Tractorbot Bobesh Mk2

Let's Make Robots Robots
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Tractorbot Bobesh Mk2 is my second robot and it’s an upgrade of Tractorbot Mk1. It helped me to win two bronze medals this year at the national championship in electronics and radio-electronics of youth and at the Czech Robotic Day in Prague on 13th and14th June 2015 at the Ketchup House contest.

 

Functions:

  1. IR remote controlled
  2. Programmed for Ketchup House

 

Home-made robotic control board with a “dual-core processor”:


PIC18F46K22 as Master MCU

  • GLCD 128x64
  • IR-receiver for remote control systems SFH 5110-38
  • 3x IDC 10-pin connectors with 20 free I/O pins of MCU (used to connect 3 external sensor boards)
  • UART communication with Slave MCU

PIC18F46K22 as Slave/MultiServo MCU

  • 3x motor driver L293D with paralleled outputs for 3 bidirectional DC motors (max 1.2 A each)
  • 1x Motor driver ULN2803A for 2 unipolar stepper motors (0.5 A per phase each)
  • N-MOSFET IRLB8743 for speaker switching
  • Voltage divider for battery control
  • Digital ampermeter AD8219 for total current measurement
  • 2x IDC 10-pin connectors with 16 free I/O pins of MCU (used to connect 2 mechanical limit switches)

 

Motors:

  • 3 geared motors salvaged from truck windshield wipers, originally for 24 VDC

2 motors for differential drive

1 motor with a gear from HP DJ printer used for a gripper (finally not applied for collecting ketchup cans; fixed wide-open collector used instead)

  • one unipolar stepper motor from a printer (just for fun)

 

External sensors boards:

  • ultrasonic ranging module HC-SR04 for an opponent detection
  • ultrasonic ranging module US-020 for ketchup can detection (finally not used)
  • 6x reflective object sensor QRD1114 (5x black line detection + 1x optical encoder) + 2 mechanical limit switches

Power:

  • 12 V SLA battery 7 Ah for motors and a speaker
  • 7805 for MCU and sensors

Mechanical parts:

  • A frame made of PC case
  • Wheels from Merkur (Czech Meccano)

 

 

500×498

 

Robotic control board:

External sensor board:

 

 

Front view:

 

 

Top view:

Bottom view on QRD1114 external board:

 

 

Bottom view on gripper gears:

Functional scheme of the control board - Master part:

 

Functional scheme of the control board - Slave part:

469×500

Soldering scheme of the control board on universal PCB (e=0.1"):

 

Scheme of the external sensor board:

Scheme of the ultrasonic module:

396×500

 

What to improve in the next version of Tractorbot Mk3:

  1. To double battery voltage to 24 V for increasing the robot´s speed.
  2. To add an electronic compass for position control after getting lost in the playground.
  3. To improve opponent detection by moving ultrasonic ranging module.

A robot made for the Ketchup House contest for the Robotic Day 2015 in Prague with a home-made robotic control board with a “dual-core processor”.

This is a companion discussion topic for the original entry at https://community.robotshop.com/robots/show/tractorbot-bobesh-mk2
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I love the video! Tracterbot
I love the video! Tracterbot did well at collecting the cans. Maybe you need to create two bots so you can setup your own private competition (or have a friend build the other, more fun that way) so you could practice detecting opponents.

If you could use a RasPi or something similar you could use vision processing to deal with the opponents, though you’d need at least three cameras. I read the rules and it says that you can only turn on the bot after the cans are placed. However, maybe they’d let the processor and sensor be on so that you could monitor where the cans are placed. Probably not in the spirit of the competition.

If you’re using vision, maybe it could keep a camera on you and you could wear a distinctive shirt so you could give your robot hand signals! Again, probably not in the spirit of the game.

I’m wondering how a balancing robot would work (30 cm square by 1 meter tall) so you could look down on the other robot and the cans?

Or how about a robot that could collect cans in a bin of its own until very shortly before the end of the match so that the other bot couldn’t steal your cans?

Though I loved one idea of splitting up into smaller robots, but while it isn’t explicitly forbidden, they would each have to have that sticker on the top which limits the size. If you could do it, you could carpet the “store” with your robots so that the opponent would push you out of the way. In my mind not in the spirit of the competition.

I do believe in keeping to the spirit of competition but I also like thinking up ways to go around the rules. I remember one time talking to the people who were setting up a firefighting competion (candle in a maze to simulate a house). The rules were very simple. I sketched out a robot for them and one of the asked me why it was so tall and large, it would have trouble getting through the maze.

My reply was: All it needed to do is get close to the center. The top part of the robot was a container filled with water and pressurized air. When it got to the center, all the water would blow out to the sides (360 degrees) and put out the candle. The water would be shot out over the walls of the maze next to the robot so it would have a good chance of finding the candle. I thought later about having a lawnsprinkler on the top that would have shot the water more up and have a better chance of getting both the candle and the judges. :slight_smile:

After everybody laughing their heads off, they rewrote the rules a bit to outlaw that. :slight_smile:

And I like the ketchup contest better. It looked like a lot of fun.

Especially since the walls of the maze were cardboard they would have had to make a new maze.

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Computer vision for Ketchup House

Hi DangerousThing,

Thanks for your extensive comment and ideas!

In fact, I am thinking about building a new version of Tractorbot Mk4 with OpenCV computer vision on a BeagleBone Black but it will sure take me a lot of learning time so I decided to make just a few changes for Mk3 for the next year’s competitions - electronic compass, double voltage = double speed and ultrasonic sensor on a servo for better opponent detection. In Mk4, I plan to put the camera on a long selfie stick above the robot to cover the whole playground.

As for the other suggestions, I am too afraid of being disqualified from the contest and loosing a few months of work so that I will just stick to the few conventional changes. I know it is not very brave but I am only 12 and judges were very strict on me ;-D.