28-01-2013, 02:46 PM
Service Robot for Inspecting Exterior Gas Pipes of High Rise Buildings
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Abstract
A service robot for inspecting exterior gas pipes of
high rise buildings is reported in this paper. The principle of
the wall climbing capability of the robot is based on vacuum
suction force generated by an ordinary vacuum cleaner motor.
The robot maneuverability is facilitated by four independent
driving motors and a control console. There are two operation
modes namely manual and automatic operation. During the
manual operation, the robot motion is control by operator with
joystick. In the automatic mode, the robot path tracking is done
by two ferric-type proximity sensor while gas leakage of pipe is
detected by a gas sensor.
INTRODUCTION
Gas is a main source of energy in Hong Kong for cooking
and heating. However, in a metropolitan city like Hong Kong,
majority of the residual buildings are high rise buildings over
100 meters tall. As such, gas is being transported to
individual home through galvanized mild steel pipes installed
on the exterior walls of buildings. In order to ensure the
safety of these pipes, frequent inspection of gas leakage is
needed. Traditionally, these pipes are being inspected
manually by technicians from the gas supply company. The
technician is required to enter into individual home and put a
gas detector, which is attached to the end of a long stick,
through a near-by window to the gas pipes to check for gas
leakages. This is often labour-intensive and time-consuming.
In addition, some of gas pipes are actually very difficult for
the technician to access since the pipes are too far from any
windows. Figure 1 shows two of such pipe installations and
they are almost impossible for the technician to check for gas
leakage. It is because the pipes are installed at a right angle
away from any windows as shown in the photographs. In the
past, this type of problems can be solved by setting up
scaffolding and carry out a full scale inspection and
maintenance every 10-15 years.
CONCEPTUAL DESIGN OF THE SERVICE ROBOT FOR
INSPECTING GAS PIPE
As shown in Figure 1, the pipe installation will always
allow some spaces next to the pipes that do not have any
obstacles so the design concept of the robot can rely on the
usage of the clear spaces for accessing the pipes.
Experimental Setup
The gas pipe inspection robot is basically a light weight
wall climbing robot using a large vacuum gripper for
attaching onto vertical wall surfaces. Wheels are used for
providing the upward, downward and turning movements. It
is operated like a remote-controlled four-wheeled vehicle on
vertical walls. The robot is designed to move on large flat
surfaces including tile walls but it is also capable of crossing
small obstacles with height less than 8mm (The height of
obstacles which the robot can handle depends on the size of
the wheel and the height of the air seals used on the robot).
The main advantages of the robot are that it is relatively fast,
low cost and easy to maneuver. In addition, it can provide
smooth continuous motion. In order to make it easier for
users to carry out the inspection process, the robot motion
will be guided by a sophisticated servo control system, which
is equipped with two proximity sensors to check the pipe
segment position.
PROTOTYPE OF THE SERVICE ROBOT
According to the conceptual design as mentioned in the
previous section, a full scale prototype of the robot is built
and shown in Figure 6. A number of trails and
demonstrations have done in the university staff quarters.
The photographs shown in Figure 6 illustrate the trial and
demonstration.
CONCLUSION
The design and demonstration of the novel service robot
for inspecting gas pipe is discussed. In term of cost to build
such kind of robot, it is around twelve thousand US dollars.
The present version of the robot is tele-wire control.
Theoretically, it is not difficulty to convert it to wireless
control. However, in order to provide a secure power supply
to the 1KW vacuum motor, it is desirable to have wire
connected to the robot to guarantee long time power supply to
the robot.