ME 224-Final Project ME 224-Final Project

Jim Lovsin Jim Lovsin Erica Morales Erica Morales Dan Sheehan Dan Sheehan Josh WidzerJosh Widzer

OverviewOverview

IntroductionIntroduction Robot ActivitiesRobot Activities Gyroscope ActivitiesGyroscope Activities Path ProgrammingPath Programming ResultsResults Future WorkFuture Work ConclusionConclusion

ObjectivesObjectives

To design and implement an To design and implement an experiment to realize the control experiment to realize the control of a commercially available robotof a commercially available robot

To enhance our knowledge of To enhance our knowledge of LabView, data acquisition, LabView, data acquisition, feedback control, and MEMS feedback control, and MEMS sensingsensing

The GoalThe Goal

To create a robot which utilizes To create a robot which utilizes gyroscopic feedback control to navigate gyroscopic feedback control to navigate the predetermined path shown below.the predetermined path shown below.

3

6

45

90°

36.9°

53.1°

The EquipmentThe Equipment

A computer with LabVIEW and a A computer with LabVIEW and a data acquisition carddata acquisition card

A gyroscope sensor A gyroscope sensor (ADXRS150EB) from Analog (ADXRS150EB) from Analog DevicesDevices

A Boe-Bot Robot Kit (A Boe-Bot Robot Kit (www.parallax.comwww.parallax.com, #28132), #28132)

Robot ActivitiesRobot Activities

Servo CenteringServo Centering

AssemblyAssembly

Basic PathsBasic Paths

Servo CenteringServo Centering

Since the servos are not preadjusted in Since the servos are not preadjusted in the factory, it is necessary to adjust the factory, it is necessary to adjust the servos so that they are stopped the servos so that they are stopped when a 1.5 ms pulse is usedwhen a 1.5 ms pulse is used

AssemblyAssembly

The Boe-Bot came unassembled so The Boe-Bot came unassembled so some assembly was requiredsome assembly was required

Followed the instructions providedFollowed the instructions provided

Basic PathsBasic Paths

ForwardForward– Both wheels rotating in the same direction at the Both wheels rotating in the same direction at the

same speedsame speed

Right turnRight turn– Both wheels rotating at the same speed but the left Both wheels rotating at the same speed but the left

wheel goes forward and the right wheel goes wheel goes forward and the right wheel goes backwardbackward

Left turnLeft turn– Both wheels rotating at the same speed but the right Both wheels rotating at the same speed but the right

wheel goes forward and the left wheel goes wheel goes forward and the left wheel goes backwardbackward

Gyroscope FamiliarityGyroscope Familiarity

Operating Principles Operating Principles – Coriolis Acceleration Coriolis Acceleration

Fc = 2mv x Fc = 2mv x ΩΩ Capacitive SensingCapacitive Sensing

Self-Test Self-Test Calibration Calibration

– First Attempt First Attempt – Second AttemptSecond Attempt

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

Vibrating MEMS Gyroscope

Self-TestSelf-Test

Followed Self-Test Followed Self-Test Procedure from Chip Procedure from Chip Data Sheet Data Sheet

Power supply, Power supply, Multimeter, and Multimeter, and OscilloscopeOscilloscope– RATEOUT Initially 2.5 V RATEOUT Initially 2.5 V – Applied 4.6 V to pin 10. Applied 4.6 V to pin 10.

RATEOUT 3.2 V RATEOUT 3.2 V – Applied 4.6 V to pin 11. Applied 4.6 V to pin 11.

RATEOUT 1.81 VRATEOUT 1.81 VSatisfactory 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

CalibrationCalibration

First Attempt First Attempt – Correlate Angle to Correlate Angle to

Voltage Signal Voltage Signal Second Attempt Second Attempt

– Correlate Angular Correlate Angular Rate to Voltage Rate to Voltage Signal Signal

LabVIEW to acquire LabVIEW to acquire and collect the data and collect the data

Excel to analyze the Excel to analyze the data data Block Diagram of LabVIEW

Calibration Program

Calibration First AttemptCalibration First AttemptCorrelate Angle to VoltageCorrelate Angle to Voltage

Θi = B0 + B1 Σ Vi Δt Θi = B0 + B1 Σ Vi Δt

Where: B0 and B1 are Where: B0 and B1 are parameters from OLS parameters from OLS

Experiment:

Turned Boe-Bot by hand to a known angle for a given time

Angles

•90 and 180 (deg)

Problems

•Accurate Positioning and Timing

•Numerical Integration

Theta versus integral of dV

y = -0.0028x + 161.61

R2 = 0.042

0

20

40

60

80

100

120

140

160

180

200

0 2000 4000 6000 8000 10000 12000 14000

integral of dV (deg)

an

gle

(d

eg

)

R2 = 0.04

Calibration Second Calibration Second AttemptAttempt

Correlate Angular Rate to Correlate Angular Rate to

Voltage d/dt (Θi) = B0 + B1ViVoltage d/dt (Θi) = B0 + B1Vi Where: B0 and B1 are Where: B0 and B1 are

parameters from OLSparameters from OLS

Experiment:

