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Autonomously Guided Intelligent Lawn Equipment. A.G.I.L.E. Team Members: Brad Ramsey Derek Rodriguez Dane Wielgopolan Project Managers: Dr. Joel Schipper Dr. James Irwin. ECE Department. PRESENTATION OUTLINE. PROJECT OBJECTIVES PREVIOUS WORK PRELIMINARY LAB WORK
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Autonomously Guided Intelligent Lawn Equipment A.G.I.L.E Team Members: Brad Ramsey Derek Rodriguez Dane Wielgopolan Project Managers: Dr. Joel Schipper Dr. James Irwin ECE Department
PRESENTATION OUTLINE • PROJECT OBJECTIVES • PREVIOUS WORK • PRELIMINARY LAB WORK • EQUIPMENT INFORMATION • PARTS LIST • SCHEDULE OF TASKS FOR NEXT SEMESTER
PROJECT OBJECTIVES • Design a lawnmower navigation system • Detect the field boundaries using RF • Track vehicle’s position and orientation • Movement using closed loop motor control • Detect and avoid objects (static/dynamic) • Safety shutoff switch
LITERATURE REVIEW • Find previous projects and their pros and cons • University of Florida project path ideal example • Series of 3 projects add up to ours • What can we do better?
Florida Project One • Project name – LawnNibbler • Student researcher – Kevin Hakala • Operating Components • Electric weed trimming platform • RF Wire Boundary • (proof of concept) Local Positioning System • No results for completed mower published
Florida Project Two • Project name – LawnShark • Student researcher – Rand Chandler and Katherine Meiszer • Operating Components • Electric Toro Lawnmower • Local Positioning System • Ultrasonic sensors (2) • No results for completed mower published
Florida Project Three • Project name – Autonomous Lawn Care Applications • Student researcher – Michael Gregg • Operating Components • Proof of Concept platform (no mowing) • RF wire containment • Obstacle avoidance • Collision Detection • Random Movement Programming • No results for completed mower published
What makes us different • Three cumulative projects compacted into one • Added Components for a better outcome • Wall following (physical and RF fence) • Efficient mowing pattern • Off unit computer processing • Unnecessary computer on mower • Utilize an existing computer • Easy to update software • Design and Create Electric RF “dog fence”
GOALS • Obtain a chassis • Drive control system • Build sensors • Detect and avoid objects • Mower/PC communication • Efficient Algorithm
SPECIFICATIONS • Max Speed: 2 ft/s • Response Time: <150ms • Mowing Coverage: 120 ft²/min @ 2 ft/s • 12v 7.2 Ah Batteries x2 • Heading Accuracy: ±1° of error (ideal)
CHASSIS • Maneuverable • Symmetrical • Dual DC Motors • Differential turning • Dimensions: • Length: 12.5’’ • Width: 18.5’’ • Height: 7’’
POWERTRAIN • Dual Pittman 12v DC motors • Gear ratio: 65.5:1 • Max RPM @no load: 4916 • Max shaft RPM @no load: 75 • Rotary encoder • 500 CPR • 2 channels • Wheels • 6” Diameter • Direct drive • Power • Dual 12v 7.2Ah Batteries
MOTOR CONTROL • User input average speed • Speed averaged between wheels • Rotary encoder feedback • PI control • PWM • Control system modeled in Simulink
SIMULINK MODELING • Single motor model • Microcontroller
MICROCONTROLLER • MICROPAC 535 (EMAC) • 8051 architecture • 3 timers • 3 serial ports (up to 230.4K baud) • 10 external interrupts • 4 PWM I/O ports • 8 A/D • 24 digital I/O
Ultrasonic sensors Coverage area maximized for front & sides OBJECT DETECTION
ULTRASONIC SENSORS • Devantech SRF05 Ultrasonic Range Finder • Interfaced to microcontroller • Multiplexer used to save digital I/O pins • 1 digital input/2 digital outputs for all sensors
DIGITAL COMPASS • R117-COMPASS • Interfaced to microcontroller
SAFETY • Safety switch on mower • Remote shutdown • User shutdown in software • Lost connection to PC • Bump switches • Last line of defense • Uses 3 pushbutton switches • Bumper connected to buttons • Interfaced to digital input on µC • Triggers high priority interrupt • Kills mower blade
Dog fence Transmitter Radio Frequency 8 kHz Sine Wave Dual receivers BOUNDARY DETECTION
RF CONTAINMENT WIRE • Better known as an electric dog fence • Band pass receiving filter
SOFTWARE • C/Assembly on EMAC • C++ On PC • EMAC will acquire data • Remote PC • Receive user settings • Process data • Implement algorithm
BASIC ALGORITHM • North-South pattern • Uses dog fence • Minimal areas missed • Ideal for square field • Starts with border
DATA SYNCHRONIZATION • Data synchronized between µC and PC • Serial to 802.11 converter • Any LAN connected PC can connect and run the software • Sets up a virtual com port on the LAN PC • Data rates up to 230400 Baud
PARTS LIST • Mowjoe chassis (motors, frame, batteries) • C80515 EMAC 8051 based microcontroller • ES1AWB (RS-232 to Wi-Fi) • Windows based PC • Digital compass • Devantech R117 for prototype • Would like a more accurate one • Ultrasonic sensors X4 • Devantech SRF05 • RF sensors X2 • Dog fence components