Robocon 2010 Report

ROBOCON 2010 Report Page 1

CONTENTS

Acknowledgement Page 2

Introduction Page 3

Team Page 4

1. ROBOCON 2010 Contest Page 5-16

1.1. Contest Theme

1.2. Arena Specification

1.3. Game Procedure

1.4. Scoring

1.5. Robot Specification

1.6. Rules

2. Construction Page 17-30

2.1. Manual Robot

2.1.1. Structural Components

2.1.2. Assembling the Robot

2.2. Auto1



2.3. Auto3



3. Automation Page 31-39

3.1. Manual Robot

3.1.1. Electronic Components

3.1.2. Interfacing PS2 Controller

3.2. Auto1

3.2.1. Basic Techniques And Game Plan


3.3. Auto3

3.3.1. Basic Techniques And Game Plan


Gantt Chart Page 40

Expenditure Page 41

Lessons Page 42

Conclusion Page 43

Photo Gallery Page 44-45


ACKNOWLEDGEMENT

First of all, on the behalf of Team Robocon, we, the team members of Robocon

2010, wish to extend our heartfelt gratitude to the college authority, especially Prof. S

Bhattacharya, Director of National Institute of Technology, Durgapur, India and Prof.

A.K. Mitra, Dean (Administration) for their complete administrative support. It is our

privilege to express our sincere regards to our External Advisor, Prof. S.K. Saha, Indian

Institute of Technology, Delhi, India for his continuous guidance, encouragement and

motivation. We deeply express our sincere thanks to our Faculty-in-charge, Mr.

Aniruddha Chandra and Prof. S.K. Datta for their consistent support, whole-hearted

cooperation and constructive criticism throughout. We are greatly indebted to them for

helping us getting funds for purchasing the components required for fabricating the

robots. We would like to take this opportunity to acknowledge the support and

encouragement of Mr. Kundu, Mr. G. Datta and the entire staff at the Workshop

department; we are very grateful to them for providing us with their valuable inputs,

speedy actions in building the robots. Moreover, we express our gratitude to our

librarian Dr. M Mondal for allowing us to work in the seminar hall of the library.

Finally, we take this opportunity to thank everyone who has directly or indirectly

contributed to ROBOCON. We pay our love and respect to NIT Durgapur and its entire

family.


INTRODUCTION

ROBOCON, short for Robotic Contest, is an interesting game-cum-intellectual exercise for budding engineers and Robotics enthusiasts. The concept of Robocon is a technically challenging event to realize the importance of originality and innovation. The event brings those future engineers the joy of realizing unique ideas and the excitement of creation. Participation in it is an end-to-end competitive experience from concept design of a system of robots programmed to perform according to rules of the game played on a precisely created challenging field and to score a victory beating the competitors; the ultimate rush of thrill and excitement for young engineers. The Asia-Pacific Robot Contest (ABU Robocon) is an Asian Oceanian College Robotic competition founded in 2002 by Asia-Pacific Broadcasting Union. In the competition robots compete to complete a task within a set period of time. The contest aims to create friendship among young people with similar interests who will lead their countries in the 21st Century, as well as help advance engineering and broadcasting technologies in the region. ABU Robocon 2010 is hosted by Egypt at Cairo scheduled on 21st September 2010.


Team

External Advisor: Prof. S. K. Saha, Professor, IIT Delhi

Internal Advisor: Prof. S. K. Datta, Professor, ECE Department, NIT Durgapur

Mr. A. Chandra, Lectrurer, ECE Department, NIT Durgapur

Team Coordinator: Naushad Rahman

Construction Team:

1. Aniket Pateil

2. Abhishek Agarwal

3. Debarun Das

4. Debesh Pradhan

5. Niraj Chaurasia

6. Debal Saha

7. Aman Agarwal

8. Pradeep Jain

9. Amrit Pal Singh Bhinder

10. K. Ashoke Raman

11. G. Manjunath Srivastava

12. Umangaraj Aryal

13. Nirjhar Debnath

Automation Team:

14. L S Bharadwaj

15. Naushad Rahman

16. Yudhir Bhattarai

17. Prakash Agarwal

18. Manoj Kumar Yadav

19. Sunil Das

20. Amit Sahani

21. Akshay Mysore

22. Subarno Banerjee

23. Amit Srivastav

24. Praveen Sagar

25. Atikant Singh


1. ROBOCON 2010 Contest

1.1. CONTEST THEME

Robo-Pharaohs Build Pyramids is the main theme of Robocon 2010. The Pyramids of Giza and other

monuments on the Giza Plateau are among the great world treasures. In fact, the Pyramids are the icons of

world heritage in general and are widely pictured as such. And it was these pyramids, which represented the

main theme of ROBOCON 2010. The construction of three Pyramids of Khufu, Khafraa and Mankaura, the

private tombs of the Pharos of the 4th

dynasty of Egypt, was modeled in the competition. These three

pyramids are built in a diagonal manner with the help of cubical blocks.

