NXT Robotics Techniques Workshop 2008

Transcription

1 ORTOP NXT Robotics Techniques Workshop 2008 Opening doors to the worlds of science and technology for Oregon s youth 9/29/2008 NXT Robotics Techniques

2 Goals Audience: Rookie coaches/mentors, experienced coaches & mentors Provide Material That Is Immediately Usable With Your Team Gain Mindstorms NXT Programming Experience You should have already attended NXT workshops I & II and/or coached a team in a 2007 tournament 9/29/2008 NXT Robotics Techniques

3 CanDo Challenge Simple project, but good learning tool What did you learn? Unexpected things happen cans get caught under the wheel, it goes the wrong direction Take it in smaller steps Let s see what happens before it hits a can Mechanical problems may do you in Clarify the rules know the requirements Experiment Just go try it. We can rework it. Keep it simple 9/29/2008 NXT Robotics Techniques

4 Instructor Contacts Ken Cone Dale Jordan Jim Ryan Roger Swanson /29/2008 NXT Robotics Techniques

5 ORTOP Project Administrator Cathy Swider /29/2008 NXT Robotics Techniques

6 Agenda Introductions (5 min) Slide Review (20 min) Break into Teams NXT Techniques lab exercises (90 min) Review & questions 9/29/2008 NXT Robotics Techniques

7 Agenda Handouts for this workshop: TechniquesNXT2008V2.ppt (this slide set) TechniquesNXT2008LabsV2.doc (lab exercises) Writing Efficient NXT-G Programs NXT Reference Books for FLL NXTMemory.doc (memory screen captures) ORTOP Workshops Website - materials also available here: 9/29/2008 NXT Robotics Techniques

8 Our Mission FLL is not just about building robots and competing in tournaments Develop team member skills technical team building research & presentation Technical problem solving can be fun The youngsters do the work Introduce possibility of a technical career 9/29/2008 NXT Robotics Techniques

9 Parts Inventory LEGO Parts Identification Have kids inventory your NXT kit & get to know the parts. Use pins and various Technic parts to build your robot Pins are stronger than original LEGO bricks with bumps 9/29/2008 NXT Robotics Techniques

10 Building Strong Structures Note how NXT parts are all pinned together using Technic parts There are only a few plates with bumps Motors are strong enough for direct drive turn a wheel on your robot to feel the gears Motors have built in rotation sensors programmed in degrees or rotations Take a minute to examine the NXT parts and motors 9/29/2008 NXT Robotics Techniques

11 Gears Gears Spur Gear (show example) instructor t holds beam class person turns axles and feels torque on other axle tactile til feedback = learning about gears and torque Gear Ratio and Speed turn large gear one complete turn. How may times does small gear turn? 9/29/2008 NXT Robotics Techniques

12 Torque Torque can be thought of as rotational force torque causes something with mass to rotate a force can create a torque by acting through a moment arm (picture a wrench turning a bolt) a motor produces a torque transferred to gears and to axles that turn the wheels gears change speed and torque e.g. changing bicycle gears to go up a hill 9/29/2008 NXT Robotics Techniques

13 Other Gears More Gears Worm Gears one way transfer of power (show example) Pulleys use for slippage during lifting Clutch slippage after torque value listed on clutch GS Day Camp pages on gears instructor hold up 3 page handout 9/29/2008 NXT Robotics Techniques

14 Defaults and Allowed Parts Default inputs: touch = 1, light = 3, Distance = 4 Allowed: 2 touch, 2 light, 1 Distance Default outputs: Left motor = C, right motor = B Allowed: 3 motors (rotation sensors built in) Allowed: (3 - number of motors) rotation sensors 9/29/2008 NXT Robotics Techniques

15 Motors Note holes for Axles and Cams One Move block in the program controls both motors The robot moves straight - motors will adjust speed as the robot moves A program with two Move blocks (one for each motor) will not go straight Try programming tests for straight and curved movements, single and multiple Move blocks There are Move blocks and Motor blocks Motor blocks allow ramp up and ramp down of speed 9/29/2008 NXT Robotics Techniques

16 Light Sensors Reads reflection from a built-in IR emitter - (the sensor responds to visible light and into the IR spectrum) (default mode) Or, reads light intensity from surroundings with emitter turned off Use NXT Brick View program or Sensor feedback box to read Black, Green, White values as in previous workshops The sensor feedback box (located in the configuration panel) displays the current light reading (0-100%). You can use it to try out different trigger values. 9/29/2008 NXT Robotics Techniques

17 Light Sensors Hints for more consistent readings: The more verticle the better Closer to the surface is better Note there are two types of light sensor blocks (similar il for other sensors) Wait for blocks (orange blocks) Blocks to read sensor values (yellow blocks) 9/29/2008 NXT Robotics Techniques

