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Article
Publication date: 11 October 2018

Mahesh Dissanayake, Tariq Pervez Sattar, Shehan Lowe, Ivan Pinson and Tat-hean Gan

Mooring chains used to stabilise offshore floating platforms are often subjected to harsh environmental conditions on a daily basis, i.e. high tidal waves, storms, etc. Therefore…

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Abstract

Purpose

Mooring chains used to stabilise offshore floating platforms are often subjected to harsh environmental conditions on a daily basis, i.e. high tidal waves, storms, etc. Therefore, the integrity assessment of chain links is vital, and regular inspection is mandatory for offshore structures. The development of chain climbing robots is still in its infancy due to the complicated climbing structure presented by mooring chains. The purpose of this paper is to establish an automated climbing technique for mooring chain inspection.

Design/methodology/approach

This paper presents a Cartesian legged tracked-wheel crawler robot developed for mooring chain inspection. The proposed robot addresses the misalignment condition of the mooring chains which is commonly evident in in situ conditions.

Findings

The mooring chain link misalignment is investigated mathematically and used as a design parameter for the proposed robot. The robot is validated with laboratory-based climbing experiments.

Practical implications

Chain breaking can lead to vessel drift and serious damage such as riser rupture, production shutdown and hydrocarbon release. Currently, structural health monitoring of chain links is conducted using either remotely operated vehicles which come at a high cost or by manual means which increase the danger to human operators. The robot can be used as a platform to convey equipment, i.e. tools for non-destructive testing/evaluation applications.

Originality/value

This study has upgraded a previously designed magnetic adhesion tracked-wheel mooring chain climbing robot to address the misalignment issues of operational mooring chains. As a result of this study, the idea of an orthogonally placed Cartesian legged-magnetic adhesion tracked wheel robotic platform which can eliminate concerns related to the misaligned mooring chain climbing has been established.

Details

Industrial Robot: An International Journal, vol. 45 no. 5
Type: Research Article
ISSN: 0143-991X

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Article
Publication date: 19 June 2009

Tariq P. Sattar and Alina‐Alexandra Brenner

The purpose of this paper is to develop a portable non‐destructive testing (NDT) robotic arm that can be carried by climbing and walking robots (CLAWAR). The arm is required to…

879

Abstract

Purpose

The purpose of this paper is to develop a portable non‐destructive testing (NDT) robotic arm that can be carried by climbing and walking robots (CLAWAR). The arm is required to maintain, during a scanning trajectory, a desired NDT probe contact force and orientation to evaluate defects in geometrically complex industrial infrastructure and products such as turbine blades.

Design/methodology/approach

A seven‐axis arm transportable by CLAWAR was developed to deploy NDT probes with suitable dexterity. It was equipped with a force sensor to scan a complex shape by keeping the NDT probe normal to the surface while maintaining a constant contact force with it. Two approaches were used. One used permanent magnet adhesion to obtain secure contact while the other used position‐force‐moment (PFM) feedback to adapt the arm.

Findings

Tests were performed on turbine blades with eddy‐current inspection techniques to assess the quality of defect data using manual inspection and automated inspection. Significant improvements in the quality of inspection were observed when using robotic scanning as compared to manual inspection.

Practical implications

The results have practical implications for the remote inspection of very large infrastructures such as petrochemical storage tanks, bridges, pressure vessels, etc. or where the inspection is performed in hazardous environments and the test surface is not known a priori with any accuracy.

Originality/value

The work is a novel application of the PFM control of a seven‐axis robot arm to scan unknown contoured surfaces to ensure reliable NDT data acquisition at scanning speeds of up to 0.5 mm s−1.

Details

Industrial Robot: An International Journal, vol. 36 no. 4
Type: Research Article
ISSN: 0143-991X

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Available. Content available
Article
Publication date: 24 August 2010

Tariq Sattar

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Abstract

Details

Industrial Robot: An International Journal, vol. 37 no. 5
Type: Research Article
ISSN: 0143-991X

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Article
Publication date: 23 October 2007

Jianzhong Shang, Tariq Sattar, Shuwo Chen and Bryan Bridge

The paper aims to develop a robot that climbs on non‐ferrous surfaces, e.g. aircraft wings and fuselages, carrying a heavy payload up to 18 kg including scanning arm and various…

1655

Abstract

Purpose

The paper aims to develop a robot that climbs on non‐ferrous surfaces, e.g. aircraft wings and fuselages, carrying a heavy payload up to 18 kg including scanning arm and various equipments, for non‐destructive testing (NDT).

Design/methodology/approach

This robot in the study uses vacuum suction cups for adhesion, and two pairs of pneumatic cylinders to drive itself, moving in two directions in stepping gait. A rotation mechanism in the centre is used to correct the off‐course deviations by ± 5 degrees. Multiple universal joints are used to make every single suction cup, every robot foot and the whole structure flexible to negotiate with varying surface curvatures presented in different parts of aircraft. This flexible structure is also rigid once the robot is stuck on the surface to enable the NDT inspection being carried out reliably.

