Application_of_Active_Scope_Camera_to_forensic_investigation_of_construction_accident

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Abstract— A rescue robot, Active Scope Camera was applied 
to forensic investigation of collapse of parking building under 
construction in Jacksonville, Florida, USA. It could enter 7 m 
deep into the rubble pile through gaps 3 cm wide and gathered 
image data, shape and direction of cracks, and section surface of 
concrete flakes, which was the world's first. 
I. INTRODUCTION 
HE most common causes of death at Hanshin-Awaji 
Earthquake, which occurred in Kobe in 1995, were crush 
and suffocation by collapse of houses. According to 
medical statistics, they resulted in 83.7% of 6,434 deaths. 
Because many voices calling rescue were reported just after 
the shake, rapid urban search and rescue (USAR) from 
crushed buildings reduce the death rate at such large-scale 
earthquake disasters. 
Improvement of search capability is one of the most 
important issues in USAR. Investigation of USAR process in 
Kobe revealed that search was the most critical task because it 
took the longest time among the whole process. Exact 
position and situation of victims must be identified for 
effective operations. However, ability of sensing of human 
and rescue canine is not sufficient. Voice from deep in debris 
is sometimes masked by surrounding noises. Direction of 
voice cannot be estimated because it is sometimes heard by 
reflection from rubbles. Dogs cannot enter narrow voids, and 
their reports are not always accurate. Risk of secondary 
collapse is high because of fragile damaged structures with 
after-quake and rain. 
Active Scope Camera (ASC) is a robot video scope for this 
purpose. It was invented by the authors' group by the support 
of MEXT DDT Project and Grant-in-Aid for Scientific 
Research. ASC can enter narrow gaps 3 cm wide and actively 
move 8 m deep to search victims by a CCD camera at the tip 
of its actuated cable [1-5]. 
ASC was applied to forensic investigation of construction 
collapse accident at Berkman Plaza II in Jacksonville, Florida 
on January 4-5, 2008 [6]. It succeeded in gathering image 
 
Manuscript received October 1, 2009. This work was supported in part by 
the Grant-in-Aid for Scientific Research. 
Satoshi Tadokoro, Masashi Konyo, Toshihiko Nishimura are with Tohoku 
University, Sendai 980-8579 Japan (corresponding author to provide phone 
+81-22-795-7022; fax: +81-22-795-7023; e-mail: 
tadokoro@rm.is.tohoku.ac.jp). Satoshi Tadokoro is also with International 
Rescue System Institute. 
Robin Murphy and Samuel Stover are with CRASAR, Texas A&M 
University, TX, USA. 
William Brack is with Bracken Eng. Co. Ltd. 
Osachika Tanimoto is with San Francisco Office, Osaka University. 
information of proof at narrow voids 7 m deep in the 
completely crushed structure. This paper reports this 
application as well as verification tests of ASC at Collapsed 
House Simulation Facility at Kobe Laboratory, International 
Rescue System Institute (IRS) as well as at Disaster City, the 
training site of the Federal Emergency Management Agency 
(FEMA) Texas Task Force 1, which is operated by TEEX, 
Texas A&M University. 
 
 
Fig. 1: The Active Scope Camera for search and rescue. 
 
