Kinematic Optimization of a Redundantly Actuated Parallel Mechanism for Maximizing Stiffness and Workspace Using Taguchi Method

2010 ◽  
Vol 6 (1) ◽  
Author(s):  
Hyunpyo Shin ◽  
Sungchul Lee ◽  
Woosung In ◽  
Jay I. Jeong ◽  
Jongwon Kim
Keyword(s):  
Taguchi Method ◽  
Parallel Mechanism ◽  
Optimization Procedure ◽  
Kinematic Parameter ◽  
Response Analysis ◽  
Kinematic Parameters ◽  
Stiffness Analysis ◽  
Second Stage ◽  
Workspace Analysis ◽  
Redundantly Actuated

We present an optimization procedure that uses the Taguchi method to maximize the mean stiffness and workspace of a redundantly actuated parallel mechanism at the same time. The Taguchi method is used to separate the more influential and controllable variables from the less influential ones among kinematic parameters in workspace analysis and stiffness analysis. In the first stage of optimization, the number of experimental variables is reduced by the response analysis. Quasi-optimal kinematic parameter group is obtained in the second stage of optimization after the response analysis. As a validation of the suggested procedure, the kinematic parameters of a planar 2-DOF parallel manipulator are optimized, which optimization procedure is used to investigate the optimal kinematic parameter groups between the length of the link and the stiffness.

Kinematic Optimization of a Redundantly Actuated Parallel Mechanism for Maximizing Active Stiffness and Workspace Using Taguchi Method

2009 ◽  
Author(s):  
Hyunpyo Shin ◽  
SungCheul Lee ◽  
Woosung In ◽  
Jay I. Jeong ◽  
Jongwon Kim
Keyword(s):  
Taguchi Method ◽  
Parallel Mechanism ◽  
Parallel Manipulator ◽  
Virtual Work ◽  
Optimization Procedure ◽  
Kinematic Parameter ◽  
Response Analysis ◽  
Stiffness Analysis ◽  
Redundantly Actuated ◽  
The Relationship

We present an optimization procedure that uses the Taguchi method to optimize the mean stiffness and workspace of a redundantly actuated parallel mechanism. The kinematic parameters of a planar 2-DOF parallel manipulator are optimized to maximize the manipulator’s workspace and mean stiffness at the same time. Kinematic analysis is performed to obtain a constraint Jacobian and forward Jacobian. And stiffness analysis of the redundantly actuated parallel manipulator is performed based on the virtual work theorem. The Taguchi method is applied to separate the more influential and controllable variables from the less influential ones in the optimization procedure. In the first stage of optimization, the number of experimental variables is reduced by response analysis. And after the response analysis, quasi-optimal kinematic parameter group is obtained in the second stage of optimization. The optimization procedure was used to investigate the optimal kinematic parameter groups and the relationship between the length and the stiffness of the link.

Optimal dimensioning of redundantly actuated mechanism for maximizing energy efficiency and workspace via Taguchi method

2016 ◽  
Vol 231 (2) ◽  
pp. 326-340 ◽  
Author(s):  
Sumin Park ◽  
Jehyeok Kim ◽  
Jay I Jeong ◽  
Jongwon Kim ◽  
Giuk Lee
Keyword(s):  
Energy Efficiency ◽  
Taguchi Method ◽  
Performance Index ◽  
Parallel Mechanism ◽  
Response Analysis ◽  
Parallel Mechanisms ◽  
End Effector ◽  
Controllable Factors ◽  
Redundantly Actuated ◽  
A Chain

A kinematic optimization of a redundantly actuated parallel mechanism is developed via the Taguchi method to maximize the sum of energy efficiency and workspace. In the optimization process, the energy consumption in a representative pathway of a predefined workspace is used as the performance index of the energy efficiency. The horizontal reach and stroke, and the vertical reach of mechanism, are used for the performance index of the workspace. The kinematic parameters of a chain that was added to the proposed non-redundantly actuated parallel mechanism as an extension to achieve redundant actuation are selected as the controllable factors. The velocity of the end-effector is considered to be a noise factor. Because the Taguchi method was originally used for robust optimization, we can improve the energy efficiency and workspace under various velocities for the end-effector. In the first stage of optimization, the number of controllable factors is reduced, and their correlations are eliminated using a response analysis. Quasi-optimized results are derived after the second stage of optimization. The optimized redundantly actuated parallel mechanism result is validated by comparing the energy efficiencies and workspaces of the original and optimal redundantly actuated parallel mechanisms.

