scholarly journals Denim-fabric-polishing robot size optimization based on global spatial dexterity

2021 ◽  
Vol 12 (1) ◽  
pp. 649-660
Author(s):  
Wenjie Wang ◽  
Qing Tao ◽  
Xiaohua Wang ◽  
Yuting Cao ◽  
Congcong Chen
Keyword(s):  
Condition Number ◽  
Performance Indicators ◽  
Jacobian Matrix ◽  
Particle Swarm Algorithm ◽  
Performance Indices ◽  
Fireworks Algorithm ◽  
Comprehensive Index ◽  
Optimization Function ◽  
Denim Fabric ◽  
Novel Method

Abstract. This paper presents a novel method to make denim-fabric-polishing robots perform their primary task flexibly and efficiently within a limited workspace. Link lengths are optimized based on an adaptive fireworks algorithm to improve the comprehensive dexterity index. A forward kinematics analysis of the denim-fabric-polishing robot is conducted via the D–H method; the workspace is analyzed according to the needs at hand to determine the range of motion of each joint. To solve the movement condition number of the Jacobian matrix, the concept of low-condition-number probability is established, and a comprehensive dexterity indicator is constructed. The influence of the robot's size on the condition number and comprehensive dexterity index is determined. Finally, the adaptive fireworks algorithm is used to establish the objective optimization function by integrating the dexterity index and other performance indicators. The optimization results show that when the comprehensive dexterity index is taken as the optimization objective, the dexterity comprehensive index and other performance indices of the robot are the lowest; that is, the robot is more flexible. Compared with the traditional genetic algorithm and particle swarm algorithm, the adaptive fireworks algorithm proposed in this paper has better solving speed and solving precision. The optimized workspace of the robot meets the requirements of the polishing task. The design also yields a sufficiently flexible, efficient, and effective robot.

scholarly journals Performance Analysis and Optimization of a 6-DOF Robotic Crusher

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Guoguang Li ◽  
Boqiang Shi ◽  
Ruiyue Liu ◽  
Jie Gu
Keyword(s):  
Performance Analysis ◽  
Condition Number ◽  
Mechanical Performance ◽  
Jacobian Matrix ◽  
Screw Theory ◽  
Practical Application ◽  
Transmission Performance ◽  
Instantaneous Power ◽  
Transmission Index ◽  
Optimization Function

Considering the complexity of multidimension parameters and the mechanical performance of a 6-DOF robotic crusher, a multiobjective optimization function based on the transmission index and condition number is established. As an important operation in the screw theory, the reciprocal product between the transmission wrench screw of an actuator and the output twist screw of the mantle assembly is used to represent the instantaneous power. The expression of transmission index is derived according to the principle that constraint wrench screws apply no work to the mantle assembly. It can be used as a criterion to evaluate the transmission performance. Then, based on the Jacobian matrix, the equation of condition number is constructed which provides a criterion for evaluating kinematic accuracy. Finally, the workspace and singularity of the 6-DOF robotic crusher are analyzed to verify the rationality of the optimized variables. The results show that the optimized structure can completely crush the material in the workspace and effectively avoid singularity, which provides a basis for practical application.

scholarly journals Asymmetric reconfiguration of a 3-dof parallel manipulator

2020 ◽  
Vol 33 (01) ◽  
pp. 137-147
Author(s):  
A. L. Balmaceda-Santamaría ◽  
A. E. Chávez-Toruño
Keyword(s):  
Condition Number ◽  
Parallel Manipulator ◽  
Jacobian Matrix ◽  
Parallel Robot ◽  
Performance Indices ◽  
Kinematic Chains ◽  
Delta Type

In this paper an asymmetric reconfigurable parallel manipulator is presented. Asymmetric configurations are obtained by modifying the angle between each of the kinematic chains. Thanks to the reconfiguration proposal significant improvement of the manipulator performance can be obtained with respect to a Delta-type parallel robot. The computation of the best condition number is obtained, the results show that by using the redundancy, all the performance indices that depend on the Jacobian matrix can be improved as well.

