Kinematic analysis of a three degrees of freedom in-parallel actuated manipulator

Author(s):  
Kok-Meng Lee ◽  
D. Shah
2015 ◽  
Vol 7 (3) ◽  
Author(s):  
Hamed Khakpour ◽  
Lionel Birglen ◽  
Souheil-Antoine Tahan

In this paper, a new three degrees of freedom (DOF) differentially actuated cable parallel robot is proposed. This mechanism is driven by a prismatic actuator and three cable differentials. Through this design, the idea of using differentials in the structure of a spatial cable robot is investigated. Considering their particular properties, the kinematic analysis of the robot is presented. Then, two indices are defined to evaluate the workspaces of the robot. Using these indices, the robot is subsequently optimized. Finally, the performance of the optimized differentially driven robot is compared with fully actuated mechanisms. The results show that through a proper design methodology, the robot can have a larger workspace and better performance using differentials than the fully driven cable robots using the same number of actuators.


Robotica ◽  
2001 ◽  
Vol 19 (3) ◽  
pp. 305-309 ◽  
Author(s):  
Raffaele Di Gregorio

Only one parallel wrist with three equal legs containing just revolute pairs has been already presented in the literature. This parallel wrist is overconstrained, i.e., it involves three degrees of freedom required to orientate the end effector by using repetitions of constraints. The overconstrained mechanisms have the drawback of jamming or undergoing high internal loads when geometric errors occur. This paper presents a new parallel wrist, named 3-RUU wrist. The 3-RUU wrist is not overconstrained. It has three equal legs just involving revolute pairs and actuators adjacent to the frame and uses an architecture (3-RUU) already employed to obtain manipulators that make the end effector translate. The 3-RUU wrist kinematic analysis is addressed. This analysis shows that the new parallel wrist can reach singular configurations (translation singularities) in which the spherical constraint between end effector and frame fails. The singularity condition that makes finding all the 3-RUU wrist singular configurations possible is written in explicit form and geometrically interpreted.


2014 ◽  
Vol 19 (1) ◽  
pp. 5-15 ◽  
Author(s):  
J. Bałchanowski

Abstract The paper presents elements of the topology, geometry and the kinematic analysis of a translational parallel mechanism with three degrees of freedom. In such mechanisms the selection of a proper structure and geometry ensures that the driven link maintains a fixed orientation relative to the base. The method of determination of the configuration of mechanisms using contour vector notation was elaborated in the paper. The equations for the analysis of the direct and inverse kinematics task are determined. An analytical procedure for determining the system’s singular positions is presented and illustrated with examples


Author(s):  
G.S. Filippov

The article presents a synthesis of a mechanism of parallel-sequential structure with five degrees of freedom capable of processing objects with an extended dimention in one direction, wherein the considered mechanism can have a high bearing capacity. Corresponding problems are associated with manufacturing jet turbine airfoil as well as vertebrae operations (on the human spine). Movement along a coordinate that is linked to large dimensions of a processed object is provided using the initial translation pairs equipped with a motor. It is followed by a flat partial parallel structure mechanism with three degrees of freedom, and further – by a revolute kinematic pair. A kinematic analysis of the considered mechanism is performed, and the inverse kinematic problem is solved. The Angeles-Gosselin method for parallel structure mechanisms is used when performing velocity calculations of the parallel-sequential structure mechanism. The results of the numerical experiment are presented.


Robotica ◽  
2014 ◽  
Vol 33 (4) ◽  
pp. 884-897 ◽  
Author(s):  
Yaobin Tian ◽  
Yan-An Yao

SUMMARYIn this paper a rolling robot resembling the shape of a triangular-bipyramid is proposed. The robot has three degrees of freedom and is formed by connecting two tripod mechanisms with three spherical joints. By kinematic analysis, the robot can be viewed as a planar four-bar linkage. Further, its dynamic rolling ability is discussed by Zero Moment Point (ZMP) analysis. We show that the robot has the capability to roll, adjust its step length, and switch rolling directions. These functions are verified by a series of simulations with a CAD (computer-aided design) model and experiments with a prototype.


Robotica ◽  
1999 ◽  
Vol 17 (1) ◽  
pp. 3-9 ◽  
Author(s):  
Tamio Arai ◽  
Shojiro Matsumura ◽  
Yuji Yoshimura ◽  
Hisashi Osumi

Industrial robots have a high positioning accuracy and stiffness but their work spaces are limited because their bases are fixed to the ground. To enlarge the work spaces, this paper proposes a novel mechanism, a wire suspended manipulator with three degrees of freedom. First, the kinematics of the mechanism is derived from both force and geometric constraints. Second, the volume of the work space is numerically calculated. After the evaluation of manipulability of the wire suspended system, guidelines for designing parameters are studied.


Author(s):  
J. A. Carretero ◽  
M. Nahon ◽  
B. Buckham ◽  
C. M. Gosselin

Abstract This paper presents a kinematic analysis of a three-degree-of-freedom parallel mechanism intended for use as a telescope mirror focussing device. The construction of the mechanism is first described and its forward and inverse kinematics solutions are derived. Because the mechanism has only three degrees of freedom, constraint equations must be generated to describe the inter-relationship between the six Cartesian coordinates which describe the position and orientation of the moving platform. Once these constraints are incorporated into the kinematics model, a constrained Jacobian matrix is obtained. The stiffness and dexterity properties of the mechanism are then determined based on this Jacobian matrix. The mechanism is shown to exhibit desirable properties in the region of its workspace of interest in the telescope focussing application.


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