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8/10/2019 aim.2009.5229916
http://slidepdf.com/reader/full/aim20095229916 1/5
Abstract — this paper describes an unmanned ground vehicle
that can move urban environment. The UGV technology grows
rapidly. Generally UGV is developed for military purpose. Now
a days, many university and research institute research new
UGV technology for commercial use such as transportation
service. This vehicle can drive on the urban environment. The
UGV system consists of four parts such as vehicle control system,
navigation system, obstacle detecting system and arbitration
system. In this research, we used minivan for developing
unmanned ground vehicle. And we explain each system
configuration and event driving that based on extended RDDF.
Through real driving test on the fixed environment, we want to
verify unmanned ground vehicle system
I.
INTRODUCTION
Fig. 1 DARPA Urban Challenge 2007
Recently autonomous driving technology is rapidly
developed. Through unmanned ground vehicle competition,
importance of unmanned vehicle technology is understood
and related technology is expanded. An initial stage,
unmanned ground vehicle and related technology were
Manuscript received February 15, 2009. This work was supported by theMinistry of Knowledge Economy(MKE) and Korea Institute of Industrial
Technology Evaluation and Planning(ITEP) through the Center for Automo
tive Mechatronics Parts(CAMP) at Keimyung University. Development of
Unmanned Ground Vehicles Available of Urban Drive
H.C. Moon is with Unmanned Ground Vehicle Lab of Kookmin
University, Seoul, Korea. (corresponding author to provide phone:
+82-2-943-1994; fax: +82-2-916-0991; e-mail: hcmoonr@koomin.ac.kr).
J.H. Kim is with Kookmin University, Seoul, Korea. (e-mail:
jhkim@kookmin.ac.kr)
J. C. Lee is with Keimyung University, Deagu, Korea (e-mail:
ljcds@kmu.ac.kr)
D.M. Lee is with The Center for Automotive Mechatronics Parts,
Keimyung University, Deagu, Korea (e-mail: noble26@kmu.ac.kr)
developed to use military purposes[1][2]. But now, these
abilities were used for commercial transportation service. In
this paper, unmanned ground vehicle for urban driving is
developed and verified the vehicle can drive on the urban
road.
II.
SYSTEM CONFIGURATION
For developing unmanned ground vehicle that can drive on
the urban road, minivan used for based vehicle. The vehicle
has enough space and power for installing many systems. Also
the vehicle can transport passengers[3]. Fig. 2 is unmanned
ground vehicle whole system configuration. the UGV isconsist of 4 sub system that are vehicle control system for
control vehicle’s movement, navigation system for get
vehicle’s current position and calculate vehicle’s direction,
obstacle detecting system for detect obstacles on the road and
calculate avoid path and arbitration system for control other
subsystems and generate vehicle control command for vehicle
control system.
Fig. 2 Unmanned Ground Vehicle system configuration
1. Vehicle control system
Vehicle control system is a base system of UGV. This
vehicle can drive urban environment and have enough space
for install many sensors and actuators. In this research, we use
minivan produced by Hyundai motor company. Fig. 3 is
vehicle control system configuration of unmanned ground
vehicle[4].
Vehicle control system has independent power supply
system for sensor, actuator and subsystems. This power
system is isolated from vehicle power system. Generator of
DC 24V and 60Ah is mounted on engine room of the vehicle
and battery of DC 24V 200Ah is mounted on rear of vehicle.
Development of Unmanned Ground Vehicles
available of Urban Drive
HeeChang Moon, JaeCheon Lee, JungHa Kim, and DongMyung Lee, Member, IEEE
2009 IEEE/ASME International Conference on Advanced Intelligent MechatronicsSuntec Convention and Exhibition Center Singapore, July 14-17, 2009
978-1-4244-2853-3/09/$25.00 ©2009 IEEE 786
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Fig. 3 Vehicle control system configuration
This power system can charge itself when engine is going and
have enough capacity when engine is stop.
Vehicle control system used CompactRIO is made by
National Instrument. It has expansion interface ports that
based on FPGA(Field Programmable Gate Array). It offer
various interface module such as RS232 multi port module,
DAQ module for sensor data acquisition and digital
input/output module for control several switches and relays.And E-stop function is expressed using RF data transmitter
and receiver that is shown fig. 4. It was used for emergency
case during vehicle driving. When vehicle’s movement is
unstable, operator push button of transmitter then vehicle
recognize this signal then generate command of vehicle stop.
The vehicle must have this function for safety.
Fig.4 RF transmitter and receiver
2. Navigation system
Navigation system of unmanned ground vehicle is to get
current position of the vehicle using GPS and to generate
global path to objective position. And this system makes
steering angle command for following the generated global path[5]. Fig. 5 is shown navigation system configuration.
GPS is used for get current position of the vehicle. In this
research, navigation system has GPS and DGPS because GPS
has good receiving rate and low position accuracy but DGPS
has good position accuracy and low receiving rate. So
navigation system use two kinds of GPS receiver. In this
research, 18-5Hz of Garmin and SF-2050M of Navcom are
used. Using GPS, vehicle can get vehicle’s current position
and direction of travel when vehicle is moving. If the vehicle
Fig. 5 Navigation system configuration
doesn’t move, it is hard to get direction of travel. So, digital
compass is used for get heading angle of the vehicle against
magnetic north. In this research, C-100 of KVH is used for
navigation system.
3. Obstacle detecting system
For driving stabilization of a vehicle, Obstacle detectingsystem is an essential part in Unmanned Ground Vehicle
system.. It detects most of the obstacles around the vehicle that
are on the front and side of the vehicle[6]. And it make
steering value for obstacle avoidance. The fig. 6 shows the
details of obstacle detecting system configuration.