 
Fig. 2: Ciliary vibration drive mechanism. 
II. ACTIVE SCOPE CAMERA 
A. What is Active Scope Camera? 
Figure 1 shows the ASC. It is a robot video scope, and a 
small-size camera at the end of the cable capture image. The 
cable of a video scope is covered by inclined cilia. Motors 
with eccentric mass installed in the cable excite vibration and 
cause up-and-down motion of the cable. When the cable 
move down, the tips of the cilia sticks on the floor, and the 
cable move forward because of the inclination. On the other 
Application of Active Scope Camera to Forensic Investigation of 
Construction Accident 
Satoshi Tadokoro, Fellow, IEEE, Robin Murphy, Member, IEEE, Samuel Stover, William Brack, 
Masashi Konyo, Member, IEEE , Toshihiko Nishimura, and Osachika Tanimoto 
T
47
2009 IEEE Workshop on Advanced Robotics 
and its Social Inpacts 
Tokyo, Japan, November 23-25, 2009 
978-1-4244-4394-9/09/$25.00 © 2009 IEEE
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hand, when it moves up, the tips slip against the floor, and the 
cable does not move back. By repetition of this process, the 
cable can slowly move in narrow space of rubble piles as 
shown in Fig. 2. 
B. Advantages and Disadvantages 
The ASC has the following advantages and disadvantages. 
(1) Mobility 
By adding the mobility to a video scope, the area of search 
is drastically enhanced. The ASC can enter into the space 
where conventional scopes could not move by negotiating 
with steps and slopes. It can ascend steps 20 cm high, and can 
climbs slopes 20 deg, when the conditions are good. 
(2) Controllability in narrow spaces 
The direction of motion in confined space can be 
controlled by bending the end of the scope using the original 
function of video scopes. The cable moves to follow obstacle 
faces. By the bending control from a handy controller, 
operators can select the faces to follow, holes to enter, and a 
passage at branches in order to determine the direction. 
The ASC can ascend steps by the same principle. When 
the cable bends upward, it climbs up walls by pushing force 
from the latter part of the actuated cable. 
 (3) Controllability in open spaces 
In open spaces, the direction of motion can be controlled 
by twisting/pulling/pushing the cable. Gentle curve of the 
fore-end causes imbalance of the force generated on the 
whole surface of the cable. Under natural condition, the cable 
moves to the direction of the curve. The curve direction 
changes when the cable is twisted because the torsional 
stiffness is high. If the cable is pulled, the driving force of the 
fore-part straightens the cable. Pushing control bends the 
cable more. 
 (4) Simple and intuitive operation 
Control of the ASC is not difficult. After exercise of 10 
minutes, most people can control the cable motion on flat 
floors. The control methods mentioned above are intuitive 
and user friendly. 
On the other hand, control in rubble piles is not easy, and 
intensive training is necessary. The most difficult issue is not 
the control but situation awareness. This is common with 
conventional video scopes. 
(5) Robustness 
The environmental robustness is high. The cable is 
covered by soft cilia. The motors and wirings are sealed. The 
ASC had no hardware problem at a three-day exercise at 
Disaster City, where the temperature was 42 Co. It is 
water-proof, and can move in water. 
III. VERIFICATION EXPERIMENTS 
Testing and improvement are essential process for 
practical systems. Intensive experiments have been 
performed to develop practical functions, performance, 
properties and quality. 
A. Experiments at Collapsed House Simulation Facility 
IRS set up Collapsed House Simulation Facility in Kobe 
Laboratory for test and verification of research products of 
DDT Project. A small-size Japanese wooden house that 
simulated typical collapse at Hanshin-Awaji Earthquake was 
built in a warehouse. 
On December 28, 2006, the first verification experiments 
of the ASC were performed there. 
Wooden blocks, coat hangers and dishes were scattered on 
plywood floor in a collapsed house. Dummy victims (two 
adult arms and an infant) were buried. A polyvinyl tube 2 m 
long was inserted into the rubble pile as shown in Fig. 5 to 
guide the active scope camera. Two operators controlled the 
scope for urban search exercise. One inserted the cable, and 
the other watched the video display and controlled the head 
bending. The operators could not see inside of the house, but 
they have known the approximate positions of the victims. 
The active scope camera was controlled to search the victims 
using only the image information from the scope camera. 
Figure 3 shows three routes experimented.The dummies 
exist at the end of the routes. Thick solid lines indicate the 
moving route of the active scope camera. 
As for the route 1, the camera moved from the pipe to the 
left, got over a piece of plywood 10 mm thick and a coat 
hanger, and found a victim in 3 minutes 57 seconds. The 
length of insertion was 5 m. Bending the scope head enabled 
the cable change its motion direction along wood at an angle 
of 90 deg. 
As for the route 2, the camera entered from the same place 
as the route 1. After the pipe, it moved downward, got over 
plywood 5 mm thick and a square timber of 30 mm, and 
found a victim after 8 minutes 28 seconds. The distance of 
insertion was 6.3 m. The bending motion was effective to 
select the route. 
As for the route 3, after the pipe, it turned around to the 
opposite direction. It climbed over plywood 10 mm, turned 
along a wall, and reached the destination after 3 minutes 21 
seconds. The inserted length was 5 m. 
These results demonstrated that the active scope camera 8 
m long was able to search victims deep in rubble piles. 
 
Fig. 3: Verification experiments at Collapsed House Simulation 
Facility, Kobe Laboratory, International Rescue System Institute on 
December 28, 2006. 
IRS-U, a volunteer unit of firefighters in active service, 
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tested the ASC at Collapsed House Simulation Facility as 
shown in Fig. 4. By comparing to the other robots and 
systems developed in DDT Project, they evaluated the ASC 
as one of the most capable system for deployment to real 
disasters. 
 
 
Fig. 4: Verification experiments by IRS-U personnel. 
 
 
 
Fig. 5: Verification experiments at Disaster City on June 18-22, 
2007. (Upper-left: search in a breached hole, upper-right: insertion 
into a pipe of a train, and lower: search using a hope on a wall.) 
 
