Performance Analysis of 3-URU Spherical Parallel Mechanism Designed Based on Velocity Transmission and Force Constraint Indices

2015 ◽  
Vol 758 ◽  
pp. 71-76
Author(s):  
Syamsul Huda ◽  
Syafri ◽  
Mulyadi Bur
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Output Link ◽  
Kinematic Synthesis ◽  
Platform Motion ◽  
Spherical Parallel Mechanism ◽  
Velocity Transmission ◽  
Maximum Inclination ◽  
Three Degrees Of Freedom ◽  
Spherical Motion

In this paper was observed performances of developed three degrees of freedom (dof) parallel mechanism named 3-URU spherical parallel mechanism. The mechanism is composed of three identical limbs mounted symmetrically to base (fixed link) and platform (output link). The limb is constructed by universal-revolute and universal joints. The kinematic constants of mechanism consisting of link lengths, radius of platform, radius of base, mounting angle of limb and platform to base and platform were determined with consideration of velocity transmission and force constraint indices. To evaluate performance of mechanism, it was manufactured a prototype of mechanism designed base on these two mentioned indices. There are three steps proposed to realize the mechanism, (i) kinematic synthesis to determine of kinematic constants, (ii) design of mechanical components to define shape and dimension of links and joints by considering collision in wokingspace and static analysis, (iii) evaluation of mechanism performances consisting of workingspace, controllability of platform motion and static payload. Based on obtained results, it can be clarified that, the mechanism can produce spherical motion of platform which rotates on steady point recognized as center of platform rotation. The platform can achieve maximum inclination angle, 80 degree and at this posture occurs translational error, 0.0102 mm. On the other hand, the mechanism can support payload ten times of weight of moving parts.

scholarly journals A Sensor Based on a Spherical Parallel Mechanism for the Measurement of Fluid Velocity: Physical Modelling and Computational Analysis

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2867 ◽  
Author(s):  
Roque Saltarén ◽  
Gerardo Portilla ◽  
Alejandro Barroso ◽  
Juan Cely
Keyword(s):  
Parallel Mechanism ◽  
Inertial Measurement Unit ◽  
Degrees Of Freedom ◽  
Fluid Velocity ◽  
Physical Modelling ◽  
Measurement Unit ◽  
Adams Software ◽  
Spherical Parallel Mechanism ◽  
The Impact ◽  
Three Degrees Of Freedom

In this article, a new method was developed to measure the velocity of a fluid using a sensor, based on the use of a spherical parallel mechanism with three degrees-of-freedom (DOF). This sensor transforms the kinetic energy of the fluid into potential energy by deforming the parallel mechanism. This deformation is due to the impact of the fluid on a sphere attached to the platform of the parallel mechanism. Through the acquisition of data from a sensor using an inertial measurement unit (IMU) in the sphere, an algorithm calculates the velocity and direction of the fluid. In this article, a mathematical model of the mechanism and an algorithm for correctly measuring the velocity and direction of the fluid is developed; this algorithm is tested through a simulation in the Adams software, and the MATLAB software is used to execute the algorithm. The results show that the algorithm calculates the velocity and the direction of the fluid correctly, demonstrating the technical feasibility of the sensor.

Kinematics Analysis of a 3-RRR Spherical Parallel Mechanism with Coaxial Input Shafts

2013 ◽  
Vol 404 ◽  
pp. 237-243
Author(s):  
Yu Lei Hou ◽  
Xin Zhe Hu ◽  
Da Xing Zeng
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Jacobian Matrix ◽  
Screw Theory ◽  
Inverse Solution ◽  
Kinematics Analysis ◽  
Motion Feature ◽  
Displacement Problem ◽  
Spherical Parallel Mechanism ◽  
Three Degrees Of Freedom

As an important mechanism with special and extensive application, the three degrees of freedom spherical parallel mechanism is always a research hot in the mechanical fields. In this paper, the feature of the 3-RRR spherical parallel mechanism with coaxial input shafts is introduced, and its motion feature is analyzed based on the screw theory. The mobility of the spherical parallel mechanism is calculated by using the Modified Kutzbach-Grübler criterion, and the inverse displacement problem of the mechanism is solved. Then the expression of the Jacobian matrix is deduced based on the kinematics equation and its inverse solution. The contents of this paper should be useful for the further application of the spherical parallel mechanism.

scholarly journals Strategies of traversing obstacles and the simulation for a forestry chassis

