UEzMOW University Of Evansville Team: Mark Randall Systems Design (Team Captain) Zachariah Fuch High Level Control s Addisu Taddes Low Level Controls

Low Level Control Overview Hall Effect sensor based encoders are used to calculate speed of motors Hall Effect sensor based encoders are used to calculate speed of motors Each motor is connected to an H-driver which utilizes pulse width modulation Each motor is connected to an H-driver which utilizes pulse width modulation Digital PID (Proportional, Intergral, Derivative) controller is used to make the lawn mower move straight. Digital PID (Proportional, Intergral, Derivative) controller is used to make the lawn mower move straight.

Low Level Control Block Diagram

Low Level Control Results

Axis Rotation Converts global GPS longitude and latitude data into localized x and y coordinates. Converts global GPS longitude and latitude data into localized x and y coordinates.

Waypoint Generation MATLAB program generates a series of waypoints that cover the entire field. MATLAB program generates a series of waypoints that cover the entire field.

Waypoint Navigation Determines if the robot needs to travel in the x or y direction. Determines if the robot needs to travel in the x or y direction. Tracks the appropriate coordinate and adjusts motors velocities accordingly. Tracks the appropriate coordinate and adjusts motors velocities accordingly. Determine if the next waypoint has been reached and increment the appropriate index. Determine if the next waypoint has been reached and increment the appropriate index.

Power System 2 X 12 V DC Lead Acid Batteries (24 V DC) 2 X 12 V DC Lead Acid Batteries (24 V DC) 17 Ah 17 Ah 4 hour fast charge 20 hour slow charge 4 hour fast charge 20 hour slow charge 2 X 5 volt Power supplies 2 X 5 volt Power supplies Stepped down from main 24 V supply Stepped down from main 24 V supply Isolated/Unisolated Isolated/Unisolated

GPS Trimble BD950 Trimble BD950 2cm Accuracy 2cm Accuracy Standalone, Differential, and Real Time Kinematic (RTK) Standalone, Differential, and Real Time Kinematic (RTK) 20Hz Sample Rate 20Hz Sample Rate Bluetooth Radio Modem (9600 bps Full Duplex) Bluetooth Radio Modem (9600 bps Full Duplex)

Obstacle Detection Maxbotix LV-EZ1 Maxbotix LV-EZ ” 6-255” Pulse width (147us/inch), analog voltage, or serial digital output Pulse width (147us/inch), analog voltage, or serial digital output

System Design

2 X 8 bit Micro Controllers 2 X 8 bit Micro Controllers Main Processor AT89c51ed2 (Atmel) Main Processor AT89c51ed2 (Atmel) 6 X 8bit I/O Ports 6 X 8bit I/O Ports 8 bit data buss 8 bit data buss 1 Uart 1 Uart ISP ISP Pre ProcessorAT89c51rd2 Pre ProcessorAT89c51rd2 4 X 8bit I/O Ports 4 X 8bit I/O Ports 8 bit data buss 8 bit data buss 1 Uart 1 Uart ISP ISP

Hand Shaking Inter Processor Communication Inter Processor Communication 2 way Communication 2 way Communication 2 X 8 bit Tristate Latches 2 X 8 bit Tristate Latches Interrupt Structure (Data ready/Received) Interrupt Structure (Data ready/Received)

Mechanical System Five 24 volt DC motors Five 24 volt DC motors 2 X drive motors 2 X drive motors Geared 60 to 1 Geared 60 to 1 3 X mowing blades 3 X mowing blades 21” cutting width 21” cutting width 5800 RPM 5800 RPM 2 X 10.5” knobby tires 2 X 10.5” knobby tires Dim. 35” l X 26” w X 26” h Dim. 35” l X 26” w X 26” h

Mechanical System Noise Level db Noise Level db Battery life 2-3 hours sq ft Battery life 2-3 hours sq ft

Results GPS System with < 1” Resolution GPS System with < 1” Resolution Mechanical system fulfilling all Contest Requirement Mechanical system fulfilling all Contest Requirement Robot that can locate and avoid obstacles Robot that can locate and avoid obstacles Functional manual and remote kill switches Functional manual and remote kill switches Robot capable of successfully navigating L shaped field. Robot capable of successfully navigating L shaped field.