The Explosive Ordnance Disposal Robot: CEO Mission EOD

Amon Tunwannarux and Supanunt Tunwannarux

Electronics & Telecommunication Engineering Department

School of Engineering, The University of The Thai Chamber of Commerce

126/1 Vibhavadee-Rangsit Rd., Dindaeng, Bangkok 10400

THAILAND

Abstract: - This paper presents the design and development of the explosive ordnance disposal robot named CEO

Mission EOD. It is the enhanced project from the rescue robot called CEO Mission IV. The mechanical arm with the

X-ray equipment set attached for improvised explosive device inspection (IED inspection) is installed on the track

wheel type universal robot platform of the CEO Mission IV robot. The X-ray set which is composed of X-ray source

and screen is installed and plugged into the versatile controlling and monitoring system so the X-ray image can be sent

to the teleoperator control suitcase wirelessly and easily. Software and hardware interface box is developed in order to

control and get image from the X-ray set without its hardware modification. The X-ray source is installed on the top

of robot body and the X-ray screen is attached on the tip of four bar linkage mechanical arm. The position of the X-ray

screen is controlled by two servo motors which have 2 degrees of freedom. The first degree is the forward angle of

four bar linkage and the second degree is the downward linear range of X-ray screen. The maximum height of

suspicious object that the robot can inspect is 85 cm. because the design target is for the inspection of the objects

which are hidden under the cushion of motorcycle. The user friendly GUI software on the teleoperator control suitcase

is developed further from the rescue version. The X-ray control function, the disrupter ignition control function and the

X-ray image manipulating function are implemented. The number of exposed X-ray pulses is used as the control

factor of the inspection image depth. In addition, the high pressure water jet gun (disrupter) is attached in order to

destroy the IED objects. The 100 Volts high voltage is pumped up step by step for the ignition preparation in order to

achieve high security. This project is researched and developed for giving to the Royal Thai Air Force. The results are

excellent and good enough for using it in the practical applications of the EOD mission in Thailand.

Key-Words: - explosive ordnance disposal, EOD robot, IEDD robot, rescue robot, X-ray source, X-ray image screen,

high pressure water jet gun, disrupter, ignition, mechanical arm

1 Introduction In the Explosive Ordnance Disposal (EOD) or

Improvised Explosive Device Disposal (IEDD) fields,

Robotized solutions with effective sensing capabilities

properly sized with suitable modularized, mechanized

structure and well adapted to local conditions can greatly

improve the safety of personnel as well as work

efficiency and flexibility [1]. With the large number of

IEDs and Unexploded Ordnance (UXO) being

encountered during recent military operations, there

exists a need for EOD mobile robots. These robots are

predominately used for surveillance, inspection and

neutralization of these explosive threats from a safe

distance. The nature of the mission means that these

robots are prone to being damaged or destroyed [2].

Thus, the functional low cost EOD robots are needed in

both EOD and IEDD missions. Some robots called the

MARCbot, LVUSS, Packbot, Talon EOD robot, Murv-

100, Andros, Johnny5 and more are remote observation

platforms which provides safe stand off when inspecting

suspicious IEDs.

From World Robocup Rescue Robot Competition,

started in 2001 until now, many rescue robots are

invented. One of the rescue robot competition team

names “CEO Mission team” has its series of rescue

robot development. The first robot from the team called

CEO Mission I helps the victim explorers to look from

(a) (b)

Fig.1 The Explosive Ordnance Disposal Robot: CEO

Mission EOD in the real mission (a) inspecting a big

box, (b) inspecting the cushion of a motorcycle.

10th WSEAS Int. Conf. on AUTOMATIC CONTROL, MODELLING & SIMULATION (ACMOS'08), Istanbul, Turkey, May 27-30, 2008

ISBN: 978-960-6766-63-3 433 ISSN: 1790-5117

top views or to look over partitions for making decision

of exploring route. The camera on the top of 125-cm.

high mast is used for looking over the 80-cm. high

partitions and accurately marks the locations of victims

in the competition arena [3]. Then the second robot in

this series, CEO Mission II, can solve the previous

robot’s problem which is the limitation of having only

two degrees of freedom in searching [4]. It comes with a

5-joint and 5-degree of freedom mechanical arm with a

four bar linkage which can stretch to 125 cm. long.