Turned Boe-Bot at a known angular rate for a given time

Angular Rate

•2.06, 3.05, 1.78 (rad/s)

Problems

•Accurate Positioning and Timing

•Numerical Integration

Theta versus integral of dV

y = -0.0028x + 161.61

R2 = 0.042

0

20

40

60

80

100

120

140

160

180

200

0 2000 4000 6000 8000 10000 12000 14000

integral of dV (deg)

an

gle

(d

eg

)

R2 = 0.64

Path following Path following programsprograms Basic Stamp ProgramBasic Stamp Program

– Directly creates the PWM signal Directly creates the PWM signal needed for the servosneeded for the servos

LabView ProgramLabView Program– Reads & analyzes readings from Reads & analyzes readings from

gyroscope, controls basic stamp gyroscope, controls basic stamp programprogram

Basic Stamp ProgramBasic Stamp Program' Robotics with the Boe-Bot - PathProgram.bs2' Robotics with the Boe-Bot - PathProgram.bs2' Closed loop path control for the Boe-Bot.' Closed loop path control for the Boe-Bot.' {$STAMP BS2} ' Stamp directive.' {$STAMP BS2} ' Stamp directive.' {$PBASIC 2.5} ' PBASIC directive.' {$PBASIC 2.5} ' PBASIC directive.DEBUG "Program Running!"DEBUG "Program Running!"'-----------------[Variables]--------------------'-----------------[Variables]--------------------INPUT 0INPUT 0INPUT 1INPUT 1INPUT 2INPUT 2INPUT 3INPUT 3DODOMain:Main: IF ( IN0 = 1 ) THEN StoIF ( IN0 = 1 ) THEN Sto IF ( IN1 = 1 ) THEN ForwardIF ( IN1 = 1 ) THEN Forward IF ( IN2 = 1 ) THEN RightIF ( IN2 = 1 ) THEN Right IF ( IN3 = 1 ) THEN LeftIF ( IN3 = 1 ) THEN LeftLOOPLOOPENDENDSto:Sto: PULSOUT 13, 750PULSOUT 13, 750 PULSOUT 12, 750PULSOUT 12, 750 PAUSE 18PAUSE 18 GOTO MainGOTO MainForward:Forward: IF ( IN2 = 1 ) THEN ForrightIF ( IN2 = 1 ) THEN Forright IF ( IN3 = 1 ) THEN ForleftIF ( IN3 = 1 ) THEN Forleft PULSOUT 13, 700PULSOUT 13, 700 PULSOUT 12, 800PULSOUT 12, 800 PAUSE 18PAUSE 18 GOTO MainGOTO Main

Main

Sto

Forward

Left

Right

Forleft

Forright

Forright: PULSOUT 13, 600 PULSOUT 12, 800 PAUSE 18 GOTO MainForleft: PULSOUT 13, 700 PULSOUT 12, 950 PAUSE 18 GOTO MainRight: PULSOUT 13, 775 PULSOUT 12, 775 PAUSE 18 GOTO MainLeft: PULSOUT 13, 725 PULSOUT 12, 725 PAUSE 18 GOTO Main

LabView ProgramLabView Program

2

1

3

4

5

67

89

9053.1

36.9

143.1

180There are three types of steps:

•Stopped (0,9)

•Straight line (1,3,5,7)

•Turning (2,4,6,8)

Nine total steps

LabView ProgramLabView ProgramFront Panel

Stop Step

LabView ProgramLabView ProgramTurning StepStep 8: 180 degrees CCW

LabView ProgramLabView ProgramStraight Path Step

Forright

Zero?No Yes

Greater than Zero?

No Yes

Forward

Forleft

Read AccumulatedVoltage

Path DemonstrationPath Demonstration

Reliability TestingReliability Testing

Performed ten trials to see Performed ten trials to see accuracy of Boe-Botaccuracy of Boe-Bot

Measured x and y distance from Measured x and y distance from starting point and endpointstarting point and endpoint

Recorded angles robot made Recorded angles robot made using LabVIEW using LabVIEW

Results of Reliability Results of Reliability TestingTesting

X Error (mm) Y Error (mm) Theta Error (deg)

Average 20.1 17.5 3.15

Standard Error 7.680422442 10.84486566 1.901023116

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

Deviation from Starting Point:

Angle Results:

Future Works Future Works

Create large deviation correction Create large deviation correction functionality.functionality.

Closed loop control of distance.Closed loop control of distance.– Use encoders on servo wheels.Use encoders on servo wheels.

Use LabVIEW Realtime to improve Use LabVIEW Realtime to improve performance over Windows.performance over Windows.

Use wireless 802.11g or bluetooth Use wireless 802.11g or bluetooth protocol to remove cable from system.protocol to remove cable from system.– Parallax has kits for sale.Parallax has kits for sale.

ConclusionConclusion

Successfully completed the task Successfully completed the task of programming the Boe-Bot to of programming the Boe-Bot to execute a pathexecute a path

Enhanced our knowledge of Enhanced our knowledge of LabVIEW, Basic Stamp, data LabVIEW, Basic Stamp, data acquisition, feedback control, and acquisition, feedback control, and MEMS sensing MEMS sensing

Questions?Questions?