1. Robotics Abstractions: Levels of language, world view
Introduction to Lego Mindstorms
Build basic robot
Write & download program
Homework: postings

2. Levels of language Distinguish between
task: what you want to do
procedure: how you/your program directs robot to do it
Even procedure level distinguishes between
moving robot joints to get to an endpoint vs
moving robot joints

3. World view What does the robot (you?) know about the work area?
What are assumptions / constraints?
Related to: how robust is it necessary to make the program / strategy

4. Levels of language: Task level
[Unconstrained]: block A somewhere on table, block B somewhere on table
PUT BLOCK A ON BLOCK B
[More constrained]: block A a specific place on the table, block B a specific place

5. Levels of language: Procedure
[Unconstrained]: block A somewhere on table, block B somewhere on table
LOCATE BLOCK A
LOCATE BLOCK B
PICK UP BLOCK A
MOVE BLOCK A OVER TO CALCULATED POSITION ABOVE B
MOVE BLOCK A TO CALCULATED POSITION ON B
[More constrained]: block A a specific place on the table, block B a specific place
MOVE BLOCK A OVER TO ABOVE BLOCK B
MOVE BLOCK A DOWN UNTIL CONTACT

6. Levels of Language: joints, sensors, etc.
[Unconstrained]: block A somewhere on table, block B somewhere on table
Invoke vision system to locate block A and block B OR invoke search program ….
Calculate joint positions for path to get to block A
Calculate gripping position
Set joints so as to move block A over to calculated position above B
Set joints so as to move/lower block A…possibly do move until touch
[More constrained]: block A a specific place on the table, block B a specific place

7. Language, world view
My choices of levels of language (task, procedure, robot joints) not the only ones
Can pose higher levels and lower levels!
These are general concepts to keep in mind. Will return to it.

8. Assembly is …. Challenging Concept of ‘preserving orientation’
Locating parts
Calculating trajectories
Allowing for variability …
Concept of ‘preserving orientation’

9. Exercise[s]
Pick task and describe in task terms and in procedural terms
(Shoe tying)
Opening/unwrapping gift
Put on coat
Sharpening a pencil using automatic or manual pencil sharpener
Cooking scrambled eggs
Building the basic Mindstorms robot!
ANSWER this on moodle!!!!

10. Lego parts Electronic Structural Connectors Gears Miscellaneous
the Brick, motors, sensors, cables
Structural
beams, other
Connectors
some friction, some smooth
Gears
transfer and/or change torque
Miscellaneous
tires, Lego people, other

11. NXT-G Level of language is low.
Note: considerable computation at motors and sensors
You/your NXT-G program direct tribot actions directly: procedure, not task.
Preview:
Task: hit the red ball
You will program: Procedure:
move forward using certain motors until certain sensor indicates time to stop
check light level to determine which ball
if red ball, move arm motor to swing

12. Lego Mindstorm NXT Create program using drag-and-drop of “blocks”
Iconic form of programming
Each icon/block has its own set of settings (parameters) and (possibly) data links to be set
Add comments. File/Save As (…save)
Then download program to NXT brick
Compile and download. Any syntactic errors will be caught.
Missing data link
Failure if lack of space on the NXT brick
Will need to be conscious of space

13. Move block: initial setting
Motors B & C
75% power
1 Rotation
Brake after 1 rotation (not coast)

14. Important fact…
You (the builder of the robot) must make sure that motor B and motor C do what you want. This depends on
Where/how you build
What port
External conditions
The program doesn’t know anything. It just sends a signal to a port.

15. Direction now set to curve
Power at 25%
5 seconds
Coast after 5 seconds

16. How… Do you get robot to travel specific distance?
Use trial-and-error to set time or rotations
Use feedback: keep computer connected to NXT and monitor rotations
Next class!

17. Data links: input & output
Feedback information

18. Sound block
built-in sounds + capability for individual tones & sound files
WARNING: sound files are big.

19. Build Basic robot NXT brick serves as main chassis
Carried around by wheels operated by 2 motors
Attached to appropriate ports
Will add
Grabber
Sensors
More programs

20. Today’s challenge Build basic robot Program to Go forward,
Say “Have a nice day” ,
Turn around in a curve
Go back

21. Program has been saved
on computer
File/Save
Used comment writer to document action
Program consists of
Move block
Sound block
Move block (turning)

22. Comment Blocks may Do something Start something
Make sound and wait for completion versus…
Turn motors for X rotations/degrees/seconds
Start something
Start sound
Turn motors on unlimited (will do this next class)
Actually, mostly blocks: Try to do something
Motors try to turn in rough terrain….

23. Go! Use directions in the kit. DON’T MIX PARTS. DON’T LOSE PARTS.
Page 8 to 22 which is
Steps 1 to 17
NOTE: step 14: putting in batteries has already been done
These kits use Lithium battery, which needs to be charged up.
Turn on and try demo program
Write program and download
DON’T MIX PARTS.
Be careful: especially with small pieces
DON’T LOSE PARTS.
Need to be careful that cables are not in the way!
Make haste slowly.

24. Team work For this activity: everyone should be aware of all details.
Take turns.
Don’t assume you can’t do anything.
For bigger projects, there may be specialists.