Many sensors are installed at tip of arm, for situation

surveillance from the high level as well as getting the

vital signs of victims easier and faster. It is controlled by

a teleoperator via the user-friendly control and

monitoring GUI program [5]. Until now, this series

robot becomes to CEO Mission IV which is designed for

real practical usages as the universal robotic platform. It

also designed with the modular concept and the concept

for reproduction and ease to maintenance. Because of

the rescue robot, CEO Mission IV, not only is the track

wheel type vehicle which is ready to move on any rough

terrain but also has the rich ports controller which can

use in several functions. So it can be easily modified to

fit several practical applications. One of the

modifications is the installation of the mechanical arm

which the X-ray equipment set attached for IEDs

inspection. Its mechanical arm is designed to work with

the big box which has the maximum dimensions up to

85 cm. high and 40 cm. deep so it can inspect the object

hidden under the cushion of motorcycle as shown in

Fig.1. Moreover a high pressure water jet gun is set up

on the robotic platform as the disrupter for destroying

IEDs. That is the main purpose and concepts of CEO

Mission EOD.

In this paper, we focus on the design and

implementation of hardware and software which is

related to X-ray set, four bar linkage mechanical arm

and high pressure water jet gun. The design and

implementation details of the CEO Mission IV universal

robot platform which has the versatile controlling and

monitoring system are not included. The rest of this

paper is structured as follows. Section two gives the

details of the hardware on the robot. In section three, the

robot mechanical arm are explained. Section four

illustrates the concept and hardware details for secured

firing of disrupter. Section five gives the details of

software on the teleoperator station. GUI of X-ray set

and GUI of ignition system are presented. Section six is

the testing results and discussions. Section seven is the

conclusion and the future work.

2 The EOD Robot Hardware Concept Our main design concept is using the simple method but

Fig.2 Block diagram of the EOD robot system (operator

side and robot side)

LCD 16*2

Serial

4 KeyPads

2 DC Motors with

Encoders of

Mechanical Arm

(for X-ray Screen)

Serial

Serial

Serial

Controlling Function

Monitoring Function

A/D 10 Bit 16 Ch.

- Battery Voltage 24 V

- Power Supply 5V

- Power Supply 6V

- Power Supply 12V

- High Voltage for

Firing Ignition 100V

Access

Point

802.11

A/G

Serial

to

TCP/IP

Module

Speed Control

of Left / Right

Locomotion

Motor and

Left / Right

Flipper Motor

Multi-channel

PWM

Signal

Controller

Switch

5 Ports

CPU1

CPU2

X-ray

Source

X-ray

Screen

Serial

X-ray Beam

Video Server1 Ch. / 4 Ch.

Video Server

3 Ch / 4Ch

Camera

x3

Serial

Interface

box

Control Relay

X-ray Set6 Relay Outputs

- Laser Pointer

- Light

- Spare Relay

- Step Voltage

Pumping up

- Gun Firing Ignition

- High Voltage

Discharge

High

Voltage

Circuit

Serial

PI Controller

for Position

Control

High Pressure

Water Jet Gun

(Disrupter)

CPU3

Encoder

L &R

WheelSerial

Yaw/

Pitch/

roll

sensors

Serial

Laser

Range

Finder

2.4GHz

5 GHz

Fig.3 Block diagram of hardware on robot (monitoring

function and controlling function)

highly effective and reliable. The block diagram of the

EOD robot system is shown in Fig.2. The robotic system

design can be divided into two sides of operations as the

operator side and robot side. All of the transmitted

controlling commands and the received monitoring

information are communicated between operator’s

computer and robot via WiFi 802.11 a or g. The operator

can switch frequency between 2.4 GHz and 5 GHz to

avoid the signal disturbance instantly. Because

monitoring function and controlling function are divided

clearly as shown in Fig.3, the hardware on robot is quite

simple and easy to understand.