 
Fig. 6: Collapsed construction site in Jacksonville, FL, USA. 
B. Experiments at Disaster City 
Disaster City is the largest training site of first responders 
for USAR in the world. It is the main facility of FEMA 
TX-TF1and is managed by TEEX, Texas A&M University. 
The 4th Response Robot Evaluation Exercise was held on 
June 18-22, 2007. This event was organized by NIST as a 
part of their DHS project on USAR robot performance 
standards [7]. The Active Scope Camera was tested in this 
exercise using the various simulated disaster situations in 
Disaster City. 
The following tests were performed: 
- search in a house from outdoor by utilizing a hole on wall; 
- search in a train by inserting the ASC into a pipe; 
- search under a train on gravel field with controlling the 
motion direction; 
- search in a drain pipe; 
- search under floor of an office building; 
- motion in RC rubble pile; 
- motion in wooden rubble pile; 
- motion on random step field of proposed standard test for 
UGVs; 
- motion in maze of proposed standard test for UGVs; 
- visual acuity test of proposed standard test; and 
- demonstration on concrete floor. 
In these experiments, the ASC showed better ability in 
penetrating narrow spaces and rubble piles than conventional 
scopes. As a result, it was selected by the FEMA managers as 
one of the two most convincing rescue robots among 18 
robots and systems that participated in this event. 
IV. APPLICATION TO CONSTRUCTION ACCIDENT 
On December 6, 2007, a collapse accident of 5-story 
parking garage occurred at Berkman Plaza II, Jacksonville, 
Florida, USA during its construction. When pouring concrete 
for the top floor, the whole structure broke and fell down. 
USAR operations for a few days resulted in one death and 23 
injuries. In forensic investigation, scopes and robots were 
used to gather information, but they could not obtain the most 
difficult but important information on situation deep in the 
rubble pile. 
On December 12, 2007, an e-mail of call-out of the ASC 
was sent by Murphy to Tadokoro. He flew to Jacksonville 
with Nishimura and Tanimoto on January 3, 2008, and 
performed investigating operation on January 4-5 using the 
ASC 8 m long in cooperation with Murphy, Stover, Brack 
and a few students. The ASC was operated by Stover and 
Tadokoro, and Brack indicated its motion and the place to be 
watched. 
As a result the following image information in the rubble 
pile was obtained successfully, where the maximum depth of 
observation was 7 m: 
- shapes and directions of cracks of RC columns and 
beams; 
- shapes and surface face images of RC flakes; and 
- other situations in the space inside such as existence of 
columns. 
These facts are important proof of the collapse mechanism 
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and cause of the accident. The authors cannot write these in 
detail because they are used in court. 
This information could not be obtained by the other 
methods. Larger robots could not enter the narrow gap of 
rubble piles. Conventional video scopes can enter only 1 m 
deep because they are not actuated. Removal of rubbles by 
construction machines causes loss of important information 
such as cracks and stripped flakes. Therefore, this was the 
first case in the world where this type of information could be 
gathered. 
The reasons why the ASC was effective are summarized 
below. 
(1) Compact driving mechanism: 
The ASC is enough thin (2.5 cm in diameter) and long (8 m 
in length). It can enter narrow gaps 3 cm wide into the full 
length. 
(2) Distributed actuation mechanism: 
Distributed force of actuation on the whole surface of the 
cable enabled the ASC rather stable driving even in rubble 
pile irrespective of shapes of gaps. 
(3) Softness: 
The ASC can adapt its shape to many gaps and voids by 
bending its cable and the cilia on the surface. 
(4) Controllability: 
Direction of motion and view can be controlled both in 
narrow gaps and in wide spaces to change the point of 
inspection. 
(5) Simplicity: 
The simple structure of the ASC contributes high reliability 
even in disaster situations. 
(6) Mobility: 
Its mobility enabled horizontal insertion as well as vertical 
insertion of conventional video scopes. It can avoid obstacles 
and gaps. 
(7) Reduction of friction: 
Friction between the cable and the rubbles is reduced 
because of the vibration. Draw-out motion is not interfered 
much by the friction, and the cable does not hook much. 
Stover, FEMA USAR IN-TF1 Search Team Manager, 
mentioned that this success apparently showed the 
effectiveness in search and rescue operation in collapsed 
houses. 
V. CONCLUSIONS 
This paper presented application of the Active Scope 
Camera, which is a robot video scope, to forensic 
investigation of construction accident as well as its 
verification experiments at simulated disaster situations. The 
results showed its effectiveness and possibility in urban 
search and rescue. 
On the basis of these achievements, the ASC was awarded 
the Robot Award from Ministry of Economy, Trade and 
Industry of Japan, and Highest Award from Fire and Disaster 
Management Agency Commissioner. 
The Cologne Historical Archive collapsed on March 3, 
2009. The ASC was on standby for possible use at real urban 
search and rescue at this accident on March 6-8. However, it 
was not used because the operation was so dangerous that the 
secondary damage might occur. 
The ASC became commercially available in May, 2009 as 
a self-moving guide tube by Olympus Co. Ltd as an option of 
their video scopes. 
The ASC has no record of usage in real urban search and 
rescue until now. More improvement of its performance and 
functions [8], development of appropriate direction for use, 
and continuous training exercises by first responders are 
essential. 
The ASC should be effective also for various inspectionsof narrow deep spaces such as in chemical plants. In order to 
reduce the price, industrial applications should be explored to 
expand its market. 
The authors expect that the ASC contributes to safe human 
lives in the near future. 
 
 
Fig. 7: Operation of forensic investigation on January 4-5, 2008. 
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