Evaluation of the Kinematic Performance of a 3-RRS Parallel Mechanism

Robotica ◽  
2020 ◽  
pp. 1-12
Author(s):  
Manxin Wang ◽  
Qiusheng Chen ◽  
Haitao Liu ◽  
Tian Huang ◽  
Hutian Feng ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Parallel Mechanism ◽  
Jacobian Matrix ◽  
Mean Value ◽  
Spherical Joint ◽  
Performance Indices ◽  
Active Joint ◽  
Strongly Coupled ◽  
The Mean ◽  
Kinematic Performance

SUMMARY This paper proposes a set of novel indices for evaluating the kinematic performance of a 3-RRS (R and S denote revolute and spherical joint respectively, R denotes active joint.), parallel mechanism whose translational and rotational movements are strongly coupled. First, the indices are formulated using the decoupled overall Jacobian matrix, which is developed using coordinate transformation. Then, the influences of the homogeneous dimensionless parameters on these indices are investigated. In addition, the dimension synthesis of the 3-RRS parallel mechanism is carried out by minimizing the mean value of the kinematic performance indices and their standard deviation. The results demonstrate that the established approach facilitates good global kinematic performance of the parallel mechanism.

scholarly journals Jacobian, Manipulability, Condition Number, and Accuracy of Parallel Robots

2005 ◽  
Vol 128 (1) ◽  
pp. 199-206 ◽  
Author(s):  
J. P. Merlet
Keyword(s):  
Optimal Design ◽  
Condition Number ◽  
Jacobian Matrix ◽  
Parallel Robots ◽  
Condition Numbers ◽  
Accuracy Index ◽  
Positioning Errors ◽  
Local Accuracy ◽  
Early Beginning ◽  
Accuracy Indices

Although the concepts of Jacobian matrix, manipulability, and condition number have existed since the very early beginning of robotics their real significance is not always well understood. In this paper we revisit these concepts for parallel robots as accuracy indices in view of optimal design. We first show that the usual Jacobian matrix derived from the input-output velocities equations may not be sufficient to analyze the positioning errors of the platform. We then examine the concept of manipulability and show that its classical interpretation is erroneous. We then consider various common local dexterity indices, most of which are based on the condition number of the Jacobian matrix. It is emphasized that even for a given robot in a particular pose there are a variety of condition numbers and that their values are not coherent between themselves but also with what we may expect from an accuracy index. Global conditioning indices are then examined. Apart from the problem of being based on the local accuracy indices that are questionable, there is a computational problem in their calculation that is neglected most of the time. Finally, we examine what other indices may be used for optimal design and show that their calculation is most challenging.

Development of Kinematic/Kinetic Performance Tools in Synthesis of Multi-D.O.F. Mechanisms

1991 ◽  
Author(s):  
Ming-Yih Lee ◽  
Arthur G. Erdman ◽  
Yevsey Gutman
Keyword(s):  
Computer Aided Design ◽  
Graphical Representation ◽  
Jacobian Matrix ◽  
Robotic Manipulators ◽  
Efficiency Index ◽  
Performance Characteristics ◽  
Design Stage ◽  
Performance Indices ◽  
Coupling Index ◽  
Aided Design

Abstract Kinematic and kinetic performance are important issues in designing multi-degree of freedom mechanisms such as robotic manipulators. In the engineering design stage, it is especially important that the designer can grasp the characteristics of the mechanism. The aim of this study is to develop a means of representing the kinematic and kinetic performance of the mechanism in such a way that the performance characteristics are quantified analytically and visible graphically to the designer in their entirety in the conceptual design stage. Various performance indices derived from the Jacobian matrix and its quadratic form. These performance indices are the local kinematic cross-coupling index, the local directional mobility index, and the local efficiency index. Graphical images of these performance characteristics using eigen-ellipsoid and workspace trajectory contours are introduced. Critical performance points in mechanism workspace are identified and elaborated for design considerations. Based on the graphical representation of these performance characteristics, design rules for achieving different performance objectives can easily be implemented. This method is applicable to computer-aided design of a mechanism and predetermination of its kinematic and kinetic performance.