10th WSEAS Int. Conf. on AUTOMATIC CONTROL, MODELLING & SIMULATION (ACMOS'08), Istanbul, Turkey, May 27-30, 2008

ISBN: 978-960-6766-63-3 434 ISSN: 1790-5117

2.1 Monitoring Function From the top half of Fig.3, it shows the robot hardwares

which work as the monitoring function. The monitoring

informations are composed of the data from all sensors

on the robot, audio/video from 3 cameras. teleoperator

can see four video with image size of 324x248 and 30

frames/sec in real time. For fast and real time

processing, most of monitoring data will be sent to

compute at the computer on the teleoperator side such as

the scanning data from laser range finder, the odometer

encoder data and yawn/pitch/roll sensor data. There are

three CPUs on the robot main board. They communicate

with each other via serial port. The CPU1, 40pins,

MCS51, is assigned for collecting all sensor data such as

battery voltages, all power supply voltage, high voltage

for firing and compass/pitch/roll angle of robot body.

The CPU3, 20 pins, MCS51, is used only for counting

the encoder pulses of left/right robot wheels. In addition,

the CPU1 also handles 4 key pads and 16 x 2 characters

LCD display which is used for maintenance and testing

at robot side.

2.2 Controlling Function From the bottom half of Fig.3, it shows the robot

hardwares which work as the controlling function.The

controlling commands are composed of all commands

that control the locomotion control, the robot’s device

on-off, the multi-joint mechanical arm movement, X-ray

set manipulation, the ignition preparation and the firing

control. The CPU2, 40 pins, MCS51, is set up for all

different types of control. The left/right flipper control

and speed control for locomotion need four PWM

signals so the multi-channel PWM controller is used for

interfacing. Because the multi-joint mechanical arm has

to hold the X-ray screen in long range, the driving

motors should be powerful enough. So we decided to

implement the PI controller for controlling two powerful

dc motors of mechanical arm. To avoid the X-ray set

modification, we studied the communication protocol of

X-ray equipment set and used CPU2 to simulate

commands for controlling X-ray sets via the serial

interface box. So we can control the number of exposing

X-ray pulses and get the X-ray image from its screen.

The image will be sent to video server and transmitted to

the operator via access point.

3 The Robot Mechanical Arm The mechanical arm is composed of three joints and one

sliding guide. Because the four bar linkage technique is

used, the angles of three joints are controlled by only

one base joint angle. This design reduces the number of

controlling point. Fig.4 shows the mechanical arm from

home position to the inspecting position. This arm has

(a) (b) (c)

(d) (e) (f)

Fig.4 Multi-joint mechanical arm with 2 degrees of

freedom in variety positions

Fig.5 The robot with dimensions and the maximum size

of object it can inspect (unit is mm.)

only two degrees of freedom. The first one is used for

spreading arm out as shown in Fig.4 (a-c). The second

one is used for sliding the X-ray screen down as shown

in Fig.4 (d-f). A powerful dc gear motor is installed

directly for the base joint angle driving. Another dc gear

motor, which is installed at base, works with sling and

some pulleys for achieving the mechanical advantage

and best motor position. This arm is designed to inspect

the big box which has maximum size of 85 cm. high and

40 cm. deep. Fig.5 shows the dimensions of the robot

and the maximum size of object the robot can inspect.

10th WSEAS Int. Conf. on AUTOMATIC CONTROL, MODELLING & SIMULATION (ACMOS'08), Istanbul, Turkey, May 27-30, 2008

ISBN: 978-960-6766-63-3 435 ISSN: 1790-5117

With the long segment of arm, it can inspect the objects

which are hidden under the cushion of motorcycle.

4 The Hardware for Secured Firing of

Disrupter In this project, the 20 mm. calibre disrupter is used.

