The UPThe UP--1 Robot1 Robot

Developed for ECE Core Digital DesignLabs at the Georgia Institute of Technology

9/5/2010 Georgia Institute of Technology

Outline of Presentation

• UP1 robot project background

• About the UP1 robot

• The Altera student program

• Future enhancements

• Other UP1 board projects

• Questions

9/5/2010 Georgia Institute of Technology

UP1 Robot Project Background

• Why did we start this project?– Need for additional / new digital design labs for

the new semester curriculum

– Wanted to use advanced CAD tools earlier inthe curriculum to motivate student interest

– Wanted to have exciting labs that were alsoeducational for the team design projects

• Like MIT robot design class but with more digitaldesign

9/5/2010 Georgia Institute of Technology

UP1 Robot Project Background

• Origins of Design– PIC microcontroller implementation found on

the web that used low cost RC servo motors

– Decided on Altera UP-1 board as a controller

– Additional modules added using VHDLinterface and programmable logic chips

• Trial runs of new labs conducted since Fall1998

9/5/2010 Georgia Institute of Technology

The Altera Student Program

• Why Altera?– Free software development kit on CDROM

• digital logic simulator, synthesizer, and programmer

• both schematic and VHDL designs possible

• all students can use this software on their home PCs

• Altera donated $1.5M in commercial CAD softwareand fifty UP-1 boards for use in PC labs in ECE

– Low cost of Altera’s Field Programmable GateArray (FPGA) logic development board

– Plenty of design options

9/5/2010 Georgia Institute of Technology

Altera UP-1 Development Board

• About the UP-1 Development Board– Contains two programmable logic devices that can

be programmed using a PC’s printer port

– 20,000 Gate FLEX and 2,500 Gate MAX chips

– Three DIP switches

– Seven segment displays

– Four pushbuttons

– Female header sockets

– PS/2 Keyboard, Mouse, and VGA ports

9/5/2010 Georgia Institute of Technology

Altera UP-1 Development Board

• Potential modifications for the UP-1 board– Replacement of 20,000 gate FLEX chip with a

70,000 gate FLEX chip - used in CmpE 4500and 4510 Senior Design Projects in 1998

– Installation of female header sockets for FLEXdesign expansion - used for UP1 robot interface

– Installation of a heat sink on the voltageregulator

9/5/2010 Georgia Institute of Technology

UP-1 Robot Design

9/5/2010 Georgia Institute of Technology

UP-1 Robot Design

• Basic Components– 10 inch Plexiglas disk

– two modified R/C servo motors

– 7.2V rechargeable battery

– Modified UP-1 development board and software

– wheels

– toggle switch, battery and UP-1 board connectors

– jumper wires for connecting UP-1 board with the modules

– IR sensor plus additional add-on sensor modules

9/5/2010 Georgia Institute of Technology

UP-1 Robot Design

• Ten robots have been constructed

• Cost of Parts– UP1 board => $129

– Sensor Modules => $20 to $50

– Other parts => under $50

• All parts are commercial off the shelf andcan be purchased from hobby shops

9/5/2010 Georgia Institute of Technology

Servo Modification

• Servos are controlledDC motors

• Simple modificationsare required for use asrobot drive motors

• Potentiometer sets the‘dead zone’ for the DCmotor control

9/5/2010 Georgia Institute of Technology

Using the Servo Motor

• Control– One control signal; VDD and GND power

• Timing for PWM Control Signal– Single pulse every 20 ms

– Length of pulse (1.5 ms -> 2.5 ms) determinesspeed and direction of servo motor

– Pulses must be constantly sent

9/5/2010 Georgia Institute of Technology

Implementing the Servo Motor

• Counter circuits in VHDL createdappropriate pulse widths

• Speed control algorithms– Pulse width algorithm did not work consistently

with different servos / environments

– A timed pulse implementation was developed

• Different size wheel and different servobrands taken into account

9/5/2010 Georgia Institute of Technology

Timed Pulse Servo Driver

• Send a pattern of threepulses every 60 ms

• No pulses result in a‘dead stop’ condition

• The number of ones andzeros determines thespeed and direction

• First bit is directioncontrol

Pattern Speed0000 Dead Stop0001 Slowest Reverse0010 Slower Reverse0011 Slow Reverse0100 Reverse0101 Fast Reverse0110 Faster Reverse0111 Full Reverse1000 Dead Stop1001 Slowest Forward1010 Slower Forward1011 Slow Forward1100 Forward1101 Fast Forward1110 Faster Forward

9/5/2010 Georgia Institute of Technology

UP1 Robot Sensors

• Infrared Module– Communicate with other robots

– Avoid walls and obstacles

• Line Tracker Module

• Sonar Module

• Digital Compass

• Analog Compass

9/5/2010 Georgia Institute of Technology

UP1 Infrared Module

• Lynxmotion ProximityDetector Kit– Two Infrared LEDs

– One Sharp GP1U5infrared sensor

• Modifications– Heat Shrink for LEDs

– Female Header Socket

9/5/2010 Georgia Institute of Technology

Using the Infrared Module

• Four Different Modes of Operation– Signal left

– Signal right

– Signal left and right

– Listen

– 38 Khz supplied by VHDL driver

• ‘Listen’ protocol can supportcommunications between robots

9/5/2010 Georgia Institute of Technology

Line Tracking Module

• Three red LEDs

• Three phototransistors

• Black lines do notreflect the LED signal

• Three signals (left,right, center) areproduced

9/5/2010 Georgia Institute of Technology

Sonar Module• Range is six inches

to 35 feet

• 16 cycles at 49Khz

• Listen for returnpattern

• Sound travels .9 f/s

• UP-1 timerdetermines distance

9/5/2010 Georgia Institute of Technology

Digital Compass

• Pins for N,S,E,W

• Multiple pins can beactive at the same time,giving NE, NW, SE, SW

• Four 2.2k pullup resistorsare needed to interfaceopen collector outputs

9/5/2010 Georgia Institute of Technology

Analog Compass

• One degree of accuracy

• Dual Sinusoid outputs– Measure the phase difference to determine the

current direction that the compass is pointing

– Either a D/A chip or digital timing of the phaseis required to interface this device with the UP1

– Phase timer is currently being developed

9/5/2010 Georgia Institute of Technology

2031 Lab Development Status

• Lab manual developed containing– Tutorials on CAD Tools, FPGAs, and VHDL

– Train Control Simulation with a State Machine

– Simple Computer and RISC MIPS Design

– UP-1 Robot Design and Sensors

– Keyboard and Mouse Interfaces

– 640 by 480 VGA graphical and text displayinterfaces for UP-1 board

9/5/2010 Georgia Institute of Technology

Lab Curriculum Status

• The robots have been used in three labs

• They will be further tested in multipleCmpE 3500 labs this quarter

• Five additional robots are under construction

• Robots have been standardized

• Additional sensors are under development

9/5/2010 Georgia Institute of Technology

Getting the Word Out

• Paper presented at workshop on ComputerArchitecture Education, February 1998

• Invited Demo at the Design AutomationConference University Booth, July 1998

• Paper submitted to Microelectronic SystemsEducation, July 1999

• 2031 Lab manual submitted for publishing

• Altera’s web site links to our ECE web page