Paul Heinemann, Penn State Dept. of Ag & Biol. Engineering

Tara Baugher, Penn State Extension

Advanced Technologies for Thinning of Tree

Fruit -- Engineering Solutions Workshop, CMU

11-27-12

Multi-State Project

WA

CA

IL

SC

PA

MD

WV

Partners involved:

• Penn State

• WSU

• UC-Davis

• Clemson

• U Maryland

• U Illinois

• CMU (selective thinning)

• USDA

• Extension

• Grower partners

• Other industry partners

Problem Statement

Fruit thinning is a labor-intensive and expensive task; time and crew availability limitations often result in orchards not being thinned in an optimal way for maximum fruit quality

Why is fruit thinned?

Crowding results in low quality, small fruit

Thinning results in high quality, large fruit

Technology – mechanized thinning

Two levels of technology are being used for fruit thinning mechanization:

Non-selective

Selective

Non-selective thinners

String thinners

Darwin 300

PT 250

Drum shaker

Hand held string thinners

From the Washington State investigators

Positioning issues

String thinner positioning – making the work easier for the operator

Two-tiered approach to controlled positioning

• Joystick control

• Sensor control

Joystick control

This is an interim step for providing easier manual positioning control

Joystick for Tilt and Offset

E- Stop

Autonomy Controls

LED Indicator Lights

Controller adjusts the spindle accordingly

Two degrees of motion: angle of spindle, lateral position of spindle

Modifications:

Thinner Moved to Rear Sonar sensors

SICK laser

hydraulics and controls added

components: Proportional

Control

Valves

Tilt

Cylinder Lateral

Offset

Cylinder

Flow

Divider

Ultrasonic Sensing

• Arduino Microcontroller

– $65

• 4 Sonar Range Finders

– Maxbotix LV-MaxSonar-WR1

– $100

• Low Cost GPS

– USGlobalSat EM-406A GPS Module

– $60

Sensor Mast

z

y

x

Best Fit Line

Orchard Row

Sensor Distance Readings (dashed lines)

Ultrasonically Sensed Position

Laser Sensing

• Trimble AG GPS 442

• SICK LMS 120 Laser Rangefinder

• $ thousands

Automated positioning

Selective Thinning

Select blossoms/small fruit to be removed for higher precision in thinning using machinery

Components

Integrated unit

Vision

Robotic arm

Platform

End effector

Integrated unit

Vision

Robotic arm

Platform

End effector

Vision system

Projected texture in 2010

23

2009: White Light

2010: Textured Light

Credit: UC Davis

Xbox Kinect

24 Credit: UC Davis

: Real-time acquisition

25

Real-time Industrial Cameras

Texture Illumination (reverse “view camera”)

Strobe

Credit: UC Davis

Building the 3D Map of all Trees in a row from the Individual Sequences

VectorNAV (yaw,pitch, roll)

GPS (x,y,z)

R-camera

L-camera

Θ Pattern strobe (or floodlight)

Lidar

Credit: UC Davis

Real-time 3D Tree and Blossom Mapping System

27

Lidar

Right Camera

Left Camera

Pattern Strobe

GPS

Tilt Sensor

Credit: UC Davis

Processing the LIDAR points

No

rmal

Credit: UC Davis

3D StereoVision Blossom Mapping 500 images @ 0.8sec per image

29 Credit: UC Davis

End effector

Integrated unit

Vision

Robotic arm

Platform

End effector

Brush end effector fabricated

Reuben Dise & David Lyons

End-Effector

2nd Generation Brush End-Effector

Improvements

Electric powered

Shorter Brushes

Softer Brushes

End-Effector

1st Generation Hand Gripper End-Effector

Brush end effector fabricated

David Lyons

Counter-rotating brushes

Open/close based on the position along branch

Robotics

Integrated unit

Vision

Robotic arm

Platform

End effector

Could not gain external control of the Fanuc unit

Fabricating components for lab unit

¼ - scale robot designed and fabricated

David Lyons

Results of Non-Selective Thinning Trials in 4 States

New molded hollow cords tested in 2009

Blossom Removal – 35 to 50% Before thinning

After thinning

Follow-Up Hand Thinning $100 to $400/acre savings

Hrs/ acre

Treatments with different letters are significantly different at P=0.05

Molded Strings - 2 Rows - No Gaps - 2 mph

y = 0.528x - 38.833

R2 = 0.9872

y = 0.588x - 46.533

R2 = 0.9815

y = 0.788x - 82

R2 = 1

y = 0.614x - 36.883

R2 = 0.9308

y = 0.552x - 49

R2 = 0.9845

y = 0.588x - 53.967

R2 = 0.9278

y = 0.436x - 47.7

R2 = 1

0

10

20

30

40

50

60

70

80

90

100

100 125 150 175 200 225 250

Spindle Rotation (rpm)

Flo

we

r R

em

ov

al

(%)

California

200 rpm, 1.8mph220 rpm, 1.8 mph

Control

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Small

Medium

LargePe

rce

nt P

rod

uct

ion

Fruit Size Distribution from Three Thinning Treatments in Nesstar Peaches

South Carolina

Washington

Pennsylvania % Flower Removal in Bloom Stage Trials

Pennsylvania % Flower Removal in Pruning Trials

Drum Shaker Trials - PA

• String thinner at bloom/drum shaker for green fruit thinning an effective combination

• New drum shaker at green fruit stage more consistent than previous citrus shaker prototypes – Smaller rods, tilting drums, front or side-mount

• Tree damage still a problem

Thinning results from 2011 (controlled positioning)

Upper canopy Lower canopy Scaffold

Manually operated joystick 62.8 a 63.5 a 63.1 a

Ultrasonic controlled positioning 49.7 a 35.4 b 43.7 b

Laser controlled positioning 61.2 a 51.9 a 58.7 a

Upper canopy Lower canopy Scaffold

Manually operated joystick 3.9 a 1.3 a 3.6 a

Ultrasonic controlled positioning 4.7 a 2.7 b 5.8 a

Laser controlled positioning 4.7 a 1.9 a 4.8 a

% blossoms thinned

Blossom density, flowers/cm2 cross-sectional area

Challenges and Limitations

• Non-selective thinners work well with stone fruit, but major challenges with pome fruit

• Selective thinning is an extremely complex task • Locating branches, blossoms, 2-D and 3-D • Mobility of robotic in field • Cost of robotic approach • Speed of activity

Economic Evaluations

Net Economic Impact

Processing Peach Plantings

• $236 to $1490/acre

Fresh Peach Plantings

• $185 to $934/acre

Labor savings and yield increases (due to larger fruit size) were of greater importance for canning peach growers

Increased fruit size had a greater positive impact for fresh market producers

Blossom Thinned with String Thinner

Hand Thinned

Technology Adoption Case Study Interviews

11 growers who had thinned a total of 154 acres

Employees liked thinner - saved time/minimized ladder use

Hand thinning completed earlier - more timely work in other crops

100% said hand thinning time reduced 80% said fruit were larger

Commercialization

Thank You! Funded by the USDA SCRI Program

Questions?