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Article
Publication date: 3 March 2023

Yanbing Ni, Yizhang Cui, Shilei Jia, Chenghao Lu and Wenliang Lu

The purpose of this paper is to propose a method for selecting the position and attitude trajectory of error measurement to improve the kinematic calibration efficiency of a one…

Abstract

Purpose

The purpose of this paper is to propose a method for selecting the position and attitude trajectory of error measurement to improve the kinematic calibration efficiency of a one translational and two rotational (1T2R) parallel power head and to improve the error compensation effect by improving the properties of the error identification matrix.

Design/methodology/approach

First, a general mapping model between the endpoint synthesis error is established and each geometric error source. Second, a model for optimizing the position and attitude trajectory of error measurement based on sensitivity analysis results is proposed, providing a basis for optimizing the error measurement trajectory of the mechanism in the working space. Finally, distance error measurement information and principal component analysis (PCA) ideas are used to construct an error identification matrix. The robustness and compensation effect of the identification algorithm were verified by simulation and through experiments.

Findings

Through sensitivity analysis, it is found that the distribution of the sensitivity coefficient of each error source in the plane of the workspace can approximately represent its distribution in the workspace, and when the end of the mechanism moves in a circle with a large nutation angle, the comprehensive influence coefficient of each sensitivity is the largest. Residual analysis shows that the robustness of the identification algorithm with the idea of PCA is improved. Through experiments, it is found that the compensation effect is improved.

Originality/value

A model for optimizing the position and attitude trajectory of error measurement is proposed, which can effectively improve the error measurement efficiency of the 1T2R parallel mechanism. In addition, the PCA idea is introduced. A least-squares PCA error identification algorithm that improves the robustness of the identification algorithm by improving the property of the identification matrix is proposed, and the compensation effect is improved. This method has been verified by experiments on 1T2R parallel mechanism and can be extended to other similar parallel mechanisms.

Details

Industrial Robot: the international journal of robotics research and application, vol. 50 no. 4
Type: Research Article
ISSN: 0143-991X

Keywords

Article
Publication date: 10 May 2019

Wilma Polini and Andrea Corrado

The purpose of this paper is to model how geometric errors of a machined surface (or manufacturing errors) are related to locators’ error, workpiece form error and machine tool…

Abstract

Purpose

The purpose of this paper is to model how geometric errors of a machined surface (or manufacturing errors) are related to locators’ error, workpiece form error and machine tool volumetric error. A kinematic model is presented that puts into relationship the locator error, the workpiece form deviations and the machine tool volumetric error.

Design/methodology/approach

The paper presents a general and systematic approach for geometric error modelling in drilling because of the geometric errors of locators positioning, of workpiece datum surface and of machine tool. The model can be implemented in four steps: (1) calculation of the deviation in the workpiece reference frame because of deviations of locator positions; (2) evaluation of the deviation in the workpiece reference frame owing to form deviations in the datum surfaces of the workpiece; (3) formulation of the volumetric error of the machine tool; and (4) combination of those three models.

Findings

The advantage of this approach lies in that it enables the source errors affecting the drilling accuracy to be explicitly separated, thereby providing designers and/or field engineers with an informative guideline for accuracy improvement through suitable measures, i.e. component tolerancing in design, machining and so on. Two typical drilling operations are taken as examples to illustrate the generality and effectiveness of this approach.

Research limitations/implications

Some source errors, such as the dynamic behaviour of the machine tool, are not taken into consideration, which will be modelled in practical applications.

Practical implications

The proposed kinematic model may be set by means of experimental tests, concerning the industrial specific application, to identify the values of the model parameters, such as standard deviation of the machine tool axes positioning and rotational errors. Then, it may be easily used to foresee the location deviation of a single or a pattern of holes.

Originality/value

The approaches present in the literature aim to model only one or at most two sources of machining error, such as fixturing, machine tool or workpiece datum. This paper goes beyond the state of the art because it considers the locator errors together with the form deviation on the datum surface into contact with the locators and, then, the volumetric error of the machine tool.

Details

Engineering Computations, vol. 36 no. 4
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 16 May 2016

Yanbing Ni, Biao Zhang, Wenxia Guo and Cuiyan Shao

The purpose of this paper is to develop a means of the kinematic calibration of a parallel manipulator with full-circle rotation.

Abstract

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.

Details

Industrial Robot: An International Journal, vol. 43 no. 3
Type: Research Article
ISSN: 0143-991X

Keywords

Article
Publication date: 8 May 2019

Feiyan Guo, Fang Zou, Jian Hua Liu, Qingdong Xiao and Zhongqi Wang

Manufacturing errors, which will propagate along the assembly process, are inevitable and difficult to analyze for complex products, such as aircraft. To realize the goal of…

Abstract

Purpose

Manufacturing errors, which will propagate along the assembly process, are inevitable and difficult to analyze for complex products, such as aircraft. To realize the goal of precise assembly for an aircraft, with revealing the nonlinear transfer mechanism of assembly error, a set of analytical methods with response to the assembly error propagation process are developed. The purpose of this study is to solve the error problems by modeling and constructing the coordination dimension chain to control the consistency of accumulated assembly errors for different assemblies.

