P.E.R.C.H.

This page is dedicated to the project work for the senior design group the Picker Enhancement Rover for Careful Harvesting (P.E.R.C.H.).

Introduction:


This page is dedicated to the project work for the senior design group the Picker Enhancement Rover for Careful Harvesting (P.E.R.C.H.).

Joe Rumble owns an orchard in Washington that has grades within the orchard of up to 20 degrees. He currently has each of the workers in the orchard pick the fruit by hand and place it in a bag hanging down the worker’s chest. The worker must move around with this bag and a ladder in order to navigate the trees in the orchard. This can be a dangerous endeavor because the bag can get up to 60 pounds before it is emptied into a bin. There are also time inefficiencies in this process because of the constant re-positioning of the ladder, and the worker emptying their bag every tree or less. The steep grades in the orchard prevent the current picking platforms to be a viable option. Although the picking will still have to be done by hand because of the delicacy of the fruit, a machine that will aid the workers in their picking, and eliminate the constant movement of an individual ladder is our goal. The current state of the picker working conditions has not been changed in nearly 100 years, and is need of a safer, more efficient option for sloped orchards.

Group Members

 * Spencer Marquis
 * Cole Lewis
 * Sydney Osterloh
 * Jordan Schwers

Problem Specifications
Design a machine that:
 * Allows 1-2 pickers to safely and effectively pick fruit or prune trees from heights 6’ to 13’ off the ground
 * Incorporates emergency safety features
 * Propels itself effectively and efficiently on terrain that has grades as high as 20 degrees (36% grade)
 * Provides for stationary picking/pruning and remain stable on grades ranging from 7-35%
 * Incorporates a mechanism or procedure to improve the ease and speed of transporting the fruit from the tree to the bin
 * Transports 4’x4’x30” bins of up to 1100 lbs and can leave full bins behind easily and efficiently
 * Overall improves fruit picking efficiency, safety and range when compared to a traditional ladder

Background
The original method for picking and pruning the apple and pear orchard first had to be researched in order to find key areas of improvements that needed to be made. Each picker had a physically demanding job by constantly moving a ladder in order to reach the tallest branches on the tree. The picker carried a bag, strapped to their front, that would have each fruit placed in. Once the bag was full, the picker would have to empty the bag into a bin carefully in order to minimize damage to the fruit. This was a time consuming process, and there was a lot of wasted time in each of these actions. The technology has not improved for almost 100 years because of the need for a human hand to pick the fruit. The inefficiencies in this system is what needed to be improved.

Project Learning
In order to see an orchard and the equipment that was used, the group visited Bishop's Orchard in Garfield, Washington. Although this was not our client's orchard, the sense of the slopes through the orchard were similar. The only power equipment used by this orchard was a picker lift. This was a three-wheeled device that would raise and lower a picker so that the top branches could be reached. The type of bag that was used was the same as a picker climbing a ladder, so the bag had to be emptied manually. This platform was sturdy due to the three-wheeled design, but the user expressed their concern of traction up some of the inclines in the orchard.

Main Problems

 * 1) Picker Positioning
 * 2) Fruit Transport
 * 3) Bin Management

Each of these issues have been researched and potential solutions have been found.

Picker Positioning
Ladder or Platform...?

Possible Alternative
Ladder Mechanism

One potential alternative for picker positioning would be a hydraulically operated ladder mechanism. The ladder would be attached to a laterally moving bracket on rails that could move along the P.E.R.C.H.'s sides parallel to the long axis of the machine. The ladder's angle of incline would be manipulated by hydraulic pistons while the axis of rotation for the ladder would be attached to the bracket by a hinge. The ladder could also possibly bend at its midpoint hydraulically to move the ladders axis of rotation out away from the machine to create a smaller angle of incline at lower picking heights. The ladder could include a sliding safety harness that could be moved up and down the ladder to allow picker mobility.

Dual "Cherry Picker" Platforms

Fruit Transport
Transporting the fruit from the picker to the tree to the bin has to be as economic and gentle as possible. Many options have been researched in order to find a solution to this problem. Large picking platforms have been created to solve these problems on level ground, however the issue of slope of the orchard has not yet been addressed. One particular platform uses vacuum suction and tubes in order to transport the fruit from the worker to the machine. The worker has a tube strapped to them so the tube is always readily available. The tube system created by Whoosh Innovations is gentle on the fruit and is able to transport the fruit very quickly. The fruit is then put on a conveyor belt and processed by a bin filling device that deposits the fruit into the bottom of the bin, slowly raising as the bin fills.

Another system that is used currently is a platform called the Pluk-O-Trak. The picker is on a fixed platform and places the picked fruit on a conveyor belt. This small conveyor belt has cleats which separate the fruit from one another, and prevent the fruit from rolling and damaging themselves. The conveyor will lead to a larger conveyor that gathers the apples from four pickers situated at different points on the platform. The apples are then fed into a flexible vertical conveyor in order to fill the bin. The bin is rotated constantly so that the bin will fill evenly on all sides. The workers are not required to level the fruit in the bin because of this innovation.

Although both of these platforms have great innovations for harvesting fruit, the technology is new and therefore, expensive. To incorporate even part of these inventions, it would be tens of thousands of dollars. For the P.E.R.C.H. these ideas will be kept as inspiration, and alternative solutions are being considered.

For other ideas for solutions a paper by William Messner and Brian Kliethermes on Augmented Fruit Harvesting was consulted. They present several solutions on how to handle fruit when filling bins and when transporting the fruit from the tree. When commenting on conveyor systems, Messner and Kliethermes note that nearly 100% fruit singulation can be attained. This is ideal

Possible Solutions

Conveyor belts

Conveyor belts could be used in our design to transport the fruit away from the picker. We would have to incorporate cleats on our conveyor because the picker would be up on a ladder, and the angle of the conveyor would be very steep. However, the changing angle of the picker on the ladder could pose an issue because the conveyor would not be as mobile as the picker. A conveyor belt is more useful when collecting the fruit from several pickers and transporting it into the bin. The conveyor would stay in a fixed location so additional hydraulics would not be necessary.

Gravity-Fed Tubes

Since the pickers will constantly be higher than the bin, a tube using gravity could feed the fruit away from the picker. A semi-flexible tube could be attached to the picker, and they could simply drop the fruit into the opening. To slow the fruit, baffles within the tube could be placed to slow the fruit as it falls.

Bin Management
Bin management refers to the way the P.E.R.C.H. will house bins that are being filled and how these bins will be swapped with new, empty bins. One solution is by using forks incorporating a conveyor system much like the Bin Runner made by Crendon Machinery. There would be a set of forks on both the front and back of the P.E.R.C.H. which would incorporate two belts ran by drivetrain. The belts would run in either direction from one set of forks at one end all the way along the machine's long axis to the other set of forks. These forks can also change their angle and incorporate a guard which keeps them from digging into the ground when loading. Using this solution, the empty bins can be loaded from either the front or back of the machine and then deposited on the ground either behind or in front of the P.E.R.C.H.

Design Progression
The initial design for the P.E.R.C.H. platform was drawn by Joe Rumble. He had some basic ideas of what we wanted to incorporate into the design of the platform. This was then modeled in SolidWorks, so that we would have a basic idea of what the platform consisted of. This first platform was put into a virtual orchard that based off the dimensions of Joe's orchard. With the original design, the platform was extremely large, and did not fit between the trees. This showed us that the design had to be changed immediately to smaller size so that it could navigate through the trees and allow the workers to had room between the platform and the fruit.