Kinematic calibration and error compensation of a hexaglide parallel manipulator

2017 ◽  
Vol 233 (1) ◽  
pp. 215-225 ◽  
Author(s):  
Jiangzhen Guo ◽  
Dan Wang ◽  
Rui Fan ◽  
Wuyi Chen ◽  
Guohua Zhao
Keyword(s):  
Error Compensation ◽  
Parallel Manipulator ◽  
Least Squares Method ◽  
Orthogonal Design ◽  
Kinematic Model ◽  
Calibration Method ◽  
High Accuracy ◽  
Geometric Error ◽  
Kinematic Calibration ◽  
Parallel Mechanisms

A calibration method of a hexaglide parallel manipulator is presented to improve its accuracy. A prototype of the hexaglide parallel manipulator is first proposed and its kinematics is analyzed. Through differentiating kinematic equations, 54 geometric error parameters are generated to present the pose error of the moving platform, on which an iterative algorithm for the calibration is based. The experiment starts with the data acquisition. All of measuring poses are newly selected based on the orthogonal design, and the deviations in each pose are measured by a laser tracker. Subsequently, 54 actual geometric parameters are identified by least squares method and compensated to the nominal kinematic model, which is assessed by 25 configurations to obtain the accuracy of the calibrated hexaglide parallel manipulator. It is discovered that the pose errors of the calibrated hexaglide parallel manipulator are significantly reduced and illustrate the validity of the calibration method to improve its accuracy. Finally, we discussed the feasibility of implementing this method in high-accuracy calibration of variant-scale parallel mechanisms.

CALIBRATION OF THE 3-PRS PARALLEL MANIPULATOR USING A MOTION CAPTURE SYSTEM

2005 ◽  
Vol 29 (4) ◽  
pp. 645-654
Author(s):  
C.G. van Driel ◽  
Juan A. Carretero
Keyword(s):  
Motion Capture ◽  
Parallel Manipulator ◽  
Kinematic Model ◽  
Calibration Method ◽  
Kinematic Calibration ◽  
Virtual Model ◽  
Motion Capture System ◽  
Parallel Mechanisms ◽  
Kinematic Parameters ◽  
Preliminary Testing

In this paper, a kinematic calibration method for the 3-PRS parallel manipulator using a motion capture system is presented. Although parallel mechanisms present numerous advantages over their serial counterparts, an accurate kinematic model must be developed to facilitate their operation. Kinematic calibration is used to accurately determine the kinematic parameters of the kinematic model to improve the overall accuracy of the mechanism. The kinematic calibration of the 3-PRS parallel manipulator will be examined by identification of the manipulator's kinematic parameters, an introduction to the motion capture system used, and the presentation of die calibration method itself. For preliminary testing purposes, a virtual model of the manipulator has been generated in CAD to validate the calibration method. The calibration method initially determines the joint locations and orientations, from which the remaining kinematic parameters can be resolved. Preliminary testing using the virtual model indicates the method is valid and can accurately determine the modelled parameters. Once the physical manipulator is operational, alterations the calibration method will be required to account for manufacturing and assembly tolerances/errors, joint offsets and noise during the static captures.

scholarly journals A Kinematic Calibration Method of a 3T1R 4-Degree-of-Freedom Symmetrical Parallel Manipulator

Symmetry ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 357
Author(s):  
Fengxuan Zhang ◽  
Silu Chen ◽  
Yongyi He ◽  
Guoyun Ye ◽  
Chi Zhang ◽  
...  
Keyword(s):  
Parallel Manipulator ◽  
Kinematic Model ◽  
Calibration Method ◽  
Error Modeling ◽  
Degree Of Freedom ◽  
Least Square ◽  
Kinematic Calibration ◽  
Recursive Least Square ◽  
Local Product ◽  
Branched Chain

This paper proposes a method for kinematic calibration of a 3T1R, 4-degree-of-freedom symmetrical parallel manipulator driven by two pairs of linear actuators. The kinematic model of the individual branched chain is established by using the local product of exponentials formula. Based on this model, the model of the end effector’s pose error is established from a pair of symmetrical branched chains, and a recursive least square method is applied for the parameter identification. By installing built-in sensors at the passive joints, a calibration method for a serial manipulator is eventually extended to this parallel manipulator. Specifically, the sensor installed at the second revolute joint of each branched chain is saved, replaced by numerical calculation according to kinematic constraints. The simulation results validate the effectiveness of the proposed kinematic error modeling and identification methods. The procedure for pre-processing compensation on this 3T1R parallel manipulator is eventually given to improve its absolute positioning accuracy, using the inverse of the calibrated kinematic model.

