A manipulator size optimization method based on dexterous workspace volume

Cobot ◽  
2022 ◽  
Vol 1 ◽  
pp. 3
Author(s):  
Yuanhai Huang ◽  
Zhi Li ◽  
Kefan Xing ◽  
Haoqin Gong
Keyword(s):  
Genetic Algorithm ◽  
Kinematic Analysis ◽  
Degrees Of Freedom ◽  
Optimization Method ◽  
Size Optimization ◽  
Maximum Volume ◽  
Six Degrees Of Freedom ◽  
Working Point

Background: Manipulators for robots are required to have high manipulability for adaptability in different tasks. However, general methods for designing manipulators with high manipulability are deficient. Here, aiming at improving the manipulability of the six degrees-of-freedom (DOF) manipulator, a method for optimizing structure size parameters based on the dexterous workspace volume is proposed. Methods: Firstly, the kinematic analysis of the manipulator is performed. Then, the manipulability of the single working point of the manipulator is judged based on reachability in different postures. The workspace of the manipulator is discretized to obtain the volume of the overall dexterous workspace. By taking the maximum volume of the dexterous workspace as the optimization goal, Genetic Algorithm (GA) is used to optimize the structure size parameters to achieve optimal manipulability. AUBO 6-DOF manipulator is defined and analyzed as an example. Results: The optimization results indicate that the dexterous workspace of the manipulator expands in volume and its manipulability is improved. The validity of the proposed optimization method is verified by comparing the distribution of dexterous workspace of the manipulator. Conclusions: This article proposes an optimization method for the structure size parameters of a 6-DOF manipulator, which can be implemented to improving the manipulability of the manipulator.

Study on Welding Path Planning of Welding Position Flock for Welding Robot Based on Improved Genetic Algorithm

2014 ◽  
Vol 602-605 ◽  
pp. 1332-1335
Author(s):  
Hong Wei Lv
Keyword(s):  
Genetic Algorithm ◽  
Degrees Of Freedom ◽  
Mathematic Model ◽  
Welding Robot ◽  
Improved Genetic Algorithm ◽  
Complete Coverage ◽  
Six Degrees Of Freedom ◽  
Filial Generation ◽  
Full Rotation ◽  
Welding Position

With full rotation articulated ABB-IBR140-M2000 robot with six degrees of freedom used as welding robot, the exploring of efficient complete coverage of welding position flock is an important way of improving the performance of welding robot. Making use of improved genetic algorithm, in which the best father generation is saved and using ordered cross and reverse ordered mutation to constitute filial generation, and this method makes sure that the algorithms is convergent. The complete coverage of welding position optimization mathematic model whose objective is the minimum distance is established, making use of the improved genetic algorithm to solve the problem, an example is analyzed in detail, and the result shows that the algorithms is convergent and efficient.

Kinematic analysis and path planning of a new kinematically redundant planar parallel manipulator

Robotica ◽  
2008 ◽  
Vol 26 (3) ◽  
pp. 405-413 ◽  
Author(s):  
Iman Ebrahimi ◽  
Juan A. Carretero ◽  
Roger Boudreau
Keyword(s):  
Path Planning ◽  
Condition Number ◽  
Kinematic Analysis ◽  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Six Degrees Of Freedom ◽  
Displacement Problem ◽  
Singular Configurations ◽  
Planar Parallel Manipulator

SUMMARYIn this work, the 3-RPRR, a new kinematically redundant planar parallel manipulator with six-degrees-of-freedom, is presented. First, the manipulator is introduced and its inverse displacement problem discussed. Then, all types of singularities of the 3-RPRR manipulator are analysed and demonstrated. Thereafter, the dexterous workspace is geometrically obtained and compared with the non-redundant 3-PRR planar parallel manipulator. Finally, based on a geometrical measure of proximity to singular configurations and the condition number of the manipulators' Jacobian matrices, actuation schemes for the manipulators are obtained. Different actuation schemes for a given path are obtained and the quality of their actuation schemes are compared. It is shown that the proposed manipulator is capable of following a path while avoiding the singularities.

