Chief Delphi - Autonomous Perception

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Chief Delphi (http://www.chiefdelphi.com/forums/index.php)

- Programming (http://www.chiefdelphi.com/forums/forumdisplay.php?f=51)

- - Autonomous Perception (http://www.chiefdelphi.com/forums/showthread.php?t=85072)

kamocat

08-04-2010 15:55

Autonomous Perception

With the goal of making a robot fully autonomous:

What information would be useful to a robot during autonomous?

How can that information be measured or acquired?

kamocat

08-04-2010 15:56

Re: Autonomous Perception

Some things a robot might want to know are:

Where am I on the field?
Where are the robots around me? (what alliance are they?)
Where are the balls around me? (on the floor, presumably)
Where are the goals? The bumps? The towers? The walls?
Have I flipped over?
What are the other robots doing? Do they need help? (Inter-robot communication)

kamocat

08-04-2010 15:59

Re: Autonomous Perception

Quote:

Originally Posted by kamocat (Post 950214)

Some things a robot might want to know are:

Where am I on the field?
Where are the robots around me? (what alliance are they?)
Where are the balls around me? (on the floor, presumably)
Where are the goals? The bumps? The towers? The walls?
Have I flipped over?
What are the other robots doing? Do they need help? (Inter-robot communication)

I've copied this message from http://www.chiefdelphi.com/forums/sh...t=84797&page=3

Quote:

Originally Posted by biojae (Post 949606)

This is where the GDC may play nice again, and bring back something like the 2 freq. IR beacons.
But, even if they don't there are simple ways for determining where you are on a field using encoders (Assuming the wheels don't slip. Hard for last year).

Using kinematic formulas:

Code:

S = (Delta Left + Delta Right) / 2

Delta Theta = (Delta left - Delta right) / wheelbase

Theta = Theta + Delta Theta

X = X + (S * cosine ( Theta ) )

Y = Y + (S * sine    ( Theta ) )

This satisfies one item on the list, but only slightly.

As far as knowing where other robots are, that would need a lot of DSP, or an external observer telling the bots where they are, or all bots to communicate with each other

billbo911

08-04-2010 16:07

Re: Autonomous Perception

Continuing:

Q1) What direction am I heading.
Q2) How far have I traveled.
Q3) How fast am I moving.
Q4) Am I turning.
Q5) How fast am I turning.
Q6) Can I visualize my objective.

To answer some of these question:

A1) Read from a Gyro or Compass.
A2) Read from an Encoder.
A3) Read rate from an Encoder.
A4) Read from a Gyro or compass and compare to a previous reading.
A5) See answer "A4" and divide by time between measurements.
A6) Use camera and analyze the image.

kamocat

08-04-2010 16:13

Re: Autonomous Perception

Did I run into something? (limit switches on bumper?)
Am I going to run into something? (sonar? Infrared? Something else?)

kamocat

08-04-2010 18:01

Re: Autonomous Perception

Here's a clarified list of things that need to be measured for field-awareness, based on the Autonomous Planning discussion.

What region of the field am I in?
How available are the gamepieces?
What is the current score?
Are there any 'bots blocking me?
Are there any 'bot helping me?

(1)"region of the field" has been pretty much covered: track your location with the gyro and encoders. However, there's still a high possibility that this would get thrown off when a robot goes over a bump. Is there a way to compensate?

(2)"where are the game pieces" could probably be done with a camera. Is there a faster or more efficient way to find soccer balls?

(3) "what's the current score?" The camera has been brought up as a method of reading the scores off of the screen. I think that would be extremely difficult (due to lack of testing) to have working at competition. Would this information have to be supplied by the drivers?

(4 -5)"Finding nearby 'bots". This year, the bumpers were the key to determining a robot and their alliance. I'm still reluctant to use the camera for that, but I wonder about the possibility of a directional color sensor. I2C would probably be ideal, since it won't take up analog channels, and therefore several could be used for each side of the 'bot.

Robototes2412

08-04-2010 22:33

Re: Autonomous Perception

actually, this would be a good use for an arduino board, communicating with the cRIO over serial.

the arduino would have a camera hooked up to the analog inputs, running a sketch that looks for either red or blue, depending on what the cRIO passes to the arduino.

davidthefat

08-04-2010 22:44

Re: Autonomous Perception

I am not trusting any 8 bit micro controllers on this project, I am going for the robot boards that are pretty much the bare minimum computer boards, 8 bit MCs do not have enough juice to process all that data for autonomous IMHO

Robototes2412

08-04-2010 22:51

Re: Autonomous Perception

it has the juice, but its not fast. if you bump the image quality down to QQVGA, it can find the blue/red bumpers in 2 seconds

davidthefat

08-04-2010 22:55

Re: Autonomous Perception

Quote:

Originally Posted by Robototes2412 (Post 950535)

it has the juice, but its not fast. if you bump the image quality down to QQVGA, it can find the blue/red bumpers in 2 seconds

Then its use less during the fast paced matches.

Robototes2412

08-04-2010 23:05

Re: Autonomous Perception

oh, yeah.

isn't there such a thing as a color sensor?

kamocat

08-04-2010 23:45

Re: Autonomous Perception

Quote:

Originally Posted by Robototes2412 (Post 950545)

oh, yeah.

isn't there such a thing as a color sensor?

I'd love for there to be an inexpensive I2C color sensor, but all the ones I can find are serial.
http://www.sparkfun.com/commerce/pro...oducts_id=8924
http://www.sparkfun.com/commerce/pro...oducts_id=8663

Robototes2412

08-04-2010 23:57

Re: Autonomous Perception

The cRIO has a serial port, as does an arduino

kamocat

09-04-2010 22:51

Re: Autonomous Perception

Wouldn't serial limit us to one color sensor? Or can multiple sensors be on the same serial line?
If we connected an arduino to a color sensor via serial, what would we use to connect the color sensor to the robot? Analog?

Could we use three phototransistors instead?

kamocat

09-04-2010 22:57

Re: Autonomous Perception

Going back to the gamepieces, is the camera really the best way of finding them?
Could a robot have "whiskers" along the sides, so it could tell if it brushed up against a ball?
For now, I'm going to ignore how much IO each sensor (or set of sensors) might require.

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