Transcript ME 224-Final Project Jim Lovsin Erica Morales Dan Sheehan Josh Widzer Overview        Introduction Robot Activities Gyroscope Activities Path Programming Results Future Work Conclusion.

ME 224-Final Project
Jim Lovsin
Erica Morales
Dan Sheehan
Josh Widzer
Overview







Introduction
Robot Activities
Gyroscope Activities
Path Programming
Results
Future Work
Conclusion
Objectives


To design and implement an
experiment to realize the control of a
commercially available robot
To enhance our knowledge of
LabView, data acquisition, feedback
control, and MEMS sensing
The Goal

To create a robot which utilizes gyroscopic
feedback control to navigate the
predetermined path shown below.
6
3
53.1°
90°
4
5
36.9°
The Equipment



A computer with LabVIEW and a data
acquisition card
A gyroscope sensor (ADXRS150EB)
from Analog Devices
A Boe-Bot Robot Kit
(www.parallax.com, #28132)
Robot Activities

Servo Centering

Assembly

Basic Paths
Servo Centering

Since the servos are not preadjusted in the
factory, it is necessary to adjust the servos
so that they are stopped when a 1.5 ms
pulse is used
Assembly


The Boe-Bot came unassembled so some
assembly was required
Followed the instructions provided
Basic Paths

Forward
– Both wheels rotating in the same direction at the same
speed

Right turn
– Both wheels rotating at the same speed but the left wheel
goes forward and the right wheel goes backward

Left turn
– Both wheels rotating at the same speed but the right
wheel goes forward and the left wheel goes backward
Gyroscope Familiarity

Operating Principles
– Coriolis Acceleration
Fc = 2mv x Ω
 Capacitive Sensing



Self-Test
Calibration
– First Attempt
– Second Attempt
Vibrating MEMS Gyroscope
Ref: K. Elliot, P. Gupta, K. Reed, and R. Rodriguez
“Micromachined Vibrating Gyroscopes: Design and
Fabrication” (2002) Northwestern University Mechanical
Engineering 381: Introduction to Microelectromechanical
Systems Final Project
Self-Test


Followed Self-Test
Procedure from Chip Data
Sheet
Power supply, Multimeter,
and Oscilloscope
– RATEOUT Initially 2.5 V
– Applied 4.6 V to pin 10.
RATEOUT 3.2 V
– Applied 4.6 V to pin 11.
RATEOUT 1.81 V
Satisfactory Self-Test
Schematic of ADXRS150EB
Ref: Analog Devices, ±1500/s Single Chip Yaw Rate Gyro with Signal Conditioning,
ADXRS150EB Data Sheet
http://www.analog.com/UploadedFiles/Data_Sheets/778386516ADXRS150 B.pdf
Calibration

First Attempt
– Correlate Angle to
Voltage Signal

Second Attempt
– Correlate Angular
Rate to Voltage
Signal


LabVIEW to acquire
and collect the data
Excel to analyze the
data
Block Diagram of LabVIEW
Calibration Program
Calibration First Attempt
Correlate Angle to Voltage
Θi = B0 + B1 Σ Vi Δt
Where: B0 and B1 are parameters
from OLS
Experiment:
Turned Boe-Bot by hand to a
known angle for a given time
Theta versus integral of dV
200
Angles
180
160
•90 and 180
(deg)
•Accurate
Positioning and
Timing
angle (deg)
Problems
140
120
y = -0.0028x + 161.61
R2 = 0.042
100
80
R2 = 0.04
60
40
20
•Numerical
Integration
0
0
2000
4000
6000
8000
integral of dV (deg)
10000
12000
14000
Calibration Second Attempt
Correlate Angular Rate to Voltage
d/dt (Θi) = B0 + B1Vi
Where: B0 and B1 are parameters
from OLS
Experiment:
Turned Boe-Bot at a known
angular rate for a given time
Theta versus integral of dV
200
Angular Rate
180
160
•2.06, 3.05,
1.78 (rad/s)
•Accurate
Positioning and
Timing
angle (deg)
Problems
140
120
y = -0.0028x + 161.61
R2 = 0.042
100
80
60
R2 = 0.64
40
20
•Numerical
Integration
0
0
2000
4000
6000
8000
integral of dV (deg)
10000
12000
14000
Path following programs

Basic Stamp Program
– Directly creates the PWM signal needed
for the servos

LabView Program
– Reads & analyzes readings from
gyroscope, controls basic stamp program
Basic Stamp Program
Main
Forward
Forleft
Forright
Left
Right
Sto
' Robotics with the Boe-Bot - PathProgram.bs2
' Closed loop path control for the Boe-Bot.
' {$STAMP BS2}
' Stamp directive.
' {$PBASIC 2.5}
' PBASIC directive.
DEBUG "Program Running!"
'-----------------[Variables]-------------------INPUT 0
INPUT 1
INPUT 2
INPUT 3
DO
Main:
IF ( IN0 = 1 ) THEN Sto
IF ( IN1 = 1 ) THEN Forward
IF ( IN2 = 1 ) THEN Right
IF ( IN3 = 1 ) THEN Left
LOOP
END
Sto:
PULSOUT 13, 750
PULSOUT 12, 750
PAUSE 18
GOTO Main
Forward:
IF ( IN2 = 1 ) THEN Forright
IF ( IN3 = 1 ) THEN Forleft
PULSOUT 13, 700
PULSOUT 12, 800
PAUSE 18
GOTO Main
Forright:
PULSOUT 13, 600
PULSOUT 12, 800
PAUSE 18
GOTO Main
Forleft:
PULSOUT 13, 700
PULSOUT 12, 950
PAUSE 18
GOTO Main
Right:
PULSOUT 13, 775
PULSOUT 12, 775
PAUSE 18
GOTO Main
Left:
PULSOUT 13, 725
PULSOUT 12, 725
PAUSE 18
GOTO Main
LabView Program
1
8
9
180
2
6
53.1
7
There are three types of steps:
90
•Stopped (0,9)
•Straight line (1,3,5,7)
•Turning (2,4,6,8)
3
5
Nine total steps
36.9
4
143.1
LabView
Program
Front Panel
Stop Step
LabView Program
Turning Step
Step 8: 180 degrees CCW
LabView
Program
Straight Path Step
Read Accumulated
Voltage
No
Zero?
Yes
Greater than
Zero?
No
Yes
Forward
Forright
Forleft
Path Demonstration
Reliability Testing



Performed ten trials to see accuracy of
Boe-Bot
Measured x and y distance from
starting point and endpoint
Recorded angles robot made using
LabVIEW
Results of Reliability
Testing
Deviation from Starting Point:
X Error (mm)
Y Error (mm)
Theta Error (deg)
Average
20.1
17.5
3.15
Standard Error
7.680422442
10.84486566
1.901023116
Angle Results:
Desired Angle
(degrees)
90
143.1
-53.1
-180
Average
Value
(degrees
90.568
143.727
-53.702
-180.581
Standard
Deviation
0.422027
0.357026
0.281772
0.256361
Future Works


Create large deviation correction functionality.
Closed loop control of distance.
– Use encoders on servo wheels.


Use LabVIEW Realtime to improve
performance over Windows.
Use wireless 802.11g or bluetooth protocol to
remove cable from system.
– Parallax has kits for sale.
Conclusion


Successfully completed the task of
programming the Boe-Bot to execute a
path
Enhanced our knowledge of LabVIEW,
Basic Stamp, data acquisition,
feedback control, and MEMS sensing
Questions?