18 Touch Sensors Touch sensor Responds to being pressed, or released, or bumped (pressed then released) Note axle slot for extending sensor capability Click More help? in lower right corner of Mindstorms screen. This works like Show Context Help in ROBOLAB 9/29/2008 NXT Robotics Techniques

19 Program Memory Firmware & programs stored in flash (like photos on a digital camera) Maximum available memory is ~125KB Firmware refresh and all files deleted Each program is ~0.1KB overhead E.g. Move block ~5.1KB, two ~5.8KB E.g. Move + Wait for light sensor ~7.7KB Use My Blocks for subroutines for better memory usage Click NXT Window then Memory to view memory usage Instructor show this command Refer to NXTmemory.doc for more details Instructor, show this file 9/29/2008 NXT Robotics Techniques

20 Writing Efficient NXT-G Programs Maximize free space by deleting default files that are downloaded with firmware Maximize code reuse Use only Move or only Motor blocks Loops and My Blocks Combine multiple programs can combine 2 programs into 1 and select which of the two sequences to run programmatically (using a touch sensor, for example) Minimize Sound and Display blocks Use Mini-Blocks 9/29/2008 NXT Robotics Techniques

21 NXT Software v1.1 New version released summer/fall kits will have v kits may or may not. Check and see Main advantage is performance enhancements Downloading to NXT is faster Size of blocks on the NXT is smaller Mini-Blocks can be downloaded: mindstorms.lego.com/support/updates 9/29/2008 NXT Robotics Techniques

22 Lab Exercises Lab Sections Lab 1 - The Distance Sensor Lab 2 Data Hubs & Variables This exercise shows 4 different techniques to program the robot to go in a square Introduces different programming techniques Shows memory usage of different techniques Lab 3 - Switches & Range Blocks Advanced lab - Light sensor calibration 9/29/2008 NXT Robotics Techniques

23 Lab Exercises Show video: examples of robots with fixtures for each mission Introduce yourself to other team members Begin with Lab1 exercise Continue with as many labs as you can 90 min to complete the labs Ask questions, chances are someone else has the same question Have fun! 9/29/2008 NXT Robotics Techniques

24 Other Lab Exercises Finish the CanDo Challenge Sequential events spin until the touch sensor is hit, then go straight until a black line is reached The famous robot dance forward to black line, back to wall, forward to yellow dot, spin 5 sec. in each direction, stop Use all the sensors touch, light, rotation, distance OR conditions -- Go until the touch sensor is hit OR a black line is reached Count the green lines you encounter 9/29/2008 NXT Robotics Techniques

25 Lab Conclusions LAB Conclusions Each team briefly explain a section of what you learned in this workshop What advice would you have for a team starting out with NXT? Teaching for understanding di creates challenging situations in which students test their knowledge by solving problems, building products, and giving performances or writing reports that synthesize thorough analysis of a topic, a concept, or an idea. * 9/29/2008 NXT Robotics Techniques

26 Next Steps Next Steps NXT Robotics Techniques slides NXT Techniques labs Mindstorms NXT tutorial (show tutorial) INSciTE tutorial Build and test some robots Test tracks Oval track with hill Make up your own exercises stress basics 9/29/2008 NXT Robotics Techniques

27 Programming Resources Tutorials, Dale Yocum Download from oads.html takes time,,go through in sections NXT Tutorial is also available online: Requires Adobe Macromedia Shockwave Player and high speed download connection 9/29/2008 NXT Robotics Techniques

28 Information Resources Inscite Google FLL programming and look for FLL programming 101 nxt g.pdf This file is on the NXT Workshops Website 9/29/2008 NXT Robotics Techniques

29 Parting Thoughts From All I Really Need to Know (About Creative Thinking) I Learned (By Studying How Children Learn) in Kindergarten* Tips from 12 year olds on being creative: Start simple Work on things that you like If you have no clue what to do, fiddle around Don t be afraid to experiment Find a friend to work with, share ideas! It s OK to copy stuff (to give you an idea) Keep pyour ideas in a sketch book Build, take apart, rebuild Lots of things can go wrong, stick with it *MIT Media Lab 9/29/2008 NXT Robotics Techniques

30 Review & Questions Please give us your input Let ORTOP know how we can improve the program Thanks for volunteering, your effort makes learning possible! Disassemble robots and put pieces back into kits 9/29/2008 NXT Robotics Techniques

31 Our Mailing Lists ortopvol All volunteers you can opt out One way from ORTOP to our volunteers We add you when you volunteer ortopcoaches You are added d when you register your team with FLL Communication from ORTOP to registered coaches very important channel 9/29/2008 NXT Robotics Techniques

32 Contact Us Website: for answers to your questions Phone: (Cathy Swider) or (Bruce Schafer) 9/29/2008 NXT Robotics Techniques