Figure 1.1: Virtual Image of the Giza Pyramids Site

Figure 1.2: Giza Pyramids Positioning


Robo-Pharaohs Build Pyramids is the main theme of this contest. The idea is based on a virtual time

machine that takes ancient Egyptian Great-Pyramids builders inside classrooms of technical schools. The

new target is to build parts of the three Pyramids in sequence. Competing team members should be accurate,

fast and cooperative. They should adhere to the main requirement of not using binding material between

blocks. The winner team is the "Robo-Pharaoh" which succeeds to finish building assigned parts of the three

Pyramids first. During three minutes, red and blue teams compete in order to mimic one of the surviving

Seven World Wonders.

1.2. ARENA SPECIFICATION

The game field consists of two Automatic Zones and a Manual Zone and three Pyramids (Khufu,

Khafraa and Mankaura).

Automatic Zone #1 is the area surrounding Khafraa Pyramid.

Automatic Zone #2 is the area surrounding Mankaura Pyramid.

Figure 1.3: Game Field General View Structure and Specifications


Figure 1.4: Game Field Detailed Dimensions

The shape and dimensions of the game field are shown in Figure 4. A wooden fence of 100 mm

height and 30 mm wide surrounds Automatic Zone #1, Automatic Zone #2, and Manual Zones.

However, the width of the fence, marked F and G, is 140 mm.

White lines are drawn on the floor of the game field. These white lines are drawn 500 mm center to

center, from the center of Khafraa Pyramid and Mankaura Pyramid respectively as shown in Figure

3. Each white line is 50mm wide.

Automatic Zones

The Automatic Zones are divided into two exclusive plateaus. Each plateau is divided into

twosections, one for the red team and the other for the blue team. A wooden fence, of 100 mm

height and 30 mm wide, separates the two sections.

The Automatic Zones (1st Plateau: Khufu and Khafraa Pyramids) contain four Start Zones and two

Stock Zones for the automatic units; namely (RA1, RA2, SRA1/2) for the red team and (BA1,

BA2,SBA1/2) for the blue team.

The Automatic Zones (2nd Plateau: Mankaura Pyramid) contains two Start Zones and two Stock

Zones for the automatic units: (RA3, SRA3) for the red team and (BA3, SBA3) for the blue team.

Each team is free to decide how to arrange the blocks in its stock zones.


(i)Start Zones;

The dimensions of the Start Zones are shown in Figure 1.4.

The floor surface is red with RGB (255, 0, 0) for the red team and blue RGB (0, 0, 255) for the blue

team.

The floor surface of the start zone is considered as part of automatic zones.

(ii)Stock Zones;

The dimensions of the Stock Zones are shown in Figure 1.4.

The floor surface is red with RGB (255, 0, 0) for the red team and blue RGB (0, 0, 255) for the blue

team.

The floor surface of the stock zones is considered as part of automatic zones.

The stock zones has respectively for each team:

(seven+2=9) blocks for Khafraa

(one+1=2) blocks for Mankaura

(one top+1=2) Golden blocks for each Pyramid.

Each team decides the arrangement of the blocks left in the Stock Zone once they preload some

blocks on their robots.

Automatic Zones Colors: The field surface color is green with RGB (0, 255, 0) with white lines of

50 mm width.

Manual Zone

The field surface color has an RGB (255,192,192) for the red team and has an RGB (192,192, 255)

for the blue team

(i)Start Zones;

The Start Zone and its dimensions are shown in Figure 1.3 and Figure 1.4.

The colors of the Starting Area are red with RGB (255, 0, 0) for the red team and blue with RGB (0,

0, 255) for the blue team.

(ii) Stock Zones;

There are two manual stock zones, one for each team.

Each stock zone has (seven+2=9) blocks and (one top +1=2) golden blocks.


Figure 1.5: Competition Game Field

Specifications of the Pyramids Blocks

Organizers provided samples of prefixed Pyramids' blocks whose specifications are given in Figure

1.6 with RGB (255, 210, 110) of all sides.

