5.1Wireless teaching pendant using a PDA
The teaching pendant is a hand-held robot control terminal
that provides a convenient means to run the robot programs.
Nowadays, most teaching pendants are connected to a robot
controller by cables. The connecting cables and the size of the
teach pendant are not of concern here but a large, wired teaching
pendant is not suitable for a portable mobile welding robot which
has a controller inside, since a worker should follow the robot to
every location in the into the double-hulled structures.
Thus, there is a great need for wireless teaching pendants to
enable workers to control the number of welding robots without
any physical connections. Fig. 9 shows the existing and the
developed wireless teach pendant and the functions and perfor-
mance of the wireless teach pendant have been verified from the
field testing trials carried out throughout this project [14]
(Table 3).
Fig. 10 shows the hardware structure of the PDA TP and the
main controller of the RRXC. The CPU board and the motion
controller are connected to the wireless access point with LAN
cables. Fig. 10 also shows the multiple connections for simulta-
neous control of a number of RRXCs, with just one teach pendant,
will lead to improvements in the operational efficiency, and
reduce the cost of labor.
5.2. Sensory systems
The 3-dof shock sensor and laser distance sensor are installed
on the end-effector of the 3P3R manipulator, through harmonic
drive systems. The straight welding torch is also installed on
the top side of the laser distance sensor assembly. In the case
of the shock sensor, since the RRXC works in hazardous
environments, malfunctions such as a wrong motion of the
end-effector may suddenly occur and this can lead to critical
damage to the RRXC. Thus, the shock sensor, which can detect a
sudden impact, should be installed on to the industrial robot.
The laser distance sensor for the initial sensing of the U-shaped
trajectories, rather than the touch sensor, should help reduce
the required time, thus, leading to a rise in efficiency and
productivity.
5.3. Portable auxiliary transportation device
Portable auxiliary transportation devices are important in the
field applications of the RRXC, since they can control the mobile
functions within the double-hulled structures. This consists of
electric winches, hand-clamps, a bridge plate, a sliding plate,
hand-winches, and steel wire. The electric winch, bridge plate,
and sliding plate are customized to meet a common requirement
on the weight of each device, which should be less than 10 kg for
achieving the hand-held mode in the field.