Kinematic calibration of parallel manipulator with full-circle rotation

2016 ◽  
Vol 43 (3) ◽  
pp. 296-307 ◽  
Author(s):  
Yanbing Ni ◽  
Biao Zhang ◽  
Wenxia Guo ◽  
Cuiyan Shao
Keyword(s):  
Error Compensation ◽  
Parallel Manipulator ◽  
Calibration Method ◽  
Kinematic Calibration ◽  
Error Sources ◽  
Content Type ◽  
Position Errors ◽  
Full Circle ◽  
Simulation And Experiment ◽  
Circle Rotation

Purpose The purpose of this paper is to develop a means of the kinematic calibration of a parallel manipulator with full-circle rotation. Design/methodology/approach An error-mapping model based on the space vector chain is formulated and parameter identification is proposed based on double ball-bar (DBB) measurements. The measurement trajectory is determined by the motion characteristics of this mechanism and whether the error sources can be identified. Error compensation is proposed by modifying the inputs, and a two-step kinematic calibration method is implemented. Findings The simulation and experiment results show that this kinematic calibration method is effective. The DBB length errors and the position errors in the end-effector of the parallel manipulator with full-circle rotation are greatly reduced after error compensation. Originality/value By establishing the mapping relationship between measured error data and geometric error sources, the error parameters of this mechanism are identified; thus, the pose errors are unnecessary to be measured directly. The effectiveness of the kinematic calibration method is verified by computer simulation and experiment. This proposed calibration method can help the novel parallel manipulator with full-circle rotation and other similar parallel mechanisms to improve their accuracy.

Optimal Design of the Three-Degree-of-Freedom Parallel Manipulator in a Spray-Painting Equipment

Robotica ◽  
2019 ◽  
Vol 38 (6) ◽  
pp. 1064-1081
Author(s):  
Guang Yu ◽  
Jun Wu ◽  
Liping Wang ◽  
Ying Gao
Keyword(s):  
Optimal Design ◽  
Parallel Manipulator ◽  
Optimization Design ◽  
Virtual Work ◽  
Kinematic Model ◽  
Geometrical Parameters ◽  
Parallel Mechanisms ◽  
Spray Painting ◽  
Conditioning Performance ◽  
Accuracy Performance

SUMMARYSpray-painting equipments are important for the automatic spraying of long conical objects such as rocket fairing. This paper proposes a spray-painting equipment that consists of a feed worktable, a gantry frame and two serial–parallel mechanisms and investigates the optimal design of PRR–PRR parallel manipulator in serial–parallel mechanisms. Based on the kinematic model of the parallel manipulator, the conditioning performance, workspace and accuracy performance indices are defined. The dynamic model is derived using virtual work principle and dynamic evaluation index is defined. The conditioning performance, workspace, accuracy performance and dynamic performance are involved in multi-objective optimization design to determine the optimal geometrical parameters of the parallel manipulator. Furthermore, the geometrical parameters of the gantry frame are optimized. An example is given to show how to determine these parameters by taking a long object with conical surface as painted object.

A Calibration Method for a Three-Degrees-of-Freedom Parallel Manipulator with a Redundant Passive Chain

2012 ◽  
Vol 162 ◽  
pp. 171-178 ◽  
Author(s):  
Takaaki Oiwa ◽  
Harunaho Daido ◽  
Junichi Asama
Keyword(s):  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Least Squares Method ◽  
Coordinate Measuring Machine ◽  
Calibration Method ◽  
Displacement Sensor ◽  
Measurement Experiment ◽  
Measuring Machine ◽  
Measured Length ◽  
Three Degrees Of Freedom

