Development of an Autonomous Sensing and Positioning System for Use With Fruit Production Equipment

Development of an Autonomous Sensing and Positioning System for Use With Fruit Production Equipment
Reuben Dise and Matthew Aasted
June 23, 2010

Labor is one of the biggest challenges the Specialty Crop Industry currently faces.
% Variable Production Costs (TFPG, 2010)

Thinning is an area that could significantly reduce labor if mechanized and automated.
Labor Intensive
31% of cling peach cultural costs
Chemical Thinning
Limited uses, especially in Stone Fruit and Organic Production
Mechanization is being adopted by growers.
(Schupp et al., 2008, Baugher et al., 2009)

Mechanized alternatives like the Darwin String Thinner have been shown to have a large impact on production costs.
Hand Thinned
Blossom Thinned with String Thinner
Net Economic Impact
CA = $1490/acre
PA = $934/acre
WA = $847/acre
SC = $264/acre
(Baugher et al., 2010)

Improving quality and efficiency of mechanized non-selective thinners is the next step.
Improve Actuation
Improve Control
Add Sensing and Autonomy
Increase speed

Darwin String Thinner
Speed Controller
Rotating Spindle
3 pt Mounting
Chords
Hydraulic Angle Adjustment
Hydraulic Motor
Flow Control Valve

Modifications

Setup
Thinner Moved to Rear

Actuation
Flow Divider
Spindle Rotation Remains Unchanged
Proportional Control Valves
Position Sensors (Potentiometers)
35 degree Tilt (unchanged)
610 mm Lateral Offset Added

Controls
E- Stop
LED Indicator Lights
Joystick for Tilt and Offset
Autonomy Controls

Testing

New controls and actuation will meet or exceed the performance of the standard Darwin and testing will provide baseline data for autonomous control.
Treatments:
Manually Actuated Darwin (walk behind)
Fixed angle Darwin, moved in and out of canopy by steering tractor
Hand Thinned Control

Blossom Removal
Blossom Removal in Saturn Peaches
Blossom Removal in White Lady Peaches
* Letters Represent Statistically Different Groups at alpha = 0.05

Fruit/Blossoms Per Cross Sectional Area
Blossom and Fruit per Limb Cross Sectional Area in Saturn Peaches
Blossom and Fruit per Limb Cross Sectional Area in White Lady Peaches

Hand Thinning Times
Followup Hand Thinning Times in Saturn Peaches
Followup Hand Thinning Times in White Lady Peaches

Sensing

Using speed and distance sensors an accurate map of the trees can be created and a device can be precisely positioned.
Speed Sensor
Distance and Mapping Calculations
Distance Sensors
Autonomous Positioning
Tree Map

Sensing Setup
GPS
Ultrasonic Sensor Mast
Position Feedback Sensors
Computer and Microcontroller
Laser Rangefinder

Ultrasonic Sensing
Arduino Microcontroller
$65
4 Sonar Range Finders
Maxbotix LV-MaxSonar-WR1
$100
Low Cost GPS
USGlobalSat EM-406A GPS Module
$60

Best Fit Line
z
Sensor Distance Readings (dashed lines)
x
Orchard Row
Sensor Mast
y

Laser Sensing
Trimble AG GPS 442
SICK LMS 120 Laser Rangefinder

3D Map of Laser Data

Algorithms
Ultrasonics
Linear Least Squares Regression
Laser
Collision Search in a Voxel Grid
Positioning Heuristic
Angle is less expensive because it is faster
Fully extended and angled out is preferred

Testing

Testing is currently being done to evaluate and refine autonomous positioning algorithms.

Future Work

Much more work is needed to fully develop an autonomous thinning device.
Further Develop Autonomy Algorithms
Compare:
Manually Controlled (baseline)
Ultrasonic Sensing
Laser Sensing
Next step is a selective thinner

Acknowledgments
Advisor: Dr. Paul Heinemann, PSU ABE
Committee Members:
Dr. Jude Liu, PSU ABE
Dr. Jim Schupp, PSU FREC
Dr. Tara Baugher, PSU Adams Co. Ext.
Dr. Ben Grocholsky, CMU Robotics Institute
Co-researcher: Matt Aasted, CMU Robotics Institute

Acknowledgments
Special Thanks To:
Jim Schupp
Edwin Winzeler
Tom Kon
Celine Kuntz
Russell Rohrbaugh
Amelia Jarvinen
Terry Saluda
Research Sponsored by:
USDA SCRI
Assistantship Support by:
California Canning Peach Association

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Development of an Autonomous Sensing and Positioning System for Use With Fruit Production Equipment

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Development of an Autonomous Sensing and Positioning System for Use With Fruit Production Equipment Presentation Transcript