Orchard Picker Positioning Platform
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| Current Design of the PERCH | |
| Sponsors : | Joe Rumble - Owner of Rumble Orchards |
| Team Name : | P.E.R.C.H. |
| Duration : | Fall 2013 - Spring 2014 |
| Faculty Advisors : | Dr. Steve Beyerlein |
| Mentor : | David Eld |
| Group Members : | Cole Lewis
Spencer Marquis Jordan Schwers Sydney Osterloh |
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.). The purpose of this project is to design a prototype that will aid orchard workers in picking and pruning apple and pear orchards.
Introduction:
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. This was not only time consuming, but physically demanding on each of the workers. 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.
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 maneuverability of the machine was limited because the entire machine would rotate to get the arm with the picker into the correct position. This was clumsily done, and could easily cause damage to the trees because of all the branches it could hit during its movement.
Design Specifications
| Design point | Description | Prototype | Idealized |
|---|---|---|---|
| Working platform | Platform will be used to allow workers to pick fruit with ease at many different levels on the trees. | Platform will be able to safely raise and lower a person 2 feet and level up to 10 inches on both axes. Each of these systems will be operated manually. | Platform will be able to easily raise and lower 6 feet and level as needed for slopes. The systems will be operated with hydraulics and controlled in a centralized location. |
| Transport Bins | Fruit bins will be able to be lifted and carried with the machine in order to deposit fruit easily and minimize time spent on transporting fruit to bins. . Must work with bins that are 4’x4’x30” and up to 1100 pounds when full of fruit. | The prototype will be able to drive over bins, and lift them off the ground and set them back down, manually driven. | Bins will be lifted at capacity using a hydraulic system and controlled in a centralized location. |
| Safety | Safety must be incorporated on each part of the prototype to have a simple and usable machine for all orchard workers. | Standard operating procedures will be established, and must be followed when working the manual systems. | All automatic systems will have emergency stops and safety measure in place. Controls will be located centrally, with emergency stops in several locations. |
| Fruit Transport | The fruit has to safely be moved from the tree to the bin without bruising or breaking the stem of the fruit, that is more efficient than the current method. It should cut down on time that the worker is spending depositing fruit into bins, and have minimal labor involved. | Workers will be able to pick fruit and deposit into the bin will minimal amounts of effort. | Fruit will be placed on a conveyor, and then a bin filler will be used to safely deposit the fruit into the bin. |
| Propulsion | The orchard workers should be easily able to move the entire design through and orchard and between rows with minimal hassle. | Wheels will be installed for the machine to be transported, but another vehicle will have to be used to move the machine long distances. | An electrically powered design that can be driven safely through the orchard by a picker when shifting from tree to tree, and have a short turning radius. |
| Platform Arms | Arms will be attached to the platform in order to access a greater portion of the tree when at a single location. | An arm attached to the platform will allow worker to pick part of the tree sides. The arm will be moved manually. | A hydraulic arm that will be able to reach 1/4 of the tree easily and safely. The arm will be able to retract and extend with a simple control. |
| Overall Machine | Machine will be able to improve the current method for pick and pruning. | A platform that will show the ideas for the PERCH and generally show the capabilities of the platform. | A platform that is fully automatic and easy to use in order to pick apples and pears efficiently with minimal exertion. |
Main Design Areas
Each of these areas have been researched and potential solutions have been found.
Picker Positioning
One of the major problems that needs to be addressed is the picker positioning. The picker must be able to get into each tree to pick all of the fruit without hassle. They must be as maneuverable, or more, than they are currently with the picking ladders that they are using. The picker must be able to get from the very top of the tree, down to about 6 feet above the ground. They also need to be able to get from the near center of the tree, out to the edges to pick the most fruit possible. Current picking platforms have tiered areas where the workers stand and can move from side to side along the tree, however they are not able to reach far into the tree, so the type of orchard it can be successfully used on is very specialized. If the orchard still has circular or oval shaped trees, the worker would be missing a lot of fruit on the inner parts of the tree.
Ladder Mechanism
One potential solution 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 Scissor Lift Platforms
This solution would have the workers on a scissor lift type platform that they could maneuver around to get approximately 3 to 4 feet of width of the tree at a single height. The scissor lift could then be hydraulically moved up or down the tree as needed. The platform could be leveled individually so the picker would always have a level platform to work on. To get into the inner parts of the tree, a rotating arm on one side of the platform could be attached so that it could be rotated to "hug" one side of the tree, and allow the worker to walk into the side of the tree as well. Ideally, the platform could also move laterally into the tree so that different sized trees could be accommodated, depending on the tree's maturity.
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 a drive train. 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.
Another solution for bin management is to have a fork lift type mechanism, that would slip into the front and back of the bin pallet. This would allow the bin to be raised in order to move with the rest of the machine, and deposited when it became full. The arms would have to be hydraulically operated in order to raise the weight of a full fruit bin.