Because the disrupter is the high pressure water jet gun

which has a lot of power of destroying, the secured

firing is required. Our secured design concept is the

more difficult ignition, the more secured firing. The

secured ignition system comprises of components as

shown in the block diagram of Fig.6. Each step boosting

command from CPU2 will enable high voltage boost up

circuit to increase 20 Volts per step and store energy in

capacitor tank. It needs to pump up five to six times in

order to reach 100 Volts to be ready to ignite. Firing

command from CPU2 is required again by pressing with

both hands at operator side. However CPU2 will

automatically command discharge energy from tank

after 15 seconds of voltage pumping.

Fig.6 Block diagram of secured ignition system of

disrupter

5 Software on Teleoperator Station For USAR tasks, an effective user interface (UI) must be

centered on providing the human operator sufficient

information to make correct decisions about future

actions of the robot at the required level of decision-

making [6]. The user must be able to easily monitor the

robot orientation, location and power, operate various

equipments such as cameras, lights and gripper on-board

and precisely control robots movements as well as

receive images from cameras [7]. Thus, the software on

the teleoperator station is one of challenging research

fields. Due to this CEO Mission EOD robot is developed

further from our previous version of CEO Mission IV

which was designed for USAR tasks, this effective UI

concept is also considered. In this paper, we will

illustrate only the software involving the control and

monitoring of X-ray set and disrupter firing system.

1525

(2) X-ray

Pulse

Number

(3) drag-drop controland monitor displayfor mechanical arm

(1) X-ray Image

Fig.7 Graphic user interface (GUI) of the EOD robot

which shows the X-ray image (1), the number of

controlling exposed X-ray pulses (2) and drag-drop

control and monitoring display for four bar linkage

mechanical arm (3)

99.8

15

Fig.8 Graphic user interface (GUI) of the EOD robot

which shows the pumped up voltage display in the gun

firing system (1) and video from front camera which has

the laser point on the firing target (2)

5.1 Control / Monitoring Software for X-ray set The method of determining tip position in 2D

coordinating system to control the movement of this

mechanical arm is implemented in this software. The

angles of each link are calculated from the tip position

by using inverse kinematics analysis [5][8][9]. The

Graphic User Interface (GUI) of the EOD robot which

shows the X-ray image, the number of exposed X-ray

pulses and drag-drop control and monitoring display for

the four bar linkage mechanical arm are shown in Fig.7.

The user-friendly control and monitor GUI is developed

for easier usage. By clicking the determined target point

or dragging the tip of the mechanical arm on screen to

the desired target, the robot will move its arm to the pose

as seen on the GUI screen. The angles of each joint are

calculated and sent to all joint servos simultaneously in

order to move the mechanical arm to the desired position

10th WSEAS Int. Conf. on AUTOMATIC CONTROL, MODELLING & SIMULATION (ACMOS'08), Istanbul, Turkey, May 27-30, 2008

ISBN: 978-960-6766-63-3 436 ISSN: 1790-5117

[5]. The operator can also use the joystick to control the

movement of mechanical arm and the locomotion of the

robot. The X-ray image which has resolution up to

648x496 can be edited and saved to desired location.

Operator can control number of expose X-ray pulse by

adjusting the slide bar or key number in the filled box.

5.2 Control/Monitoring Software for Ignition

System The graphic user interface of the EOD robot which

shows the pumped up voltage display in the gun firing

system and video from the front camera which has the

laser point on the firing target is shown in Fig.8. Video

from three cameras can be displayed at the same time or

selected for single display. However the control system

does not support the disrupter pan and tilt because there

is quite high reaction force when it is firing.

The software on operator side is installed on the

notebook computer which is set up in the teleoperator

control suitcase as in Fig.9. In this mobile case, the UPS

system with two 7 AH batteries can operate for 7 hours

and work in the field situation. Block diagram of the

teleoperator control suitcase is illustrated in Fig.2.