2018 ◽  
Vol 15 (3) ◽  
pp. 172988141877390 ◽  
Author(s):  
Yue Zhu ◽  
Jiangming Kan ◽  
Wenbin Li ◽  
Feng Kang
Keyword(s):  
Multibody Dynamics ◽  
Inclination Angle ◽  
Degrees Of Freedom ◽  
Ride Comfort ◽  
Hydraulic Cylinder ◽  
Single Side ◽  
Simulation Results ◽  
Maximum Inclination ◽  
Three Degrees Of Freedom ◽  
Small Inclination

As to the complicated terrain in forest, forestry chassis with an articulated body with three degrees of freedom and installed luffing wheel-legs (FC-3DOF&LW) is a novel chassis that can surmount obstacles. In addition, the rear frame of FC-3DOF&LW is regarded as the platform to carry equipment. Small inclination angle for rear frame contributes to stability and ride comfort. This article describes the strategy of traversing obstacles and simulation for FC-3DOF&LW that drives in forest terrain. First, key structures of FC-3DOF&LW are briefly introduced, which include articulated structure with three degrees of freedom and luffing wheel-leg. Based on the sketch of luffing wheel-leg, the movement range of luffing wheel-leg is obtained by hydraulic cylinder operation. Second, the strategy of crossing obstacles that are simplified three models of terrain is presented, and the simulation for surmounting obstacles is constructed in multibody dynamics software. The simulation results demonstrate that the inclination angle of rear frame is 18° when slope is 30°. A maximum 12° decrease of inclination angle for rear frame can be acquired when luffing wheel-legs are applied. For traversing obstacles with both sides, the maximum inclination angle of rear frame is about 1.2° and is only 3° for traversing obstacles with single side.

Architecture Optmization of a 3-DOF Parallel Mechanism

1998 ◽  
Author(s):  
J. A. Carretero ◽  
R. P. Podhorodeski ◽  
M. Nahon
Keyword(s):  
Parallel Mechanism ◽  
Architectural Design ◽  
Degrees Of Freedom ◽  
Jacobian Matrix ◽  
Design Parameters ◽  
Objective Functions ◽  
Constraint Equations ◽  
Three Degree Of Freedom ◽  
Architecture Optimization ◽  
Three Degrees Of Freedom

Abstract This paper presents a study of the architecture optimization 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. Since the mechanism has only three degrees of freedom, constraint equations describing the inter-relationship between the six Cartesian coordinates are given. These constraints allow us to define the parasitic motions and, if incorporated into the kinematics model, a constrained Jacobian matrix can be obtained. This Jacobian matrix is then used to define a dexterity measure. The parasitic motions and dexterity are then used as objective functions for the optimizations routines and from which the optimal architectural design parameters are obtained.

Kinematics and Workspace Analysis of 3-RPP Parallel Mechanism

2013 ◽  
Vol 456 ◽  
pp. 146-150
Author(s):  
Zhi Jiang Xie ◽  
Jun Zhang ◽  
Xiao Bo Liu
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Parallel Mechanisms ◽  
Vector Method ◽  
Workspace Analysis ◽  
Inverse Solutions ◽  
Three Degrees Of Freedom

This paper designed a kind of parallel mechanism with three degrees of freedom, the freedom and movement types of the robot are analyzed in detail, the parallel mechanisms Kinematics positive and inverse solutions are derived through using the vector method. And at last its workspace is analyzed and studied systematically.

Kinematic Synthesis and Modeling of a Three Degrees-of-Freedom Hybrid Mechanism for Shoulder and Hip Modules of Humanoid Robots

2016 ◽  
Vol 8 (4) ◽  
Author(s):  
Samer Alfayad ◽  
Ahmad M. Tayba ◽  
Fethi B. Ouezdou ◽  
Faycal Namoun
Keyword(s):  
Degrees Of Freedom ◽  
Research Work ◽  
Humanoid Robots ◽  
Kinematic Synthesis ◽  
Hybrid Mechanism ◽  
Generic Hybrid ◽  
Hybrid Mechanisms ◽  
Large Motion ◽  
Linear Actuators ◽  
Three Degrees Of Freedom

This paper deals with a research work that aims to develop a new three degrees-of-freedom (DoF) hybrid mechanism for humanoid robotics application. The proposed hybrid mechanism can be used as a solution not only for several modules in humanoid robots but also for other legged robots such as quadrupeds and hexapods. Hip and shoulder mechanisms are taken as examples in this paper; torso and spine mechanisms, too, can be based on the proposed solutions. In this paper, a detailed analysis of the required performances of the hip and shoulder mechanisms is first carried out. Then, using a kinematic synthesis, a novel solution for the hip mechanism is proposed based on one rotary and two linear actuators. Improving this solution allows us to fulfill the requirements induced by the large motion ranges of the shoulder module, leading to a new management of the linear actuators contributions in the motion/force achievement process. Kinematic and geometrical models of a generic hybrid mechanism are achieved and used to get the optimized solutions of both hybrid mechanisms addressed in this paper.

