Date post: | 17-Dec-2015 |
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Autonomous Golf CartDREW GAYNOR, TYLER LATHAM, IAN ANDERSON, CAMERON JOHNSON
ADVISORS: 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