Kinematic Calibration for Redundantly Actuated Parallel Mechanisms

2004 ◽  
Vol 126 (2) ◽  
pp. 307-318 ◽  
Author(s):  
Jay il Jeong ◽  
Dongsoo Kang ◽  
Young Man Cho ◽  
Jongwon Kim
Keyword(s):  
Optimization Algorithm ◽  
Parallel Mechanism ◽  
Kinematic Calibration ◽  
Parallel Mechanisms ◽  
Geometrical Constraint ◽  
Kinematic Parameters ◽  
Angle Error ◽  
Calibration Algorithm ◽  
Redundantly Actuated

We present a new kinematic calibration algorithm for redundantly actuated parallel mechanisms, and illustrate the algorithm with a case study of a planar seven-element 2-degree-of-freedom (DOF) mechanism with three actuators. To calibrate a nonredundantly actuated parallel mechanism, one can find actual kinematic parameters by means of geometrical constraint of the mechanism’s kinematic structure and measurement values. However, the calibration algorithm for a nonredundant case does not apply for a redundantly actuated parallel mechanism, because the angle error of the actuating joint varies with position and the geometrical constraint fails to be consistent. Such change of joint angle error comes from constraint torque variation with each kinematic pose (meaning position and orientation). To calibrate a redundant parallel mechanism, one therefore has to consider constraint torque equilibrium and the relationship of constraint torque to torsional deflection, in addition to geometric constraint. In this paper, we develop the calibration algorithm for a redundantly actuated parallel mechanism using these three relationships, and formulate cost functions for an optimization algorithm. As a case study, we executed the calibration of a 2-DOF parallel mechanism using the developed algorithm. Coordinate values of tool plate were measured using a laser ball bar and the actual kinematic parameters were identified with a new cost function of the optimization algorithm. Experimental results showed that the accuracy of the tool plate improved by 82% after kinematic calibration in a redundant actuation case.

Optimal trajectory planning considering optimal torque distribution of redundantly actuated parallel mechanism

2018 ◽  
Vol 232 (23) ◽  
pp. 4410-4419 ◽  
Author(s):  
Sumin Park ◽  
Jongwon Kim ◽  
Giuk Lee
Keyword(s):  
Parallel Mechanism ◽  
Optimization Procedure ◽  
Optimal Operation ◽  
Operation Planning ◽  
Parallel Mechanisms ◽  
Planning Stage ◽  
End Effector ◽  
Torque Distribution ◽  
Redundantly Actuated ◽  
Two Stages

Previous studies on the optimal operation planning of redundantly actuated parallel mechanisms have focused on optimal torque distribution for a predefined trajectory. However, the optimized result obtained for a predefined trajectory cannot guarantee an optimal operation plan, because the torque distribution ability of a redundantly actuated parallel mechanism is highly dependent on the shape of the end-effector trajectory. Therefore, we can expect the redundantly actuated parallel mechanism performance to be enhanced when both the trajectory and torque distribution are optimized during the optimal operation planning stage. We propose a novel redundantly actuated parallel mechanism optimization procedure that can optimize both the end-effector trajectory and torque distribution. The proposed procedure is composed of two stages of optimizers, i.e. upper- and lower-level optimizers that generate the end-effector trajectory and distribute the torques along the generated trajectory, respectively. Composition of these two stages of the optimization procedure allows optimization of both the trajectory and torque distribution, despite the correlation between them. The proposed optimization procedure is simulated using two types of cost functions. All the simulation results show that the proposed procedure facilitates optimization of the end-effector trajectory and the torque distribution concurrently. Also, the cost function value is minimized to a greater extent than in the result with the optimal torque distribution along the initial trajectory.

scholarly journals Calibration Method of Parallel Mechanism Type Machine Tools

2020 ◽  
Vol 14 (3) ◽  
pp. 429-437
Author(s):  
Keisuke Nagao ◽  
◽  
Nobuaki Fujiki ◽  
Yoshitaka Morimoto ◽  
Akio Hayashi
Keyword(s):  
Machine Tools ◽  
Parallel Mechanism ◽  
Least Squares Method ◽  
Coordinate Measuring Machine ◽  
Calibration Method ◽  
Kinematic Parameter ◽  
Forward Kinematics ◽  
Kinematic Parameters ◽  
Type Machine ◽  
Measuring Machine

This paper proposes a calibration method for a parallel mechanism type machine tool (XMINI, Exechon Enterprises L.L.C.). In this method, the kinematic parameters are calculated using forward kinematics and the least squares method from the results obtained by a coordinate measuring machine. By using an articulated arm coordinate measuring machine (AACMM), we can measure a wide space, and the measuring machine position do not have to be determined strictly. This paper provides a solution for the forward kinematics problem to identify the kinematic parameters. The results from the kinematic parameter calculation are evaluated using the experimental results from an actual machine.