Figure 1.6: Specifications of Fixed Blocks

Guidance rigid bars of 18 mm diameter are fixed in the base with the appropriate heights (300 mm,

600 mm, and 900 mm). The blocks are assembled through the holes in these bars.

Organizer fixed the required axe for the Top Golden block on top of all prefixed blocks. Its

specifications are given in Figure 1.7. The bottom plate of the guidance pin (2 mm Thickness) may

be of steel and can be welded and/or glued to the prefixed blocks.


Figure 1.7: Specifications of the Bottom Plate of the Golden Block

Organizers prepared necessary building blocks to be used by the robots with the specifications given

in Figure 1.8.

.

Figure 1.8: Specifications of Main Block


The Top Golden block was provided by the organizer (Figure 1.9).

Figure 1.9: Specifications of Golden Block

All blocks are similar in dimensions and weight.

The blocks are made of foam polystyrene. Each block weighs 750 gm approximately. The organizer

shall provide a sample of the building block.

1.3. GAME PROCEDURE

(i) Duration of a match

Each match lasts 3 minutes.

In the following cases, a match ends even before the passage of 3 minutes.

When the task is achieved.

In the event of disqualification.

When the referees judge that continuation of the match is impossible.

(ii)Match division

Each match is divided into three phases.

A manual unit can be preloaded (before game start) with 4 blocks at maximum.

An automatic unit can be preloaded (before game start) with any arbitrary number of blocks.

Each phase is dedicated to build a Pyramid.


Only one manual unit should be used.

The number of automatic units should be one to three units.

The first phase is to build parts in Khufu Pyramid by the Manual Robot only. The second phase is to

build parts in Khafraa Pyramid by one or two Automatic Robots. The third phase is to build parts in

Mankaura Pyramid by one Automatic Robot. The following Table shows the three phases and

assigned durations.

Phase 1

Phase 2

Phase 3

Pyramid Khufu Khafraa Mankaura

Duration (Seconds) 90 60 30

(iii)Setting of robots

Two minutes are provided for setting of all robots before the start of each match. This includes

preloading and arranging blocks in the stock zone.

Three members of each team may engage in setting of robots.

A team who fails to complete setting of robots in two minutes shall be able to resume the setting

work once the match has begun.

(iv) During a Match

One team member is responsible of starting and operating the Manual Robot.

The operator of the Manual Robot should move freely in the Manual Area with a controller in the

hands during building Khufu.

The operator of the Manual Robot should leave the Game Area after turning-off and parking the

Manual Robot anywhere in the Manual zone.

If two Automatic Robots are used (For Khafraa construction), they should be started manually at or

after the assigned start timing to build Khafraa (the Second Pyramid).

If two Automatic Robots are used (For Khafraa construction), they should power-off manually at or

slightly after the ending beep.

After switching the robot on, the team member who performs the starting operation shall

immediately leave the Game Field.

The Automatic Robot, that builds Mankaura Pyramid, can be loaded and started manually or

autonomously.

Correct positioning of blocks (see Figure 1.10) in different layers was judged by the referees

according to the following:


Figure 1.10: Prefixed Blocks and Complete Pyramids

For all layers, the maximum allowable tolerance was 25 mm in the horizontal plane. No tolerance

was allowed in any other plane.

For a normal block: in case of exceeding the maximum allowable tolerance, no points would have

been given.

For the Top Golden Block: in case of exceeding the maximum allowable tolerance, only 50% of its

assigned points would have been given.

No points would have been given to any non-horizontal block, including the Top Golden Block.

(v) Retries of Robots

In the case of faulty Automatic Robot movements, it was possible to start again (Retry) with the

referees permission.

Team members are permitted to move a Robot to its start zone while preparing for a Retry.

It is not permitted to load an Automatic Robot with any new blocks.

At the time of the Retry, team members shall switch the robot on to start it. After switching the

robot on, the team member who performs the starting operation shall immediately leave the Game

Field.


Retries can be made as many times as necessary.

Strategies premised on the use of Retries are banned.

1.4. SCORING

The team who places the three Golden Top Blocks of the three Pyramids in the correct directions

first is the winner. This terminates immediately the game if all blocks are in their correct positions

and/or within the allowed tolerance. This typical winner will be declared as Robo-Pharaoh (Figure

12).