Performance Analysis and Optimal Design of a 3-DOF 3-PRUR Parallel Mechanism

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Daxing Zeng ◽  
Zhen Huang ◽  
Wenjuan Lu
Keyword(s):  
Optimal Design ◽  
Performance Analysis ◽  
Parallel Mechanism ◽  
Jacobian Matrix ◽  
Screw Theory ◽  
Performance Indices ◽  
Geometrical Characteristics

In this paper, a 3-DOF 3-PRUR parallel mechanism (PM) is chosen for performance analysis and optimal design. First, the mobility of the PM is analyzed by using screw theory. Then, the kinematics of this PM is studied based on the geometrical characteristics and the Jacobian matrix is derived. Furthermore, we research some performance indices with respect to the Jacobian matrix over the whole workspace and nondimensional parameters when the input is given, and their performance atlases are obtained with different inputs. Finally, the optimal design of the PM is determined according to the performance atlases, and some examples are presented.

scholarly journals Probabilistic Decomposition Method on the ServerIndices of anMξ/G/1 Vacation Queue

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Renbin Liu
Keyword(s):  
Decomposition Method ◽  
Queueing System ◽  
Stochastic Order ◽  
Single Server ◽  
Production Facility ◽  
Performance Indices ◽  
Illustrative Purpose ◽  
Novel Method ◽  
The Mean ◽  
Convolution Equations

This paper develops a probabilistic decomposition method for anMξ/G/1 repairable queueing system with multiple vacations, in which the customers who arrive during server vacations enter the system with probabilityp. Such a novel method is used to analyze the main performance indices of the server, such as the unavailability and the mean failure number during(0,t]. It is derived that the structures of server indices are two convolution equations. Further, comparisons with existing methods indicate that our method is effective and applicable for studying server performances in single-serverMξ/G/1 vacation queues and their complex variants. Finally, a stochastic order and production system with a multipurpose production facility is numerically presented for illustrative purpose.

On the kinematics of a new parallel mechanism with Schoenflies motion

Robotica ◽  
2015 ◽  
Vol 34 (9) ◽  
pp. 2056-2070 ◽  
Author(s):  
Po-Chih Lee ◽  
Jyh-Jone Lee
Keyword(s):  
Closed Form ◽  
Condition Number ◽  
Kinematic Analysis ◽  
Parallel Mechanism ◽  
Parallel Manipulator ◽  
Matrix Algebra ◽  
Degrees Of Freedom ◽  
Jacobian Matrix ◽  
Pick And Place

SUMMARYThis paper investigates the kinematics of one new isoconstrained parallel manipulator with Schoenflies motion. This new manipulator has four degrees of freedom and two identical limbs, each having the topology of Cylindrical–Revolute–Prismatic–Helical (C–R–P–H). The kinematic equations are derived in closed-form using matrix algebra. The Jacobian matrix is then established and the singularities of the robot are investigated. The reachable workspaces and condition number of the manipulator are further studied. From the kinematic analysis, it can be shown that the manipulator is simple not only for its construction but also for its control. It is hoped that the results of the evaluation of the two-limb parallel mechanism can be useful for possible applications in industry where a pick-and-place motion is required.

Design and Kinematics Analysis of a Novel Planar Parallel Mechanism

2014 ◽  
Vol 568-570 ◽  
pp. 904-910
Author(s):  
Yan Bin Zhang ◽  
Hui Ping Wang
Keyword(s):  
Condition Number ◽  
Parallel Mechanism ◽  
Jacobian Matrix ◽  
Screw Theory ◽  
Kinematics Analysis ◽  
Moving Platform ◽  
One To One ◽  
Actuated Joints

A novel 3-dof planar parallel mechanism, which is composed by three different limbs, is designed. The moving platform can translate along two directions and rotate around one axis with respect to the base. Mobility of the mechanism is discussed and calculated based on the screw theory. The forward and the inverse analytical position equations are derived and the veloctiy analysis is addressed too. The Jacobian matrix is an identical one, so there exists one-to-one corresponding linear controlling relationship between one of the actuated joints and one of the outputs of the platform. Moreover, the condition number of the Jacobian matrix is constantly equal to one and the mechanism shows fully-isotropic throughout entire workspace.

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