Complete kinematic calibration of a 6-RRRPRR parallel kinematic machine based on the optimal measurement configurations

2019 ◽  
Vol 234 (1) ◽  
pp. 121-136 ◽  
Author(s):  
Chunyang Han ◽  
Yang Yu ◽  
Zhenbang Xu ◽  
Xiaoming Wang ◽  
Peng Yu ◽  
...  
Keyword(s):  
Kinematic Model ◽  
Inverse Kinematic ◽  
Error Model ◽  
Kinematic Calibration ◽  
Universal Joint ◽  
Parallel Kinematic Mechanism ◽  
Simulation And Experiment ◽  
Parallel Kinematic ◽  
Kinematic Mechanism ◽  
Selection Of

This paper presents a kinematic calibration of a 6-RRRPRR parallel kinematic mechanism with offset RR-joints that would be applied in space positioning field. In order to ensure highly accurate and highly effective calibration process, the complete error model, which contains offset universal joint errors, is established by differentiating inverse kinematic model. A calibration simulation comparison with non-complete error model shows that offset universal joint errors are crucial to improve the calibration accuracy. Using the error model, an optimal calibration configuration selection algorithm is developed to determine the least number of measurement configurations as well as the optimal selection of these configurations from the feasible configuration set. To verify the effectiveness of kinematic calibration, a simulation and experiment were performed. The results show that the developed approach can effectively improve accuracy of a parallel kinematic mechanism with relatively low number of calibration configurations.

Elastic Deformation Error Model for Calibration and Compensation of Parallel Kinematic Mechanism Machine Tool

2012 ◽  
Vol 6 (2) ◽  
pp. 188-195
Author(s):  
Tetsuya Matsushita ◽  
◽  
Hiroshi Ueno ◽  
Atsushi Matsubara ◽  
Keyword(s):  
Machine Tool ◽  
Elastic Deformation ◽  
Calibration Method ◽  
Compensation System ◽  
Error Model ◽  
Parallel Kinematic Mechanism ◽  
Internal Forces ◽  
Parallel Kinematic ◽  
Deformation Error ◽  
Kinematic Mechanism

In the motion error of parallel kinematic mechanism machine tools, the elastic deformation caused by external forces, such as gravity, as well as the kinematic parameter error, is a significant factor. Internal forces generated by the rotational resistance of passive joints also deform mechanical components. In this paper, an elastic deformation error model that can deal with external and internal forces is presented. A compensation system and a calibration method of kinematic parameters employing this model are also presented. It is experimentally verified that this calibration method and compensation system improve the motion accuracy of a parallel kinematic mechanism machine tool.

Design and Kinematic Analysis of a Novel 3UPS/RPU Parallel Kinematic Mechanism With 2T2R Motion for Knee Diagnosis and Rehabilitation Tasks

2017 ◽  
Vol 9 (6) ◽  
Author(s):  
Pedro Araujo-Gómez ◽  
Vicente Mata ◽  
Miguel Díaz-Rodríguez ◽  
Angel Valera ◽  
Alvaro Page
Keyword(s):  
Screw Theory ◽  
Kinematic Model ◽  
Closed Form Solution ◽  
Form Solution ◽  
Parallel Mechanisms ◽  
Forward Displacement ◽  
Parallel Kinematic Mechanism ◽  
Parallel Kinematic ◽  
Displacement Model ◽  
Kinematic Mechanism

This paper proposes a two translational and two rotational (2T2R) four-degrees-of-freedom (DOF) parallel kinematic mechanism (PKM) designed as a knee rehabilitation and diagnosis mechatronics system. First, we establish why rehabilitation devices with 2T2R motion are required, and then, we review previously proposed parallel mechanisms with this type of motion. After that, we develop a novel proposal based on the analysis of each kinematic chain and the Grübler–Kutzbach criterion. Consequently, the proposal consists of a central limb with revolute-prismatic-universal (RPU) joints and three external limbs with universal-prismatic-spherical (UPS) joints. The Screw theory analysis verifies the required mobility of the mechanism. Also, closed-loop equations enable us to put forward the closed-form solution for the inverse-displacement model, and a numerical solution for the forward-displacement model. A comparison of the numerical results from five test trajectories and the solution obtained using a virtual prototype built in msc-adams shows that the kinematic model represents the mechanism's motion. The analysis of the forward-displacement problem highlights the fact that the limbs of the mechanism should be arranged asymmetrically. Moreover, the Screw theory makes it possible to obtain the Jacobian matrix which provides insights into the analysis of the mechanism's workspace. The results show that the proposed PKM can cope with the required diagnosis and rehabilitation task. The results provide the guidelines to build a first prototype of the mechanism which enables us to perform initial tests on the robot.

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.

Accuracy Synthesis of Redundant Parallel Kinematic Mechanism with Weighted Least Square Method

2012 ◽  
Vol 499 ◽  
pp. 3-8
Author(s):  
Xin You Li ◽  
Wu Yi Chen
Keyword(s):  
Machine Tool ◽  
Conventional Method ◽  
Least Square Method ◽  
Least Square ◽  
Tolerance Allocation ◽  
Manufacturing Processes ◽  
Manufacturing Cost ◽  
Parallel Kinematic Mechanism ◽  
Parallel Kinematic ◽  
Kinematic Mechanism

In order to reduce manufacturing cost, a methodology of accuracy synthesis for machine tool was recommended by combining both machining cost and Least Square method. Weighted coefficients representing the machining difficulty of manufacturing processes were introduced. 3PRS/UPS redundant parallel kinematic mechanism (3PRS/UPS PKM) was taken as an example, and its component tolerances were derived by the proposed method. Comparing with conventional method, the component tolerances were allocated reasonably. A further tolerance allocation for spherical and rotational joints was studied in detail. And hence, the producibility of component was improved and the manufacturing cost was reduced. The results showed that the proposed method was capable of producing tolerance allocations economically and accurately.

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