IEEE Robotics & Automation Magazine - September 2013 - 67

motions, R1 was programmed to navigate throughout a chairlike structure.
This structure comprises a vertical and a horizontal square
plane, which is the minimal needed test bed for the robot.
Any bigger sized structure would just consist of additional
vertical and horizontal planes. This structure also allows for
the testing of the robot's transition between the two planes.
The steps performed by the robot can be seen in Figure 7 and
are described below.
Step 1) Start out on the front, lower side of the horizontal
rod and travel to the right.
Step 2) Move to the right lower horizontal rod and travel
to the end of the right lower horizontal rod.

Step 3)
Step 4)
Step 5)
Step 6)
Step 7)
Step 8)
Step 9)
Step 10)
Step 11)
Step 12)

Move to the lower back rod.
Rotate to the top of the lower back rod.
Move to the vertical left rod.
Connect to the left vertical rod and move upwards
to the horizontal top rod.
Traverse at the bottom of the top vertical rod.
Move down the right vertical rod.
Move to the top side of the back horizontal rod.
Rotate to the bottom side of the back horizontal
rod.
Move to the left side of the back horizontal rod.
Move to the left lower rod before moving to the
front lower bar (the original position).

Table 4. Basic motions of Robot R2.
Basic Motions

Steps

Translational motion

1) Disengage one translational mechanism.
2) Activate second translational mechanism and move
the robot until the reflectivity sensors detect the stop
marking.
3) Operate the hinge to align the second translational
mechanism to the rod and engage its translational
mechanism.

(1)

(2)

(3)

Disassembly motion

(1)

(2)

(3)

Vertical assembly motion

(1)

1) Open the hinge slightly and engage the second translational mechanism, adjust the hinge angle to 90°. (This
step is critical for ensuring that there is no discrepancy
between the angle of the male and female gearings.)
2) Disengage the translational mechanism halfway (so as
to hold the rod in place without preventing it from rotating) and engage the rotational mechanism.
3) Disengage the translational mechanism completely and
operate the rotational mechanism for 180°, unlocking
the connector. Disengage the rotational mechanism to
release the rod.
1) Align rod with connector.
2) Operate the rotational mechanism for 180° to lock the
connector. Disengage the rotational mechanism and
engage the translational mechanism. (If the rotational
mechanism was not turned 180°, the engagement of the
translational mechanism will correct misalignments up
to 15°.)

(2)

Disassembly, 90° rotation, and reassembly of truss

(5)

(4)

(3)

(2)

(1)

(6)

(7)

1) Perform disassembly motion (1)-(3) as described above
on horizontal rod without performing the last step of
releasing the rod.
2) Decrease hinge angle slightly and move robot away
from node.
3) Engage rotational mechanism on vertical rod and disengage translational mechanism.
4) Rotate robot 90°.
5) Engage translational mechanism on vertical rod and
disengage rotational mechanism.
6) Set hinge angle to 90° and translate robot to node using
feedback from reflectivity sensors.
7) Operate the rotational mechanism for 180°, locking the
connector. Disengage the rotational mechanism and
engage the translational mechanism. (If the rotational
mechanism was not turned 180°, the engagement of the
translational mechanism will correct misalignments up
to 15°.)

september 2013

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IEEE ROBOTICS & AUTOMATION MAGAZINE

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Table of Contents for the Digital Edition of IEEE Robotics & Automation Magazine - September 2013