If neither team has placed the three Golden Top Blocks of the three Pyramids at the end of the 3

minutes match, the winner shall be whoever has more points than the other according to the

following:

Khufu Pyramid (22 points)

1 point for a block in the 1st middle layer.

2 points for a block in the 2nd middle layer.

3 points for a block in the 3rd middle layer.

10 points for the Golden Top Block.

Khafraa Pyramid (44 points)

2 points for a block in the 1st middle layer.

4 points for a block in the 2nd middle layer.

6 points for a block in the 3rd middle layer.


Mankaura Pyramid (12 points)

2 points for a block in the middle layer.


The match result will be announced at the end of the 3 minutes as follows:

The total number of points (score) gained by each team will be announced after deduction

of any violation acts.

The team declared "Robo-Pharaoh" will be attributed 30 points over i.e. of a maximum

score of`108 points.

The winner is the team having the higher score.


1.5. ROBOT SPECIFICATION

Each team should use one Manual Robot and 1 to 3 Automatic Robots.

The robots must not be divided into sub-units.

Communication between the Automatic Robots is allowed.

The robots used in the contest must be made by students of the university.

(i)Automatic Robots

The Automatic Robots shall move automatically once it has been started within one phase.

At the beginning of the game, in the start zone, the dimensions of the Automatic Robot including the

preloaded blocks should not exceed 1,000 mm (long) x 1,000 mm (wide) x 1,500 mm (height).There

was no size limitation after starting the game.

(ii)Manual Robot

The Manual Robot can be operated by means of a cable connection or by remote control using

infrared, visible rays or sound waves. Wireless radio control was not permitted. The operator was

not permitted to ride on the Manual Robot.

In the case of cable operation, the cable connecting the Manual Robot and the controller should be at

least 1,000 mm and not more than 3,000 mm long. The cable should be connected to the robot at

aheight of not less than 1,000 mm above the floor surface of the Field.

The dimensions of the Manual Robot was not allowed to exceed 1,000 mm (long) x 1,000 mm

(wide) x 1,500 mm (height) in the start zone. A robot should be capable of stretching its arms and

other parts within the range delimited by a circle that is 2,000 mm in diameter as viewed from

above.

(iii)Weight of the robots

The combined weight of all of a team’s robots and other devices to be used in the entire contest,

including the power source, cables, controllers, and other equipment, should not exceed 50 kg. The

weight of back-up batteries of the same type, weight and voltage as the primary batteries was,

however, exempted from this rule.

(iv)Power sources for the robots

Each team must prepare the power sources for the robots.

The voltage of the power source used by each robot should not exceed DC24V.

Any power source deemed dangerous or inappropriate by the organizer may not be used.


(v)Detailed rules of safety

The use of explosives, fire and dangerous chemicals was prohibited.

If a laser was used, it shall be of Class 2 or less. In designing and preparing the laser, full care must

be taken to protect all persons at the venue from harm during all procedures. In particular, the

beams must be so oriented that they cannot shine into the eyes of the spectators.

Participating robots was checked and tested, according to the ROBOCON 2010 rule book, the day

before the contest. They were checked again before starting the matches. Passing this check test was

a necessary condition to allow the robot to participate in the contest. In the other case, the robot was

not allowed to participate in the contest.

1.6 RULES

(i) Violations

If a violation occurs, two points would have been deducted as a result of such violation. The following cases

were considered violations:

Intentional obstruction over the top plate was not permitted.

Any part of either the robot or its operator enters onto the zone of the opposing team or into the

space above it except while placing the Gold Top Block.

Manual Robot should not enter the Automatic Zone and the space above it except while placing

blocks on the Khufu Pyramid.

Other actions that infringe on the rules without producing disqualification.

(ii) Disqualification

A team could be disqualified if it committed any of the following during the match:

The team damages or tries to damage the Game Field, and/or facilities and equipment of opponent’s

robots.

Either the teams' robots or their operators crossed the outer boundary of their Game Field on ground

or in air.

The team had made a false start twice in the same match.

The team performs any act that was not in the spirit of fair play.

The team fails to obey instructions and/or warnings issued by the referees.

Three violations were considered as disqualifications


2. CONSTRUCTION

2.1. MANUAL ROBOT

2.1.1 Structural Components The manual robot made by the Team ROBOCON, NIT Durgapur can be divide into 4 basic sub-assemblies:

1) Cage Sub-assembly

2) Base Sub-assembly

3) Arms Sub-assembly

4) Accessories

CAGE SUB-ASSEMBLY The Cage was made using L-shaped Aluminium Sections. One section was 40cm long and the other 145cm

Figure 2.1.1

long. There were Four sections of each type and all were joined with Screws and nuts as shown below, to

create a cage like structure a shown above.