Findings

The paper finds that the walking speed is limited by the cylinder stroke, time for generating vacuum and changing legs. Although most NDT inspection is time‐consumable, it is still desirable to increase the robot speed.

Practical implications

The application of this robotic NDT can significantly reduce the cost of aircraft inspection, eliminate labour‐intensive and monotonous inspection tasks and eliminate the need for an operator to work in confined and dangerous spaces.

Originality/value

The paper introduces the structure that combines flexibility and rigidity for a robot climbing on non‐ferrous curvatures.

Details

Industrial Robot: An International Journal, vol. 34 no. 6
Type: Research Article
ISSN: 0143-991X

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Article
Publication date: 2 May 2008

Jianzhong Shang, Bryan Bridge, Tariq Sattar, Shyamal Mondal and Alina Brenner

The project Climbing Robot Cell for Fast and Flexible Manufacture of Large Scale Structures seeks to modernise and take into the future the technology of the manufacture of large…

1690

Abstract

Purpose

The project Climbing Robot Cell for Fast and Flexible Manufacture of Large Scale Structures seeks to modernise and take into the future the technology of the manufacture of large fixed welded structures. It creates a transportable manufacturing cell consisting of a team of cooperating climbing robot work tools whose activities are coordinated and integrated through a central intelligence. The purpose of this paper is to present a wheeled robot, called NDT robot, designed for the real time inspection of long weld lines simultaneously with the welding process.

Design/methodology/approach

Neodymium permanent magnets are used for adhesion, which are capable of producing a maximum adhesion pressure of 4 × 104 Nm−2 at a 20 mm air gap. The strong neodymium magnets give the robot a high payload carrying capability. The arrangement of the magnet array increases its performance at large air gaps so that the robot has excellent capability to overcome obstacles, such as weld caps. The design of the wheeled robot with two sections jointed by a hinge joint has the advantage of high speed and good manoeuvrability, as well as working on curved surfaces and transferring between angled adjoining surfaces.

Findings

The NDT robot has been developed with the capability of climbing on steel walls carrying the specified payload and the ability to overcome the obstacles. The robot is also able to climb on curved surfaces with excellent manoeuvrability, and transfer between angled adjoining surfaces.

Originality/value

The arrangement of the magnet array enables the robot to retain a strong holding force at big air gap, so that the ability of the robot to overcome obstacles and work on curvatures is strengthened. The two‐section design improves the robot's performance on curvatures and enables it to transfer between angled adjoining surfaces.

Details

Industrial Robot: An International Journal, vol. 35 no. 3
Type: Research Article
ISSN: 0143-991X

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Article
Publication date: 19 June 2009

Tariq P. Sattar, Hernando Leon Rodriguez and Bryan Bridge

Structural integrity inspection of offshore wind turbine blades poses problems of gaining access to the blades, danger to human operatives and large costs of removing a blade and…

1489

Abstract

Purpose

Structural integrity inspection of offshore wind turbine blades poses problems of gaining access to the blades, danger to human operatives and large costs of removing a blade and transporting it off‐shore for inspection. The purpose of this paper is to show that a climbing robot that can perform in situ blade inspection with micro/nano focus computed axial X‐ray tomography is a solution to find defects in the thickest blade sections and reduce the cost of inspection.

Design/methodology/approach

The weight of such an inspection system will be high, typically 200 kg and cross sectional scanner dimensions of 1 × 2 m to envelope a blade. The design of a climbing ring robot that completely encircles a turbine tower, typically 3 m in diameter, will provide the best means of climbing with this payload. Because of the development costs of such a huge robot, the optimal design path is to first prototype a small scale model.

Findings

First results on such a model are described and from its performance the load carrying capabilities of a full scale version computed. The robot is able to climb either straight up or down, or with a spiralling motion, or rotate around the circumference at the same height. Furthermore, the design is entirely modular thus enabling easy on‐site assembly of the robot.

Originality/value

A climbing robot with high payload and versatile motion capability, with adhesive forces between the robot and climbing surface provided entirely by mechanical means rather than by vacuum suction or magnetic force, making the system much safer and easier to manipulate.

