A Planar Spring-Loaded Cable-Loop-Driven Parallel Mechanism

2010 ◽  
Author(s):  
Hanwei Liu ◽  
Cle´ment Gosselin ◽  
Thierry Laliberte´
Keyword(s):  
Numerical Simulations ◽  
Inverse Kinematics ◽  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Static Equilibrium ◽  
Equilibrium Equations ◽  
Two Degrees Of Freedom

A novel architecture of planar spring-loaded cable-loop-driven parallel mechanism is introduced in this paper. By attaching springs to the cable loops, two degrees of freedom can be controlled using only two actuators. In this mechanism, spools are eliminated. Therefore, it is expected that the accuracy of this mechanism is improved compared with conventional cable-driven mechanisms making use of spools. The mechanism can be actuated using either linear sliders or rotary actuators driving the motion of a cable or belt. This paper presents the inverse kinematics and the static equilibrium equations for the new architecture. It is verified that the cables and the springs can be kept in tension within the workspace. Results of numerical simulations are also given.

A New Planar Two Degrees of Freedom Parallel Mechanism

2001 ◽  
Vol 34 (4) ◽  
pp. 113-117 ◽  
Author(s):  
Xin-Jun Liu ◽  
Feng Gao ◽  
Jinsong Wang ◽  
Jianfeng Li
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Two Degrees Of Freedom

scholarly journals Turning characteristics of biomimetic robotic fish driven by two degrees of freedom of pectoral fins and flexible body/caudal fin

2018 ◽  
Vol 15 (1) ◽  
pp. 172988141774995 ◽  
Author(s):  
Zonggang Li ◽  
Liming Ge ◽  
Weiqiang Xu ◽  
Yajiang Du
Keyword(s):  
Numerical Simulations ◽  
Degrees Of Freedom ◽  
Robotic Fish ◽  
Flexible Body ◽  
Caudal Fin ◽  
Two Degrees Of Freedom ◽  
Pectoral Fins ◽  
Turn On ◽  
Biomimetic Robotic Fish ◽  
Two Degree Of Freedom

This article considers the turning characteristics of robotic fish with two-degree-of-freedom pectoral fins and flexible body/caudal fin. The hydrodynamics are first established for three cases propelled by both sides of pectoral fins, flexible body/caudal fin, and composite of them. Then, the turning characteristics of such three cases are analyzed by numerical simulations and experiments. The results show that if robotic fish is cooperatively propelled by pectoral fins and flexible body, it can obtain the fast turning speed and the average turning speed is up to 0.6 rad s−1. The smallest turning speed is achieved as robotic fish is only propelled by pectoral fins; however, it can turn on the spot in this case. The presented results provide the more abundant ways of turning, the better maneuverability, and the higher turning speed for the proposed robotic fish.

scholarly journals Simulation of a parallel mechanical elbow with 3 DOF

2009 ◽  
Vol 7 (02) ◽  
Author(s):  
J. R. Mendoza-Vázquez ◽  
E. Tlelo-Cuautle ◽  
J.L. Vázquez-Gonzalez ◽  
A. Z. Escudero-Uribe
Keyword(s):  
Inverse Kinematics ◽  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Mechanical Support ◽  
Simulation And Modeling ◽  
Matlab Simulation ◽  
Geometric Methods ◽  
Kinematics Simulation ◽  
Linear Actuators ◽  
Simulation Results

The kinematics simulation and modeling of a mechanical elbow of 3 degrees of freedom, is introduced by highlighting the main features of the mechanism related to the design criteria. The mechanical elbow is used as a transhumeral prosthetic part, and it has been built as a parallel topology consisting of electric linear actuators and universal joints. The parallel mechanism has 4 legs. 3 are electric linear actuators, and the fourth leg provides mechanical support for the whole structure and holds a DC Motor that performs the action of gripping objects. Furthermore, this paper shows the inverse kinematics for the elbow by geometric methods, and the MatLab‐simulation results show the workspace of the movement and the ability of the mechanical elbow to replicate the movements of a biological one.

