RobolabTutorialSlides

Robolab Tutorial

Steve Dakin

Hacienda Robotics

[email protected]

Introduction

• Target audience– Coaches and parents of kids in the FIRST LEGO

League program

• Objectives– Overview of Robolab programming environment

and concepts

– Some tips and tricks acquired over the years

– Help you so that you can better help your kids

Contents

• Setting up Robolab– Administrator area, Robolab settings, RCX settings

• Beginner Topics– Writing programs, Basic control blocks (motors, waits,

modifiers), Conditionals (forks, resets)

• Intermediate Topics– Flow control (jumps, loops), Variables (containers), LEGO

MINDSTORMS Remote Control

• Advanced Topics– Subroutines, Sub VIs, Data logging (Investigator)

Robolab Main Menu

Administrator Screen

Robolab Settings

RCX Settings

Select Program

New Program

Programming Strategy

• Define what you want the program or robot to do

• Identify high-level tasks

• Write pseudo-code (in pseudo-English)

• Use pseudo-code as comments to define program skeleton

• Divide and conquer

• Program in pairs: pilot and co-pilot

Functions Palette

Function Sub-palettes and the Tools Palette

Writing Robolab Programs

• Four ways to add blocks to a program:– Functions palette

– Context menu

– Insert command

– Replace command

• Use auto-wiring tool

• Connection point introspection

• Block arrangement commands

• Include Comments

Modifiers

• Two types of modifiers– Reference– Value-of

• Reference modifiers specify the “where”• Value-of modifiers specify the “what”• Not very intuitive, but with practice and use

of the online help choosing the right modifier gets easier.

• Can connect multiple blocks to same modifier

Modifiers Program

• Reset the rotation sensor on port 1

• Turn on motors on ports A and C

• Wait until touch sensor on port 2 is pressed

• Stop motors on ports A and C

• Display the value of port 2 on the RCX

Conditionals and Resets

• Robolab term: forks• Used to branch the flow of

execution in your program• Usually associated with sensors• Every fork must have a corresponding merge• Nested forks can be tricky• In some situations you may

need to reset sensors before using them

Conditional and Reset Program

This program demonstrates one way of using a single RCX program slot to run two different programs. Start with a robot containing a downward facing light sensor. Next, find a brick that is sufficiently different in color than the mat area in base. The blue container will contain 1 if you use the brick, 0 otherwise. In your main program you can use a fork that branches depending on the value in the blue container.

Flow Control

• Robolab terms: jumps and loops

• Used to repeat a portion of your program

• Can be controlled with sensors, containers or other factors

Variables

• Robolab term: containers

• Containers hold values that can change during the execution of a program

• 23 value containers, including 3 defaults:0 = red container

1 = blue container

2 = yellow container

• 25 Task containers

• Good tool for teaching abstraction

Advanced Containers

• Formula container– Sets a container value based on a formula– Supports basic arithmetic expressions and

shorthand mnemonics for other values (containers, input ports, mail messages, etc.)

• Container’s container– Analogous to a pointer in traditional

programming languages– A modifier that specifies which container to use

based on the value of another container

Advanced Container Program

As noted in the comment this program can be used to show container values on the RCX’s display. Container 22 holds the number of the container to display (0, 1 or 2). Container 21 holds a computed value that shows the container number followed by its value. The program uses the formula container to multiply the value in container 22 by 1000 to move it to the left three places on the display. Next it adds the value of the container whose container number is specified in container 22 (this is accomplished using the container’s container). The last block before the red jump displays the computed container value on the RCX’s display.

LEGO Remote Control

• Amazingly useful prototyping tool

• Send motor (output) commands to RCX

• Start and stop programs easily

• Send mail messages to RCX

• Best $20 you can spend on equipment

Subroutines

• Analogous to subroutines in other programming languages

• Allow you to reuse code– Reduces program size

– Makes programs more robust

• Define first then call as many times as you’d like

• Another good tool for teaching abstraction

Subroutine Program

This program demonstrates how you can define two subroutines and call them from within your program based on the value in a container. By changing the value in the container you control which subroutine is called. This is a useful way to observe what your program is doing while it runs.

Sub VIs

• VIs (Virtual Instruments) = programs

• Sub VIs are like program modules (libraries)

• Act like macros (code is repeated each time it is used)

• Improve readability– Can create your own icons for Sub VIs

– Only the Sub VI block appears in your main program

How to Create Sub VIs

• Select the blocks you want in the Sub VI (to make input parameters to the Sub VI exclude modifiers)

• Select the Edit Createmenu command

• Tidy up the Sub VI and include it in your programs

FLL Program (Two Missions)

Data Logging

• Robolab and the RCX are a form of embedded device programming– Download and run

– Difficult to monitor and debug interactively

• Data logging captures values while a program runs on the RCX

• Analyze captured data in the Investigator area

Data Logging in Robolab

• Change Inventor level to Program Level 4 (adds an Investigator palette and specialized modifiers to the modifiers palette)

• Include blocks to initialize, start and stop data logging

• Run the program on the RCX

• Upload data to Robolab and analyze it in the Investigator area

Data Logging Program

• Data logging modifiers

• Sample program– Initializes the red data set

to capture data from the light sensor connected to port one

– Starts data logging and captures 1 data point every second until 10 data points are collected

– Stops data logging

Uploaded Data

Other Advanced Topics

• Tasks– Enable your program to do multiple things at the

same time

• Events– Monitor and respond to specific conditions

• Direct mode– Another way to prototype

• LASM– A hacker’s delight

Questions and Comments

• Please let me know what you think– Email: [email protected]

– Web: www.haciendarobotics.com/resources

– Tip: use Adobe Reader 7’s commenting support

• More info– www.legoeducation.com/sharedimages/resources/Mindstorms_Quickstart.pdf

– www.ceeo.tufts.edu/robolabatceeo/

– www.ceeo.tufts.edu/robolabatceeo/References/documentation/default.asp