KINEMATICS AND WORKSPACE ANALYSIS OF A 3 DEGREE OF FREEDOM PARALLEL MECHANISM WITH PARALLELOGRAM LINKAGE

2017 ◽  
Vol 41 (5) ◽  
pp. 922-935
Author(s):  
HongJun San ◽  
JunSong Lei ◽  
JiuPeng Chen ◽  
ZhengMing Xiao ◽  
JunJie Zhao
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Analytical Method ◽  
Theoretical Basis ◽  
Parallel Mechanism ◽  
Graphical Method ◽  
Degree Of Freedom ◽  
Workspace Analysis ◽  
Fixed Base ◽  
Moving Platform

In this paper, a 3-DOF translational parallel mechanism with parallelogram linkage was studied. According to the space vector relation between the moving platform and the fixed base, the direct and inverse position solutions of this mechanism was deduced through analytical method. In addition, the error of the algorithm was analyzed, and the algorithm had turned out to be effective and to have the satisfactory computational precision. On the above basis, the workspace of this mechanism was found through graphical method, which was compared with that of finding through Monte Carlo method, and there was the feasibility for analyzing the workspace of the mechanism by graphical method. The characteristic of the mechanism was analyzed by comparing the results of two analysis methods, which provided a theoretical basis for the application of the mechanism.

Force analysis of the redundantly actuated parallel mechanism 2RPR+P considering different control methodologies

2021 ◽  
pp. 103783
Author(s):  
Yundou Xu ◽  
Ze Jiang ◽  
Zhongjin Ju ◽  
Zengzhao Wang ◽  
Wenlan Liu ◽  
...  
Keyword(s):  
Parallel Mechanism ◽  
Force Analysis ◽  
Redundantly Actuated

Kinematic Analysis of a Novel 3-DOF Parallel Mechanism with Actuation Redundancy

2013 ◽  
Vol 816-817 ◽  
pp. 821-824
Author(s):  
Xue Mei Niu ◽  
Guo Qin Gao ◽  
Zhi Da Bao
Keyword(s):  
Kinematic Analysis ◽  
Parallel Mechanism ◽  
Rbf Neural Network ◽  
Analysis Method ◽  
Parallel Kinematic Mechanism ◽  
Redundantly Actuated ◽  
Parallel Kinematic ◽  
Forward Kinematic ◽  
Kinematic Mechanism ◽  
Kinematic Solution

Kinematic analysis plays an important role in the research of parallel kinematic mechanism. This paper addresses a novel forward kinematic solution based on RBF neural network for a novel 2PRRR-PPRR redundantly actuated parallel mechanism. Simulation results illustrate the validity and feasibility of the kinematic analysis method.

scholarly journals Dynamic response analysis for multi-degrees-of-freedom parallel mechanisms with various types of three-dimensional clearance joints

2021 ◽  
Vol 18 (3) ◽  
pp. 172988142110177
Author(s):  
Jia Yonghao ◽  
Chen Xiulong
Keyword(s):  
Dynamic Response ◽  
Multibody Systems ◽  
Parallel Mechanism ◽  
Three Dimensional ◽  
Response Analysis ◽  
Parallel Mechanisms ◽  
Dynamics Model ◽  
Clearance Joints ◽  
Clearance Joint ◽  
Spatial Parallel Mechanism

For spatial multibody systems, the dynamic equations of multibody systems with compound clearance joints have a high level of nonlinearity. The coupling between different types of clearance joints may lead to abundant dynamic behavior. At present, the dynamic response analysis of the spatial parallel mechanism considering the three-dimensional (3D) compound clearance joint has not been reported. This work proposes a modeling method to investigate the influence of the 3D compound clearance joint on the dynamics characteristics of the spatial parallel mechanism. For this purpose, 3D kinematic models of spherical clearance joint and revolute joint with radial and axial clearances are derived. Contact force is described as normal contact and tangential friction and later introduced into the nonlinear dynamics model, which is established by the Lagrange multiplier technique and Jacobian of constraint matrix. The influences of compound clearance joint and initial misalignment of bearing axes on the system are analyzed. Furthermore, validation of dynamics model is evaluated by ADAMS and Newton–Euler method. This work provides an essential theoretical basis for studying the influences of 3D clearance joints on dynamic responses and nonlinear behavior of parallel mechanisms.

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