Fig.9 The operator’s mobile control suitcase with battery

included

6 Testing Results and Discussion The CEO Mission EOD robot were built as design and

tested with different manner as shown in Fig.1 In this

figure it shows how the robot can inspect things inside

the big box and cushion of motorcycle. In Fig.10, all

apparatus on robot platform are specified. The results of

inspection of the suspicious box in Fig.10 show in

Fig.11 (b) and (c) and the real IED objects inside the box

are shown in Fig.11 (a). The difference between the X-

ray image (b) and (c) is controlled by the number of X-

ray pulses which we set to expose. The more number of

pulses we expose, the deeper X-ray image we get. We

designed and developed the controller of X-ray set in

Fig.10 All apparatus on robot’s platform

(a)

(b) (c)

Fig.11(a) The IED objects in the suspicious box (cell

phone, electric wire, electronic board inside

and explosive device C4)

(b) The X-ray image when the number of expose

pulse is 10

(c) The X-ray image when the number of expose

pulse is 20

order to operate with X-ray sets from Thai Royal Air

Force without their hardware modification. So it is easy

and no expert requirement to set it up and remove it out

from our robot. Because the total weight of the EOD

robot is about 60 kg and its mechanical arm is quite long

even being home pose as shown in Fig.12, we designed

the mechanical arm to be able to disassemble from robot

platform before transporting to operation place. The

lock system between the X-ray set, the mechanical arm,

and robot platform is designed to be the toolless type.

10th WSEAS Int. Conf. on AUTOMATIC CONTROL, MODELLING & SIMULATION (ACMOS'08), Istanbul, Turkey, May 27-30, 2008

ISBN: 978-960-6766-63-3 437 ISSN: 1790-5117

Fig.12 The robot with home pose of mechanical arm and

the maximum size of object it can inspect (unit is mm.)

Only two hands of one operator can assemble and

disassemble mechanical arm, X-ray source and screen in

30 seconds.

In the field operation, the teleoperator control

suitcase can operate for 4 hours if use one battery and

for 7 hours if use two batteries. So the bottle neck of

operation time is on the robot. The operation time of this

robot depends on its mission. If the robot has to run at

all time on roads, rough terrain and stairs, it will be able

to operate for 1 hour. But if the robot runs to the

suspicious object and spends most of the time for

inspecting IEDs, it experiences for 2 – 3 hours. For its

EOD mission, this looks like long enough.

The communication range of the robot is about 100

meters line of sight. That is fair range, which will be

improved in the next version. The full speed of running

on road is 53 cm/s or 1.9 km/hr. This speed is good

enough for its mission because it usually work in rough

terrain and not necessary to travel in far distance.

Because most of terrorist operations in our country

use cell phone as bomb remote controller, the

frequencies of their operations usually are 900MHz,

1800MHz and 1900MHz. Therefore the design of two

frequency system in this robot is very useful and

practical in our country mission. The first operation of

officer is disturbing terrorist frequency with jammer. It

sends and sweeps the jamming frequency from 3 GHz

down to 400 MHz. In the operation of CEO Mission

EOD, operator could switch the communication

frequency to 5 GHz for avoiding the jammer.

7 Conclusion and Future Work The CEO Mission EOD robot was designed and

implemented. The robotic system has been described

especially the things relate to X-ray set and disrupter.

The result of this work is close to be a final prototype

design, which is currently undergoing extensive testing

to characterize its capabilities. Some of these tests

include robot characteristics such as robot speed and

mobility, robot weight and size, communication range

and battery longevity as well as operating among

jammers. Its performances were observed to be

excellent. For further work, mechanical arm in different

sizes and different situations should be implemented, for

example the arm for inspecting small box in the public

phone cabinet.

Finally, we would like to thanks the University of the

Thai Chamber of Commerce, UTCC who supports the

research grant and the Thai Royal Air Force who gives

the problem of this mission and all knowledge about

EOD/IEDD.

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10th WSEAS Int. Conf. on AUTOMATIC CONTROL, MODELLING & SIMULATION (ACMOS'08), Istanbul, Turkey, May 27-30, 2008

ISBN: 978-960-6766-63-3 438 ISSN: 1790-5117