Figure 2.1.2

Pulleys were mounted on the cage to enable the arm sub-assembly to move in Vertical direction.

Figure 2.1.3 Figure 2.1.4

The pulley is shown in Figure 2.1.3. And their mounting on the cage is shown in Figure 2.1.4.


BASE SUB-ASSEMBLY The base was made of Iron metal and was of dimension 90cm*90cm*25cm. It had mounting for four

driving motors which were then fixed with wheels as shown in Figure 2.1.6.


A High torque motor of 20 kgf was fixed to the base to drive the pulley system.

Figure 2.1.7

Sections were fixed on the base to mount the cage on the structure as shown.


Figure 2.1.8

ARM SUB-ASSEMBLY The arm sub-assembly consisted of a base and two arms , with each arm containing a high torque(20 kgf)

motor at its end (Figure 2.1.9).

Figure 2.1.9


Then each motor was fixed with a rod. The left rod was 40cm long where as the right rod was 80 cm

long(Figure 2.1.10).

Figure 2.1.10

The left arm was provided with a slider(Figure 2.1.11) and a rack and pinion arrangement (Figure 2.1.14).

Figure 2.1.11(a) Figure 2.1.11(b) Figure 2.1.11(c)


The rack and pinion when fixed with a 10 rpm (Figure 2.1.13) motor enabled the left arm to move along a

normal line joining the two high Torque motors.

Figure 2.1.12



ACCESSORIES

The accessories include the screws, nuts, rivets and fasteners used for making the joints.


Mainly three types of motors were used. The driving motors were encoder motors of 200 rpm (Figure

2.1.17). The high torque motors of 20kgf (Figure 2.1.18) were used for lofting the arm sub-assembly and for

actuating the rods connected to the arms. The 10 rpm motors(Figure 2.1.13) actuated the rack and pinion

arrangement.

Figure 2.1.17 Figure 2.1.18(b)

Figure 2.1.18(b)


There was a pulley system which enabled vertical motion of the arm sub assembly inside the cage.

Figure 2.1.19 Figure 2.1.20(b)

Figure 2.1.19 represent the pulleys attached to the cage top and Figure 2.1.20 represent the pulley attached

to the high torque motor mounted on the base which actuated the whole pulley system.

The electric circuitry and the Sony Play Station 2 Controller(Figure 2.1.21) (used as controller of the manual

robot) also are considered accessories but there details are not mentioned here.

Figure 2.1.21

Figure 2.1.20(b)


2.1.2 Assembling the Robot

Figure 2.1.22

Figure 2.1.23


AUTONOMOUS ROBOTS

2.2. AUTO1

2.2.1 Structural Components The Autonomous robot AUTO1 can be divide into 3 basic sub-assemblies:

1) Platform Sub-assembly


3) Accessories

BASE SUB-ASSEMBLY The base frame was made up of aluminium L sections (1.5” X1.5”), riveted together.

Figure 2.2.1: Base

PLATFORM SUB-ASSEMBLY

AUTO1 robot had to build pyramid having 4 layers. Our strategy was to push blocks over the rolling

platforms and to place the blocks.

Platforms were made up of aluminium L section (1.5”X1”) and channels riveted together

o Chain drive was used in platforms to unload the blocks.

o Thrust bearings were used for rotational degree of freedom of the rotating pipes at the front of each

platform.


o Telescopic channels were used to move the platform linearly for proper positioning of blocks.

o The platforms were supported by heavy aluminium sections attached to the base.

Figure 2.2.2: Lower platform

Figure 2.2.3: Middle platform


Figure 2.2.4: Upper Platform

2.2.2 Assembling the Robot After assembling the structure, robot looked like as below.

Figure 2.2.5


Figure 2.2.6


2.3. AUTO3

2.3.1 Structural Components The Autonomous robot AUTO3 can be divide into 3 basic sub-assemblies:


2) Forebar Mechanism

3) Accessories

BASE SUB-ASSEMBLY

The base frame was made up of aluminium L sections (1.5” X1.5”), riveted together.

A bidirectional chain drive mechanism was fitted in the middle section of the base for placing the square

block in the first layer.

FOREBAR MECHANISM

The Forebar mechanism was implemented for placing the golden block on the top layer.

