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PREFACE
In summer 2003, when the 1
st
Field Robot Event was “born” at Wageningen University, it has been an
experiment to combine the “serious” and “playful” aspects of robotics to inspire the upcoming student
generation. Specific objectives have been:
• Employing students creativity to promote the development of field robots
• Promoting off-curriculum skills like communication, teamwork, time management and fundraising
• Attracting public interest for Agricultural Engineering
• Creating a platform for students and experts to exchange knowledge on field robots
Driven by the success of the 2
nd
Field Robot Event in 2004 Wageningen University organised in June 2005
the 3
rd
Field Robot Event. This event was accompanied by a workshop about robots and a fair where the
teams presented their robots. The teams also had to write a paper describing the hard- and software
design of their robot. The papers collected in this
Proceedings of the 3
rd
Field Robot Event
are a very
valuable source of information. This edition of the proceedings ensures that the achievements of the
participants are now documented as a publication and thus being accessible as basis for further research.
Moreover, for most of the student team members it is the first (scientific) publication in their career - a well-
deserved additional reward!
Wageningen, September 2005
Jan Willem Hofstee,
Chairman 3
rd
Field Robot Event 2005
INDEX
1 Cornhoolio 1
2 Cornickel 11
3 Eye-Maize 25
4 Microcallum 27
5 OptoMaizer 41
6 Padvinder 57
7 Rowbo 63
8 SmartWheels 73
9 Whirligig Beetle 91
The field robot Cornhoolio
Design and constructional overview
Daan Blaauw, Wouter van Gulik, Jorn Kommer, Dennis de Koning
Hogeschool van Amsterdam, The Netherlands
Amsterdamse Hogeschool voor Techniek
E-Technology
Internet:
http://www.rttc.tk
Contact: dennis.de.koning@hva.nl
27-06-2005
Abstract
Cornhoolio is an autonomous vehicle, developed for the Field Robot Event 2005, and
designed for navigating through a field of maize and counting the plants along the
way. A technical overview of the design of the robot and the technology that is used
is presented in this document.
Keywords
Autonomous agricultural robot, navigation systems, sensor technique, maize.
1 Introduction
Field Robot Event, organised by Wageningen University, The Netherlands, is an
event in which international and interdisciplinary teams compete by building a field
robot. In 2005, the objective of the robot was to move autonomously through a field
of maize and to count the plants along the way. Moving through the field includes
navigating through straight and curved rows of maize and turning at the end of a row.
A freestyle session was also part of the competition.
Cornhoolio is the robot developed by the Riders Through The Corn, a team that
consists of four E-Technology students from the Amsterdam School for Higher
Education. Design, building and testing of all the hard- and software was done by the
team. A chassis was obtained by sponsorship.
The main objective of the Field Robot Event, from the team point of view, has been
learning to cooperate as a team and to work together on technical solutions for
complex problems. Real problems, because agricultural robots are thought to make
an important contribution to the future of farming.
1
2 Materials and methods
2.1 Hardware
2.1.1
Chassis
The base for our self-developed electronics is formed by The Stadium Raider model
car, sponsored by Conrad Electronics. The Stadium Raider is based on a Tamiya TL-
01 chassis. The vehicle is electrically driven and features four-wheel-drive and servo
steering. Spike wheels are mounted tot provide maximum grip.
Figure 1 - The Tamiya Stadium Raider chassis in development stage
2.1.2 Sensors
To detect maize plants we make use of six Sharp GP2D12 infrared sensors. Four of
them are mounted on the front of the vehicle and are used to navigate through the
maize. The other two are placed on both sides of the vehicle and are used to count
the plants. The sensors feature a range of approximately 10-80 cm.
Figure 2 - The Sharp GP2D12 infrared sensor
To turn our vehicle at the end of the row we make use of a digital compass, the
Devantech CMPS03. The compass determines the average heading of the vehicle
while driving through the maize field. This heading is used to calculate the opposite
of it, which forms the heading to reach during the end turn.
Figure 3 - The Devantech CMPS03
2
To determine and control the current speed of the vehicle we use very small infrared
sensors that are placed near the front and back left axle. Dark slopes in the reflective
aluminium material are used to detect rotation and thus speed. Furthermore, voltage
sensors are used to measure several system voltages. By doing this, we can easily
monitor the battery conditions.
2.1.3
Supply circuit
The vehicle makes use of two independent power sources. A model car racing pack
of 7,2V is used to drive the electrical engine of the car and also powers an electronic
display and the GP2D12 infrared sensors. The power is distributed via a Tamiya
electronic speed regulator. Four rechargeable NiMH batteries of AA-size (penlite),
power an analogue circuit, which delivers a stable 5V supply voltage. This is used for
the digital compass, temperature sensors and the microprocessor.
2.1.4
Main board
The main board is the place where the all the hardware comes together. The heart of
the vehicle is formed by an Atmel ATMega 32 microprocessor. The main board
features a UART-connection and a parallel programmer connection with the PC.
Also, an electronic display on which information from the microprocessor can be
displayed is connected to the board. Furthermore, a steering servo and speed
sensors can be connected. For human-machine interfacing, three switches can be
connected to the board. Connectors for the six infrared sensors and the digital
compass can also be plugged onto the board. Finally, the board has a connection for
two digital temperature sensors that can measure the inner and outer temperature of
the vehicle.
Figure 4 - The main board
3
2.2 Software
Below is a schematic of the software. We will describe some parts of the software in
the following texts. For some parts there meaning and relevance is obvious and they
will not be discussed.
Figure 5 - Schematic of the software
2.2.1 VT100 terminal
Cornhoolio is equipped with a terminal emulator. Using this terminal emulator we are
able to control en measure all our sensors within the robot. This is an easy way of
making our car accessible and it runs on almost every computer. Through the menu’s
we have created in the robot we are able to drive him manually while observing the
sensors or watching the speed sensors and starting several test routines.
2.2.2
I
2
C bus
To access the different devices in the system the I
2
C bus is used. The I
2
C bus
consists of only two wires. This reduces the use of wires and reduces the complexity
of the circuit boards. For most I
2
C devices there is a driver available. We used the
available I
2
C library from Procyon. However, for the CMPS03 and the temperature
sensor we had to write our own drivers. We have also rewritten the drivers for the
A/D converters so it was more efficient for us.
2.2.3
Engine and steering control
The speed control for the engines and the steering control are done by the same unit.
The type of interfacing is a PWM signal with a 50Hz cycle; this is a typical servo
steering signal. The speed controller uses the same type of control and thus reducing
the complexity and the amount of software. All the control is now done by a simple
timer, running at a 50Hz cycle with two compare outputs, toggling at the desired
moment.
2.2.4
4
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