamics of N-Celled Tetrahedron-Tetrahedron Variable Geometry Truss Manipulators

1998 ◽  
Author(s):  
Li Ju Xu ◽  
Hong Li ◽  
Shou Wen Fan
Keyword(s):  
Analytical Model ◽  
Variable Geometry ◽  
Symbolic Form ◽  
Model Method ◽  
Variable Geometry Truss Manipulator ◽  
Variable Geometry Truss

Abstract In this paper some fundamental formulae are derived for tetrahedron-based variable geometry truss manipulator which is composed of a series of tetrahedrons stacked upon each other such that one link in each cell is made variable on length. Analytical model for dynamics of the manipulator is established, and expressions in numeric-symbolic form of model matrices are derived. An example is given for illustration.

A Direct Displacement Solution to the Dodecahedron Variable Geometry Truss Manipulator

1996 ◽  
Author(s):  
Li-Ju Xu ◽  
Sui-Xian Yang ◽  
Zhao-Fei Zhou
Keyword(s):  
Solution Procedure ◽  
Homotopy Continuation ◽  
Variable Geometry ◽  
Numerical Example ◽  
Position Problem ◽  
Variable Geometry Truss Manipulator ◽  
Variable Geometry Truss

Abstract Homotopy continuation algorithms for solving the direct position problem of the dodecahedron variable geometry truss manipulator are proposed in this paper. The homogeneous equations and the division of groups are presented which give the lowest Bezout number. The solution procedure is given in detail. A numerical example is presented for illustration.

Kinematics of a n–bay triangle–triangle variable geometry truss manipulator

Robotica ◽  
1992 ◽  
Vol 10 (3) ◽  
pp. 263-267
Author(s):  
L. Beiner
Keyword(s):  
Iterative Method ◽  
Closed Form ◽  
Inverse Kinematics ◽  
Variable Length ◽  
Variable Geometry ◽  
Closed Form Solutions ◽  
Numerical Example ◽  
Forward And Inverse Kinematics ◽  
Variable Geometry Truss Manipulator ◽  
Variable Geometry Truss

SUMMARYVariable geometry truss manipulators (VGTM) are static trusses where the lengths of some members can be varied, allowing one to control the position of the free end relative to the fixed one. This paper deals with a planar VGTM consisting of a n–bay triangle-triangle truss with one variable length link (i.e. one DOF) per bay. Closed-form solutions to the forward, inverse, and velocity kinematics of a 3-DOF version of this VGTM are presented, while the forward and inverse kinematics of an n–DOF (redundant) one are solved by a recursive and an iterative method, respectively. A numerical example is presented.

Determination of the Workspace of the 3-DOF Double-Octahedral Variable-Geometry-Truss Manipulator

1992 ◽  
Author(s):  
V. Arun ◽  
Babu Padmanabhan ◽  
Krishnan Kolady ◽  
Charles F. Reinholtz
Keyword(s):  
Parallel Manipulators ◽  
Variable Geometry ◽  
Geometric Properties ◽  
Variable Geometry Truss Manipulator ◽  
Variable Geometry Truss

Abstract This paper presents methods to determine the workspace of the 3-DOF double-octahedral variable-geometry-truss manipulator (VGTM). These methods take advantage of some of the geometric properties inherent in octahedral VGT construction and define regions in space whose intersection results in the workspace of the manipulator. This approach of obtaining a ‘common volume’ can be extended to other parallel manipulators.

scholarly journals Inverse kinematics for the variable geometry truss manipulator via a Lagrangian dual method

2016 ◽  
Vol 13 (6) ◽  
pp. 172988141666677 ◽  
Author(s):  
Yanchun Zhao ◽  
Shiqiang Hu ◽  
Yongsheng Yang
Keyword(s):  
Inverse Kinematics ◽  
Optimal Solution ◽  
Optimization Procedure ◽  
Variable Geometry ◽  
Quadratic Constraints ◽  
Fixed Base ◽  
Inverse Kinematics Problem ◽  
Central Curve ◽  
Variable Geometry Truss Manipulator ◽  
Variable Geometry Truss

This article studies the inverse kinematics problem of the variable geometry truss manipulator. The problem is cast as an optimization process which can be divided into two steps. Firstly, according to the information about the location of the end effector and fixed base, an optimal center curve and the corresponding distribution of the intermediate platforms along this center line are generated. This procedure is implemented by solving a non-convex optimization problem that has a quadratic objective function subject to quadratic constraints. Then, in accordance with the distribution of the intermediate platforms along the optimal center curve, all lengths of the actuators are calculated via the inverse kinematics of each variable geometry truss module. Hence, the approach that we present is an optimization procedure that attempts to generate the optimal intermediate platform distribution along the optimal central curve, while the performance index and kinematic constraints are satisfied. By using the Lagrangian duality theory, a closed-form optimal solution of the original optimization is given. The numerical simulation substantiates the effectiveness of the introduced approach.

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