The forebar was made up of aluminium U and □ sections.

It was mounted on the base frame by an aluminium star section.

It was spring loaded and thus retained its initial lowered position by spring action.

2.3.2 Assembling the Robot


3. AUTOMATION

3.1 Manual Robot

The Manual robot was semi-autonomous. It was

controlled by a human operator and was autonomous in

speed control of driving motors. The operator controlled

the robot through a standard PS2 Gamepad interfaced to

an Atmega16 microcontroller.

3.1.1 Electronic Components Used in Manual Robot :-

1. PS2 Gamepad i. It’s easy to interface with MCUs.

ii. It facilitates more decisive functions using key combinations.

iii. The Analog stick is easy to use and provides better maneuverability.

2. Atmega32 AVR series microcontroller

i. Advanced RISC architecture.

ii. Fast Performance. Up to 16 MIPS throughput.

iii. Integrated peripherals like ADC and PWM channels. ADC is required for

joystick control. The programmable PWM channel can be used to run the

driving motors directly.

iv. Less programming overhead.

3. Hercules 16V, 30Amp Motor Driver

i. Operating voltage: 6V to 36V

ii. Output current 30A peak(15Amp nominal)

iii. PWM operations up to 20 KHz

iv. Current Sense output

v. Over voltage and under voltage shutdown

vi. Thermal shutdown

vii. Protection against loss of GND and Vcc.

viii. MOSFET based reverse polarity protection


3.1.2 Interfacing PS2 Gamepad

The PS2 console gamepad has 9 wires- 5 communication lines, VCC,

GND, vibration motor power, and a reserved line for future use.

PS2 Socket

Pin Color Name Description

1 Brown DATA Data: This is the signal from controller to host. It is an 8-bit serial transmission synchronous to

the falling edge of the clock.

2 Orange CMD Command: This is the signal from the host to the controller. Again, it is an 8-bit serial

transmission on the falling edge of the clock.

3 Grey 7.6V Vibration Motors Power: 6-9V.

4 Black GND Ground

5 Red VCC Variable power from 5 V down to 3V.

6 Yellow ATT Attention: This signal is used to get the attention of the controller. This signal will go low for the

duration of a transmission.

7 Blue CLK Clock: 500kH/z. The communication appears to be SPI bus.

8 White NC Not Connected. Reserved for future use.

9 Green ACK Acknowledge: This signal is low for at least one clock period after each 8 bits are sent and ATT is

still low.

Transmission Protocol

The PlayStation controller communicates with the host MCU via SPI protocol. All transmissions are 8-bit serial LSB

first synchronous to the falling edge of the clock. In fact, it behaves like a big shift register. So, it transmits and

receives data at the same time. That means, even to read the controller data you need to send some dummy bytes.

Command Listing:

0x42: Main polling command

This command gets all the digital and analog button states. When the host MCU wants to read controller data it

pulls the ATT line low and issues a start command (0x01). The controller will then reply with its Type ID

(0x41=Digital, 0x73=Analog). At the same time as the controller is sending this ID byte the host is transmitting get

data (0x42). Following this the CMD line goes idle and the controller transmits ready (0x5A) followed by 2 (digital

mode) or 6 bytes (analog mode) data.


0x43: Enter / Exit Config Mode

This can poll the controller like 0x42, but if the first command byte is 0x01, it has the effect of entering config mode

(0xF3), in which the packet response can be configured.

PS2 Controller Data bytes

0x44: Switch modes between digital and analog

Only works after the controller is in config mode (0xF3).

Set analog mode: Command Byte 4 = 0x01

Set digital mode: Command Byte 4 = 0x00

If Command Byte 5 is 0x03, the controller mode is locked.


Autonomous Robots

The problem statement for RoboCon 2010 required two pyramids (Khafraa and Mankaura)

to be built in coordination by two or three autonomous robots. We had initially built three

autonomous robots- Auto1 and Auto2 for the Khafraa pyramid and Auto3 for Mankaura

pyramid. However, due to weight and dimensional constraints, we had to replace Auto2 for

a golden block placing mechanism on Auto1.

3.2 AUTO1 (Khaafra Pyramid)

3.2.1 Basic Techniques and Game Plan

1. Grid Navigation Algorithm: The grid navigation algorithm was based on the popular PID line following algorithm

coupled with junction counting. We implemented the basic differential drive system since it’s the easiest to

implement and control with PID. We used 7 optical sensors for line following and 2 sensors were fitted on the

extreme left and right ends of the sensor panel for junction counting. Turns were timed by delays and sensor

inputs from the same sensors used for junction counting.

