scholarly journals Design and Analysis of a Flexible, Elastic, and Rope-Driven Parallel Mechanism for Wrist Rehabilitation

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Zaixiang Pang ◽  
Tongyu Wang ◽  
Junzhi Yu ◽  
Shuai Liu ◽  
Xiyu Zhang ◽  
...  
Keyword(s):  
Inverse Kinematics ◽  
Parallel Mechanism ◽  
Inverse Kinematic ◽  
Parallel Structure ◽  
Flexible Joints ◽  
Rehabilitation Robots ◽  
Hybrid Mechanism ◽  
Compression Spring ◽  
Moving Platform

This paper proposes a bionic flexible wrist parallel mechanism to simulate human wrist joints, which is characterized by a rope-driven, compression spring-supported hybrid mechanism. Specifically, to realize the movement of the wrist mechanism, a parallel structure is adopted to support the mobile platform and is controlled by a cable, which plays the role of wrist muscles. Because the compression spring is elastic, it is difficult to directly solve inverse kinematics. To address this problem, the external force acting on the moving platform is firstly equivalent to the vector force and torque at the center of the moving platform. Then, based on inverse kinematic and static analyses, the inverse motion of the robot model can be solved according to the force and torque balance conditions and the lateral spring bending equation of the compression spring. In order to verify the proposed method, kinematics, statics, and parallel mechanism workspace are further analyzed by the software MATLAB. The obtained results demonstrate the effectiveness and feasibility of the designed parallel mechanism. This work offers new insights into the parallel mechanism with flexible joints in replicating the movements of the human wrist, thus promoting the development of rehabilitation robots and rope-driven technology to some extent.

Determining the Number of Inverse Kinematic Solutions of a Constrained Parallel Mechanism Using a Homotopy Algorithm

2010 ◽  
Vol 2 (2) ◽  
Author(s):  
Jeremy T. Newkirk ◽  
Layne T. Watson ◽  
Michael M. Stanišić
Keyword(s):  
Inverse Kinematics ◽  
Parallel Mechanism ◽  
Shoulder Girdle ◽  
Inverse Kinematic ◽  
Variable Length ◽  
Real Solutions ◽  
Homotopy Algorithm ◽  
Fixed Length ◽  
Multivalued Solution ◽  
Inverse Kinematics Problem

This paper numerically determines the number of real-valued inverse kinematic solutions to a constrained parallel mechanism composed of three triangular platforms. The base and middle platforms are connected by three fixed-length legs, while the middle and distal platforms are connected by three variable length legs that extend out of the fixed-length legs in a collinear fashion. All legs are connected to the platforms via spherical joints at the corners. This mechanism is intended to replicate the motion of a human shoulder girdle. The constrained parallel mechanism has a multivalued solution to the inverse kinematics problem. A homotopy method was used to numerically compute the inverse kinematic solutions for over 100 cases. Each case was filtered for the number of real-valued solutions. The maximum number of real solutions was found to be 8, but in some cases there were fewer solutions.

A New Type of Drill Grinder Based on the Special Universal Joint

2008 ◽  
Vol 389-390 ◽  
pp. 246-251 ◽  
Author(s):  
Ping Zou ◽  
H.R. Qiu ◽  
Shan Min Gao ◽  
Ming Hu
Keyword(s):  
Parallel Mechanism ◽  
Cutting Tool ◽  
Low Cost ◽  
Inverse Kinematic ◽  
Universal Joint ◽  
Mechanical Structure ◽  
New Type ◽  
Accurate Position ◽  
Moving Platform ◽  
Drill Point

This paper presents a new type of drill grinder based on a special universal joint. The special universal joint is composed of a parallel mechanism with three legs as the inputs. One can rotate as a spindle; other two legs can drive a moving platform and make a drill point get an accurate position in workspace. Due to the simple mechanical structure comparing the grinder with the existing conventional CNC cutting tool grinders, it should be easy for the grinder to manufacture at a low cost. In addition, inverse kinematic equations of the special type of universal joint are derived.

