Difference between revisions of "Talk:RunBot: a Robogame Robot"

Revision as of 12:20, 16 June 2010

Requirements

The robot should have:

• a dimension of about 25cm of radius, 20 cm height
• a speed of about 1 m/sec
• omnidirectional movement (Kamro wheels)
• sensors to avoid obstacles (sonars)
• a camera that can be moved up and down (and eventually left and right)
• wireless connection to a computer (Wi-fi)
• Bluetooth connection
• have power enough to move and transmit for at least 2 hours without recharging
• Have the possibility to recharge autonomously

The robot should cost as less as possible

File with considerations on parts to be ordered

TO DO

• Select HW

 ** ST ARM HW (ask Martino Migliavacca <martino.migliavacca@gmail.com>, GUMSTIX (http://www.gumstix.org/), ARDUINO (http://www.freeduino.org/), other...)
 ** Engines (WWW.robot-Italy.com, http://www.jonathan.it/)
 ** batteries (above, or standard A, AA or AAA type)
 ** Camera (ST smart cameras, with Ethernet wired link)
 ** Sonar (already available (see ROBOWII2.0))
 ** Blue tooth and WI-FI

• Design body (structure and appearance), sensor placement, eventual movements of the camera
• Implement the robot
• test the robot with a simple game (e.g. RoboWII2.0)

Design of The Robot

Mice

The results obtained so far with that setup is in the pdf file below.
The results obtained so far

Camera (Will be updated soon)

Motion Control

The angle between each wheel is 2*pi/3, which 120 degree.
The front wheels are making a pi/6 angle between the ground.
The positions of the wheels in the coordinate system is as follows.
Wheel 1 is (cos(pi/6),sin(pi/6)) = (0.866,0.5)
Wheel 2 is (cos(pi/6),sin(pi/6)) = (0.866,0.5)
Wheel 3 is (cos(3*pi/2),sin(3*pi/2))=(0,-1)

I wrote simulations in matlab, in two ways.
The first one is using the TriskarOdometry directly, and estimates the necessary wheel speeds to reach the desired frontal, lateral and angular speed of the robot.
The second one is instead giving the motor speeds in terms of rotations and estimates the frontal ,lateral ,angular speed of the robot according to motor speeds.

The matlab code for the motion control simulation is consist of the following files:

-motor_speed.m --This file which takes the motor speed as input and calculates the Vf,Vl,w of the robot.
-TriskarOdometry.m --Giving the input Vf,Vl,w calculates the motor speed
-trajectory.m --The function which draws some trajectories based on the following schema

1) DIRECT MOVEMENT
THE HEAD OF THE ROBOT ALWAYS LOOKING IN A FIXED DIRECTION
2) ANGULAR MOVEMENT
THE ROBOT WILL MOVE IN A CIRCULAR TRAJECTORY WITH FIXED HEAD
DIRECTION
3) SPIN & GO
THE ROBOT EITHER GOES ANGULAR BUT THE HEAD POSITION
IS ALSO CHANGES
4) SPIN & GO DIRECT
THE ROBOT EITHER GOES DIRECT BUT THE HEAD POSITION
IS ALSO CHANGES

-direc_motion.m --DIRECT MOVEMENT
-angular_motion.m --ANGULAR MOVEMENT
-spin_go.m -- SPIN & GO
-spin_go_d.m --SPIN & GO DIRECT
-draw_arrow.m --A function that is used to draw arrow.
File with the matlab files listed above.

Processor Comparison

This is the processor comparison table, the cells without entry is left blank

Motor Suggestion

http://www.pololu.com/catalog/product/1092

no load speed: 500 rpm stall torque: 29 kg-cm ~= 0.282 Nm

maximum power output = Pmax = 26.190 rad/s * 0.141 Nm = 3.692 W occuring at W= 250 rpm and t=0.141 Nm

http://www.pololu.com/catalog/product/1085/

no load speed: 470 rpm stall torque : 7 oz ( 0.5 kg-cm ) ~= 0.049 Nm

maximum power output = Pmax = 24.619 rad/s * 0.0245 Nm = 0.603 W occuring at W=235 rpm and t = 0.0245 Nm

calculations made according to the reference paper at the link http://lancet.mit.edu/motors/motors3.html http://lancet.mit.edu/motors/motors4.html

Wheel Specification

2052-3/8X CAT-TRAK

Description

• Standard 2" O.D. - 3/8" Bore Double Row
• Metric 49.2mm O.D. - 9.5mm Plain Bore.
• Recommended max load.
  • Steel Bottom = 25 lbs. 11.3kg.
  • Plywood Surface = 15 lbs. 6.8kg.
• 200# Test Corrugated Bottom = 10 lbs. 4.5kg.
• Weight = 1.75 oz.
• Synthetic rubber coated polypropylene rollers.
• Price:$7.48.
• Source: http://store.kornylak.com/ProductDetails.asp?ProductCode=FXA314

2052BX CAT-TRAK

Description

• Standard 2" O.D. - 1/4" I.D. Bushing Double Row
• Metric 49.2mm O.D. - 6.35mm Bushing
• Recommended max load
  • Steel Bottom = 25 lbs. 11.3kg
  • Plywood Surface = 15 lbs. 6.8kg
• 200# Test Corrugated Bottom = 10 lbs. 4.5kg
• Weight = 1.75 oz
• Synthetic rubber coated polypropylene rollers.
• Price :$7.48
• Source: http://store.kornylak.com/ProductDetails.asp?ProductCode=FXA317

2052KX CAT-TRAK

Description

• Standard 2" O.D. - 1/2" Bore Double Row w/ Keyway
• Metric 49.2mm O.D. - 12.7mm Bore w/ Keyway
• Recommended max load
  • Steel Bottom = 25 lbs. 11.3kg
  • Plywood Surface = 15 lbs. 6.8kg
• 200# Test Corrugated Bottom = 10 lbs. 4.5kg
• Weight = 1.75 oz
• Synthetic rubber coated polypropylene rollers.
• Price :$7.48
• Source: http://store.kornylak.com/ProductDetails.asp?ProductCode=FXA315