Storm Compass - Software

Simar Kareer, Gregory Hazen

This presentation: http://tinyurl.com/n4f3om4

Why vision?

• When it isn’t practical to do it any other way
• Shooting
• NOT GEAR(We’re stupid yes ik)
• IT SEES

Our Overview

• We do the vision processing on our raspberry pi
• We use GRIP to get contours from the vision target
• We write in python and send the data to the robot over networktables
• This determines the angle to the target, approximate distance and other things
• The Robot then moves accordingly
• https://github.com/WPIRoboticsProjects/GRIP/wiki/Running-GRIP-on-a-Raspberry-Pi-2
• https://github.com/2729StormRobotics/StormCV2017
• These are for set up

Prereqs

• Python3 on pi
• Mjpg streamer on pi
• OpenCV on pi

How to GRIP(firmly grasp it)

Ima show you

HSL>>Erode>>Dilate>>Find Contour>>Filter

tools>>export

Python

https://github.com/2729StormRobotics/StormCV2017/blob/master/GRIP-CodeGeneration/run_cv.py

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Recognizing targets

<show them runcv.py>

Finding angles (easy way)

• Find your field of view(how many degrees)
• 2*arctan(SomeObject/(2*distance))

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Angles cont...

Once you know how many angles just do a linear calculation to translate pixels to degrees

Let’s say FOV = 50 degrees and your x resolution is 320.

Then each pixel is 50/320 degrees

Turn to a specific target - ez way

if(target > centerPixel){

*turnRight*

}else{

*turnLeft*

}

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The hard, but *kewl* way

PID!!! But your own values. (I stole this from the cheesy poofs pres(it’s not plagiarism if you credit them))

error = centerPixel - target pixel;

Output = kp*error + ki*Sumerror + kd*Derivativeerror;

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Quick PID (just forget about the F now)

Proportional

Increases *proportionally* based on the error(fixes stuff faster when it’s more wrong)

Any problems with this???

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Derivative Control

Welp how do we dun do a fix??

Consider rate of change of error(Calc Trigger Warning)

Problems??

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Integral Control

Fixes Steady State Error

Often caused by friction etc

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Tuning it(it’s like an instrument)

https://docs.google.com/presentation/d/1_D8RkpKMOcsGaR1Tjba90VsQoI3Abe81k5sg9Yg9H2o/edit#slide=id.g13a00d37e6_1_182

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He goes step by step to easily tune your motors

LEDz(pretty colors)

Leds run off an arduino that gets serial data(preset bytes) from the RIO

Depending on which alliance we’re on and whether were lined up with the vision target or not different colors and different sections of the robot will light up

<<LED code>>

https://github.com/2729StormRobotics/Storm2017Arduino/blob/master/Arduino_LED_Cases.ino/Arduino_LED_Cases.ino.ino

https://github.com/2729StormRobotics/StormRobotics2017/blob/master/src/org/usfirst/frc/team2729/robot/subsystems/LEDz.java

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