AUTO1 Sensor Panel

Since the direction of unloading the blocks and that of driving the base were not same, the path for Auto1 was

dependent on the allotted team or color for the match.

AUTO1 Paths


2. Block Unload Sequence: Once the robot was

successfully navigated to its unloading position, the

block unload sequence will initiate the chain drive of

the lowest platform. Following this the robot will

have to move forward by a distance of half the grid

square in order to place the next layer in position.

This movement was synchronized by a 10th optical

sensor fitted at suitable distance from the end.

Following the unload of the middle layer, the middle

platform will slide forward to push the blocks in by

the required distance. The same will be repeated for

the top layer. We used bump sensors to detect

termination of chain drive and platform slide

processes.

AUTO1

AUTO1 Platforms


3.2.2 Electronic Components Used in AUTO 1 :-

1. PIC18F4550: Locomotion control unit. This unit was responsible for the grid

navigation.

2. PIC16F8770: Actuation Sequence Control unit. This unit was responsible for

the actuation of chain drive systems and the sliding of the upper platforms.

3. Optical Sensors: 10 optical sensors with 12V analog output were

suitably placed for robot localization.

4. Bump Sensors: 5 bump sensors were suitably placed to detect

termination of chain drive and platform slider processes.

5. Actuation Motors:

5 12V 100 RPM DC geared motors for chain drive actuation.

2 12V 60 RPM DC geared motors for platform slider actuation.

We used CMOS motor drivers with a suitable current rating that was

sufficient to drive the actuation motors.

6. Driving Motors: 2 12V 100 RPM high torque DC motors with

quadrature incremental hall effect encoders were driven by Herculean

motor drivers to suit the high current and power rating.

7. Tap Switches: 2 tap switches for team select operation. Our game plan

had team dependent paths.

8. Power Supply: 12V 7.2 AH rechargeable Lead Acid Battery.


Why PIC18F4550 ??

i. Pin-to-pin compatible with PIC16F8770. ii. Larger Memory Space- Flash Memory 32K, SRAM 2048 bytes EEPROM 256 bytes.

iii. USB V2.0 Compliant. iv. Four Crystal modes, including High-Precision PLL for USB. v. Integrated 10-bit, Up to 13-Channel ADC module with Programmable Acquisition Time.

vi. C Compiler Optimized Architecture with Optional Extended Instruction Set. vii. Easy availability due to commercial and industrial applications.

Why PIC16F8770 ??

i. High performance RISC CPU ii. Operating speed: 20 MHz

iii. Up to 8K x 14 FLASH Program Memory, 368 byts Data Memory (RAM), 256 bytes EEPROM iv. Upto 14 External Interrupt sources v. Selectable oscillator options

vi. Wide operating voltage range: 2.0V to 5.5V vii. Low-power consumption

viii. Integrated peripherals like 8-bit/16-bit Timer/Counter, Capture and 10-bit PWM modules ix. Easy availability due to commercial and industrial applications.

3.3 AUTO3 (Mankaura Pyramid)

3.3.1 Basic Techniques and Game Plan

1. Grid Navigation Algorithm: The Grid navigation algorithm for Auto3 was based on a timed combination of lane

and line following. The lane following was achieved by simple bang-bang line avoiding while the line following

was achieved by the PID algorithm. We used 3 optical sensors for line following and 2 sensors were fitted on the

extreme left and right ends of the sensor panel for lane following.

AUTO3 Sensor Panel

The robot was to follow the lane as shown, unload the preloaded block and return by the same lane until it

bumped with the arena back wall, then turn and lift the golden top block, follow the line and place it over the

plate. We translated the whole grid navigation through a sequence of bumps. The paths for the two teams or

colors were exactly anti-symmetric.


AUTO3 Paths

2. Block Unload Sequence: The square block was to be unloaded by an actuated chain drive system. We

implemented an actuated forebar mechanism to lift and place the golden top block.

AUTO3 Forebar Mechanism AUTO3 Chain Mechanism

AUTO3


3.3.2 Electronic Components Used in AUTO 3 :-

1. PIC16F8770: This controller unit was responsible for navigation &

actuation of chain drive system and the fore bar mechanism.

2. Optical Sensors: 5 optical sensors with 12V analog output were suitably

placed for robot localization.