Fruit Transport and Bin Filling
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. Bin filling is a large issuer because this is when there is a large amount of fruit in one spot, with the greatest potential for damage. The fruit cannot be dropped into the bin, so an alternative method must be used. When commenting on conveyor systems, Messner and Kliethermes note that nearly 100% fruit singulation can be attained. This is ideal so that fruit will not be damaged by other fruit during its transportation.
Conveyor belts
Conveyor belts could be used in our design to transport the fruit away from the picker. Cleats would be incorporated on our conveyor because the picker would be up on a ladder, and the angle of the conveyor would be very steep. The picker could pick the fruit and place it on the conveyor. This would eliminate the use of bags, and would cause much less strain on the worker. The picker would also be more productive because there would be no need to climb down from the ladder to empty a bag. A conveyor belt could also be useful when collecting the fruit from several pickers and transporting it into the bin. The conveyor could have several smaller conveyors deposit onto it, and then travel to the bin.
Gravity-Fed Tubes
Since the pickers will usually 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. Gravity would pull the fruit down to the bin. To slow the fruit, baffles within the tube could be placed to slow the fruit as it falls. This is a very simple solution, but would not work it the picker was level to, or below the bin they are filling.
Bin Fillers
There are several solutions on how to fill a bin with fruit quickly and gently. The vertical conveyor that is on the Pluk-O-Trak is a great solution and would only require the workers manually crank the filler to the bottom of the bin. After that sensors would take over and slowly raise the bin as the fruit filled it. Along the same idea, a sensors could be installed on a large flexible fan that would rotate and deposit fruit as it spun.
Design Solution
The design of the PERCH has progressed continuously from an original sketch from Joe Rumble to current designs. The current design has incorporated a forklift-type mechanism to lift fruit bins, and carry them along with the machine, so there would be no struggle to get fruit to the bins efficiently. The machine would pick up an empty bins, have it filled with fruit, and then drop the full bin off to be transported later.
The platform the the worker will be standing on would be a scissor lift. This would allow the picker to reach the height that was needed while standing on a stable platform. In addition to the platform there is an extendable arm that is able to rotate in between the trees to pick fruit.
The leveling system is incorporated on each wheel of the so the entire machine will be leveled on slopes, and allow the platform to be level at all times. This increases safety when picking on large orchard slopes.
Future Work
Due to constraints with budget and time, we were not able to incorporate all the design ideas to their fullest capacity. The prototype shows the concept of each of the full components that could be expanded upon. In a full design, all components would be fully motorized and controlled by a centralized command center. Our recommendation for future work would be quite extensive if building a working prototype was the goal. The first design concept that would need to be perfected is the swing-arm mechanism on the platforms. Orchard data would need to be gathered to find an adequate size for the entire platform. The mechanism would need to need to provide the desired reach and angle deviation while also being robust enough to support the moment generated by a picker. We see this being achieved by a multiple linear guide rail system with internal bearings that would allow the extending and rotating section of the platform to move along the rails. The platform of the next generation prototype should also include safety rails, so actual pickers can test the machine safely. The next issue to be addressed in the future would be the leveling system. In a next-generation prototype, automatic leveling would be an important concept to prove. This would require either building the hardware and circuitry and sensor system or simply outsourcing the work to another company. After receiving a quote from Power Gear for a capable leveling system for just under $5,000, purchase of a system such as this seems to be easier than building the system from scratch. A system that did not make it into our final design is the fruit transport system. Through our research we found that a vacuum tube coupled with a deceleration chamber would be the most effective type of design, but a conveyor system could also work just as effectively. The system designed in the future would need to be able to be used anywhere on the platform to eliminate the need for a picking bag to be worn. The last piece of building a functional version of our machine would be the system that powered it. A large motor would be needed to power the hydraulics and feature an alternator that could provide power to the batteries located at each wheel. We feel that all of this is possible, but likely not feasible in the near future. A piece of equipment as large and expensive as this would require continued design, testing and funding to achieve a final product.
Group Members
| Team Member | About |
|---|---|
| Spencer Marquis | I am studying to be a Mechanical Engineer, originally from Yakima Washington. I enjoy golf and hiking, after graduation I hope to join the workforce fairly close to home. |
| Cole Lewis | I am studying to be a mechanical engineer. I grew up in Kellogg, Idaho. After graduating in May, I will be attending graduate school. My favorite activities include camping and fishing along with many other outdoor activities. During the summer, I have been working as a mechanical engineer at the Clearwater Paper Corporation in Lewiston, Idaho. |
| Sydney Osterloh | I am currently a Mechanical Engineering student at University of Idaho. I grew up in Colorado and enjoy horseback riding, skiing and traveling. Upon graduation I will be entering the U.S. Navy and hopefully pursuing a career within the submarine community. |
| Jordan Schwers | I am a Bio Ag Engineer also working towards a minor in Mechanical Engineering. I grew up in Eagle, ID and enjoy athletics and outdoor activities of any kind. Upon graduating I will pursue either graduate studies in the Biomedical Field or enter the job market. |