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.

Design and Analysis of 3R2T and 3R3T Parallel Mechanisms With High Rotational Capability

2015 ◽  
Vol 8 (1) ◽  
Author(s):  
Congzhe Wang ◽  
Yuefa Fang ◽  
Sheng Guo
Keyword(s):  
Inverse Kinematics ◽  
Kinematic Model ◽  
Inverse Kinematic ◽  
Velocity Analysis ◽  
Parallel Mechanisms ◽  
Workspace Analysis ◽  
Moving Platform ◽  
Displacement Theory ◽  
Lie Subgroup ◽  
Orientation Workspace

This paper describes the design, kinematics, and workspace analysis of 3R2T and 3R3T parallel mechanisms (PMs) with large rotational angles about three axes. Since the design of PMs with high rotational capability is still a challenge, we propose the use of a new nonrigid (or articulated) moving platform with passive joints in order to reduce the interference between limbs and the moving platform. According to the proposed nonrigid platform and Lie subgroup of displacement theory, several 3R2T and 3R3T PMs are presented. Subsequently, the inverse kinematics and velocity analysis of one of the proposed mechanisms are detailed. Based on the derived inverse kinematic model, the constant-orientation workspace is computed numerically. Then, the analysis of rotational capability about the three axes is performed. The result shows that even if interference and singularity are taken into account, the proposed mechanisms still reveal the high continuously rotational capability about the three axes, by means of actuation redundancy.

A Novel Three-DOF 3-RRRRR Parallel Platform Mechanism and Its Position Analysis

2005 ◽  
Author(s):  
Shihua Li ◽  
Zhen Huang ◽  
Jianguang Wu
Keyword(s):  
Inverse Kinematics ◽  
Parallel Mechanism ◽  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Initial Configuration ◽  
Parallel Platform ◽  
Moving Platform ◽  
General Configuration ◽  
Novel Model ◽  
Three Degrees Of Freedom

In order to enrich deficient-DOF parallel mechanism models, a novel model of a 3-DOF platform manipulator is presented and establish its inverse kinematics equation. Here, studies instantaneous motions of 3-RRRRR parallel manipulator at initial configuration and general configuration. Find: it has three degrees of freedom at initial configuration and after translated along the X, Y, Z axis. Secondly, the relation is given between every active input (θ1) and moving platform position by using D-H means, the solution is developed for inverse kinematics, numerical example for the position kinematic is presented, the figure of workspace along the Z-axis is drawn finally. The mechanism can be applied to jiggle mechanism.

Inverse Dynamics of 2UPS-RPU Parallel Mechanism by Newton-Euler Formation

2010 ◽  
Vol 29-32 ◽  
pp. 738-743
Author(s):  
Wen Hua Wang ◽  
Zhi You Feng ◽  
Ting Li Yang
Keyword(s):  
Computer Simulation ◽  
Dynamic Equation ◽  
Driving Force ◽  
Inverse Kinematics ◽  
Parallel Mechanism ◽  
Inverse Dynamics ◽  
Inverse Dynamic ◽  
Moving Platform

2UPS-RPU is a new 4-DOF parallel mechanism with serial input limb. In this paper, the inverse dynamic equation of this mechanism is formulated by Newton-Euler formation based on each limb and moving platform as the studying objects. The inverse kinematics of the mechanism is analyzed. The driving force, driving moment and the constraint moment can be obtained. Finally, a computer simulation is carried out to solve the inverse dynamics of the mechanism when the motion of moving platform is given.

Exploiting the Kinematic Redundancy of a 6+3 Dofs Parallel Mechanism

2018 ◽  
Author(s):  
Louis-Thomas Schreiber ◽  
Clément Gosselin
Keyword(s):  
Trajectory Planning ◽  
Inverse Kinematics ◽  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Stewart Platform ◽  
Kinematic Redundancy ◽  
Compressive Loads ◽  
Planning Methods ◽  
Moving Platform

This paper presents trajectory planning methods for a kinematically redundant parallel mechanism. The architecture of the mechanism is similar to the well-known Gough-Stewart 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.

