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CHAPTER 6. MODERN MECHATRONIC SYSTEM
6.1 Mobile robots for inspection and
repair of underground pipelines
The problem of operation and repair of pipelines relevant for oil and gas
pipelines, water supply and sewage networks (especially large cities), channels,
spillway and water intake. The use of mobile robots for CCTV inspection and
maintenance of highways to prevent technogenic and ecological accidents and
disasters (not counting multi-million dollar damages and describe the dead-
weight loss in nature than often busy environmental services) and implement
trenchless methods of repair [26].
Robotics also allows for the reorganization of the old highways, the accep-
tance of new pipelines, environmental monitoring and control of existing net-
works, to map underground utilities. The use of mobile technological robots for
inspection and repair of underground pipelines is a bright example of fulfill-
ment of mechatronic system fundamentally new functions.
A leading domestic developer and manufacturer of inspection robots for
pipelines is an SPA «TARIS» (Moscow). With an equal level of quality, the
price of mobile robots of the firm «Taris» is 15...20% lower than imported
analogues, while the benefits in warranty and service maintenance of equipment
on the territory of Russia and UIS. According to the available estimates, the
annual economic effect of the use of inspection robots is about 2 times greater
than their cost.
General appearance inspection and technological robots of the company
«TARIS», which are currently used by municipal services of Moscow, is shown
in Fig. 6.1.
Figure 6.1 – General view of mobile robots of the firm «Taris»
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Inspection robot P-200 is designed for teleinspection of pipelines with
a diameter of 150...1200 mm. This mobile robot has a set of interchangeable
wheels and a color rotary camera. The robot is operated by a remote operator
from the control station located in the car (cable length up to 200 m).
The control post has a color monitor and a digital computer-based documen-
tation system in industrial design. The camera is equipped with an aiming
device (rocking, rotation and lifting mechanisms) for inspecting the pipe walls,
main and additional lighting units, an electromechanical windshield wiper, and
a remote focusing drive.
The robot has a hermetic design, is able to work with immersion in water,
the body is pumped with nitrogen to prevent condensation of moisture inside it
and misting up the glasses of the camera.
Moving actuators are mechatronic modules of the motor-wheel type based
on direct-current motors. In addition to the vision system, the robot is equipped
with path sensors, roll angles and trim of the body, as well as angle sensors
of the camera’s orientation. These sensors are needed not only to control the
movement of the robot, but also for tracing the occurrence of the pipeline,
give information about the profile of the pipe and the coordinates of the defect
(fistula, cracks) or the detected foreign matter.
Mobile robots of SPA «Taris» allow not only to detect, but also to eliminate
a number of defects. One of the effective methods of repairing pipes is banding
(Figure 6.2).
Figure 6.2 – Mobile robot with a bandage device of the firm «Taris»
The installed band consists of a metal shell and layer of fabric impregnated
with a polymer. Under pressure acting on the hoses, the packer inflates and
presses the shell with the polymer to the pipe walls. Shells made of corrosion-
resistant or carbon steel are used.
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Instead of a fabric with a polymer, a layer of rubber can be used as a
material for sealing the defect. The mobile robotic complex S-200 (Figure
6.3) includes: a technological robot, a cable drum, a workstation with a vision
system, an operator control station.
Fig. 6.3 – Mobile robotic complex S-200 of the firm «Taris»
The robot is equipped with replaceable operating elements - milling and tool
heads for performing repair operations inside the pipe. The working bodies are
designed for local cleaning of surfaces, drilling, pruning of protruding elements
(sags, grates on welded seams, pins), cutting off lateral branches after the pipe
is sanitized with plastic.
The arrows in Fig. 6.3 the main motions of this mechatronic system are
indicated: A – movement of the robot due to the wheel drive (speed 0...0.2
m/s); B – extension of the stop (force 500 N); C – extension of the working
element (stroke 100 mm, force 500 N); D – transverse feed of the tool head
(stroke 50 mm, force 500 N); E – rotation of the worker which body (angle ±
180°, moment 50 Nm); F – swing of the video camera (swing angle ± 140°);
G – moving the wiper of the video camera; H – rotation of the tool head.
Prospects for the development of mobile robotics are associated with the
intellectualization of control devices and sensors, which makes it possible to
improve the quality of operations and the autonomy of their implementation.
Automatic decision making by robot (without direct training the person-
operator) is expedient here on the following operations:
– automatic detection and recognition of foreign objects in the pipeline
with the use of vision systems and location sensors;
– planning of the trajectory and speed of the movement when cornering on
the basis of signals from the heel-trim sensor and photo-impulse speed
sensors;
– control of the operating modes of the tool head on the basis of information
on the acting forces and moments when performing machining operations
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(cleaning the inner surface of the pipe or welds, pruning the pins protru-
ding inside the pipe, etc.);
– diagnostics of the internal surface of the pipe and flaw detection of welds;
– opening of lateral branches in a new plastic pipe after the procedure of
relining.
Figure 6.4 – Prototype of the mobile robot IRIS-1:
a – the general form; b – front view
A prototype of the mobile robot «IRIS-G» was created at the Department
of Robotics and Mechatronics of MSTU «STANKIN», a significant part of
the work was carried out within the framework of the project of international
cooperation «Computer Aided Mobile Robotics for Severe Environmental
Applications» with the support of the Royal Society (Great Britain) were MSTU
«STANKIN» and Montfort University (Great Britain) [24].
The improvement of the robot had the following objectives:
• research of new techniques for autonomous navigation of mobile robots;
• experimental study of the influence of new constructive solutions applied
in the prototype;
• testing of various sensors for environmental recognition;
• testing of multisensor technology for environmental inspection;
• creating a prototype for the further development of laboratory equipment.
The prototype of a mobile robot with computer control based on a DC motor
consists of a basic, sensor, transport, electronic communication, power modules
and a control module.
The basic module consists of a rigid support frame with a number of holes
for variable mounting of sensors and a transport module. Also on the base
module are two terminal blocks for fixing power and information cables.
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The sensor module (Table 6.1), includes ultrasonic and photo-pulse sensors,
a microwave sensor, a video camera, a set of two-dimensional accelerometers.
For effective functioning of the video camera inside the pipe, there is a source
of additional lighting on the robot.
Table 6.1. Sensors used in the prototype of a mobile robot
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