Six degrees of freedom parallel robots with C5 links

Robotica ◽  
1992 ◽  
Vol 10 (1) ◽  
pp. 35-44 ◽  
Author(s):  
Y. Amirat ◽  
F. Artigue ◽  
J. Pontnau
Keyword(s):  
Automotive Industry ◽  
Kinematic Analysis ◽  
Degrees Of Freedom ◽  
Parallel Architecture ◽  
Parallel Robot ◽  
Parallel Architectures ◽  
Parallel Robots ◽  
Left Hand ◽  
Six Degrees Of Freedom ◽  
Assembly Tasks

SummaryThis paper presents at first a static and kinematic analysis of closed chains mechanisms which permits to deduce different possible fully parallel architectures. Then we focus on a particular parallel architecture with C5 links designed to perform precise assembly tasks. A general modeling of this C5 parallel robot is presented. Two typical assembly tasks in the automotive industry are also proposed; the first one uses the C5 links parallel robot as a left-hand device, while the second one uses it as the terminal tool of a sequential manipulator.

GLOBAL OPTIMIZATION METHOD APPLIED TO THE KINEMATICS OF GAIT IN PREGNANT WOMEN

2016 ◽  
Vol 16 (06) ◽  
pp. 1650084 ◽  
Author(s):  
LILIANA AGUIAR ◽  
CARLOS ANDRADE ◽  
MARCO BRANCO ◽  
RITA SANTOS-ROCHA ◽  
FILOMENA VIEIRA ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Pregnant Women ◽  
Degrees Of Freedom ◽  
Morphological Changes ◽  
Optimization Method ◽  
Second Trimester ◽  
Hip Joints ◽  
Six Degrees Of Freedom ◽  
The One ◽  
Soft Tissue Artifact

Morphological changes are associated to pregnancy, such as weight gain and increased volume of the trunk. The soft tissue artifact can also increase with these characteristics and affect the real joint kinematics. The main objective of this study was to understand the effect of using three different constraining sets in the lower limb joints, in the amount of soft tissue artifact (STA) of pregnant women, in order to obtain the most appropriated joint set to be used in gait and in this population. The ankle, knee and hip joints were modeled respectively with the following characteristics: (1) Universal–revolute–spherical (URS), (2) spherical–revolute–spherical (SRS) and (3) spherical–spherical–spherical (SSS). The six degrees of freedom (6DOF) model was used as the basis for comparison and considered the one with the highest error associated to the STA. In pregnant women, the URS model seems to affect more the kinematic variables when compared with the 6DOF model. Assuming that the kinematic error associated with pregnant women is increased due to the STA, the URS model may be affecting more the angular kinematics of the knee joint. SSS model seems to be more appropriated to analyze gait in second trimester pregnant women.

Full-Mobility Three-CCC Parallel-Kinematics Machines: Kinematics and Isotropic Design

2017 ◽  
Vol 10 (1) ◽  
Author(s):  
Wei Li ◽  
Jorge Angeles
Keyword(s):  
Kinematic Analysis ◽  
Degrees Of Freedom ◽  
Large Region ◽  
Parallel Kinematics ◽  
Six Degrees Of Freedom ◽  
Parallel Kinematics Machines ◽  
The Subject ◽  
Moving Platform

The subject of this paper is twofold: the kinematics and the isotropic design of six degrees-of-freedom (DOF), three-CCC parallel-kinematics machines (PKMs). Upon proper embodiment and dimensioning, the PKMs discussed here, with all actuators mounted on the base, exhibit interesting features, not found elsewhere. One is the existence of an isotropy locus, as opposed to isolated isotropy points in the workspace, thereby guaranteeing the accuracy and the homogeneity of the motion of the moving platform (MP) along different directions within a significantly large region of their workspace. The conditions leading to such a locus are discussed in depth; several typical isotropic designs are brought to the limelight. Moreover, the kinematic analysis shows that rotation and translation of the MP are decoupled, which greatly simplifies not only the kinetostatic analysis but also, most importantly, their control. Moreover, it is shown that the singularity loci of this class of mechanism are determined only by the orientation of their MP, which also simplifies locus evaluation and eases its representation.

