PAMM · Proc. Appl. Math. Mech. 8, 10311 – 10312 (2008) / DOI 10.1002/pamm.200810311

© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

The modular robotic systems

O. Tătar*,1, S. Stan**,2, and D. Mandru***,3 1,2,3 Department of Mechanisms, Precision Mechanics and Mechatronics, Faculty of Mechanics, Technical University of

Cluj-Napoca, B-dul Muncii, nr. 103-105, 400641, Cluj-Napoca, Romania

A very important design goal of these robotic systems is the adaptability to the inner diameters of the pipes. In this paper, we proposed two wheeled-type in-pipe modular robotic systems. Thus, the studied modular robotic systems are characterized by an adaptable structure, based on linkages mechanisms. The prototypes were designed in order to inspect pipes with variable diameters within 140 and 200 mm.

© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

1 Introduction

These modular systems prezented in the paper are composed of driving modules (which are using mechanisms with articulated links) and passive modules. The first module (driving module) generates the traction force. The passive module is necessary to carry the control electronic equipment and for the transport of the needed equipment for realization of the in-pipe inspection. Pipe diameter, which is one of the important size parameters, limits the working space occupied by the inspection robot. Therefore, it is necessary to be considered that a modular robotic system is designed for a certain size of pipe diameter.

2 The developed in-pipe modular robotic system

2.1 The first prototype

The driving module contains the three mechanisms, symmetrically disposed along the longitudinal axis of the robot. The force that the driving module mechanism exercises on the pipe walls is generated with the help of an extensible spring. The helical spring disposed on the central axis assures the repositioning of the structure, in the case of the pipe diameters’ variation. The components of the driving module are (Fig. 1 a): 1 – helical spring, 2 – translational element, 3 – worm wheel, 4 – worm gear, 5 – worm, actuator support, 6 – actuator, 7 – actuator support, 8 – link, 9 – central axis, 10 – wheel [1], [2].

a) b)

c) Fig. 1 a) The components of the driving module b) The structural scheme for modular robotic system c) The photo of the first in-pipe modular robotic system.

____________________ * Corresponding author: e-mail: olimpiut@yahoo.com, Olimpiu.Tatar@ mmfm.utcluj.ro, Phone: +40 264 401 681, Fax: +40264-415490 ** e-mail: sergiustan@ieee.org, Phone: +40 264 401 755, Fax: +40264-415490, *** e-mail: Dan.Mandru@ mmfm.utcluj.ro, Phone: +40 264 401 645, Fax: +40264-415490

Sessions of Short Communications 04: Structural mechanics

© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim www.gamm-proceedings.com

10312

The weight of the driving module (the weight of current feeding wires is also considered) is 978 g and the weight of the passive module is 1070 g. The wheels have the radius r = 25 mm and the length 17 mm and the component elements of the driving module have the lengths are (Fig. 1b): h1=30 mm; h2 = 70 mm, h3 = 135 mm. The actuation of the driver wheels is made through three worm gears with z1 = 1 (one thread), z2 = 52 teeth. These robot systems have movement capacities for inspection in (140 – 200) mm diameter pipes in horizontal or vertical configuration (Fig. 1c).

2.2 The second prototype

The second modular robotic system will contain two motor modules and a passive module. In figure 2 a., a structure of a driving module is presented, composed of 6 slider-crank mechanisms. These are placed each two in three plans at 120˚ around the central axis. Each driving modules has a weight of 630 g. The wheels have a radius r = 25 mm, a length of 17 mm and the component elements have the lengths: h1= 95 mm, h2= 58 mm, h3= 53 mm. The actuation of the driver wheels is made through three worm gears with z1 = 1 (one thread), z2 =42, z3 =38, z4=38 teeth. The passive module have a weight of 700 g, the wheels have the radius r = 17 mm, a length of 7 mm and they are equipped with tires. The passive module has 6 wheels that slide perpendicular to the axis of module disposed at 120˚ around the central axis. The second modular robotic system, that has the 3D model presented in figure 2b, is in developing stage. This robotic system has movement capacities for inspection in (140 – 180) mm diameter pipes.

E2

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F2

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G2

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B1 O1

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a) b)

c)

Fig. 2 a) The structure of a driving module b) The 3 D model of modular robotic system c) The photo of the second in-pipe modular robotic system ( in developing stage)

3 Conclusion

In this paper, we proposed two wheel type in-pipe robotic systems, defined by adaptable structures, based on different mechanisms. A very important design goal of the mobile in-pipe robotic systems is the adaptability to the inner diameters of the pipes. The first prototype was designed in order to inspect pipes with variable diameters between 140 and 200 mm, and second prototype has movement capacities for inspection of 140 - 180 mm pipe diameters. The force which the mechanism from the driving module exercises on the pipe walls is generated with the help of several extensible resorts. The driver wheel is actuated by a D.C. motor through gear wheel transmission. In the second part, another one structures based on slider-crank mechanisms are proposed; for this, the experimental prototypes are under development.

Acknowledgements This work is supported by PNII - IDEI Project, ID 1056: Modelling, simulation and development of robotic system families used for inspection and exploration

References [1] O. Tătar, D. Mândru, and V., Roş, Agricultural pipe networks maintenance using robotic systems Proceedings of the 35th

International Symposium Actual Tasks On Agricultural Engineering, Opatija, Croatia, , p.187-197, (2007). [2] O. Tătar, D. Mândru, and I.Ardelean, Development of mobile minirobots for in pipe inspection tasks, Mechanika, Nr. 6(68), p. 60-64,

(2007).