Autonomous Golf CartDREW GAYNOR, TYLER LATHAM, IAN ANDERSON, CAMERON JOHNSONADVISORS: DR. DAVID MIKESELL AND DR. FIRAS HASSAN

Requirements

Travel to a destination selected by a user Select the best route to the chosen destination Accurately follow this planned path along campus roads and

sidewalks No other user input required during trip, except in the case of an

emergency Transport passengers safely

Detect obstacles and avoid collisions Stop immediately if an inadvertent collision occurs Provide emergency stop buttons

System Overview

System Overview

System Overview

Acceleration System Block Diagram

Pre-autonomous mode: Binary signals for direction and

enable come from cart The analog signal for speed is

sent from the potentiometer wiper arm on the pedal to the speed controller

Normally open switches

Acceleration System Block Diagram

Autonomous mode: Binary signals for

direction,enable, and analog output speed are calculated in LabVIEW program

Acceleration relay pushbutton closes the relays(puts cart in autonomous mode)

Binary signals are sent from the Relay module to speed controller

Cart speed signal is sent from Analog Output module to speed controller

Steering System Block Diagram

Pre-Autonomous mode: The cart’s heading is controlled

by the steering wheel on the cart

Steering System Block Diagram Autonomous mode: The clutch pushbutton is pressed

which disengages the steering shaft and allows the servo motor to steer the cart

The relay is closed so the amplifier is enabled and the cart is in autonomous mode

The heading has been calculated in LabVIEW and is outputted to the amp from the Analog Output module

Steering System Block Diagram Amp will amplify the signal and

then send it to the filter card to add inductance.

This signal is passed to the Servo motor which steers the cart.

The encoder output or position of the servo motor is then sent back to the Servo module

Java ApplicationSwitch modes

Choose destination

Autonomous start/stop button: drives to destination or cancels current trip

Position adjustment controls: offset GPS position drift or other error

Java Application

Cart (always centered)Path points

Destinations (nodes)

GPS/Inertial

Project’s OXTS RT2500 GPS unit has a stated accuracy for position values of 2-3 meters

We were able to get an OXTS RT3002 on loan: much more accurate than RT2500

Path Following Results

• Travelled autonomously from Biggs loading dock to Kinghorn northwest doors with RT3002

• Route shown in yellow• Data collected with

RT3002• Collected more• But focused on

this route

Path Following Results

• Collected path data shown in blue

• Actual route navigated shown in red

• Followed route fairly accurately

• On right of graph, consistent gap probably due to drift

• Position adjustment controls designed to account for this

Path FollowingVideo(Video removed to reduce file size. Original video can be retrieved from project website)

LIDAR (Light Detection and Ranging)• Housing tilted downward• Angle resolution: 0.5 degrees• Baud rate: 38400 (Sampling rate = 4Hz)

Speed Reduction

Detection Field (Wheels turned < 8°)

Detection Field (Wheels turned > 8º)

Collision AvoidanceVideo(Video removed to reduce file size. Original video can be retrieved from project website)

Complete System Video(Video removed to reduce file size. Original video can be retrieved from project website)

Questions?

Potential Future Improvements

Weatherproofing: isolation of electronics under the hood LIDAR

Housing LMS 511

GPS: RT3002 differential GPS Wiring: automotive wiring harnesses Zippswitch

Speed Reduction Algorithm