Design/methodology/approach

First, with the modeling of basic error sources, mutual interaction relationship of matting error and deformation error is analyzed, and influence matrix is formed. Second, by defining coordination datum transformation process, practical establishing error of assembly coordinate system is studied, and the position of assembly features is modified with actual relocation error considering datum changing. Third, considering the progressive assembly process, error propagation for a single assembly station and multi assembly stations is precisely modeled to gain coordination error chain for different assemblies, and the final coordination error is optimized by controlling the direction and value of accumulated error range.

Findings

Based on the proposed methodology, coordination error chain, which has a direct influence on the property of stealthy and reliability for modern aircrafts, is successfully constructed for the assembly work of the jointing between leading edge flap component and wing component at different assembly stations.

Originality/value

Precise assembly work at different assembly stations is completed to verify methodology’s feasibility. With analyzing the main comprised error items and some optimized solutions, benefit results for the practical engineering application showing that the maximum value of the practical flush of the profiles between the two components is only 0.681 mm, the minimum value is only 0.021 mm, and the average flush of the entire wing component is 0.358 mm, which are in accordance with theoretical calculation results and can successfully fit the assembly requirement. The potential user can be the engineers for manufacturing the complex products.

Details

Assembly Automation, vol. 39 no. 2
Type: Research Article
ISSN: 0144-5154

Keywords

Article
Publication date: 19 April 2013

Marlon Wesley Machado Cunico and Jonas de Carvalho

The purpose of this paper is to analyse the conception of the positioning system of fused deposition modeling (FDM) machines, optimising design parameter and components accuracy…

1003

Abstract

Purpose

The purpose of this paper is to analyse the conception of the positioning system of fused deposition modeling (FDM) machines, optimising design parameter and components accuracy to decrease mechanical errors of equipment, which, consequently, results in the increase of parts accuracy. This paper also reports studies related to analytical estimation of machine errors, describing a theoretical model which was used for the multivariable study. Additionally, an alternative conception is proposed, according with the result of this study.

Design/methodology/approach

For elaboration of the numerical model of equipment, the authors have focused on conception of first generation of FDM, specifying as design parameters, timing belt stiffness, linear bearing clearance, and accuracy grade of ball screw housing, support and pulley. In order to identify the main effect of each design parameter for the final error of machine, the authors have applied a multivariable method in addition to identifying the error budget of model. Also indicated are the two factors that promote more errors, undergoing a proposal of conception which consists in replacing one component of machine.

Findings

With reference to the evaluation of the numerical model, equivalency was found between the resultant error of model and the current FDM accuracy. The result of multivariable study identified the main causes of errors in machine, implying on an optimized solution which decreases the initial error in 69 μm. Similarly, the evaluation of the proposed conception resulted in the reduction of general error in almost 20 μm, even though the worst case was studied for this comparison.

Originality/value

Although the number of applications for additive manufacturing has been growing in recent years, implying an increase of demand for high precision parts, there are still several challenges to be overcome, such as the improvement of equipment. For that reason, the motivation of this work concerns the contribution for development of new equipment, as well the improvement of current technologies. Furthermore, the authors' focus was the reduction of mechanical errors through an analytical approach.

Details

Rapid Prototyping Journal, vol. 19 no. 3
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 30 November 2021

Bence Tipary and Ferenc Gábor Erdős

The purpose of this paper is to propose a novel measurement technique and a modelless calibration method for improving the positioning accuracy of a three-axis parallel kinematic…

Abstract

Purpose

The purpose of this paper is to propose a novel measurement technique and a modelless calibration method for improving the positioning accuracy of a three-axis parallel kinematic machine (PKM). The aim is to present a low-cost calibration alternative, for small and medium-sized enterprises, as well as educational and research teams, with no expensive measuring devices at their disposal.

Design/methodology/approach

Using a chessboard pattern on a ground-truth plane, a digital indicator, a two-dimensional eye-in-hand camera and a laser pointer, positioning errors are explored in the machine workspace. With the help of these measurements, interpolation functions are set up per direction, resulting in an interpolation vector function to compensate the volumetric errors in the workspace.

Findings

Based on the proof-of-concept system for the linear-delta PKM, it is shown that using the proposed measurement technique and modelless calibration method, positioning accuracy is significantly improved using simple setups.

Originality/value

In the proposed method, a combination of low-cost devices is applied to improve the three-dimensional positioning accuracy of a PKM. By using the presented tools, the parametric kinematic model is not required; furthermore, the calibration setup is simple, there is no need for hand–eye calibration and special fixturing in the machine workspace.

