Final Presentation of “Toolbot”

EEL 5666Intelligent Machines Design

LaboratoryDecember 3, 2002

Jeno Nagy

Abstract

Purpose of “Toolbot”Platform and DesignElectronics Systems for motion and deliveryOverview of each mechanismProblems and solutionsOverall performance

Purpose of “Toolbot”

Autonomous tool delivery systemDispenses proper sized sockets as neededFollows user and waits for commandsIdeally fits under vehicle and survives a garage type environment

Platform and Design

Two wheeled round bodyLarge battery tray between servos

Keeps center of gravity low

Huge battery

Elevated carousel for sockets with dispensing doorTop mounted camera

Vertically adjustable camera angle

Electronics

Power Pack YUASA NP2-12 12V

2.0Ah Lead-Acid Battery

Voltage regulation 4 5V

regulators Main controller

board Camera 2 servos

Electronics

Controller Microchips PIC 16F877

at 4Mhz 8K FLASH

Main Board Supporting Devices

EDE 702 Serial LCD Driver

Densitron LM2202A LCD Display

Altera 7032SLC44-10F CPLD

Systems for motion and delivery

Movement 2 GWS S03N BB servos

Motion/Behaviors Obstacle Avoidance

IR proximity sensors 2 Sharp GP2d12 forward

looking IR 4 contact bump ring with

voltage divider network

Systems for motion and delivery

Motion People tracking/following

CMUcam Vision Board SX28 microcontroller at 75 Mhz Digital data extraction from image Serial interface at 9600 Baud with PIC

Systems for motion and delivery

Delivery Carousel type

holder with 10 sockets One GWS 303N BB

servo for rotation Dispensing door

under carousel One GWS PICO BB

servo for door movement

Systems for motion and delivery

Delivery Voice command

recognition using Voice Direct 364 Board

RF headset for increased accuracy

Systems for motion and delivery

RF link Small transmission box

with headset Internals

Voice Direct 364 board Rentron TWS-434 RF

transmitter 433.92 MHz

PIC 16F84A at 4Mhz for serial transmission from voice board at 2400 Baud

All calculations done inside, serial data sent identifies location of socket to dispense

Systems for motion and delivery

RF link Transmitter Board Receiver

Rentron RWS-434 RF receiver

Serial link to main controller PIC at 2400 Baud

Systems at work

Color following using CMUcam

Follow yellow object Stop if confidence is

low and wait Search left-right if

found but unsure which way to go

Yellow LED array for feedback

Systems at work

Carousel Dispensing socket

upon voice command

Self alignment on startup using beam break

Wait for voice command

Dispense right socket

Systems at work

Carousel Dispensing socket Transmitter is shown Green blink indicator

shows key word recognized

Second red indicator blinks between 1 to 10 to show which command is sent

Problems and Solutions

Problem #1 CMUcam

Very sensitive to light conditions Works 100% on my desk Works 70% on kitchen table Works 0% on kitchen floor

LCD indicates a pixel level of 208 which causes software to sit and wait for command

Conclusion: Image gets flooded with light and tracks it. Fix: turn off and try again

Initially there was no color lock

Solution #1 Had software stop servos if pixel count was locked

instead of driving around in crazy rampage

Problems and Solutions

Solution #1 cont. Initialized CAM with stricter settings

and adjusted white-balance and auto-gain

Still affected by surroundings but better

Problems and Solutions

Problem #2 Carousel alignment

Direct driven by servo in center Attached to 4 inch “lazy susan” for stability The servo was off-center with respect to support Carousel would turn half way then get stuck

Solution #2 Have support free-spin under carousel. Not as stable as before but it turns 360 degrees

Problems and Solutions

Problem #3 Unreliable voice recognition

Low accuracy with words

Solution #3 RF link solved most of the problem Over 90% accuracy

Compromises in design

Inconsistent (jerky) motion due to PWM driving issuesSlow reaction to movement due to calculations needed to extract decimal values out of serial ASCII streamDelays in receiving dispense command due to SERIN command limitations

Overall Performace

All systems operate within specs except for the CMUcam which works in certain lightThe obstacle avoidance, tool delivery, RF link all function as neededThe CMUcam problem is outside the scope of the actual robot design. Experimenting with IR filtering might improve it.

Lessons Learned

Don’t use a PIC for anything needing servos with a 50Hz signal Hardware can’t generate it unless

clock speed is less then 1 Mhz

Stay away from products of other universitiesKeep it simple in design

Conclusion

The EndAny questions?

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