first fare 2010 lab-view overview
DESCRIPTION
TRANSCRIPT
1
FIRSTFare 2010LabVIEW Overview
Dennis C. Erickson ~ Senior Mentor for Teams 1510 and 2898
Daniel Bramblett ~ Team 1510Amy Wiegand ~ Team 2915
2
Introduction
Working with National Instrument’sHardware and Software
Specifically:Software ~ LabVIEW
Hardware ~ cRIO
3
Introduction
LabVIEWVI = Virtual Instrument
EW = Engineering Workstation
VI = Virtual Instrument or in other languages “Routine”, SubVI = Subroutine
4
Why LabVIEW?•Graphical Interface (Not Text Based)•Dataflow (All inputs must be updated before VI – Virtual Instrument – executes)•Self Documenting (You know what the code does)
5
Why LabVIEW?•Portable Code (VIs are easily reused)•Advanced set of diagnostic tools; probes, execution highlighting, error reporting, ability to surround the code with a “virtual world simulation environment” for testing.
6
Why LabVIEW?•Perfectly tailored for NI hardware•Automatically handles multiple cores and threads•Easily compiles to RT (Real-time) Operating Systems and FPGA (Field Programmable Gate Arrays) used in the cRIO processor
7
Why Do More Than Necessary to Win the
Contest?While it is entirely possible to win
a contest with a robot that is “bare bones” the better goal is to learn how to do things along the
way that may or may not be used.
8
The FRC Topology
9
The SoftwareUsed to Make Stuff Move
This section offers a brief short course on the language LabVIEW
10
To start a new project
Launch LabVIEW to create a new project
11
To start a new projectName your project .You might for example use your team name and year in the name:i.e., “Team 1510 for 2010 Robot Project”
Be sure that you enter your team IP in the following format:10.15.10.02
12
To start a new projectAdding a VI to your project:If its new, then right-click to “VI” and select and name it.
If adding an existing one select the menu item “Add”.
13
LabVIEW Functions - Front PanelSome example controls and indicators for the Front Panel
Numerical Controls and
Indicators
14
LabVIEW Functions - Front PanelSome example controls and indicators for the Front Panel
Booleans
15
LabVIEW Functions - Front PanelSome example controls and indicators for the Front Panel
Strings and Paths
16
LabVIEW Functions - Front PanelSome example controls and indicators for the Front Panel
Arrays, Clusters,
Matrices and Dialog Boxes
17
LabVIEW Functions - Front PanelSome example controls and indicators for the Front Panel
List Boxes, Tables and Trees
18
LabVIEW Functions - Front PanelSome example controls and indicators for the Front Panel
2D, 3D Digital
Charts and Graphs and
Special Plots
19
LabVIEW Functions - Front PanelSome example controls and indicators for the Front Panel
Rings and Enums
20
LabVIEW Functions - DiagramSome example controls and indicators for the Diagram
Structures
21
LabVIEW Functions - DiagramSome example controls and indicators for the Diagram
Arrays
22
LabVIEW Functions - DiagramSome example controls and indicators for the Diagram
Structures, Classes and Variants
23
LabVIEW Functions - DiagramSome example controls and indicators for the Diagram
Numerics, Booleans and Files
24
LabVIEW Functions - DiagramSome example controls and indicators for the Diagram
Hundreds of other functions
Timing, Dialog Boxes, Waveforms, etc, etc
25
An Example of Virtual TestingTesting the Joystick Power Function VI
Task: Test the VI with 1000 simulated Joystick positions from 0 to +1 to 0 to -1 (White Line) and create 9 plots with the following function:
Plotn = (motor speed)m
Where:
Plotn = a series of plots
(9 total)Motor speed = voltage input to the motor (from 1 to -1)m = power function (use to alter the forward sensitivity of the Joystick)
26
The HardwareUsed to Move Stuff
This discussion touches on the following principle areas:
•The cRIO hardware (The Brain)•The Sensors, Motors and Actuators that can be used •The DS Drive Station (Link from the User to the robot’s brain)
27
cRIO HardwarecRIO – Compact Real-time Input/Output
A PAC (Programmable Automation Controller) which is an industrial controller that is used in advanced systems incorporating software capabilities such as control, communication, data logging, and signal processing requiring rugged hardware performing logic, motion, process control, and vision. For FIRST applications, ideal for robot building.
A fully populated cRIO example
28
cRIO HardwareReal-time operating system
FPGA – Field Programmable Gate Arraylocated under the cRIO chassis
cRIO connected to a Laptop
29
How to Set up a Virtual Test Environment
The following Example code shows how to create an environment to test and calibrate VI modules. In this case we are testing the Camera Servo motors
First Initialize the test (note the “Data Dependency” wire)
Next run the test in a While loop. Note the Loop Sweep constant which defines the loop cycle (20ms). Here the loop is stopped using the Stop Test? command
Finally End the test by closing all references, etc. Again note the Data Dependency and use of a Frame structure as the SubVI has no wired input to use
30
State DiagramsThe following slides start with a State Chart to show what the State Diagram will do. The next slides show the State Diagram created.
31
State Diagrams
The Application starts by selecting the Initialize Test State (case). Note that we check for errors and if the Stop Test? Button is pressed. Note that the Enum (far left constant control) has 3 possible states; Initialize Test, Run Test and End Test
State diagrams are extremely useful in creating small or large applications. Since LabVIEW is a DataFlow language, this approach adds to the robustness of the application
32
State Diagrams
Next if no errors, run the While loop until an error happens or the Stop Test? Button is pressed the go to the next State
These slides show a typical State Diagram that tests camera servos. Note the inputs from the joystick and a smoothing control to test filtering.
33
State DiagramsOne of the interesting features of the State Diagram is confining the application code to one screen, thus self documenting codeFinally, there has been an error or the Stop Test? Button has been pressed so end the test by closing references, etc. Note that now the Boolean constant is now TRUE which stops the loop
Questions?
Dennis C. Erickson - [email protected]