team gps rover critical design review alex waskiewicz andrew bousky baird mckevitt dan regelson zach...
Post on 21-Dec-2015
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Team GPS RoverTeam GPS RoverCritical Design ReviewCritical Design Review
Alex Waskiewicz
Andrew Bousky
Baird McKevitt
Dan Regelson
Zach Hornback
OverviewOverview
Project DescriptionHardware ImplementationSoftware ImplementationMilestonesRisks and Contingencies
Project GoalsProject Goals The human user will be able to remotely control the rover from a
laptop computer– Direct driving control– Issue location commands
Rover will calculate its current bearing Rover will calculate desired bearing to user specified location Rover will autonomously maneuver to its assigned destination Rover will transmit telemetry to the user Rover will sense and avoid obstacles Rover could have onboard camera(s) providing visual feedback to user. Rover could carry and deploy instrumentation packages
– Examples: Rocket launch platform Environmental sensors Mechanical Manipulator
VEHICLEVEHICLE
Traxxas Rustler– 445x311x178 mm– 1.69 kg– Top Speed 35 mph– $203 with batteries– High Load Capacity– Replaceable parts
Electronics Platform– Attaches to the chassis– Carries electronics, sensors, and batteries– Interfaces directly with car controls– Weight and Size are constraints
Test: Steering and DrivingTest: Steering and Driving The steering and speed of the vehicle can be controlled
using the PWMs of the microcontroller. Both are controlled by altering the duty cycle of the
input square wave. – The wave (for both steering and speed) has an amplitude of
4.2 Volts and a frequency of 49.75Hz•The duty cycles for steering are:
•Straight – 7.72%•Full Left – 10.21%•Full Right – 5.37%
•The duty cycles for driving are:•Idle – 7.46% •Full Forward – 9.95% •Full Reverse – 4.71 %
Hardware Block DiagramHardware Block Diagram
Microcontroller
DigitalCompass
GPSModule
ProximitySensors
I2CModule
SCIModule
SCIModule
PWMModule
PWMModule
User PC
SteeringMotor
DriveMotor
Test: GPS PartsTest: GPS Parts
Serial communication OOB
Acquired outside signal Impressive spatial
resolution (probably to WAAS enable)
1 Hz update rate – Documentation says
modifiable and/or query-able but currently having technical difficulties
Digital CompassDigital Compass
$60 ½ degree resolution I2C interface Testing will be
imminent once I2C communication on the development board is established
SensorsSensors
Two-forward facing sensors to allow obstacle avoidance
Ultrasonic: 2 x Devantech SRF08 Ranger ($62) 6m range I2C interface
Testing will be imminent once I2C communication on the development board is established
Development BoardDevelopment Board
Serial PortsLCDDIP SwitchesLEDsShaft EncoderMini-BreadboardGreat for testing!
Power SubsystemPower Subsystem
3.3V, 5V systemsNeed to pick batteryUse of 2 voltage regulators
– Need to pick type
Will be implemented upon completion of PCB fabrication– Due to development board usefulness
Microcontroller: Freescale Microcontroller: Freescale HCS08HCS08
60K of low-speed Flash4K of internal ram – Requires no external
routingInternal A/DInternal PWM3.3V
Microcontroller: Freescale HCS08 Microcontroller: Freescale HCS08 Memory MapMemory Map
Internal module status/comm registers
Preliminary PCB Layout:Preliminary PCB Layout:
PCB:
•Microcontroller
•RF link
•Voltage Regulators: Power Bus
•Caps/Resistors
4 4 6
US2US1 GPS
Power
V/R
Milestone #1 Milestone #1 (Implementation Cycle 1)(Implementation Cycle 1)
User control with Arrow Keys– Serial
Communication (tethered)
– Independent PWM Control
– Windows-based GUI Why?
– Tests many subsystems that are required for GPS Control (i.e. Milestone #2)
Milestone #2 Milestone #2 (Implementation Cycle 2)(Implementation Cycle 2)
GPS Feedback – GPS
communication– Digital
Compass communication (IIC)
– Bearing calculation
Implementation Cycle 3Implementation Cycle 3 Obstacle Avoidance
– Left and Right Sensors with minimal common FOV
– Left and Right allows for an easy avoidance algorithm
Left sensor = high go Right
Right sensor = high go Left
Both = high requires long range detection to avoid
ALEX ANDREW BAIRD DAN ZACH
•Windows XP GUI
•Development board testing
•Implement control software
•GPS Module
•Schematic & PCB layout
•Chassis Fabrication
•Power Sub-system
•Ultrasonic Sensors
•Digital compass
•Documentation
•Chassis Fabrication
•Schematic and PCB layout
•PWM interface
•Power sub-system
•GPS module
•Implement control software
•Development board testing
Updated Risks and ContingencyUpdated Risks and Contingency
Parts availability and shipping times We have purchased many of our discrete
components The car interface is electrically simple• Interfacing I2C components• Microcontroller RAM/Storage limitations• RF Link• Learning curve on design software (CodeWarrior & Altium)• Power Consumption