Fig. 6 Obstacle detecting system configuration
In this research, laser scanners and vision cameras were
chosen for obstacle detecting. We use the LMS291-S05 laser
scanner which is more accurate from SICK Optic Inc. and it is
composed of four positions. Laser scanners was mounted in a
different location (fig. 7), they each have a different scanning
area.
Obstacle detecting system use Vision cameras for line
detecting and obstacle detecting. In this research, we detect a
line on the road way in urban environment and fuse laser
scanner data for indicates into a local map. Follow picture
represents a result of line detecting using though transform.
Vision cameras also detect speed bumps that are met with
everywhere in urban environment. Generally, speed bumps
have same color pattern and frequent color pattern change is
followed by pattern recognition and edge change. It is possibl
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Fig. 7 Mount position of laser scanner and camera
Fig. 8 Obstacle detecting range of laser scanner
Fig. 9 Result of lane detection and local map expression
le for the detecting speed bumps how it compare the number
of edge. Fig.10 represents the results of image processing
process and speed bumps detecting.
Fig. 10 Process and result of speed bump detection
III. DRIVING ALGORITHM
1. Global waypoint driving method
Driving algorithm for UGV using a DGPS unit, multiple GPS
units, encoders and a compass is lateral control. The UGV has
heading vector V, which is calculated using current position
and compass azimuth, and waypoint vector W, between the
current position and WP. The steering angle (β ) is calculated
using a simple trigonometric formula[7].
Fig. 11 calculation of steering angle
The direction of UGV is defined as using rotation and
transpose matrix. If the way point is being on right from
driving direction, UGV is turned the right. The other case,
UGV is turned the left.
The Ex-RDDF includes the WP’s X and Y position and
lateral boundary offset (LBO). The UGV uses the waypoints
from the Ex-RDDF to drive. If the current vehicle position is
found to pass within the LBO, the goal WP is updated to the
next WP in the Ex-RDDF.
Latitude and longitude are changed into X and Y
coordinates. Stop & Go and Steer Angle are event information
used to perform some mission.
cosV W
V W β =
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Fig. 12 Concept of calculating steering direction
2. Local event driving method
The Ex-RDDF consists of seven text messages. The
following figure shows an example of these messages.
Fig. 13 Extended RDDF for event driving
Table 1 Event list for unmanned ground vehicle event driving
IV.
TEST AND RESULT
For driving tests of our unmanned ground vehicle, we
performed at driving test environment where is shown in
Fig.14. We operated driving tests in our college ground,
because unmanned ground vehicle couldn’t be tested on the
real road. The driving course was about 500m, and fixed
obstacles, moving obstacles, a cross line were set up on the
test road. Then, we made an experiment how tests were
driving unmanned ground vehicle.
Before we got this test, we used the eRDDF (extended Route
Data Definition File, table 2 shows an eRDDF list table)
which had been made coordinates about start point, way-point
and finish point. Table Extended RDDF listThe data had been post-processed to test the driving ability
of unmanned ground vehicle to coast through GPS trajectory
as shown in Fig. 15. The vehicle was driven through the
way-points also it had to avoid obstacles. Then, missions that
operated a stop signature, avoidance fixed obstacles, detected
pedestrians completed successfully.
As the result of driving, the vehicle’s driving is stable
because generated path is smooth.
Fig. 14 Test environment at Keimyung Univ.
Table 2 RDDF list of test field
Fig. 16 shows the graph of changed steer angles during
driven on the ground road. A steer command signal of
unmanned ground vehicle was generated by both navigation
and obstacle detection system. A steer command that was
generated by those systems transferred to arbiter system, it
determined according to priority of vehicle state. The green
and red lines represent each steer angle of the obstacle
detection and vehicle control system, the blue line also
represents a steer angle that was responded from arbiter
system. So, we could prove that vehicle was controlled by
other systems.
Navigation system limits maximum speed by various road
conditions. This limited speed is sent to arbitration system
then the system can control vehicle’s speed by vehicle’s state
and other system’s condition. If navigation system make
vehicle speed command at 10km/h and obstacle detecting
system detect obstacle, the arbitration system make decision
to avoid or to stop. Then result of decision is sent to vehicle
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Fig. 15 Test result of vehicle driving
Fig. 16 Steering angle command of arbiter and obstacle
detecting system and steering angle response of vehicle
Fig. 17 Response of vehicle velocity command
control system. Vehicle control system controls vehicle’s
speed. Fig. 17 shows result of vehicle velocity control.
Continuous line is current velocity of the vehicle and dashed
line is vehicle velocity command that made arbitration system.
As the result of velocity control, the vehicle control system
controls vehicle speed by the command. At a pedestrian
crossing and emergency case, the vehicle rapidly stops using
brake actuator. Then the vehicle continuous drives after get
start command.
V.
CONCLUSION
This research presents the opportunity to develop an
unmanned mini-van that was automatic drivable on the urban
environment, and operated a driving test. We had proved it
how unmanned ground vehicle could react against missions in
7Km/h of average speed. Our test could become prohibitive
due to being drivable with another human driven vehicle. So,
we could have operated limitedly.
However, we can prove it that our unmanned ground vehicle
was able to drive successfully in urban environment in this
research.
ACKNOWLEDGEMENT
This work was supported by the Ministry of Knowledge
Economy(MKE) and Korea Institute of Industrial Technology
Evaluation and Planning(ITEP) through the Center for
Automotive Mechatronics Parts(CAMP) at Keimyung
University.
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