Vex robotics tutorial

Vex Robotics Tutorial
EECS 690: Robot Intelligence
Christopher M. Gifford Ph.D. Student, Computer Science The Robotics Group, CReSIS cgifford@cresis.ku.edu

September 11, 2007

Overview
Past Robots for Course Vex Robotics Design System
Contents of Robot Kit Overview of Basic Features Available Sensors Example Robot: Squarebot

easyC Development
Interface API and Programming OverviewDownloading Code to Robot

Troubleshooting Resources

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Past Robots for Course
Rug Warrior Pro Mobile Robot
Interactive C (IC) Shaft encoders, 2 wheels, skirt LCD debugging 32K memory

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Past Robots for Course

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Past Robots for CoursePalm Pilot Robot Kit (PPRK)
BrainStem C Tiny Embedded Application (TEA) 3 omnidirectional wheels Limited EEPROM and slots

http://www.acroname.com/technology/103/abstract.html

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Past Robots for Course

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Vex Robotics Design System
Inventor’s Guide Starter Kit Sensors and SubsystemsMicrocontroller Specifications Programming Kit easyC Development
User Interface User API Compiling and Downloading Code Vex Inventor’s Guide

Sample and Testing Programs Debugging Troubleshooting Resources Example Vex Robots
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Inventor’s Guide
Supports several skill levels Covers everything in your starter kit Broken up into several subsystemsStructure Motion Power Sensors Logic Control Programming

Instructions to build, program, and operate Squarebot Troubleshooting Resources

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Starter Kit

Extra: 2 linear sliders, 2 ultrasonic range finders, 2 light sensors
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Structure: Stability
Structure is very important in robotdesign Should design robot for the expected environment and task Sensing should be taken into account during design as well
What sensors can help accomplish the task? How and where do those sensors fit into/onto the robot?

Center of gravity
Average of both weight and position on the robot Heavier objects count more than lighter ones Pieces further out count more as well

Support polygonFormed by connecting points where robot touches the ground There is always one support polygon in any configuration
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Structure: Stability
Stability
Most stable when center of gravity is centered over support polygon Robot will topple over if center of gravity falls outside support polygon Gripping and moving objects alters center of gravity WRTsupport polygon Adding weights or larger support polygon larger can help offset changes

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Structure: Sturdiness and Vulnerability
Sturdiness and stress
There are over 100 screws in the kit, so use them Secure parts together well using multiple screws, if necessary If you don’t want something to rotate, use two screws More weight (especiallysuspended) strains the mounting point Bracing heavy or long parts can help provide support to reduce strain

Vulnerability
You will be running into things Protect cables, microcontroller, crystal, and volatile components from
Collisions Getting caught on something Being run over

Protecting the sensors and technology from the environment, obstacles, or other bloodthirsty robots can helpincrease your lifetime and reliability

September 11, 2007

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Motion: Motors
Motors and servomotors
Motors transform electrical into mechanical energy Electrical power converted to physical motion Spin in opposite directions due to internal motor designs Clutch: protect internal gearing from damage (breaks connection)

Standard motors (3 in kit)
Spin axle...