Details

Industrial Robot: the international journal of robotics research and application, vol. 49 no. 1
Type: Research Article
ISSN: 0143-991X

Keywords

Article
Publication date: 12 October 2020

Xi Luo, Yingjie Zhang and Lin Zhang

The purpose of this paper is to improve the positioning accuracy of 6-Dof serial robot by the way of error compensation and sensitivity analysis.

Abstract

Purpose

The purpose of this paper is to improve the positioning accuracy of 6-Dof serial robot by the way of error compensation and sensitivity analysis.

Design/methodology/approach

In this paper, the Denavit–Hartenberg matrix is used to construct the kinematics models of the robot; the effects from individual joint and several joints on the end effector are estimated by simulation. Then, an error model based on joint clearance is proposed so that the positioning accuracy at any position of joints can be predicted for compensation. Through the simulation of the curve path, the validity of the error compensation model is verified. Finally, the experimental results show that the error compensation method can improve the positioning accuracy of a two joint exoskeleton robot by nearly 76.46%.

Findings

Through the analysis of joint error sensitivity, it is found that the first three joints, especially joint 2, contribute a lot to the positioning accuracy of the robot, which provides guidance for the accuracy allocation of the robot. In addition, this paper creatively puts forward the error model based on joint clearance, and the error compensation method which decouples the positioning accuracy into joint errors.

Originality/value

It provides a new idea for error modeling and error compensation of 6-Dof serial robot. Combining sensitivity analysis results with error compensation can effectively improve the positioning accuracy of the robot, and provide convenience for welding robot and other robots that need high positioning accuracy.

Details

Engineering Computations, vol. 38 no. 4
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 1 November 1995

P.A.C. Miguel and T.G. King

Due to the increase in the use and importance of co‐ordinatemeasuring machines (CMM) in manufacturing systems, it is necessary todevelop reliable and accurate performance tests…

1076

Abstract

Due to the increase in the use and importance of co‐ordinate measuring machines (CMM) in manufacturing systems, it is necessary to develop reliable and accurate performance tests for their verification to assure the quality of manufactured components. Presents general requirements and a classification of test methods. Surveys and compares some performance methods to evaluate CMM and concludes that is necessary to find a multi‐purpose method that is quick and easy to use and which could be widely accepted by manufacturers and users.

Details

International Journal of Quality & Reliability Management, vol. 12 no. 8
Type: Research Article
ISSN: 0265-671X

Keywords

Article
Publication date: 13 August 2018

Abubaker Shagluf, Simon Parkinson, Andrew Peter Longstaff and Simon Fletcher

The purpose of this paper is to produce a decision support aid for machine tool owners to utilise while deciding upon a maintenance strategy. Furthermore, the decision support…

Abstract

Purpose

The purpose of this paper is to produce a decision support aid for machine tool owners to utilise while deciding upon a maintenance strategy. Furthermore, the decision support tool is adaptive and capable of suggesting different strategies by monitoring for any change in machine tool manufacturing accuracy.

Design/methodology/approach

A maintenance cost estimation model is utilised within the research and development of this decision support system (DSS). An empirical-based methodology is pursued and validated through case study analysis.

Findings

A case study is provided where a schedule of preventative maintenance actions is produced to reduce the need for the future occurrences of reactive maintenance actions based on historical machine tool accuracy information. In the case study, a 28 per cent reduction in predicted accuracy-related expenditure is presented, equating to a saving of £14k per machine over a five year period.

Research limitations/implications

The emphasis on improving machine tool accuracy and reducing production costs is increasing. The presented research is pioneering in the development of a software-based tool to help reduce the requirement on domain-specific expert knowledge.

Originality/value

The paper presents an adaptive DSS to assist with maintenance strategy selection. This is the first of its kind and is able to suggest a preventative strategy for those undertaking only reactive maintenance. This is of value for both manufacturers and researchers alike. Manufacturers will benefit from reducing maintenance costs, and researchers will benefit from the development and application of a novel decision support technique.

Details

Journal of Quality in Maintenance Engineering, vol. 24 no. 3
Type: Research Article
ISSN: 1355-2511

Keywords

Article
Publication date: 1 June 1996

Ian Gibson

As rapid prototyping technologies improve in accuracy and reliability so the range of applications increases. A number of new systems have recently come on the market and already…

771

Abstract

As rapid prototyping technologies improve in accuracy and reliability so the range of applications increases. A number of new systems have recently come on the market and already established systems are showing significant improvements in the materials being used. The systems available appear to be focused on two distinct market sectors. Machines are being used as design office support facilities or “desktop” manufacturing units. Machines are also being used as “shopfloor” systems, concentrating on downstream activities. Suggests that one future for this technology is side‐by‐side with conventional machine tools as one of the process route options for a manufacturing company. One way of achieving this may be to integrate industrial robotics with the technology in the form of flexible manufacturing (or rapid prototyping) cells.

Details

Rapid Prototyping Journal, vol. 2 no. 2
Type: Research Article
ISSN: 1355-2546

Keywords

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