This paper deals with parameter identification for a three-degrees-of-freedom (3-DOF) parallel manipulator, based on measurement redundancy. A redundant passive chain with a displacement sensor connects the moving stage to the machine frame. The passive chain is sequentially placed in three directions at approximately right angles to one another to reliably detect the motion of the stage. Linear encoders measure changes in lengths of the passive chain and the three actuated chains of the manipulator during traveling of the moving stage. Comparison between the measured length and the length calculated from forward kinematics of the 3-DOF manipulator reveals a length error of the passive chain. The least-squares method using a Jacobian matrix corrects 27 kinematic parameters so that the length errors of the passive chain are minimized. The above calculations were accomplished in both numerical simulations and experiments employing a coordinate measuring machine based on the parallel manipulator. Moreover, a length measurement simulation of gauge block measurement and a measurement experiment using the measuring machine were performed to verify the identified parameters.

A Simple Two-step Geometric Approach for the Kinematic Calibration of the 3-PRS Parallel Manipulator

Robotica ◽  
2019 ◽  
Vol 37 (5) ◽  
pp. 837-850
Author(s):  
Genliang Chen ◽  
Lingyu Kong ◽  
Qinchuan Li ◽  
Hao Wang
Keyword(s):  
Parameter Identification ◽  
Parallel Manipulator ◽  
Parallel Manipulators ◽  
Calibration Method ◽  
Kinematic Parameter ◽  
Geometric Constraints ◽  
Kinematic Calibration ◽  
Kinematic Parameters ◽  
Positioning Accuracy ◽  
Kinematic Parameter Identification

SummaryKinematic calibration plays an important role in the improvement of positioning accuracy for parallel manipulators. Based on the specific geometric constraints of limbs, this paper presents a new kinematic parameter identification method for the widely studied 3-PRS parallel manipulator. In the proposed calibration method, the planes where the PRS limbs exactly located are identified firstly as the geometric characteristics of the studied parallel manipulator. Then, the limbs can be considered as planar PR mechanisms whose kinematic parameters can be determined conveniently according to the limb planes identified in the first step. The main merit of the proposed calibration method is that the system error model which relates the manipulator’s kinematic errors to the output ones is not required for kinematic parameter identification. Instead, only two simple geometric problems need to be established for identification, which can be solved readily using gradient-based searching algorithms. Hence, another advantage of the proposed method is that parameter identification of the manipulator’s limbs can be accomplished individually without interactive impact on each other. In order to validate the effectiveness and efficiency of the proposed method, calibration experiments are conducted on an apparatus of the studied 3-PRS parallel manipulator. The results show that using the proposed two-step calibration method, the kinematic parameters can be identified quickly by means of gradient searching algorithm (converge within five iterations for both steps). The positioning accuracy of the studied 3-PRS parallel manipulator has been significantly improved by compensation according to the identified parameters. The mean position and orientation errors at the validation configurations have been reduced to 1.56 × 10−4 m and 1.13 × 10−3 rad, respectively. Further, the proposed two-step kinematic calibration method can be extended to other limited-degree-of-freedom parallel manipulators, if proper geometric constraints can be characterized for their kinematic limbs.

Novel Design of a 3-DOF Parallel Manipulator for Materials Handling

2008 ◽  
Author(s):  
Dan Zhang ◽  
Zhen Gao ◽  
XiaoLin Hu ◽  
Jason Parise
Keyword(s):  
Parallel Manipulator ◽  
High Speed ◽  
Degrees Of Freedom ◽  
Kinematic Model ◽  
Industrial Applications ◽  
Surface Finishing ◽  
Material Surface ◽  
System Modelling ◽  
Parallel Mechanisms ◽  
Element Analysis

In this paper, a new design of a parallel manipulator is proposed for industrial applications, specifically for material surface finishing processes. Though most current parallel mechanisms have been based on the Stewart-Gough platform which has 6 degrees of freedom (DOF), the focus of this design is on a 3-DOF manipulator with one novel configuration. In order to benefit production, a parallel kinematic machine (PKM) capable of high speed industrial operations with high accuracy and rigidity is necessary. First, system modelling includes mobility study, inverse kinematic model, Jacobian matrix, singularity analysis and workspace calculation are conducted. Then, a CAD model is presented showing the optimum design features and detailed mechanics. Finally, finite element analysis is carried out for the device optimization.

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