Details

Industrial Robot: An International Journal, vol. 36 no. 4
Type: Research Article
ISSN: 0143-991X

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Article
Publication date: 20 October 2014

Mohammed Abdullah Al Rashed and Tariq Pervez Sattar

The purpose of this paper is to develop a wireless positioning system. The automation of non-destructive testing (NDT) of large and complex geometry structures such as aircraft…

477

Abstract

Purpose

The purpose of this paper is to develop a wireless positioning system. The automation of non-destructive testing (NDT) of large and complex geometry structures such as aircraft wings and fuselage is prohibitively expensive, though automation promises to improve on manual ultrasound testing. One inexpensive way to achieve automation is by using a small wall-climbing mobile robot to move a single ultrasound probe over the surface through a scanning trajectory defined by a qualified procedure. However, the problem is to guide the robot though the trajectory and know whether it has followed it accurately to confirm that the qualified procedure has been carried out.

Design/methodology/approach

The approach is to use sophisticated bulk electronics developed for game playing in combination with MATLAB to develop a wireless positioning system.

Findings

The paper describes the development of an inexpensive wireless system comprising an optical spatial positioning system and inertial measurement unit that relates the 3D location of an NDT probe carried by a mobile robot to a computer-aided drawing (CAD) representation of the test structure in a MATLAB environment. The probe is located to an accuracy of ± 2 mm at distances of 5 m.

Research limitations/implications

Positioning range is limited to 5 m. Further development is required to increase this range.

Practical implications

The wireless system is used to develop tools to guide the robot remotely to follow a desired scanning trajectory, obtain feedback about the actual trajectory executed by the robot, know exactly where an ultrasound pulse echo was captured, map identified defects on the CAD and relate them to the real test object.

Originality/value

An inexpensive spatial positioning system with sufficient accuracy for automated NDT purposes.

Details

Industrial Robot: An International Journal, vol. 41 no. 6
Type: Research Article
ISSN: 0143-991X

Keywords

Available. Content available
Article
Publication date: 1 March 2006

47

Abstract

Details

Industrial Robot: An International Journal, vol. 33 no. 2
Type: Research Article
ISSN: 0143-991X

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Article
Publication date: 11 July 2024

Sattar Khan, Naimat Ullah Khan and Yasir Kamal

This paper aims to examine the role of corporate governance (CG) in the earnings management (EM) of affiliated companies in family business groups (FBGs) listed on the Pakistan…

196

Abstract

Purpose

This paper aims to examine the role of corporate governance (CG) in the earnings management (EM) of affiliated companies in family business groups (FBGs) listed on the Pakistan Stock Exchange (PSX), using principal–principal agency theory.

Design/methodology/approach

The sample of 327 nonfinancial firms of the PSX, consisting of 187 group-affiliated firms and 140 nonaffiliated firms has been used in this study for the period of 2010 to 2019. The study uses different regression models for analysis, with robustness tests of various alternative measures of EM and FBG affiliation. In addition, endogeneity is controlled with the propensity score matching method.

Findings

The findings show that EM is less prevalent in affiliated firms compared to nonaffiliated companies. The results show a negative and significant relationship between FBGs affiliated firms and EM. Moreover, the results also show a positive relationship between EM and the interaction term of the CG index and group affiliation. It refers to the fact that effective governance cannot reduce EM in affiliated companies of FBGs as well as in the nonfinancial companies of the PSX. In addition, the quality of CG is higher in affiliated companies compared to its counterpart in nonaffiliated firms. The findings support the principal–principal agency theory that CG cannot mitigate the expropriating behavior of controlling shareholders against minority shareholders by reducing EM in emerging markets due to the ownership concentration phenomenon.

Research limitations/implications

This research study has implications for small investors, government agencies and regulators. The findings of the study show that CG code should make it mandatory for companies to reveal information about their complex ownership structure and ownership information about affiliated companies and directors. Furthermore, it is suggested to revisit the code of CG in the Pakistani context of principal–principal conflict instead of the agent–principal explanation of agency theory based on Anglo–Saxon countries.

Originality/value

This research study has contributed to the CG and FBG literature in relation to EM in idiosyncratic settings of Pakistan. One of the prime contributions of the paper is the development of a comprehensive CG index. This research study used detailed, manually collected novel data on affiliated firms of FBGs in Pakistan.

Details

Corporate Governance: The International Journal of Business in Society, vol. 25 no. 2
Type: Research Article
ISSN: 1472-0701

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Article
Publication date: 1 September 1999

Khalid Mahmood

Computer technology in libraries has revolutionised the concept of rapid and accurate information services. In Pakistan, though, computer technology is new and is being…

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Abstract

Computer technology in libraries has revolutionised the concept of rapid and accurate information services. In Pakistan, though, computer technology is new and is being successfully introduced in all types of libraries and information centres. This article reviews the literature on the use of computers in Pakistan’s libraries. The literature includes monographs, journal articles, reports, etc. published inside and outside Pakistan, discussing information technology, specific library applications, the activities of individual libraries and automation education. The need for library automation and the problems faced by Pakistani professionals in this respect are also discussed.

Details

Asian Libraries, vol. 8 no. 9
Type: Research Article
ISSN: 1017-6748

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