Three methods of training multi-layer perceptrons to model a robot sensor

Robotica ◽  
1995 ◽  
Vol 13 (5) ◽  
pp. 531-538 ◽  
Author(s):  
D. T. Pham ◽  
S. Sagiroglu
Keyword(s):  
Genetic Algorithm ◽  
Degrees Of Freedom ◽  
Natural Vibration ◽  
Inertial Sensor ◽  
Input Pattern ◽  
Training Methods ◽  
Six Degrees Of Freedom ◽  
Marquardt Algorithm ◽  
Levenberg Marquardt ◽  
Working Principle

SummaryThis paper discusses three methods of training multi-layer perceptrons (MLPs) to model a six-degrees-of- freedom inertial sensor. Such a sensor is designed for use with a robot to determine the location of objects it has to pick up. The sensor operates by measuring parameters related to the inertia of an object and computing its location from those parameters. MLP models are employed for part of the computation. They are trained to output the orientation of the object in response to an input pattern that includes the period of natural vibration of the sensor on which the object rests. After reviewing the working principle of the sensor, the paper describes the three MLP training methods (backpropagation, optimisation using the Levenberg-Marquardt algorithm, evolution based on the genetic algorithm) and presents the experimental results obtained.

Development of Position-Orientation Decoupled Spatial In-Parallel Actuated Mechanisms with Six Degrees of Freedom

2005 ◽  
Vol 17 (1) ◽  
pp. 59-68 ◽  
Author(s):  
Yukio Takeda ◽  
◽  
Kouji Kamiyama ◽  
Yoshihisa Maki ◽  
Masaru Higuchi ◽  
...  
Keyword(s):  
Kinematic Analysis ◽  
Degrees Of Freedom ◽  
Experimental Results ◽  
Six Degrees Of Freedom ◽  
Position And Orientation ◽  
Basic Equations ◽  
Number Synthesis ◽  
Theoretical Results

We propose a new structure for spatial in-parallel actuated mechanisms with six degrees of freedom in which the output link’s position and orientation are decoupled. Number synthesis of the position submechanism, a partial mechanism for the position-orientation decoupled mechanism, was conducted, and fifteen mechanisms were clarified. Basic equations for kinematic analysis were derived for four of the obtained mechanisms, and procedures to analyze their forward/inverse displacement were investigated. Their workspaces and swing angles were numerically evaluated based on these equations. Experimental results using an experimental position-orientation decoupled mechanism were presented to support these theoretical results.

scholarly journals Kinematic analysis and simulation of 6-DOF vehicle driving simulator

2021 ◽  
Vol 2137 (1) ◽  
pp. 012035
Author(s):  
Wenbin Shu ◽  
Haonan Yan ◽  
Lijun Meng
Keyword(s):  
Kinematic Analysis ◽  
Degrees Of Freedom ◽  
Driving Simulator ◽  
Calculation Model ◽  
Rotating Platform ◽  
Six Degrees Of Freedom ◽  
Motion Modes ◽  
Moving Cylinder ◽  
Variation Curve ◽  
Action Force

Abstract In order to reasonably design the six degrees of freedom turntable (hereinafter referred to as the transfer table), based on the structure size and motion index parameters of the turntable, The motion mechanics calculation model was established to simulate and analyze the mechanical variation curve of singing platform under different motion modes. The analysis shows that when the upper platform load and the component mass are 3000 kg, the maximum action force of the rotating platform support moving cylinder is 1376.4 kg.

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