Workspace Generation for a 2 - DOF Parallel Mechanism Using Neural Networks

2012 ◽  
Vol 162 ◽  
pp. 121-130 ◽  
Author(s):  
Emilia Campean ◽  
Tiberiu Pavel Itul ◽  
Ionela Tanase ◽  
Adrian Pisla
Keyword(s):  
Neural Network ◽  
Neural Networks ◽  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Kinematic Model ◽  
Inverse Kinematic ◽  
Two Degrees Of Freedom ◽  
Initial Testing ◽  
Network Application ◽  
Satellite Dish

The main purpose of the paper is to develop a neural network application destined to the workspace generation of a parallel mechanism, as an performant alternative to the workspace representation based on inverse kinematic model. The paper describes both algorithms. The initial testing was made for a parallel mechanism with two degrees of freedom that could be applied for the orientation of different systems like a TV satellite dish antennas, sun trackers, telescopes, cameras, radars etc.

Kinematics and Singularity Analyses of a 2-RPU&SPR Parallel Manipulator

2013 ◽  
Vol 441 ◽  
pp. 568-571
Author(s):  
Jian Hui Fan ◽  
Bin Li ◽  
Xin Hua Zhao
Keyword(s):  
Numerical Simulations ◽  
Inverse Kinematics ◽  
Parallel Mechanism ◽  
Parallel Manipulator ◽  
Jacobian Matrix ◽  
Algebraic Method ◽  
Singularity Analysis

In this paper, kinematics and singularity of a 2-RPU&SPR parallel mechanism are analyzed by algebraic method. Firstly, the inverse kinematics of the parallel mechanism is derived. Secondly, the Jacobian matrix of the parallel mechanism is obtained and the singularity of the mechanism is analyzed. Finally, the correctness of singularity analysis of the mechanism is verified by numerical simulations.

scholarly journals Some aspects of topology and kinematics of a 3DOF translational parallel mechanism

2014 ◽  
Vol 19 (1) ◽  
pp. 5-15 ◽  
Author(s):  
J. Bałchanowski
Keyword(s):  
Kinematic Analysis ◽  
Inverse Kinematics ◽  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Analytical Procedure ◽  
Method Of Determination ◽  
Fixed Orientation ◽  
Three Degrees Of Freedom ◽  
Selection Of

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

Exploiting the Kinematic Redundancy of a (6 + 3) Degrees-of-Freedom Parallel Mechanism

2019 ◽  
Vol 11 (2) ◽  
Author(s):  
Louis-Thomas Schreiber ◽  
Clément Gosselin
Keyword(s):  
Inverse Kinematics ◽  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Kinematic Redundancy ◽  
Spatial Parallel Mechanism ◽  
Compressive Loads ◽  
Moving Platform

This paper presents methods to exploit the redundancy of a kinematically redundant spatial parallel mechanism with three redundant DOFs. The architecture of the mechanism is similar to the well-known Gough–Stewart (GS) platform and it retains its advantages, i.e., the members connecting the base to the moving platform are only subjected to tensile/compressive loads. The kinematic redundancy is exploited to avoid singularities and extend the rotational workspace. The architecture is described and the associated kinematic relationships are presented. Solutions for the inverse kinematics are given, as well as strategies to take into account the limitations of the mechanism such as mechanical interferences and velocity limits of the actuators while controlling the redundant degrees-of-freedom.