3. Bump Sensors: 4 bump sensors were suitably placed for robot localization

and to detect termination of chain drive process.

4. Actuation Motors:

One 12V 100 RPM DC geared motors for chain drive actuation.

One 12V 60 RPM DC geared motors for fore bar mechanism.

We used CMOS motor drivers with a suitable current rating that was sufficient

to drive the actuation motors.

5. Driving Motors: 2 12V 120 RPM high torque DC motors were driven by

CMOS motor drivers to suit the high current and power rating.

6. Tap Switches: 2 tap switches for team select operation.

7. Power Supply: 12V 7.2 AH rechargeable Lead Acid Battery.


GANTT CHART

Task Start End date Duration

SANCTION OF BUDGET AND MODELLING OF ROBOT 11/3/2009 12/18/2009 45

CONSTRUCTION OF MANUAL ROBOT 11/3/2009 12/23/2009 50

MANUAL ROBOT REMOTE 11/13/2009 12/4/2009 21

AUTONOMOUS MODELLING 12/16/2009 12/26/2009 10

CONSTRUCTION OF AUTO1 (STRUCTURE) 12/29/2009 1/8/2010 10

COMPLETION OF AUTO1 12/13/2009 1/10/2010 28

CONSTRUCTION OF AUTO3 (STRUCTURE) 12/21/2009 12/31/2009 10

COMPLETION OF AUTO3 12/31/2009 1/30/2010 30

PRACTICE AND TROUBLESHOOTING 2/3/2010 3/5/2010 30


EXPENDITURE

Hardware

Plywood

Aluminium Sections

Chains

Racks & Pinions

Structural components

21,508.00

Electronics

Driving Motors

High Torque Motors

Motor Drivers

Sensors

MCU Boards

Accessories

154,716.41

Travel & Transport

Travel Expenses

Robot Packaging &

Transportation 22,985.00

Others

Practice Arena

ROBOCON Registration

Additional Services

27,061.00

Total 226,270.41


LESSONS

Though the team tried to approach the problem in the most fault proof and efficient

way, there remained certain points overlooked or neglected. The team takes these as a

lesson for the future and considers a rethink.

1. Power Source: We used Lithium Ion cells as power source instead of Lead Acid

Rechargeable cells as planned. They discharged too quickly and were the primary

reason for our elimination.

2. Electronic Circuits: The interfacing circuits were all soldered by hand. They were

not very durable and 'clean'. Troubleshooting was difficult and often the circuits

behaved incorrectly. We plan to design and manufacture custom PCBs from now

on.

3. Design Issues: Though our design was stable and efficient, the construction was not

well monitored. As a result, we were forced to make last minute changes to fit to

the weight constraints. We plan for a well monitored and measured approach from

now on.

4. Transporting the Robots: We dismantled the robots completely for transporting

them to the competition venue. Though the robots were designed in such a way to

support quick dismantling and re-assembling, but it posed a huge overhead of

almost rebuilding everything and cost valuable time. We plan to transport the

complete assembled robots.


CONCLUSION

ROBOCON sets an international platform for the robotics enthusiasts to enhance their technical skills and knowledge. Although the team's work was for the particular competition, tackling the competition specific problem undoubtedly had an impact on the overall technical knowledge. Applying the ideas and materializing the designs right from the scratch enhanced the hands-on experience of the members. Working out different approaches and analyzing the performance helped understand the actual dynamics and to build in-depth understanding. Building Robots enhanced our technical knowledge and skills as well as taught us team work and professionalism.

It's a matter of immense pride to participate in such a competition. This technical carnival was an enjoyable learning experience for the entire team. Apart from participation at the prestigious ROBOCON India, annual national level Robotic Contest, we presented our works to the public during many technical fests, seminars, meets and other events thus contributing to the overall learning process and technical awareness of the institution and other nearby colleges. The team looks forward to continue its participation in ROBOCON every year and indulge in research for better robot designs, efficient mechanisms and automation algorithms. The team also plans to share its experience and knowledge in the future through workshops, orientation programs and similar public interactions.


PHOTO GALLERY

With Anirudhdha Chandra Sir at Team Robocon work site.

Match 1 against IIT Chennai. Defeated 3-1.


Match 2 against IMT Ghaziabad. Won 9-0.

Team Robocon, NIT Durgapur at Balewari Indoor Stadium, site for ROBOCON INDIA 2010.

Documents

Robocon 2010 Report