Optimal synthesis of a spherical parallel mechanism for medical application

Robotica ◽  
2014 ◽  
Vol 34 (3) ◽  
pp. 671-686 ◽  
Author(s):  
T. Essomba ◽  
M. A. Laribi ◽  
S. Zeghloul ◽  
G. Poisson
Keyword(s):  
Motion Capture ◽  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Medical Application ◽  
Optimal Synthesis ◽  
Objective Functions ◽  
Ultrasound Probe ◽  
Spherical Parallel Mechanism ◽  
Real Coded Genetic Algorithms ◽  
Probe Holder

SUMMARYThis paper introduces the design and the optimization of a probe holder robot for tele-echography applications. To define its kinematic architecture, an approach based on motion capture of an expert's gestures during ultrasound examinations was proposed. The medical gestures analyzed consisted of ultrasound probe movements and were used to characterize the kinematic specifications of the proposed manipulator. The selected architecture was a Spherical Parallel Mechanism (SPM) with 3 degrees of freedom (DoF) and its optimal synthesis was performed using real-coded Genetic Algorithms (GA). The optimization criteria and constraints were established thanks to the collaboration of medical experts and were successively formulated and solved using mono-objective and multi-objective functions.

scholarly journals A Translational Three-Degrees-of-Freedom Parallel Mechanism With Partial Motion Decoupling and Analytic Direct Kinematics

2020 ◽  
Vol 12 (2) ◽  
Author(s):  
Huiping Shen ◽  
Damien Chablat ◽  
Boxiong Zeng ◽  
Ju Li ◽  
Guanglei Wu ◽  
...  
Keyword(s):  
Parallel Mechanism ◽  
Design Theory ◽  
Degrees Of Freedom ◽  
Analytic Solutions ◽  
Inverse Kinematic ◽  
Kinematic Modeling ◽  
Topological Design ◽  
Prismatic Joints ◽  
Topological Characteristics ◽  
Three Degrees Of Freedom

Abstract According to the topological design theory and the method of parallel mechanism (PM) based on position and orientation characteristic (POC) equations, this paper studied a three-degrees-of-freedom (3-DOF) translational PM that has three advantages, i.e., (i) it consists of three fixed actuated prismatic joints, (ii) the PM has analytic solutions to the direct and inverse kinematic problems, and (iii) the PM is of partial motion decoupling property. First, the main topological characteristics, such as the POC, degree-of-freedom, and coupling degree, were calculated for kinematic modeling. Thanks to these properties, the direct and inverse kinematic problems can be readily solved. Further, the conditions of the singular configurations of the PM were analyzed, which corresponds to its partial motion decoupling property.

scholarly journals Input Rationality Analysis of Three Degree of freedom Parallel Mechanism with Limbs of Embedding Structures

2019 ◽  
Vol 10 (2) ◽  
pp. 343-353
Author(s):  
Gaowei Yang ◽  
Jianjun Zhang ◽  
Weimin Li ◽  
Kaicheng Qi
Keyword(s):  
Parallel Mechanism ◽  
Group Selection ◽  
Degrees Of Freedom ◽  
Selection Rule ◽  
Direct Application ◽  
Input Selection ◽  
Selection Theory ◽  
Coupling Relationship ◽  
Three Degree Of Freedom ◽  
Three Degrees Of Freedom

Abstract. Three degrees of freedom (3-DoF) parallel mechanism (PM) with limbs of embedding structures is a kind of PM with a coupling relationship between limbs. In order to obtain a more desirable motion, the analysis of its actuated pairs shall be conducted. However, the fact that the existence of limbs coupling results in non-unique limb group, this mechanism has multiple limb groups. In this regard, the traditional input selection theory is not suitable for direct application in the input rationality analysis. Aiming to avoid this, a general extended input selection theory and limb group selection rule are proposed. The former tackles the traditional input selection theory which is not suitable for analyzing the input of PM with limbs of embedding structures since it does not take the influence of group into consideration, whereas the latter makes the calculation of the former easier. Based on the extended input selection theory and the limb group selection rule, the input and configuration of the 3-DoF PM with limbs of embedding structures are improved.

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