Method and Simulation for Kinematics of 6-SPS Parallel Mechanism

2014 ◽  
Vol 1033-1034 ◽  
pp. 1334-1337
Author(s):  
Yi Jun Zhou ◽  
Xue Ming Li ◽  
Hai Yang Xu ◽  
Heng Liang Fan
Keyword(s):  
Positive Solution ◽  
Inverse Kinematics ◽  
Parallel Mechanism ◽  
Inverse Solution ◽  
Parallel Kinematics ◽  
Forward Displacement ◽  
Inverse Simulation ◽  
Input Parameters ◽  
Moving Platform ◽  
And Control

Solving forward displacement is the difficulty of the 6-SPS parallel kinematics calculations, to make sure solving forward displacement easily, in this paper, added a initial multi-DOF drive to the 6-SPS parallel mechanism's moving platform in the ADAMS environment to make kinematical simulation, to get simulation of inverse kinematics solution and strike a theoretical inverse kinematics solution in the MATLAB environment, and prove the correctness of simulation of inverse solution. The inverse simulation position be used as input parameters to drive this parallel mechanism, by the solving forward displacement, results showed that the forward displacement is consist with the initial-DOF-driven values, indicating it is correct. It proves the use of these methods can be simply and easily calculate the required 6-SPS parallel mechanism positive solution, which can provide the reference of such institutions' solving forward position and control.

scholarly journals Kinematic Reliability Solution of 3-UPS-PU Parallel Mechanism Based on Monte Carlo Simulation

2015 ◽  
Vol 9 (1) ◽  
pp. 324-332 ◽  
Author(s):  
Guohua Cui ◽  
Muyuan Sun ◽  
Liang Yan ◽  
Hongjuan Hou ◽  
Haiqiang Zhang
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Inverse Kinematics ◽  
Parallel Mechanism ◽  
Solution Method ◽  
Simulation Method ◽  
Inverse Kinematic ◽  
Future Research ◽  
Position And Orientation ◽  
Kinematic Solution

In order to research kinematic reliability of 3-UPS-PU parallel mechanism, the structure and kinematics analysis were performed. Inverse kinematics equation can be derived by homogeneous coordinate transformation formula. Position and orientation output error forward kinematics model was obtained by the differential transformation on the basis of inverse kinematic solution of the position. The curves of the position and orientation output errors can be plotted with a large batch production by adopting Monte-Carlo simulation method. Then kinematic reliability of the mechanism can be solved through the probability statistics method and theoretical solution method respectively. Finally, these two methods were compared with each other. The results illustrate that the results of the two methods are basically consistent, and the mechanism can be work reliably and stably under general operations, which provides some valuable references for the related future research.

scholarly journals A New Approach of Soft Joint Based on a Cable-Driven Parallel Mechanism for Robotic Applications

Mathematics ◽  
2021 ◽  
Vol 9 (13) ◽  
pp. 1468
Author(s):  
Luis Nagua ◽  
Carlos Relaño ◽  
Concepción A. Monje ◽  
Carlos Balaguer
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Kinematic Model ◽  
Experimental Tests ◽  
Humanoid Robots ◽  
Inverse Kinematic ◽  
Element Analysis ◽  
New Approach ◽  
Flexible Polymer ◽  
The Mathematical Model

A soft joint has been designed and modeled to perform as a robotic joint with 2 Degrees of Freedom (DOF) (inclination and orientation). The joint actuation is based on a Cable-Driven Parallel Mechanism (CDPM). To study its performance in more detail, a test platform has been developed using components that can be manufactured in a 3D printer using a flexible polymer. The mathematical model of the kinematics of the soft joint is developed, which includes a blocking mechanism and the morphology workspace. The model is validated using Finite Element Analysis (FEA) (CAD software). Experimental tests are performed to validate the inverse kinematic model and to show the potential use of the prototype in robotic platforms such as manipulators and humanoid robots.

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