Singularity Analysis of Large Workspace 3RRRS Parallel Mechanism Using Line Geometry and Linear Complex Approximation

2010 ◽  
Vol 3 (1) ◽  
Author(s):  
Alon Wolf ◽  
Daniel Glozman
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Screw Theory ◽  
Singularity Analysis ◽  
Community Research ◽  
Parallel Mechanisms ◽  
Line Geometry ◽  
Equilibrium Equations ◽  
Six Degrees Of Freedom ◽  
Singular Configurations

During the last 15 years, parallel mechanisms (robots) have become more and more popular among the robotics and mechanism community. Research done in this field revealed the significant advantage of these mechanisms for several specific tasks, such as those that require high rigidity, low inertia of the mechanism, and/or high accuracy. Consequently, parallel mechanisms have been widely investigated in the last few years. There are tens of proposed structures for parallel mechanisms, with some capable of six degrees of freedom and some less (normally three degrees of freedom). One of the major drawbacks of parallel mechanisms is their relatively limited workspace and their behavior near or at singular configurations. In this paper, we analyze the kinematics of a new architecture for a six degrees of freedom parallel mechanism composed of three identical kinematic limbs: revolute-revolute-revolute-spherical. We solve the inverse and show the forward kinematics of the mechanism and then use the screw theory to develop the Jacobian matrix of the manipulator. We demonstrate how to use screw and line geometry tools for the singularity analysis of the mechanism. Both Jacobian matrices developed by using screw theory and static equilibrium equations are similar. Forward and inverse kinematic solutions are given and solved, and the singularity map of the mechanism was generated. We then demonstrate and analyze three representative singular configurations of the mechanism. Finally, we generate the singularity-free workspace of the mechanism.

A Novel Two Degrees of Freedom Rotational Decoupled Parallel Mechanism

2012 ◽  
Vol 215-216 ◽  
pp. 293-296 ◽  
Author(s):  
Yu Lei Hou ◽  
Da Xing Zeng ◽  
Zhan Ye Zhang ◽  
Chang Mei Wang ◽  
Xin Zhe Hu
Keyword(s):  
Control System ◽  
Dynamic Analysis ◽  
Spatial Orientation ◽  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Screw Theory ◽  
The Novel ◽  
Two Degrees Of Freedom ◽  
Application Fields

In the field of spatial orientation, the rotational parallel mechanism is widely used. While the existence of coupling brings about the parallel mechanism some difficulties in kinematics and dynamic analysis, the development of control system, and so on. This condition restricts the application fields and effects of the rotational parallel mechanism. Therefore, this paper proposes a novel 2-DOF (two degrees of freedom) rotational DPM (decoupled parallel mechanism). The feature of the mechanism is described and their movement form is analyzed with screw theory. The proposition of the novel rotational DPM will enrich the configurations of the parallel mechanism, and the contents of this paper should be useful for the further research and application of the rotational parallel mechanism.

Two-Degree-of-Freedom Decoupled Nonredundant Cable-Loop-Driven Parallel Mechanism

2013 ◽  
Vol 6 (1) ◽  
Author(s):  
Hanwei Liu ◽  
Clément Gosselin ◽  
Thierry Laliberté
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Degree Of Freedom ◽  
The Other ◽  
End Effector ◽  
Two Degrees Of Freedom ◽  
Actuation Redundancy ◽  
Rigid Link ◽  
Force Closure ◽  
Two Degree Of Freedom

A novel two-degree-of-freedom (DOF) cable-loop slider-driven parallel mechanism is introduced in this paper. The novelty of the mechanism lies in the fact that no passive rigid-link mechanism or springs are needed to support the end-effector (only cables are connected to the end-effector) while at the same time there is no actuation redundancy in the mechanism. Sliders located on the edges of the workspace are used and actuation redundancy is eliminated while providing force closure everywhere in the workspace. It is shown that the two degrees of freedom of the mechanism are decoupled and only two actuators are needed to control the motion. There are two cable loops for each direction of motion: one acts as the actuating loop while the other is the constraint loop. Due to the simple geometric design, the kinematic and static equations of the mechanism are very compact. The stiffness of the mechanism is also analyzed in the paper. It can be observed that the mechanism's stiffness is much higher than the stiffness of the cables. The proposed mechanism's workspace is essentially equal to its footprint and there are no singularities.

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